Advanced True Learn #1 Flashcards

Question

What are the drawbacks of the prone and lateral positions for posterior fossa craniotomy?

Answer 1

More superior structures difficult to reach

Answer 2

**Higher risk of Venous Air Embolism** but benefits are see entire anatomy

Answer 3

Hypertension, Bradycardia

Answer 4

Facial Muscle Movement

Answer 5

Hypotension Bradycardia

Answer 6

Arrythmias, Hypo/hypertension, Tachy/Brady dysrhythmias, Irregular breathing pattern

Answer 7

15% reduction in VO2

Answer 8

High closing volume to FRC Ratio results in closure of peripheral lung units, ventilation to perfusion mismatch, and hypoxemia

Answer 9

Increased Total Blood volume Increased Pulmonary blood volume High cardiac output Elevated LVEDP **Hence they have an increased DLCO**

Answer 10

**Residual Volume** **TLC may be unchanged** or slightly decreased

Answer 11

Snoring Unlike in OSA, there is no effort to breathe during periods of apnea in CSA. Thus, 1 of the classic signs of OSA, snoring, does not commonly occur in patients with pure CSA

Answer 12

Apneic period **\>10 seconds** without identifiable respiatory effect **\>10 episodes** per hour

Answer 13

**\>5 episodes per hour** of sleep of complete cessation of airflow during breathing **lasting \>10 seconds** despite maintenence of neuromuscular ventilatory effect, accompanied by **SaO2 decrease \>4%**

Answer 14

Reduction in airflow \>50%

Answer 15

**Total # of Apnea or Hypopnea** (reduction in 50%) divided by **total sleep time**

Answer 16

Mild 5-15 Moderate 15-30 Severe \>30

Answer 17

OSA creates - \> hypoxia/hypercapnia - \> pulmonary hypertension (Group 3) - \> right ventricle hypertrophy - \> right ventricle failure

Answer 18

In rheumatic fever, antibodies developed against ***_Streptococcus pyogenes_*** cross-react with skin, joints, and the heart.

Answer 19

There are only two factors in the coagulation cascade that are decreased during pregnancy and these are **factor XI and factor XIII.**

Answer 20

The **carbohydrates are broken into sugars which stimulate the pancreas to secrete insulin.** *_Insulin increases the activity of the sodium/potassium ATPase which pumps potassium from the serum into cells._* This effectively **lowers the serum potassium level.** The decreased serum potassium level can precipitate an attack.

Answer 21

**Calcium** Channel

Answer 22

**Acetazolamide** is a carbonic anhydrase inhibitor that is used to prevent episodes of paralysis in both hyperkalemic and hypokalemic periodic paralysis. The **mechanism for acetazolamide preventing paralysis is unknown.**

Answer 23

Often = Even daily

Answer 24

Infrequency (every few months)

Answer 25

Rest after Exercise Fasting Stress Hypothermia

Answer 26

**Strenuous exercise** **Stress** **Hypothermia** **Carbohydrate Load**

Answer 27

1. Carbonic Anhydrase Inhibitors 2. Beta Agonists 3. Potassium Wasting Diuretics

Answer 28

1. Carbonic Anhydrase Inihibitors 2. Potassium Sparing Diuretics

Answer 29

The first sign of total spinal anesthesia in neonates is typically **respiratory depression or apnea.**

Answer 30

The sympathetic blockade seen in adults is not typically seen in children less than 5-8 years old, especially in neonates and infants. **This is most likely due to the immaturity of the sympathetic nervous system (SNS) and already predominant parasympathetic tone in children.** Studies have shown that blockade even at levels of T3 in children under five years old results in few hemodynamic consequences. In addition, infants without fluid preloading tolerate total spinal anesthesia with few autonomic changes. Occasionally, bradycardia may be a later sign of total spinal anesthesia either due to decreased sympathetic input to the heart, or as a result of respiratory depression and hypoxia. Tachycardia does not typically occur. **Hypotension is unusual, again due to reduced SNS activity**, but also since there is less venous pooling in neonates and infants due to a smaller relative volume of blood in their lower extremities.

Answer 31

"FAT PAN***_GA_***S" Pregnancy Ascites Neonates General Anesthesia Obesity Supine Position

Answer 32

Morphine is metabolized primarily into **morphine-3-glucuronide (M3G) and morphine-6-glucuronide** via glucuronidation by phase II metabolism enzyme UDP-glucuronosyltransferase-2B7 (UGT2B7). About **60% of morphine is converted to M3G**, and **6% to 10% is converted to M6G.** Not only does the metabolism occur in the liver but it may also take place in the brain and the kidneys. *_M3G does not undergo opioid receptor binding and has no analgesic effect._* *_M6G binds to μ-receptors and is half as potent an analgesic as morphine in humans_*

Answer 33

**Factor V Leiden** | (especially in white people)

Answer 34

Factor V Leiden is a hereditary pro-coagulant disorder characterized by resistance to activated protein C (APC). APC is a natural anticoagulant that works by cleaving and inactivating factors V and VIII. Factor V is a pro-coagulant clotting factor that increases the production of thrombin, which is the enzyme responsible for forming fibrin from fibrinogen. In patients with factor V Leiden, **a point mutation in the gene for factor V abolishes the cleavage site of APC, making it resistant to inactivation**. *_The inability to inactivate factor V ultimately leads to increased thrombin and therefore fibrinogen production, leading to a hypercoagulable state_*.

Answer 35

1. Two or more spontaneous thromboses 2. One spontaneous thrombosis if the patient has factor V Leiden plus another prothrombotic mutation (antithrombin deficiency, protein S deficiency, homozygotes for factor V Leiden) 3. One spontaneous life-threatening thrombosis (e.g. near-fatal PE) 4. One spontaneous thrombosis at an unusual site (e.g. cerebral or mesenteric vein)

Answer 36

CNS Symptoms (Transient Blindness) Encephalopathy Nausea / Vomiting

Answer 37

Postulated mechanism is based on **glycine’s role as an inhibitory neurotransmitter on the brainstem and cranial nerves.** Glycine also structurally resembles aminobutyric acid, an **inhibitory neurotransmitter within the spinal cord and retina.** In addition, glycine is metabolized to *_glyoxylic acid and ammonia_* (Hyperammonemia may cause encephalopathy, nausea, and vomiting)

Answer 38

This may be treated with the exogenous administration of **arginine**, which promotes urea formation from ammonia and excretion.

Answer 39

**Hypertension** **Reflex Bradycardia** **CV Collapse** **Wide QRS** (If Na \<120) **Elevated ST** (If Na 110-120) **Ventricular Arrythmias** (If Na \<110)

Answer 40

Pulmonary Edema

Answer 41

Decreased Na & Serum Osmolality Cerebral Edema ("High to low brain will blow") Increased ICP

Answer 42

Deamination of glycine to glycoxylic acid and Ammonia

Answer 43

1. Hypotension 2. Hyperoxaluria (metabolite of glycine)

Answer 44

**Distilled water is hypotonic and can lead to severe intravascular hemolysis**, fluid overload, and dilutional hyponatremia. **Distilled water may also cause hemolysis of red blood cells** in the bladder and impair surgical visualization. It does not cause electrical dispersion due to its nonionic composition. Distilled water is not widely used during TURP due to the increased chance of TURP syndrome.

Answer 45

Sorbitol 3.3% / mannitol 5% combination irrigating solutions are widely used: 1. Owing to **slight hyperosmolality or iso-osmolality**. 2. They **do not cause electrical current dispersion.**

Answer 46

1. **H****yperglycemia** if absorbed 2. Osmotic Diuresis

Answer 47

1. Osmotic diuresis 2. Intravascular volume expansion and potentially pulmonary edema

Answer 48

A common etiology of postoperative hoarseness includes vocal cord palsy due to ***_recurrent laryngeal nerve injury_***. Other etiologies may include *_edema, hematoma, or trauma from the intubation (arytenoid cartilage dislocation)._*

Answer 49

1.5 - 2.5 mg/dL

Answer 50

5 - 9 mg/dL

Answer 51

1. The **source** of magnesium must be **identified and stopped.** ## Footnote 2. The actions of magnesium should be **counteracted with calcium** administration (if symptomatic), although this is only a temporary fix. 3. The elimination of magnesium can be accelerated by the **administration of loop diuretics and the extracellular fluid compartment should be expanded to promote diuresis with normal saline**. If the patient has severe renal impairment, dialysis is often necessary to remove the magnesium.

Answer 52

Renal Failure

Answer 53

Muscle paralysis Respiratory Failure Complete Heart Block

Answer 54

In patients with coronary artery disease, administration of vasopressin can cause myocardial ischemia due to the ***_vasoconstriction of stenotic areas_*** thus caution must be taken in this patient population.

Answer 55

V1 receptor activation *_increases systemic vascular resistance_* without affecting pulmonary vascular resistance. *_V2 receptor activation increases blood volume_*. Vasodilation can be seen in pulmonary and cerebral vascular beds.

Answer 56

Desmopressin (DDAVP) is typically preferred over vasopressin for diabetes insipidus as it **does not cause systemic hypertension**

Answer 57

Increases circulating von Willebran Factor and Factor VIII

Answer 58

Motor evoked potentials assess the integrity of the neural tissue and its blood supply along the entirety of the **DESCENDING neuromotor pathway**

Answer 59

Pathway of somatosensory evoked potentials. ## Footnote **Peripheral Nerve → DRG → Posterior Spinal Cord → Brainstem → Thalamus → Cortex**

Answer 60

**Pathway of brainstem auditory evoked potentials.** Cochlea → Cranial Nerve 8 → Cochlear Nucleus → Inferior Colliculus → Auditory Cortex

Answer 61

Pathway of visual evoked potentials. ## Footnote **Retina → Optic Nerve → Optic Chiasm → Optic Tract → Superior Colliculus → Visual Cortex**

Answer 62

**Anterior Spinal Cord Artery** | (Anterior Spinal Cord Perfusion)

Answer 63

***_Pacing_* Chambers** O = None A = Atrium V = Ventricular D = Dual

Answer 64

***_Sensing_* Position** O = None A = Atrium V = Ventricular D = Dual

Answer 65

***_Response_* to Sensing** O = None I = Inhibited T = Triggered D = Dual

Answer 66

**Programmability** O = None R = Rate Modulation

Answer 67

**Multisite Pacing** O = None A = Atrium V = Ventricular D = Dual

Answer 68

Hyperventilation in labor leads to **maternal respiratory alkalosis, a leftward shift of the oxyhemoglobin dissociation curve, increased maternal hemoglobin affinity for oxygen, and reduced oxygen delivery to the fetus**. Most authorities recommend that hyperventilation should be avoided in pregnancy, in part because of concerns about uterine blood flow. Hypocarbia (secondary to hyperventilation) also leads to hypoventilation between contractions, which may cause a decrease in maternal PaO2. Effective epidural analgesia blunts this “hyperventilation-hypoventilation” cycle.

Answer 69

Until the age of 2, infants’ diaphragms have a much smaller proportion of fatigue-resistant type I (slow twitch) muscle fibers

Answer 70

Oxygen consumption per kilogram is **2-3 times higher in infants as compared to adults (6-7 mL/kg vs. 2-3 mL/kg).** To meet this increased need, minute ventilation is accordingly increased.

Answer 71

Kidneys compensate for respiratory alkalosis **by increased bicarbonate excretion** **Accelerate an already physiologic process** 125-250 mg PO BID given the day before the ascent Also treats insomnia (lowers pH and improving hyperventilation)

Answer 72

**Hypo = Shortened** **Hyper = Prolonged** Calcium, Potassium and Magnesium levels

Answer 73

Hypo = Narrowed Hyper = Prolonged Applies to Potassium and Magnesium

Answer 74

It doesn't

Answer 75

**Hypo = Prolonged (Calcium and Hypokalemia)** **Hypercalcemia = Shortened** (Potassium and Magnesium have no effect

Answer 76

Flat, U waves

Answer 77

Hypomagnesemia

Answer 78

Tetanus toxin travels via **retrograde axonal transport from peripheral to central neurons.** Spastic paralysis occurs since the toxin *_prevents the release of inhibitory neurotransmitters (GABA)_* into the synaptic cleft between inhibitory interneurons and motor neurons. Tetanus toxin also enters brainstem and sympathetic nervous system neurons leading to autonomic dysfunction.

Answer 79

***_Spontaneous activity_*** of the affected muscle can be demonstrated in patients with myofascial pain syndromes.

Answer 80

1. ***_Norepinephrine_*** NE then triggers increased lipase activity in brown fat. Lipase causes hydroxylation of triglycerides and the release of free fatty acids which are then used as substrates for metabolism and uncoupled oxidative phosphorylation, yielding heat 2. ***_Glucocorticoids_*** 3. ***_Thyroxine_***

Answer 81

1. **Voluntary muscle activity** 2. **Shivering** 3. **Dietary thermogenesis** (Amino acid infusions) 4. **Nonshivering thermogenesis**

Answer 82

*_Metabolic heat production (above basal metabolic rate) not produced from muscle activity._* It primarily occurs in **brown fat** which is able to uncouple oxidative phosphorylation at the mitochondrial level, resulting in **heat generation instead of ATP production**

Answer 83

1. Inhalational anesthetics 2. Beta Blockers

Answer 84

A chloride level of 100 mmol/L approachin readiness. **Chloride level equal to or greater than 106 = goal** **Bicarbonate level goal \<30** - If they are alkalotic they wont trigger respiration

Answer 85

Leukopenia can occur during TRALI because **massive agglutination of the leukocytes in the recipients pulmonary microcirculation occurs in response to the donor anti-human leukocyte antigens (HLA) contained in the blood product**. This will cause a sometimes transient leukopenia. Leukopenia is not observed in other types of transfusion reactions.

Answer 86

Within 6 hours of blood product administration

Answer 87

Critically ill patients appear to be at highest risk for TRALI 1. **Chronic alcohol and/or tobacco abuse** 2. **Status post liver transplantation** 3. **Mechanically ventilated** with higher peak airway pressures 4. **Positive fluid balance**

Answer 88

1. Platelet concentrations 2. High-plasma-volume plasma, 3. Whole blood

Answer 89

Plasma or whole blood from **female donors** has a higher risk. The theory is during *_pregnancy the mother may develop antibodies against the HLA antigen_* and these are then transfused; more pregnancies likely result in a higher chance of development. **Multiparous females have been implicated in several instances of TRALI**

Answer 90

***_Leukoreduction_*** of blood products has decreased the incidence of TRALI.

Answer 91

1. Nickel 2. Iron 3. Cobalt

Answer 92

A sentinel event is defined by The Joint Commission as an **unexpected occurrence involving death or serious physical or psychological injury**, or the risk thereof. *_Examples:_* medication administration errors, administration of blood products of the incorrect ABO type, wrong-site or wrong-sided nerve blocks or other procedures, significant delays to care or treatment, and a variety of operative and postoperative complications.

Answer 93

Negligence refers to the **failure to use reasonable care that then results in harm to another person**

Answer 94

**type of negligence that results in patient harm due to a medical professional not following generally accepted professional standards.** For example, use of an inhalational anesthetic in a patient with a known history of malignant hyperthermia.

Answer 95

Maleficence refers to an act of **committing intentional harm to a patient.** For example, intentionally withholding pain medication due to personal prejudices against a patient.

Answer 96

**Patient Specific** Esophageal rings/strictures/webs Recent esophageal variceal bleeding Esophageal tumor Active upper GI bleeding Esophageal trauma Recent upper GI surgery Scleroderma Mallory-Weiss tear Zenker diverticulum Perforated viscous **Past Surgical** Esophagogastrectomy Esophagectomy

Answer 97

Stimulation of the common peroneal nerve results in foot **dorsiflexion and eversion** ## Footnote *_If the common peroneal nerve is damaged, the patient may lose the ability to dorsiflex, evert the foot, and extend the digits (Footdrop)_*

Answer 98

Stimulation of the tibial nerve stimulation causes foot **plantar flexion and inversion**

Answer 99

The brachial plexus supplies all of the motor and sensory innervation to the shoulder, except for the skin of the shoulder above the clavicle, which is innervated by the **supraclavicular nerve.** The supraclavicular nerve originates from the **lower cervical plexus (C3-4).** This nerve may be missed by the interscalene approach to the brachial plexus and may need to be blocked separately for arthroscopic shoulder surgery.

Answer 100

Supraclavicular brachial plexus blocks are performed at the level of the **distal trunks and upper divisions.**

Answer 101

Interscalene brachial plexus block occurs at the **level of the upper trunks of the brachial plexus** as they emerge between the two scalene muscles

Answer 102

The supraclavicular nerve supplies sensation to the skin of the **shoulder above the clavicle (arthroscope insertion site).**

Answer 103

- Spinal cord injuries **\> 24 hours** to develop and usually **peaks at 7-10 days beyond the injury date.**

Answer 104

Prolonged immobilization - **\>16 days is usually the cutoff** (Several days after probably develops), Sux usually contraindicated in ICU

Answer 105

- Neuromuscular disorders (e.g. **Guillain-Barré, Multiple Sclerosis)**

Answer 106

Myasthenia gravis is *_sensitive to nondepolarizing blockers._* ## Footnote **Myasthenia gravis is *_resistant to depolarizing blockers (Succinylcholine)_***

Answer 107

Myasthenia gravis is not associated with upregulation of acetylcholine receptors.

Answer 108

**Lambert-Eaton syndrome is *_sensitive_* to nondepolarizing blockers.** **Lambert-Eaton is *_sensitive_* to depolarizing blockers (Succinylcholine)** *_Think of it as "Lambs are sensitive"_*

Answer 109

**Unopposed parasympathetic (vagal) activity after sympathetic blockade causes increased peristalsis of the gastrointestinal tract**, which can lead to nausea and is the primary mechanism behind nausea after spinal blockade. **Atropine or Glycopyrrolate** is an anticholinergic medication, thus is useful for treating nausea after high spinal blockade.

Answer 110

Another useful medication, particularly for the parturient patient, is **glycopyrrolate**. When administered immediately before injection of subarachnoid anesthesia for elective cesarean section, **glycopyrrolate** can reduce the incidence and severity of nausea without adverse effects on neonatal Apgar scores since it **does not cross the placenta to the extent that atropine does.** ## Footnote *_Glyco = Quaternary amine (Quaternary)_* *_Atroine = Tertiary amine (Neutral)_*

Answer 111

Phenothiazine derivative; 1. Blocks postsynaptic mesolimbic **dopaminergic** receptors (Weak dopamine) in the brain; exhibits a strong alpha-adrenergic blocking effect and depresses the release of hypothalamic and hypophyseal hormones 2. Competes with histamine for the **H1-receptor;** muscarinic-blocking effect may be responsible for antiemetic activity; reduces stimuli to the brainstem reticular system

Answer 112

Nausea and vomiting of pregnancy (off-label use): Oral, IM, IV, rectal: **12.5 to 25 mg every 4 to 6 hours**, as needed (ACOG 189 2018)

Answer 113

1. Atrial Fibrillation with Aberrancy 2. Wolff - Parkinson - White Syndrome (WPW)

Answer 114

Sodium - (Chloride + Bicarbonate)

Answer 115

8 - 12 mEq/Liter

Answer 116

**(1) Chloride-containing acid administration.** Administration of chloride-containing acids or products can cause nonanion gap acidosis. For example, excess normal saline administration causes a classic hypernatremic, hyperchloremic, nonanion gap acidosis. Total parenteral nutrition often contains ammonium chloride and metabolism of the amino acids it contains can create HCl. Together, hyperalimentation can lead to excess Cl- and therefore a nonanion gap acidosis. **(2) Increased HCO3- loss or loss of HCO3- precursors from GI tract** Increased HCO3- loss is usually via the gastrointestinal (GI) tract or the kidneys. Causes of increased GI losses include diarrhea, GI fistulas (e.g. pancreatic, biliary, bowel), high ostomy output, or use of bile or phosphorus binding drugs. Renal losses can be caused by use of carbonic anhydrase inhibitors (e.g. acetazolamide) or type 2 (proximal) renal tubular acidosis (RTA). **(3) Increased HCO3- loss or loss of HCO3- precursors from Kidney** Decreased acid excretion is due to hypoaldosteronism or renal causes including acute and/or chronic renal failure or type 1 (distal) RTA. Several mnemonics exist to remember causes of nonanion gap acidosis. Examples include: ACCRUED: Acid infusion, Compensation for respiratory alkalosis, Carbonic anhydrase inhibitors, Renal tubular acidosis, Ureteral diversion, Extra alimentation, Diarrhea.

Answer 117

**ACCRUED**: Acid infusion, Compensation for respiratory alkalosis, Carbonic anhydrase inhibitors, Renal tubular acidosis, Ureteral diversion, Extra alimentation, Diarrhea. **FUSEDCARS**: Fistula, Ureteroenterostomy, Saline administration, Endocrine (hyperparathyroidism), Diarrhea, Carbonic anhydrase inhibitors, Ammonium chloride, Renal tubular acidosis, Spironolactone.

Answer 118

However, a pressure bag is usually required to optimize infusion rates because the **intramedullary (intraosseous) pressure is ~20 to 40 mm Hg**

Answer 119

The **humerus** supports significantly higher infusion flow rates compared with tibial sites (~**200cc** vs 100 mL/min via pressure bag). The **manubrium of the sternum** supports the fastest uptake of drugs and fluids into the systemic circulation even during cardiac arrest. The time to peak plasma concentrations of drugs via sternal IO during an arrest model was found to be 80 to 110 seconds, which was not significantly longer than the 60 to 80 seconds for central access.

Answer 120

A decrease in barometric pressure caused by an increase in altitude will *_increase the delivered concentration (percentage) of a volatile anesthetic_* from a variable-bypass vaporizer but the **delivered partial pressure (mm Hg) of the anesthetic remains essentially unchanged.**

Answer 121

**Potassium iodide** is capable of mitigating the majority of radiation-induced injury to the thyroid via saturating the thyroid with iodine and preventing uptake of the radioactive I-131 isotope. The effectiveness of potassium iodide drops rapidly following exposure and should be administered within the first 24 hours. **Strontium lactate** plays a similar role in preventing the accumulation of radioactive strontium in bone.

Answer 122

SOFA = Seequential [Sepsis Related] Organ Failure Assessment For patients in the ICU, the SOFA score is recommended to judge the extent of end-organ dysfunction. For infected patients in non-ICU settings, the quickSOFA (qSOFA) score can be used to identify patients at high risk for poor sepsis-related outcomes. The qSOFA score consists of: * *1. Respiratory rate \> 22/min (1 point) 2. Altered mental status (1 point) 3. Systolic blood pressure \< 100 mm Hg (1 point)** Scores of two or greater are associated with poor outcomes, however, the qSOFA score is not used to formally diagnose sepsis or septic shock.

Answer 123

SSEPs are EEG-detectable signals that represent responses to specifically applied sensory inputs via cutaneous electrical stimulation of a peripheral or cranial nerve and its associated ***_ascending sensory pathway_*** and allows detection of ischemic or surgical retraction insult to that pathway

Answer 124

MEPs are signals that are measured to discern **disruption of descending motor pathways from the cerebral cortex to the peripheral muscle groups.**

Answer 125

**Central venous oxygen saturation (ScvO2)** **ScvO2 is measured in the right heart and receives contributions from the superior and inferior vena cavae and the coronary sinus.**

Answer 126

Mixed venous oxygen saturation (SvO2) is the **percentage of oxygen bound to hemoglobin in the blood returning from the right side of the heart to the lungs**. A true SvO2 includes all of the blood returning from the superior and inferior vena cavae, coronary sinus, and the thebesian veins and must be obtained from a pulmonary artery catheter. A true SvO2 measurement is obtained via pulmonary artery catheter and includes deoxygenated blood from the **thebesian venous network.**

Answer 127

**Therefore, because it is a more distal measurement, a true SvO2 can be 5-10% lower than the ScvO2**. In practice, ScvO2 is a useful surrogate for SvO2.

Answer 128

Posterior Descending Artery is supplied by the RCA

Answer 129

Right Coronary Artery (RCA)

Answer 130

The right marginal artery supplies the ## Footnote **1. Lateral right ventricle** **2. Cardiac apex**

Answer 131

1. SA nodal artery (60%) 2. LCA (40%)

Answer 132

Posterior Descending Artery

Answer 133

Posterior Descending Artery

Answer 134

Intrathecal: IV = 1:100 1 mg of intrathecal (IT) morphine = 10 mg of epidural (EP) morphine (1:10) 1 mg of EP morphine = 10 mg of IV morphine (1:10) 1 mg of IV morphine = 3 mg of PO morphine (3:1)

Answer 135

Variable decelerations result from **baroreceptor or chemoreceptor-mediated vagal activity.** Umbilical cord occlusion, either partial or complete, results in variable decelerations. A **healthy fetus** can typically tolerate mild to moderate variable decelerations without decompensation. With sustained, severe variable decelerations or persistent fetal bradycardia, it is difficult for the fetus to maintain cardiac output and umbilical blood flow.

Answer 136

Regular, smooth, wave-like pattern that may signal **fetal anemia.** Occasionally, **maternal IV administration of an opioid** can lead to a sinusoidal FHR pattern.

Answer 137

A saltatory pattern consists of **excessive alterations in variability** (\> 25 bpm) and may signal the occurrence of **acute fetal hypoxia.**

Answer 138

The obturator block is performed by injecting anesthetic in two locations: 1) Between the **adductor longus** and **adductor brevis** muscles (primary location) 2) Between the **adductor brevis** and **adductor magnus** muscles TrueLearn Insight: The mnemonic ALABAMa is used to remember the muscles from superficial to deep: Adductor Longus, Adductor Brevis, Adductor Magnus.

Answer 139

Both sensory and motor

Answer 140

Motor only

Answer 141

Blocking this branch will produce **significant motor weakness** which may interfere with exercises after a knee replacement surgery.

Answer 142

Between Adductor Longus and Brevis

Answer 143

Chronic hyperglycemia occurs with type 1 diabetes mellitus. This can lead to **glycosylation of the joints and limited mobility**. This is known as diabetic stiff joint syndrome. Glycosylation affects the atlanto occipital (AO) joint and compromises adequate neck extension. Patients with **diabetic stiff joint syndrome may display the “prayer sign,”** which is an inability to oppose the palmar surface of the interphalangeal joints. This sign may be suggestive of difficult laryngoscopy.

Answer 144

The **CPP** value to target lies within the range of **50-70 mm Hg** according to current BTF guidelines. However, if a patient with intact autoregulation is maintaining a CPP \> 70 mmHg spontaneously, that is acceptable.

Answer 145

ICP \> 20 mmHg

Answer 146

Hyperventilation can be used as a temporizing measure, but **prophylactic hyperventilation to 25 mmHg PaCO2 or below is not recommended**. This can potentially cause ischemia, especially in the first 24 hours when CBF is often critically reduced.

Answer 147

TBIs are categorized by level of severity: mild, moderate, and severe. A mild TBI is associated with a Glasgow Coma Scale (GCS) score of **13-15 and minimal to no loss of consciousness.** A moderate TBI is associated with a **GCS of 9-12 and a loss of consciousness of 30 minutes or more.** A severe TBI is associated with a **GCS of 3-8.**

Answer 148

Preoperative pharmacologic anxiolysis is not usually necessary until the development of separation anxiety, which normally occurs at **~9 months of age.** *_Most severe = 1-5 years old_*

Answer 149

1. SA nodal artery (60%) 2. AV nodal artery 3. Posterior Descending Artery (85%) 4. Right Marginal Artery

Answer 150

1. Lateral RV 2. Cardiax Apex

Answer 151

LAD and LCX

Answer 152

The CLASSIC TRIAD OF TURP syndrome includes: 1. **Elevated systolic and diastolic blood pressures** with increased pulse pressure 2. **Bradycardia** 3. **Mental status changes** (assuming an awake patient under regional anesthesia).

Answer 153

*_Irrigating fluid absorption during TURP is determined by:_* (1) number of open prostatic venous sinuses (2) resection time (3) height between the patient and the irrigating fluid (hydrostatic pressure) (4) pressures within exposed prostatic venous sinuses

Answer 154

Relaxes the uterus

Answer 155

Increases uterine blood flow

Answer 156

decreases it

Answer 157

May decrease it because magnesium drops your BP

Answer 158

End of expiration while the patient is supine and all abdominal muscles relaxes

Answer 159

MAP - IAP (Intraabdominal pressure)

Answer 160

IAP \> 12 mmHg

Answer 161

**1. Decreased Abdominal Wall Compliance** **2. Increased intraluminal contents** **3. Increased intraabdominal contents** **4. Capillary Leakage** Decreased abdominal wall compliance: abdominal surgery, prone positioning, major trauma or burns Increased intraluminal contents: gastroparesis, ileus, volvulus Increased intraabdominal contents: acute pancreatitis, distended abdomen, intra-abdominal infection/abscess/tumors, laparoscopy with excessive inflation pressures, peritoneal dialysis Capillary leakage: acidosis, hypothermia, increased APACHE-II score, massive fluid resuscitation, massive transfusion Miscellaneous risk factors: age, bacteremia, coagulopathy, elevated head of the bed, obesity, PEEP \> 10, peritonitis, pneumonia, sepsis, shock

Answer 162

1. **3,4 diaminopyridine** (prolongs action potential and increases Ach release) 2. **immunosuppression** 3. Sometimes **steroids** 4. Rarely **plasmapheresis**

Answer 163

**Treatment for MG includes:** 1. Oral anticholinesterases (such as pyridostigmine) 2. Steroids 3. Immunosuppressants 4. IVIG 5. Plasmapheresis may be warranted in the acute setting

Answer 164

The thymus functions to produce T-lymphocytes which aid in cell-mediated immunity and antibody production. Between 15-60% of patients with MG will develop a thymoma or thymic hyperplasia. **Thymectomy produces remission or improvement in symptoms in 75% of patients.** Thymectomy is clearly indicated if thymoma is present.

Answer 165

20-40% of parturients will have worsening MG symptoms

Answer 166

Succinylcholine still can be used at doses of **1.5-2.0 mg/kg** but *_if on significant doses of pyridostigmine, may last longer than expected (Caveat)_*

Answer 167

**Some predictors of postoperative respiratory failure requiring mechanical ventilation of MG patients are:** - Disease **Duration** \> 6 years - Daily Pyridostigmine **dose** \> 750 mg - **FVC** \< 2.9 liters * _- Other chronic lung disease not related to MG_*

Answer 168

Microlaryngeal tracheal tubes are **designed with a smaller internal diameter but with a length and cuff size appropriate for the adult airway.**

Answer 169

A nerve block has a high success rate when the desired response is elicited with a stimulating current of 0.4-0.5 mA.

Answer 170

However, if the response occurs with a current \< 0.3 mA, ***_the needle may be intraneural_*** which may increase the risk for block complications without necessarily increasing the block success rate.

Answer 171

* *Diagnostic criteria for preeclampsia:** 1) New-onset hypertension of systolic \>140 mm Hg, or diastolic \>90 mm Hg occurring after 20 weeks of gestation on at least 2 occasions at least 4 hours apart * **_and_*** 2) Proteinuria of 300 mg \>24 hours or a protein:creatinine ratio of ≥0.3

Answer 172

**Preeclampsia with severe features is diagnosed with signs and/or symptoms of end-organ ischemia:** 1. Systolic \>160 mm Hg or diastolic \>110 mm Hg 2. Visual or cerebral symptoms (blurry vision, headache, altered mental status) 3. Thrombocytopenia \<100,000 μL 4. Creatinine \>1.1 or greater than 2 times the baseline creatinine level 5. Aminotransferase and alanine aminotransferase levels \>2 times normal or right upper quadrant (RUQ) pain (due to hepatic inflammation and the stretching of the liver capsule) 6. Pulmonary edema

Answer 173

Endothelial cells become abnormal and dysfunctional during preeclampsia. The dysfunctional endothelial cells produce less nitric oxide and prostacyclin and more thromboxane during preeclampsia. This imbalance of nitric oxide, prostacyclin, and thromboxane production causes profound vasoconstriction. This is why patients at high risk for preeclampsia or with a history of preeclampsia often take aspirin. ## Footnote **Aspirin decreases thromboxane production, which helps balance vasodilating and vasoconstricting elements.** *_Aspirin is a cyclooxygenase inhibitor and thereby decreases thromboxane production_* *_Patients treated with prophylactic aspirin have a 10% to 20% decreased incidence of preeclampsia._*

Answer 174

The term "ion trapping" refers to fetal drug accumulation due to pH differences between maternal and fetal blood, particularly in cases of fetal acidosis. Nonionized drug passes from maternal to fetal circulation. Since fetal blood pH is less than maternal blood pH, but the drug’s pKa remains constant, more of the drug will exist in the ionized form in fetal circulation. **Once a local anesthetic becomes ionized in the fetus, it does not readily transfer back across the placenta to the maternal circulation.**

Answer 175

Bupivacaine does not readily cross the placenta due to: **1. High protein binding (Size restrictions \>500 Daltons)** **2. High pKa of 8.1** The latter results in a greater concentration of ionized drug which does not easily cross the placenta.

Answer 176

***_Vasopressin_*** 1. Decreases catecholamine requirements 2. Effective therapy for diabetes insipidus

Answer 177

The mutation results in an **abnormally formed dystrophin protein causing sarcolemmal instability and damage to the muscle cell units.** Dystrophin is involved in skeletal, cardiac, and smooth muscle thus organ systems comprised of those cells can be affected.

Answer 178

heart is affected to various degrees depending on the type of mutation present with **50-70% of patients having some kind of cardiac abnormality** (although only 10% are clinically significant).

Answer 179

**Most (IV)** Subcutaneous IM SL/Buccal IN Rectal **Oral (Least)**

Answer 180

**Packed red blood cells (PRBC)** *_have the plasma fraction removed_* and therefore have the lowest risk of TRALI. However, the risk is not eliminated because some antibodies remain in the PRBCs.

Answer 181

Systemic blood flow is dependent on a **PDA (Patent Ductus Arteriosus)**

Answer 182

The descending inhibitory pathways are largely mediated by ***_serotonin_*** and ***_norepinephrine_***. Hence, why patients are put on SSRI and SNRI for fibromyalgia

Answer 183

Fibromyalgia is diffuse pain for **greater than 3 months** AND **without objective evidence of joint or muscle inflammation (Normal CK and ESR)**

Answer 184

Total Body Weight

Answer 185

LBW is the *_difference between a patient’s TBW and their adipose tissue_*. I ## Footnote **80% of the TBW of an obese male** **75% of the TBW of an obese female.**

Answer 186

*_Lean body weight_* LBW is the difference between a patient’s TBW and their adipose tissue. ~ 80% of the TBW of an obese male ~75% of the TBW of an obese female

Answer 187

Blood products from **multiparous women and patients who have received numerous transfusions in the past are most likely to contain antileukocyte antibodies**. The use of plasma-containing products donated by this group is limited.

Answer 188

Based on lean body weight

Answer 189

**All based on Ideal Body Weight**

Answer 190

Mild GCS 13-15 Moderate GCS 9-12 Severe \<9

Answer 191

**The American Association of Neurological Surgeons recommends maintaining:** intracranial pressure less than 20-25 mm Hg mean arterial blood pressure greater than 80\ cerebral perfusion pressure ≥60 PaO2 greater than 95

Answer 192

Oxygen is present, but it is unable to be utilized. Therefore, **PaO2 will increase.** Oxygen is present, but it is unable to be utilized. **SvO2 will be increased.**

Answer 193

Transfusion-related acute lung injury is believed to occur when **antibodies in the donor plasma activate leukocytes in the recipient**. This transfusion reaction manifests as lung injury due to *_sequestration of granulocytes in the lungs coupled with antileukocyte antibodies from the donor blood products._* This may occur during stages of acute stress and demargination.

Answer 194

Most instances of AH occur in SCI patients with lesions **above T5 (AH occurs in 85% of patients with a lesion above T5**

Answer 195

Lesions **below T12 rarely lead to AH**

Answer 196

Spinal cord reflexes from stimuli below the spinal cord injury stimuli *_trigger SNS activity (preganglionic sympathetic nerves) along the splanchnic outflow tract_*, but because of the SCI, ***_inhibitory impulses_* from higher CNS centers cannot reach below the site of SCI**.

Answer 197

Accordingly, **intense generalized vasoconstriction occurs below the level of SCI** while *_reflex cutaneous vasodilation occurs above the level of SCI._*

Answer 198

Susceptibility to AH usually starts **between two weeks and six months after injury.**

Answer 199

Heart rate generation is dependent on the **donor atrium.**

Answer 200

In the normal innervated heart, the response to a *_sudden reduction in intravascular volume is an increase in heart rate and contractility._* In a cardiac transplant recipient, the initial response is an increase in stroke volume that is dependent on an adequate preload and not an acute increase in heart rate or contractility. The increased contractility and heart rate is a secondary effect and is predominantly dependent on circulating catecholamine levels. Therefore, the transplanted heart is **critically preload dependent.**

Answer 201

Anticholinergic agents (e.g., atropine, glycopyrrolate, pancuronium) have minimal effects on heart rate. *_The response to anticholinesterases is unpredictable._* The transplanted heart **does retain its responsiveness to direct-acting agents**, such as isoproterenol, epinephrine, norepinephrine, dopamine, and dobutamine.

Answer 202

**Frank-Starling mechanism remains intact** in the transplanted heart, since this mechanism does not rely on parasympathetic tone.

Answer 203

Paroxysmal hemicrania is a *_rare form of headache that has similar characteristics of pain and symptoms as cluster and migraine headaches._* The difference between paroxysmal hemicrania, as opposed to cluster and migraine headaches, is that they are **shorter in duration, occur more frequently, are more common in females, and they respond absolutely to indomethacin** - Severe, unilateral headache that is supraorbital or temporal in location and can last between 20-30 minutes in duration - Ipsilateral conjunctival injection and/or lacrimation - Ipsilateral nasal congestion and/or rhinorrhea - Ipsilateral eyelid edema - Ipsilateral forehead and facial sweating - Ipsilateral miosis and/or ptosis

Answer 204

Distributive

Answer 205

add time frames to oliguria defining it as urine output of **\< 0.5 mL/kg for 12 hour** or urine output **\< 0.3 mL/kg for 24 hours**

Answer 206

Anuria is defined as urine output **\< 50 mL in 12 hours** or urine output **\< 50-100 mL in 24 hours**

Answer 207

The only vocal cord tensor is the **cricothyroid muscle**

Answer 208

The only vocal cord tensor is the cricothyroid muscle which is innervated by the **external branch of the superior laryngeal nerve**

Answer 209

The superior laryngeal nerve is a branch of the vagus nerve and is split into internal and external branches. **The internal branch innervates the mucosa just above the vocal cords to the epiglottis and is a sensory nerve**. *_The external branch is a motor nerve._*

Answer 210

The fibers of the recurrent laryngeal nerve most likely to be injured are **abductor fibers.**

Answer 211

Answer D: The internal branch of the superior laryngeal nerve is sensory only and damage to this nerve **would not result in any vocal cord dysfunction.**

Answer 212

**Powerful vasoconstrictive** effect in umbilical arteries and veins and in **coronary vessels**. A combination of hypotension, tachycardia, and coronary vasoconstriction after oxytocin administration can cause a ***_mismatch between myocardial oxygen demand and supply, leading to myocardial ischemia_*** even without co-existing coronary disease. Additionally, can cause **systemic hypotension which can worsen coronary perfusion pressure**

Answer 213

Increasing free calcium concentration in the myometrial tissue leading to increased uterine contractions

Answer 214

Ergot alkaloids produce significant uterine contraction but the **mechanism for this is poorly understood**

Answer 215

CaO2 = ***_(1.39 x SaO2 x Hgb) + (0.003 x PaO2)_***

Answer 216

**CaO2 = (1.39 x SaO2 x Hgb) + (0.003 x PaO2)** The dissolved oxygen component (0.003 x PaO2) becomes the main source of arterial oxygen content when oxygen saturation (SaO2) or hemoglobin (Hgb) concentration are no longer adequate to support cellular metabolism. The use of HBO, therefore, increases the PaO2 sometimes to as high as 2000 mm Hg (~3 atmospheres of pressure; 1 atm = 760 mm Hg).

Answer 217

**Initially during stress, there will be protein anabolism** which will then be *_followed by catabolism_*. The protein catabolism is stimulated by cortisol and increased cytokine concentrations. The degree of protein degradation depends on the type of surgery and also on the nutritional status of the patient.

Answer 218

No post-exposure prophylaxis is necessary for exposure to a patient with unknown HIV status who is at low risk for HIV

Answer 219

**Two drug prophylaxis** is recommended when there is exposure to a known HIV patient and the exposure is superficial or exposure occurs with a solid needle.

Answer 220

**Three drug prophylaxis** is recommended in severe exposure when the patient is known to have HIV or AIDS.

Answer 221

Postpartum headache can be categorized into ***_primary, secondary, and post-procedural causes_***. **Primary** is a recurrence of a disorder for which the patient already suffered prior to delivery: migraine, tension-type, cluster, and ‘other’ causes. **Secondary** headaches occur due to another medical condition and are attributed to head and/or neck trauma, cranial or cervical vascular disorders, nonvascular intracranial disorder, substance abuse or withdrawal, infection, and psychiatric. **Post-dural puncture headache (PDPH)** occurs after intentional puncture of the dura with a spinal needle or accidental puncture with an epidural needle

Answer 222

The rate of PDPH occurring after spinal needle puncture is between ***_1%-11%._***

Answer 223

Plasma osmolality = 2.0 \* [Na] + Glucose/18 + BUN/2.8

Answer 224

1. Ischial tuberosity 2. Greater trochanter of the femur 3. Sciatic groove

Answer 225

1. Younger children (i.e. preschool age) 2. Children with higher cognitive function 3. Children with shy or withdrawn personalities 4. Children with anxious parents

Answer 226

Waste gas exposure in the operating room is regulated by The National Institute for Occupational Safety and Health (NIOSH) and the standard acceptable level for volatiles is **2 parts per million (ppm) which is equivalent to 0.0002%.**

Answer 227

If volatiles are used with nitrous oxide, they must be **kept below 0.5 ppm.**

Answer 228

Pseudocholinesterase deficiency Personal or familial history of malignant hyperthermia Skeletal muscle myopathies Major burns Multiple trauma Extensive denervation of skeletal muscle Upper motor neuron injury

Answer 229

**Neuraxial anesthesia is commonly avoided in patients with neuromuscular disease, and it is relatively contraindicated in patients with amyotrophic lateral sclerosis for fear of exacerbating the disease.** The mechanism behind disease exacerbation is unknown. The lack of a protective nerve sheath around the spinal cord and associated demyelination may render the spinal cord more susceptible to potential neurotoxic effects of local anesthetics. If the benefit of neuraxial anesthesia outweighs the risk of disease exacerbation, epidural anesthesia may be preferable. *_Because local anesthetic concentrations are significantly smaller within the white matter of the spinal cord after epidural administration, this modality of neuraxial anesthesia is generally recommended over intrathecal techniques_*

Answer 230

If a neonate’s heart rate is less than 100 bpm, **positive pressure ventilation should be initiated**. The most common cause of bradycardia in neonates is hypoxia, so improving oxygenation typically improves heart rate. **Room air or 100% oxygen may be used for assisted ventilation, but if supplemental oxygen is used, the FiO2 should be lowered as soon as possible.**

Answer 231

Chest compressions should be performed in a **3:1 ratio with ventilation at a rate of 120 events per minute (i.e. 90 chest compressions and 30 breaths total per minute)**, and full chest recoil should be allowed after each compression. This should continue until the neonate’s heart rate is \> 60 bpm.

Answer 232

10 - 30 mcg/kg of epinephrine

Answer 233

**TCAs are a first-line therapy in the treatment of peripheral neuropathy.** A well-studied group of medications showing efficacy in treating neuropathy are antidepressants. These include TCAs like amitriptyline, selective serotonin reuptake inhibitors (SSRIs), and selective serotonin and norepinephrine reuptake inhibitors (SNRIs). In general, SSRIs have the lowest efficacy of the adjuvant options.

Answer 234

The **AFFERENT nerve impulses of carotid sinus baroreceptors** are transmitted by the Hering’s nerves to the glossopharyngeal nerve (CN IX). Arterial wall stretch at the carotid sinus, within the internal carotid artery, activates the afferent impulse. This activation leads to stimulation of the nucleus tractus solitarius (NTS) in the caudal medulla. The NTS sends excitatory signals to other regions of the medulla which in turn **inhibit stimulation of the preganglionic intermediolateral nucleus of the spinal cord which mediates the body’s sympathetic innervation**. The NTS may also stimulate vagal nuclei to activate the parasympathetic nervous system via the vagus nerve. Effects = Bradycardia and Hypotension

Answer 235

Carotid body chemoreceptors are located at the **bifurcation of the common carotid artery**

Answer 236

**Primarily** = PaO2 **Secondarily** = Serum [H+] and PaCO2

Answer 237

C. difficile bacterial antigen **Enzyme Immunoassay can rapidly detect the presence of the bacteria, although asymptomatic carriers will also be positive**. Follow-up to a positive antigen EIA is typically done with the **gold standard C. difficile cell culture cytotoxin assay**. - The latter is highly sensitive and specific for C. difficile infection but does not provide results quickly

Answer 238

Up to *_2% of the general population are asymptomatic carriers of C. difficile_* and in adults who have received antibiotics, the **carrier state can be as high as 46%.**

Answer 239

***_Pseudomembranous colitis_*** on endoscopy or direct visualization is pathognomonic.

Answer 240

Non-dependent = non-ventilated lung = Operative Lung Dependent = Ventilated Lung = Non-operative Lung

Answer 241

In fact, an **umbilical venous blood gas** sample can be used to assess the mother’s acid-base status. Similarly, a normal umbilical venous blood gas sample will appear “arterial,” as it is *_carrying maternal arterial blood to the fetus._*

Answer 242

**pH** 7.2-7.3 **PaCO2** 50-55 mm Hg * *PaO2** 18-25 mm Hg * *Bicarbonate** 22-25 mEq/L **Base excess** –2.7 to –4.7 mEq/L.

Answer 243

lower limit of normal for umbilical arterial blood pH may range from **7.02 to 7.18 and that values lower than this may be a sign of fetal asphyxia.** The American College of Obstetricians and Gynecologists (ACOG) states that umbilical arterial *_blood pH \< 7.0 and a base deficit ≥ 12 mEq/L at delivery are 1 part of the definition of an acute intrapartum hypoxic event sufficient to cause cerebral palsy_*. However, ACOG suggests that base deficit and bicarbonate values (not pH) are the most significant factors associated with neonatal morbidity when the umbilical arterial pH is \< 7.

Answer 244

**Roughtly = pH 7.35, PaCO2 41, PaO2 33, HCO3 24, Base Excess -1** Similarly, a normal umbilical venous blood gas sample will appear “arterial,” as it is carrying maternal arterial blood to the fetus. In fact, an umbilical venous blood gas sample can be used to assess the mother’s acid-base status.

Answer 245

**Plasma levels of catecholamines are significantly elevated** in geriatric patients compared to younger subjects. These elevated catecholamine levels are present at rest and during a stress response. *_For this reason, the stress response that is mounted is less significant than in younger patients._*

Answer 246

It doesn't - Resting systolic function is preserved

Answer 247

Resting systolic function is not altered by aging, but **exercise-induced increases in cardiac output, stroke volume, and heart rate are reduced**

Answer 248

Fetal head compression

Answer 249

**Uteroplacental Insufficiency** - Excessive uterine contractions, maternal hypotension, maternal hypoxemia

Answer 250

Umbilical Cord Compression

Answer 251

Addison disease is primary adrenal insufficiency and causes *_destruction of cortisol_* **Hyponatremia** **Hyperkalemia** **Hypoglycemia** **Hyperchloremia** **Hypercalcemia.** Skin hyperpigmentation is a classic finding secondary to increased ACTH stimulation.

Answer 252

A bisferiens pulse can be seen in the arterial line and is evidence of a double peak in the arterial line and is separate from the dicrotic notch.

Answer 253

Aortic regurgitation is managed by: **decreasing** afterload **maintaining a high normal** heart rate **maintaining** contractility.

Answer 254

For this reason, a combination of **neostigmine and atropine** rather than neostigmine and glycopyrrolate may be considered for reversal of nondepolarizing neuromuscular blockers in pregnant patients to minimize the risk of fetal bradycardia. ## Footnote **Atropine for Neuromuscular blockade reversal IV: 15 to 30 mcg/kg** administered with neostigmine or 7 to 10 mcg/kg (Up to 5 mg total)

Answer 255

**Static compliance** is measured after the lung has been *_held at a fixed volume for as long as possible._* **Dynamic compliance** is measured *_during the course of normal rhythmic breathing._*

Answer 256

Hypophosphatemia can occur in patients receiving TPN and this may affect the patient’s muscle strength. This is especially clinically relevant when weaning from the ventilator as hypophosphatemia can result in diaphragmatic weakness and impair the weaning process. Checking phosphate levels in a patient receiving TPN who appears weak in the perioperative period may be prudent. Administration of phosphate in hypophosphatemia may result in profound changes in muscle strength. ## Footnote **In addition, a reduction of 2,3-diphosphoglyceric acid (DPG) level may occur with the hypophosphatemia, therefore a leftward shift of the oxygen-hemoglobin dissociation curve may occur.**

Answer 257

**24 hours**

Answer 258

**Troponin levels above 1 ng/ml** are considered abnormal following cardiopulmonary bypass.

Answer 259

Phenytoin is an anticonvulsant that also has properties as a **class Ib antiarrhythmic** The mechanism, like lidocaine, is to *_prolong phase 0 (ventricular depolarization) of the cardiac action potential by binding to voltage-gated sodium channels (INa)_* to terminate ventricular arrhythmias.

Answer 260

120 - 160 bpm

Answer 261

Normal FHR can vary from beat to beat, and is referred to as "short-term variability" or "beat to beat variability." The variation from one beat to another ***_can range from 5-25 BPM._*** ***_Pathologic = FHR becomes non-reassuring if the variability is \< 5 or \> 25_*** Variability in the FHR is a ***_sign of a healthy autonomic nervous system, chemoreceptors, baroreceptors, and cardiac responsiveness._***

Answer 262

***_tHINGS_*** Heparin Insulin Non-depolarizing Muscle Relaxants Glycopyrrolate Succinylcholine

Answer 263

Overall maternal mortality has increased over the last several decades in the United States, with the most common cause attributable to **maternal cardiovascular conditions**

Answer 264

**Hemorrhage** is the leading cause of maternal death worldwide, but only responsible for 11% of pregnancy-related deaths in the United States in 2011-2016

Answer 265

**General** Prophylactic cervical cerclage is usually performed under neuraxial anesthesia. When cervical dilation and bulging membranes are present, **general anesthesia may be preferable if acceptable to the patient.** In the absence of studies showing fetal outcomes, no technique is contraindicated, however, **general anesthesia has the *_advantage of causing uterine relaxation which facilitates replacement of membranes._***

Answer 266

Sensory blockade must range from ***_T10-S4_*** because both the *_cervix (T10-L1)*_ and vagina and _*perineum (S2-S4)_* require anesthesia.

Answer 267

It will treat hyperkalemia, however, it requires several doses over hours at a time and has a **potentially fatal side effect: intestinal necrosis.** Resins may be used as an alternative to repeated insulin and glucose therapy in patients with severe hyperglycemia and no ability to perform dialysis.

Answer 268

**Volatile anesthetics** decrease CMRO2 but also cause an **“uncoupling” between CMRO2 and CBF in a dose-dependent fashion**. This means that although CMRO2 is decreased, CBF increases.

Answer 269

Volatile anesthetics decrease CMRO2 but also cause an “uncoupling” between CMRO2 and CBF in a dose-dependent fashion. This means that although CMRO2 is decreased, CBF increases. ***_Uncoupling occurs with sevoflurane and isoflurane at doses ≥1 MAC._***

Answer 270

Propofol ***_decreases both cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow (CBF)._***

Answer 271

**The P50 of maternal hemoglobin during pregnancy increases from 26.8 mm Hg in the prepregnant state, to 30 mm Hg**. This results in a rightward shift of the maternal oxyhemoglobin dissociation curve. The fetal oxyhemoglobin dissociation curve sits to the left of the normal adult and maternal dissociation curves. The **P50 of fetal hemoglobin is 19-21 mm Hg**. The increase in this gradient between P50 values of the mother and fetus *_facilitates oxygen unloading from maternal hemoglobin to fetal hemoglobin._*

Answer 272

TCA SNRI Gabapentinoids (Gabapentin and Pregabalin)

Answer 273

Fibrinogen increase Factor VII increase

Answer 274

Bottom Line: Jugular bulb venous oxygen saturation monitoring (SjVO2) assesses the degree of cerebral oxygen extraction by measuring the mixed venous oxygen saturation in the jugular venous bulb. This value represents the balance between global cerebral oxygen supply and demand. ***_It is limited to the detection of global ischemia and does not detect focal insults such as localized ischemia and neuronal death._***

Answer 275

Answer C: Severe anemia results in a global decrease in oxygenation to cerebral tissues, thereby decreasing cerebral oxygen supply and **decreasing SjVO2.**

Answer 276

Sepsis impairs global cerebral oxygen extraction, thereby **increasing SjVO2.**

Answer 277

Using a smaller injectate amount than has been preset into the cardiac output computer yields a higher cardiac output. Simply, since there is less fluid, there will be less temperature change, causing a **falsely high cardiac output reading.**

Answer 278

Conversely, using a larger injectate volume than preset into the cardiac output computer **will result in greater temperature change and therefore a falsely low cardiac output measurement.**

Answer 279

Pulmonic and **tricuspid regurgitation** will both make cardiac output measurements unreliable. Tricuspid regurgitation usually, but not always, **causes lower cardiac output measurements.**

Answer 280

This depot can take upwards of **12 to 24 hours** to equilibrate out thus alternative forms of pain medication need to be provided during this time period.

Answer 281

Elimination after discontinuation of the transdermal patch is slow with an elimination half-life of **approximately 17 hours.**

Answer 282

Patients taking between ***_45-135 mg_* of morphine would start with 25 mcg/hr fentanyl patch** Between ***_135-224 mg_* of morphine would be started on 50 mcg/hr patch**, and increasing from there.

Answer 283

There are 2 types of trigger points: active and latent. **1. *_Active_* trigger points** produce spontaneous pain and are painful on palpation. **2. *_Latent_* trigger points** produce pain only when palpated. Trigger points may result from prolonged use of muscle, overload or overuse injury, and/or trauma.

Answer 284

Electromyographic demonstration of ***_spontaneous electrical activity in the region of the tender nodule_*** helps point to trigger point disease.

Answer 285

A **decrease in amplitude** or **increase in latency** on somatosensory evoked potential recordings may indicate sensory acortex ischemia.

Answer 286

Cricoid pressure decreases lower esophageal sphincter tone

Answer 287

Tumescent anesthesia involves injecting large amounts of tumescent solution composed of saline mixed with *_lidocaine (0.05%) and epinephrine (1:1,000,000)_* subcutaneously ## Footnote **Max dose = 55 mg/kg**

Answer 288

Dilute epinephrine in local anesthetic solutions for epidural labor analgesia **enhanced analgesia due to α-2 receptor stimulation and decreased local anesthetic requirements**. It **prolongs the effect of lidocaine**, but minimally affects the duration of bupivacaine. Disadvantages include increased intensity of motor blockade, theoretical reduction in uterine activity via uterine β-2 receptor stimulation, and decreased uterine and spinal cord blood flow via α-1 agonism.

Answer 289

infants fed breast milk had **significantly higher gastric residual volumes** (average of 0.7 mL/kg) than those fed clear liquids (average of 0.3 mL/kg).

Answer 290

1) **Interference with von Willebrand factor (vWF) formation and release** leading to impaired platelet activation at the site of vascular injury. Normally, platelets are activated and subsequently aggregate by binding to subendothelial vWF. 2) **Function of glycoprotein IIb-IIIa (GPIIb-IIIa) is abnormal** in uremia. This protein found on the surface of platelets is a receptor for fibrinogen, fibronectin, and vWF, and assists in platelet activation and aggregation. 3) **Prostacyclin and nitric oxide synthesis are each increased in uremia.** These two compounds have platelet inhibitory effects. 4) **Decreased tissue factor (factor III) activity.** This enzyme complexes with factor VIIa to activate factor X to factor Xa which converts prothrombin to thrombin.

Answer 291

Rebleeding most commonly occurs within **24-48 hour**

Answer 292

Vasospasm generally occurs by **72 hours after bleed** Peaks at **4-7 days** Generally **wanes by day 14.**

Answer 293

Electrocardiogram (ECG) changes observed during subarachnoid hemorrhage (SAH) have been attributed to **high levels of circulating catecholamines** causing subendocardial ischemia. *_Hypertension and acute left ventricular strain or direct toxic effects of the increased levels of circulating catecholamines_* are thought to be the cause of the subendocardial damage.

Answer 294

Placenta accreta occurs when the placenta implants with an ***_absent decidua_*** ## Footnote Decidua Basalis = The part of the endometrium in the pregnant human female that participates with the chorion in the formation of the placenta.

Answer 295

Cardiotoxicity related to doxorubicin is related to peak serum levels. ***_A cumulative dose of greater that 550 mg/m^2_*** is associated with a 10% incidence of cardiomyopathy. The rate of cardiomyopathy ***_increases significantly for doses greater than 550 mg/m^2_***

Answer 296

Trastuzumab

Answer 297

Approximately **3-5 mL/kg** bolus of air

Answer 298

**10-15 mL/kg bolus** of CO2 are sufficient to result in a fatal air lock situation.

Answer 299

**Auditory-evoked potentials** are the most resistant to the effects of volatile anesthetics.

Answer 300

In general, **visual-evoked potentials (VEPs),** which are rarely used in clinical practice, are the most sensitive to the effects of volatile anesthetics, **closely followed by motor evoked potentials.**

Answer 301

Motor evoked potentials evaluate the functional integrity of **descending motor pathways**

Answer 302

Acute overdoses cause harm by interfering with the Kreb cycle and causing **uncoupling of oxidative phosphorylation.** This leads to a build up of organic acids such as *_lactate and ketoacids, causing an anion gap metabolic acidosis._* Salicylate also **acts directly on the respiratory center in the medulla to increase the respiratory drive leading to a respiratory alkalosis.** For this reason, patients suffering from an overdose generally have a normal to low pH

Answer 303

* **_Bicarbonate administration_*** 1. Raises systemic pH *_decreases tissue distribution of salicylate_* 2. Raises urine pH *_increases the rate of renal clearance_*

Answer 304

1. Atropine 2. pralidoxime (2-PAM chloride)

Answer 305

Onset of action: 1-2 minutes; 80% response within 3 minutes

Answer 306

Duration: Resedation occurs after **~1 hour (range: 19-50 minutes)**; duration related to dose given and benzodiazepine plasma concentrations; reversal effects of flumazenil may wear off before effects of benzodiazepine

Answer 307

Benzodiazepine reversal when used in conscious sedation or general anesthesia: IV: **Initial dose: 0.2 mg over 15 seconds** **Repeat doses (*_maximum: 4 doses_***): If the desired level of consciousness is not obtained, 0.2 mg may be repeated at 1-minute intervals. **Maximum total cumulative dose: 1 mg** (usual total dose: 0.6 to 1 mg)

Answer 308

The use of flumazenil has been associated with the **occurrence of seizures.** Also, **RESEDATION happens in 50% of patients** These are most frequent in patients who have been *_on benzodiazepines for long-term sedation or in overdose cases where patients are showing signs of serious cyclic antidepressant overdose_*. Practitioners should individualize the dosage of flumazenil and be prepared to manage seizures.

Answer 309

**Unpredictable and rapid progression of AV conduction disease.** Pacemaker placement may be considered even if only first degree heart block is present *_To do:_* *_1. EKG preop_* *_2. Defibrillator Pads on during induction_* *_3. 33% do not respond to Atropine_*

Answer 310

**Succinylcholine** use may result in contractions that last several minutes, making ventilation and intubation challenging. These contractions are not antagonized by prophylactic administration of a nondepolarizing muscle relaxant, thus **succinylcholine should be avoided and short acting nondepolarizing agents**, or no muscle relaxants at all, should be used.

Answer 311

The most common reason for not obtaining capture with transcutaneous pacing is **not adequately increasing the current.**

Answer 312

Transcutaneous pacing is generally a nonsynchronous mode that does not inhibit with the patient's intrinsic rhythm. This would be equivalent to a **VOO mode for an implanted device.**

Answer 313

Typical capture thresholds are between **20 to 120 mA however pacing may require up to 200 mA**. Most resources suggest *_starting at 10 mA and increasing the settings by 10 mA until capture_*. Once capture has occurred, the device **should be set 5 to 10 mA above that threshold (some say 25% more)**.

Answer 314

The rate should be set **10 to 20 beats per minute higher than the spontaneous heart rate to capture 100% of the beats and avoid R-on-T phenomenon.**

Answer 315

**Cerebrovascular accident (CVA)** is the most common cause of maternal death in parturients with preeclampsia. **Hemorrhagic stroke** accounts for 93% of CVAs in this setting.

Answer 316

It is defined classically as the new-onset of hypertension with proteinuria *_(0.3 g in 24 hours_*) after 20 weeks gestation up to 4-6 weeks post-partum. It should be noted that **proteinuria is not required if severe features exist.**

Answer 317

**Cardiac disease is the leading cause of maternal death in the United States**, but it is not the leading cause of death in preeclamptic parturients.

Answer 318

**Postpartum hemorrhage** is the leading cause of maternal death worldwide

Answer 319

To help prevent this and other complications, current recommendations include treating systolic blood pressures ≥160 mm Hg but **decreasing arterial blood pressure by no more than 15-25%**

Answer 320

The risk for prolonged QT intervals is greatest in patients taking **greater than 120 mg daily**, however, lower doses and acute use can still prolong the QT interval. Because methadone is metabolized by cytochrome p450, drugs inhibiting this enzyme may lead to increased methadone toxicity and further QT prolongation.

Answer 321

**Perfusion without ventilation** (Intrapulmonary Shunt) A shift of the diaphragm upward will result in a cephalad shift of the tracheobronchial tree. This shift may cause an endotracheal tube to migrate further down the trachea and into the right main stem bronchus. Even without endobronchial intubation, mean and peak airway pressures rise significantly due to the increased pressure of the abdominal contents and the reduction in compliance.

Answer 322

Methylergometrine is an ergot alkaloid that is typically given intramuscularly. It has an **effect within 10 minutes and lasts 3-6 hours**

Answer 323

Carboprost (Hemabate) typically given intramuscularly and can be **repeated at 15-90 minute intervals** for a **maximum of 8 doses.**

Answer 324

1) External ocular injury (corneal abrasion or sclera injury) 2) Cortical blindness 3) Retinal ischemia 4) Ischemic optic neuritis 5) Acute glaucoma

Answer 325

the most common cause of perioperative retinal arterial occlusion is **improper patient positioning resulting in external compression of the eye.** *_Bottom Line_*: External eye compression from patient positioning can lead to postoperative vision loss due to central retinal artery occlusion.

Answer 326

Obese patients have **higher levels of fibrinogen, factor VII, factor VIII, von Willebrand factor, and plasminogen activator inhibitor-1.**

Answer 327

**Radiation exposure = inversely proportional to the square of the distance (1/radius^ 2).** By doubling the radius from the source of radiation, the resultant incident radiation is 1/4th. Eight mrem per second divided by 4 is 2 mrem per second at the new distance.

Answer 328

Cyanide toxicity occurs at blood levels \>100 mg/dl which can be achieved when **\>1 mg/kg of SNP is administered in less than 2 hours or if \>0.5 mg/kg/hr is administered in 24 hours.** **(Usual doses are** 0.3 to 0.5 mcg/kg/minute; may be titrated by 0.5 mcg/kg/minute every few minutes to achieve desired hemodynamic effect (Rhoney 2009); maximum dose: 10 mcg/kg/minute (for a maximum of 10 minutes). *_To avoid toxicity, some recommend a maximum dose of 2 mcg/kg/minute_* (Marik 2007).

Answer 329

Amyl nitrate works as an antidote for **cyanide poisoning** by converting Hb to MetHb which avidly binds cyanide, converting it to the nontoxic cyanomethemoglobin. *_You basically cause methemoglobinemia to get the CN cleared_*

Answer 330

1. Potassium-rich meals 2. Exogenous potassium administration 3. Stress 4. Rest after exercise 5. Metabolic acidosis 6. Depolarizing muscle relaxants

Answer 331

Autosomal Dominant

Answer 332

**voltage-gated sodium channel NaV1.4 in skeletal muscle that interfere with channel inactivation**. Accordingly, these mutations result in increased sodium channel currents leading to prolonged muscle fiber depolarization and subsequent myotonia, membrane desensitization, and paralysis. Since sodium channel inactivation does not occur properly with HKPP, muscle cells are more dependent on potassium efflux for repolarization and cessation of an action potential.

Answer 333

The stellate ganglion is located at the fusion of the inferior cervical and first thoracic ganglions at the **level of the C7 transverse process.**

Answer 334

Hyperphosphatemia

Answer 335

Hypermagnesemia

Answer 336

Remifentanil is also more potent in the elderly patient owing to an **increased brain sensitivity** and therefore bolus doses should be halved. Because the **central volume of distribution and central clearance is decreased**, infusion rates of remifentanil should be decreased by one-third.

Answer 337

***_Allodynia_*** is the **perception of a non-noxious stimulus, such as clothing touching the skin, as an uncomfortable or painful sensation.** It is characteristic of neuropathic pain. ***_Hyperalgesia_*** is described as an increased pain response to noxious stimulation or pain out of proportion to physical findings. *_- Primary_* hyperalgesia occurs in the area of damaged tissue, while - *_secondary_* hyperalgesia occurs in surrounding non-damaged tissue. Opioid-induced hyperalgesia may occur in patients on chronic opioid treatment.

Answer 338

Anesthesia dolorosa is **pain in an area that lacks sensation, often involving the face**. It is a feared complication of neurolytic blocks for the treatment of trigeminal neuralgia (e.g. radiofrequency rhizotomy). Anesthesia dolorosa is an *_uncommon deafferentation pain that can occur after traumatic or surgical injury to the trigeminal nerve_*. This creates spontaneous pain signals without nociceptive stimuli.

Answer 339

The evoked potentials in order from least to most sensitive to anesthetic technique are: ***_BAEP \< SSEP \< MEP \< VEP_*** (SSEP = somatosensory evoked potential, MEP = motor evoked potential) Another way to remember: BAEP are Barely affected, SSEP are Somewhat affected, MEP are Mostly affected, and VEP are Very affected.

Answer 340

* *Variable** - Cord compression * *Early** - Head compression * *Late** - Placental insufficiency

Answer 341

Normal FHR ranges from **120-160 beats per minute (BMP).** **Normal variation from one beat to another can range from 5-25 BPM**. FHR becomes non-reassuring if the variability is ***_\< 5 or \> 25._***

Answer 342

Sinusoidal FHR pattern: a smooth sine wave (no variability present). It is rare, however, is associated with **high rates of fetal morbidity and mortality.** ## Footnote **This pattern is indicative of *_severe fetal anemia._***

Answer 343

Drugs that don't cross the placenta are tHINGS which don’t cross = **Heparin**, **Insulin**, **Nondepolarizing muscle relaxants**, **Glycopyrrolate**, and **Succinylcholine**. Additionally **phenylephrine** does not cross the placental barrier.

Answer 344

When cervical dilation and bulging membranes are present, general anesthesia may be preferable if acceptable to the patient. In the absence of studies showing fetal outcomes, *_n_**_o technique is contraindicated_*, however, **general anesthesia has the advantage of causing uterine relaxation which facilitates replacement of membranes.** *_Neuraxial anesthesia does not provide uterine smooth muscle relaxation_*, but it an excellent choice for placement of a prophylactic cerclage (without bulging membranes).

Answer 345

Hydromorphone has a ***_biological half-life of 2-3 hours_*** Duration = IV: 3 to 4 hours

Answer 346

Risk factors for uterine atony include: ## Footnote **Multiparity** **Multiple gestations** **Polyhydramnios** **Chorioamnionitis** **Prolonged labor** **Oxytocin-induced labor,** **Mechanical factors**

Answer 347

**Anytime** 1. Onset of labor 2. During cesarean delivery 3. Within 30 minutes postpartum

Answer 348

Surgery during the **second trimester carries the lowest balanced risk** of premature labor (highest in the third trimester) and abnormal fetal organogenesis (highest in the first trimester).

Answer 349

Use of FHR monitoring is first feasible at **18-20 weeks gestation**

Answer 350

**Maintain mild hypocarbia (EtCO2 of 32-36 mm Hg)** to prevent fetal acidosis due to an increased PaCO2 to ETCO2 gradient during insufflation.

Answer 351

During first two trimesters, ketamine (\> 2 mg/kg) may cause uterine hypertonus.

Answer 352

Esmolol should be avoided as it can cause fetal bradycardia.

Answer 353

In this case, normal pH can vary from 7.40 to 7.47 PaCO2 is closer to 30 rather than to 35 to 40. Serum bicarbonate decreases to compensate.

Answer 354

Pregnant patients are considered anemic when their hemoglobin ***_falls below 11 g/dL_***. Increased plasma volume also affects platelet count in a similar manner.

Answer 355

- Stage I is the onset of true labor (regular contractions) until the cervix is completely dilated. - Stage II occurs once fully dilated until the baby is delivered. - Stage III starts after delivery of the baby and ends with delivery of the placenta.

Answer 356

- Stage I is the onset of true labor (regular contractions) until the cervix is completely dilated. **See Photo** The latent phase of labor occurs with regular painful contractions without much cervical dilation. This is the period of time where the cervix may efface. There is no set point that defines when the latent phase transitions to the active phase. This typically occurs, however, when the rate of cervical dilation increases. The latent phase for primigravida parturients may last 20 hours, while multiparous women should labor less than 14 hours before transitioning to the active phase. Once active phase cervical dilation begins, nulliparous women typically dilate by 1.2 cm per hour and multiparous women usually dilate by least 1.5 cm per hour.

Answer 357

**Immediately**

Answer 358

Immediately

Answer 359

If she was receiving 7,500 or 10,000 units twice daily subcutaneous (referred to as "high dose prophylaxis") the **necessary wait would be 12 hours.** If she was receiving more than 10,000 units subcutaneous per dose or more than 20,000 U subcutaneous per day (referred to as "therapeutic") the necessary wait **would be 24 hours.**

Answer 360

A major risk factor for placenta accreta is the number of prior cesarean deliveries 0 = 3% incidence 1 = 11% 2 = 40% 3 = 61% 4+ = 67%

Answer 361

Additional sensory level blockade is required in order to ensure adequate anesthesia for a cesarean section due to manipulation of and **traction on the mesentery, peritoneum, and many other abdominal and pelvic organs.**

Answer 362

The pO2 and pCO2 of umbilical blood can be remembered at **20-30-40-50**, recalling that umbilical venous blood is oxygenated. Umbilical arterial blood therefore is deoxygenated and has more CO2.

Answer 363

The arterial partial pressure of oxygen (PaO2) is ***_increased_*** in *_pregnancy (103-107 mm Hg)_* compared to normal nonpregnant levels (100 mm Hg). This increase is most pronounced in the first trimester of pregnancy and gradually decreases thereafter, however still remains elevated compared to normal prepregnancy values in the third trimester.

Answer 364

a woman’s minute ventilation **increases** over the course of pregnancy to approximately **145%** of normal nonpregnant minute ventilation (**primarily due to increased tidal volume from 450 to 600** with a *_small contribution from increased respiratory rate by 1-2 breaths/min_*

Answer 365

**Serum bicarbonate (HCO3-) decreases** to approximately 20-21 mEq/L and the serum base excess falls by 2-3 mEq/L Why? *_Compensatory metabolic acidosis (Drop in HCO3) due to respiratory alkalosis (Increase in MV)_*

Answer 366

Carboprost tromethamine is an **analogue of prostaglandin-F2α that promotes uterine contractions.**

Answer 367

***_1st_*** - AFE in the maternal circulation triggers a release of inflammatory mediators. There is an enormous release of endothelin that causes ***_severe coronary constriction, bronchoconstriction, and pulmonary vasoconstriction_***. This results in pulmonary hypertension and right ventricular dysfunction, causing hypoxemia and hypotension. **There is also systemic vasodilation from the inflammatory response**. This phase can last up to 30 minutes. ***_2nd_*** - LV begins to fail due to impaired filling from a dysfunctional right ventricle and a deviated intraventricular septum. LV failure results in more hypotension and elevated pulmonary pressures leading to pulmonary edema. The biochemical mediators also trigger a **massive consumptive coagulopathy resulting in massive hemorrhage**

Answer 368

Simply, the greater the difference between blood pH and pKa (i.e. the more acidotic the blood pH), the greater the proportion of local anesthetic that exists in its ionized form. Accordingly, a maternal serum pH that is close to neutral (7.4) would allow for a large proportion of nonionized drug, which can readily cross the placental membrane. **However, if the fetus is acidotic (pH \< 7.4), a larger proportion of local anesthetic becomes ionized, which prevents transfer back across the placenta.** This is the “ion trapping” process by which fetal local anesthetic accumulation occurs.

Answer 369

Justification for this method centers around the idea that there is **1) less alveolar collapse due to gravity** **2) more even distribution of perfusion** in the prone position as compared to the supine position

Answer 370

VACTERL includes: ## Footnote **Vertebral** **Anal** **Cardiac** **Tracheoesophageal** **Renal** **Limb abnormalities**

Answer 371

Epinephrine and norepinephrine should be reserved for refractory bradycardia because **beta effects will be exaggerated as a result of the lack of the baroreceptor reflex.** The baroreceptor reflex response to high blood pressure normally causes a negative feedback loop which causes slowing of the heart rate. This effect is carried via the efferent vagus nerve. Since this reflex is severed, the β1 agonism may lead to unopposed tachycardia in cardiac transplant patients.

Answer 372

Vagal efferent reinnervation of the donor heart may not occur **for up to 24 months** after transplant.

Answer 373

Isoproterenol, epinephrine, norepinephrine, dobutamine, and glucagon.

Answer 374

The response to anticholinesterases is unpredictable and may **lead to profound bradycardia.**

Answer 375

1 - Systemic hypotension from **mast cell degranulation and histamine release** caused by rapid administration. It is the polycationic structure of protamine that triggers this reaction. Protamine (highly positively charged) binds to heparin (highly negatively charged) leading to acid-base complex formation and heparin inactivation (See attached)

Answer 376

Anaphylaxis from _***IgE*-mediated dose-independent reaction.**_ Previous exposure to protamine or a similar protein (such as neutral protamine Hagedorn found in *_NPH insulin_*) is required for anaphylaxis to occur.

Answer 377

Pulmonary hypertensive crisis causing pulmonary hypertension, vasoconstriction, and possible right heart failure. The mechanism for this reaction is **thromboxane A2 released from platelets and macrophages** stimulated by *_protamine-heparin complexes_*

Answer 378

The most reliable assessment of dehydration is often **weight (Weight Loss)** because other clinical signs can be influenced by factors other than hydration status.

Answer 379

Urine output in a healthy newborn and infant is **\>2 mL/kg/hr.** Moderate dehydration is associated with oliguria or a urine output **\<1 mL/kg/hr.** Urine output of **\<0.5 mL/kg/hr** is considered anuria in an infant and is associated with severe dehydration.

Answer 380

**Uterine** arteries supply about **85%** of blood flow **Ovarian** arteries supply up to **15%**

Answer 381

PAO2 - PaO2

Answer 382

PAO2 = FiO2 (Patm - PH2O) - (1.25 \* PaCO2) Note: At standard Patm (760 mm Hg) and if humidity is assumed to be 100% in the alveoli, PH2O = 47 mm Hg. PaCO2 is also assumed to be equal to PACO2, so the latter can be used instead. This is a simplified formula derived from the alveolar gas equation. **PAO2 = FiO2 (713 mmHg) - (1.25 \* PaCO2)**

Answer 383

Hypoventilation leads to CO2 accumulation and an increased PaCO2, which **reduces the space available for oxygen in the alveoli.**

Answer 384

Unlike other causes of hypoxemia, administration of oxygen to a patient with a **true shunt does not significantly increase PaO2.**

Answer 385

V/Q Mismatch

Answer 386

1. Hypoventilation 2. Ventilation/perfusion mismatch 3. Right-to-left shunt 4. Diffusion impairment 5. Low PO2

Answer 387

The classic clinical finding suggestive of impaired diffusion is a **normal PaO2 at rest but a decreased PaO2 with increased cardiac output.**

Answer 388

Horner syndrome (ptosis, miosis, anhidrosis)

Answer 389

Arousal = **Parasympathetic** Ejaculation = **Sympathetic** (Can't do this because of the sympathectomy)

Answer 390

**Diarrhea** is associated with a celiac plexus block (T5-12), which supplies innervation to all the intraabdominal organs, including most of the bowel *_diarrhea is secondary to blockade of sympathetic fibers_* In general, sympathetic stimulation causes *_inhibition of gastrointestinal secretion and motor activity_*, therefore this is lost

Answer 391

**Diagnosis is predominantly clinical** and while ultrasonography is not very sensitive (24%), it can aid in confirming diagnosis due to high specificity (96%). ## Footnote *_Cannot rule out diagnosis but can rule it in_*

Answer 392

***_Nitroglycerin_*** is the first-line therapy for immediate uterine relaxation in the setting of uterine inversion.

Answer 393

Uterine inversion is a surgical emergency and must be manually reversed before the cervical ring closes upon the uterine fundus. Nitroglycerin increases cellular nitric oxide and cGMP levels making it a potent smooth muscle relaxant. Intravenous administration (low dose) provides the most rapid and profound uterine relaxation, but sublingual administration is also effective. ***_Inhalational anesthesia (2-3 MAC) with volatile anesthetics can also be used for uterine relaxation._***

Answer 394

**Amiodarone is pregnancy *_class D_* (known fetal risk; potential benefits may outweigh risks**). It has been associated with fetal intrauterine growth retardation, preterm delivery, hypothyroidism, and neonatal bradycardia. It should only be used to treat asymptomatic SVT if other drugs have failed. Keep in mind it is the preferred drug for *_management of maternal life-threatening ventricular arrhythmias_*

Answer 395

1. Magnesium ***_competes with calcium inside vascular smooth muscle cells_*.** This prevents some actin-myosin crosslinking and can decrease the force of vascular smooth muscle contraction. 2. Acts inside endothelial cells to ***_increase nitric oxide and prostaglandin I2_***, both of which have vasodilator properties.

Answer 396

**AV conduction slow** at \>7 **AV Heart block** \>10

Answer 397

Chest compressions and ventilation should be coordinated and given in a 3:1 ratio, with **90 compressions and 30 breaths/min.**

Answer 398

Magnesium is used as both an antiseizure medication to prevent eclampsia and as an antihypertensive and vasodilating medication. ***_It reduces irritability of the central nervous system and raises the seizure threshold_*** primarily through action at central NMDA receptors.

Answer 399

***_Low FRC = Fast Inhalational Induction_*** A pregnant patient at term has a 20% reduction in FRC, thereby **increasing the speed of an inhalational induction.** *_FRC essentially dilutes the volatile anesthetic, slowing the rise in FA/FI, and slows the rate of induction of volatile agents._* The rate of inhalational induction is inversely related to functional residual capacity (FRC). FRC is the volume of air in lungs at the end of passive exhalation. When describing an inhalational induction, FRC can be thought of as the lung volume diluting volatile anesthetics.

Answer 400

The FA/FI is **faster** when using agents with a **low blood gas coefficient** ## Footnote **Ex: Nitrous and Desflurane are lowest**

Answer 401

The rate of inhalational induction is directly proportional to minute ventilation and pregnant patients have an **increased minute ventilation, which increases the FA/FI** and speeds inhalational induction.

Answer 402

Pregnant patients can have up to a ***_40% reduction in minimum alveolar concentration (MAC)_*** when compared to non-pregnant patients. The *_decrease in MAC is likely related to progesterone levels._*

Answer 403

**Gastric emptying of both solids and liquids is not slowed during pregnancy**, but is *_slowed during labor._*

Answer 404

Sodium citrate will increase gastric pH but has no effect on gastric emptying.

Answer 405

**Esophageal peristalsis and intestinal transit** are slowed during pregnancy due to increased progesterone and decreased motilin concentrations.

Answer 406

Care should be taken when administering Methylergometrine to patients with **preeclampsia, hypertension, or CAD**

Answer 407

The PaO2 for maternal hemoglobin at which 50% of the hemoglobin molecules are bound by oxygen (P50 value) is **approximately 30 mm Hg**, whereas the normal P50 for adult hemoglobin is 27 mm Hg. This **rightward shift facilitates oxygen** unloading to the fetus.

Answer 408

The P50 for fetal hemoglobin is approximately **19-21 mm Hg.** This facilitates uptake of oxygen from maternal hemoglobin.

Answer 409

**All volatile halogenated agents cause dose-related relaxation of the uterus** which may lead to increased blood loss during cesarean section. From induction to delivery of the infant 1.0 MAC is given to avoid maternal awareness. After delivery, volatile anesthetics are decreased to 0.5 – 0.75 MAC and oxytocin is given concurrently to decrease the uterine relaxation and thus blood loss. ***_Less than 0.75 MAC interfere with oxytocin’s effects and at elevated doses lead to uterine atony_***. **Nitrous oxide**, opioids, and ketamine at less than 2 mg/kg have minimal if any effect.

Answer 410

The primary risk factor for meconium passage is **later gestational age.**

Answer 411

Higher incidence and severity of pruritis

Answer 412

Beta Agonist to mom = Raise BGL = Spike maternal insulin *_Insulin doesn't cross_* Fetal pancreas begins to secrete additional insulin (Hyperinsulinemia) and hypoglycemia can happen to baby

Answer 413

The **Bezold-Jarisch reflex** occurs when stretch and chemo-receptors in the heart are stimulated. This results in **bradycardia** and **hypotension**. This reflex has been implicated as one of the causes for bradycardia, hypotension, and the cardiovascular collapse seen with spinal anesthesia.

Answer 414

The most common cause of placental insufficiency resulting in late decelerations on fetal heart tracing is **uterine contractions (Mom getting ready to deliver)** Other common maternal causes include *_hypotension, maternal cardiac output, and hypoxemia._*

Answer 415

aspiration prophylaxis if **\>18 weeks gestation**, left uterine displacement **after 18-20 weeks gestation**, and fetal heart rate monitoring dependent on gestational age (Viable)

Answer 416

***_The major risk factors are:_*** 1. Volume \> 0.4 mL/kg 2. Gastric pH less than 2.5 3. Particulates in the aspirate

Answer 417

Loss of fetal heart rate (FHR) variability is an early sign of ***_fetal hypoxia._***

Answer 418

magnesium potentiates the action of both depolarizing and non-depolarizing muscle relaxants. A standard intubating dose of succinylcholine should be used. However, a ***_lower dose of a nondepolarizing muscle relaxant_*** should be administered during the maintenance of anesthesia

Answer 419

Due to structural similarities between oxytocin and vasopressin, high-dose vasopressin administration can cause ***_uterine contractions_***

Answer 420

Arrythmias (Bigeminy) and ST changes

Answer 421

PEEP application **raises** intrathoracic pressure, **raises right ventricular afterload**, **decreases preload** and can cause hypotension in the normovolemic or hypovolemic patient without heart failure. In patients with systolic heart failure, preload is excessive, thus PEEP preload effects are minimized but afterload is decreased with resultant improvement in cardiac output and a **decrease in LVEDP.**

Answer 422

**Raise** Pulmonary arterial pressures

Answer 423

Serum osmolality (normal **280-290 mOsm/kg**) Can be quickly calculated with values from a basic metabolic profile (**2 \* Na+ + Glucose/18 + BUN/2.8**)

Answer 424

Diagnostic features of hyperglycemic hyperosmolar syndrome also include: ## Footnote **pH \>7.3** **bicarbonate \>18 mEq/L** **Serum osmolality \>320 mOsm/L.**

Answer 425

Blood PCO2 is measured by a **Severinghaus** electrode using a method that builds upon the pH electrode mechanism. Carbon dioxide from the blood sample equilibrates across a semipermeable membrane with a bicarbonate solution. The reaction generates H+ ions and the PCO2 is determined by the degree of pH change resulting from the H+ ion generation.

Answer 426

Blood PO2 is most commonly directly measured by a **Clark** electrode which detects the amount of current that flows between the two electrodes (amperometric). Oxygen from the blood sample diffuses across a semipermeable membrane and is reduced at the cathode, resulting in a reaction that produces a measurable current that is directly proportional to the PO2.

Answer 427

End-tidal CO2 (ETCO2) is measured by **infrared spectrophotometry** where a wavelength of infrared light is passed through a gas sample and the amount of energy detected is inversely proportional to the gas partial pressure. The basic idea is that infrared light is passed through a gas sample taken from the anesthesia circuit and the amount absorbed by the gas at specific wavelengths (which helps determine the identity of the gas) is proportional to the partial pressure of the gas. The intensity detected at the detector will, therefore, be less with a greater amount of infrared energy absorbed by the gas molecules. Infrared spectrophotometry only works with gases that are polar, have dissimilar atoms, and are asymmetric.\*

Answer 428

**Infrared Spectrophotometry** It operates on the principle that the amount of infrared light absorbed at a specific wavelength is proportional to the partial pressure of the gas analyzed because absorption will be greater with a greater amount of gas molecules.

Answer 429

Larger doses of neuromuscular blockers including succinylcholine (***_2-2.5 mg/kg_*** vs. 1-1.5 mg/kg) are commonly needed in children due to **larger extracellular fluid volumes by percentage of TBW** and therefore require larger weight-based dosing of muscle relaxants.

Answer 430

**Ipsilateral recurrent laryngeal nerve block**, not the superior laryngeal nerve, is common and leads to **hoarseness**.

Answer 431

Elimination half-life of ***_100 min_***

Answer 432

It is best suited for procedures ***_at or below a T10 dermatomal level_*** (e.g. lower abdominal, urologic, and lower extremity procedures).

Answer 433

Accidental intrathecal injection of local anesthetic during a caudal epidural injection is generally rare since the dural sac in newborns and infants ends at **S2-S3 (and regresses to S1-S2 by adulthood)** whereas the *_site of injection is usually S4-S5._*

Answer 434

Since ***_hypercarbia itself causes pulmonary vasoconstriction_***, the presence of hypercarbia in the setting of hypoxia enhances the effects of hypoxia pulmonary vasoconstriction (HPV) By contrast, ***_hypocarbia can inhibit HPV._***

Answer 435

Hypoxic pulmonary vasoconstriction occurs as a result of exposure of the pulmonary arteries to hypoxic lung segments and low alveolar oxygen tension. The degree of vasoconstriction is inversely dependent on size or extent of hypoxic lung segments: the smaller the hypoxic segment, the greater the degree of vasoconstriction in that region to ensure blood is distributed to better ventilated alveoli. **This promotes shunting of pulmonary blood flow** to lung segments with better oxygenation and ventilation in order to **decrease the shunt fraction.**

Answer 436

hypervolemia vasoconstrictors hypothermia Thromboembolism A large hypoxic lung segment

Answer 437

vasodilators (e.g., nitroglycerin, nicardipine, sodium nitroprusside, etc.)

Answer 438

When the burned area exceeds 10% of the total body surface area (TBSA), succinylcholine administration between ***_24 hours and 1 year_*** after the injury becomes contraindicated due to exaggerated hyperkalemia.

Answer 439

The **application of CPAP to the nonventilated lung is contraindicated**, and intermittent two-lung ventilation is either very challenging or not an option.

Answer 440

**Inducing hypotension** pharmacologically will reduce the shear force on the stent-graft and decrease the likelihood of migration. *_Systolic blood pressure between 70 and 80 mm Hg_* is used to avoid the windsock effect. **Transient asystole** during deployment of the stent-graft is also an option. Adenosine is used to provide a short period of asystole (this reduces shear force on the graft). The half-life of adenosine is about 10 seconds, because red blood cells and vascular endothelial cells rapidly inactivate it. **Rapid ventricular pacing (\> 180/min)** will cease left ventricular ejection. *_Transvenous pacing wires are placed and during deployment of the stent-graft the ventricular rate is increased to \> 180/mi_*n. After the graft is fully opened, the heart is returned to its normal rhythm.

Answer 441

Adenosine should be cautiously used in patients with asthma or upper respiratory disease because adenosine can cause **bronchoconstriction**.

Answer 442

Elective surgery should be delayed when possible **until former preterm infants are 44-weeks gestation.**

Answer 443

**Sucralfate** | (Doesn't change pH of gastric fluid)

Answer 444

Normal plasma levels of magnesium are **1.8-2.5 mg/dL.**

Answer 445

The plasma level that is aimed for during its use in obstetrics is generally **4.8-9.6 mg/dL.** ## Footnote **Think "5-10"**

Answer 446

If these patients need general anesthesia, one must be aware that they **may not have fasciculations** with succinylcholine

Answer 447

\>12 mg/dL

Answer 448

6 - 12 mg/dL

Answer 449

\>18 mg/dL

Answer 450

transversus abdominis plane (TAP) block is a regional technique that covers the: ## Footnote **Intercostal** **Subcostal (T12)** **Ilioinguinal (L1)** **Iliohypogastric (L1)**

Answer 451

**Used for Landmark based TAP block (See picture)** Inferior edge the iliac crest The posterior edge the latissimus dorsi Anterior edge the external oblique The tip of the triangle of Petit is the rib cage.

Answer 452

For anesthetic billing, one anesthesia time unit is defined by CMS as **15 minutes.**

Answer 453

**1st line** = β-blockers (Arrythmia prevention) **2nd line** = Cardiac pacemakers if refractory AICD for those at risk of SCD or QTc \>550 ms **3rd line** = Cervicothoracic ganglion blocks if V-Tach

Answer 454

Neostigmine is usually dosed at 20-70 mcg/kg. The onset of action is about 1 minute, and the **peak effect is at approximately 9 minutes**. Its duration of action is *_20-30 minutes_*

Answer 455

The afferent limb of the **oculocardiac reflex is via the trigeminal nerve (cranial nerve V), primarily via the ophthalmic division (V1).** The *_efferent limb is via the vagus nerve (cranial nerve X),_* which then synapses on the sinoatrial node of the heart.

Answer 456

Pralidoxime works by **binding to the organophosphate molecules and reactivating acetylcholinesterase.** By reactivating acetylcholinesterase, it is effective in treating both muscarinic and nicotinic symptoms. It generally only works if given within the first 48 hours of exposure.

Answer 457

*_Onset of action*_ is between _*5 and 15 minutes_* after administration **Duration** of action is **6 to 12 hours.**

Answer 458

Hydralazine, which is highly specific for arterial vessels, **reduces systemic vascular resistance and arterial pressure (Effectively cardiac output)**. Indirect cardiac stimulation (e.g., tachycardia) occurs with hydralazine administration because of a*_ctivation of the baroreceptor reflex._*

Answer 459

There are *_three major groups_* which have different sites of action 1. **Dihydropyridines** (nifedipine, nimodipine, nicardipine, amlodipine) 2. **Phenylalkylamines** (verapamil) 3. **Benzothiazepines** (diltiazem)

Answer 460

Non-selective

Answer 461

Onset of action within ***_10 minutes_*** Duration of action of ***_2 to 6 hours_***

Answer 462

90-105 mL/kg

Answer 463

65-70 mL/kg

Answer 464

70 - 80 ml/kg

Answer 465

60-65 mL/kg

Answer 466

80-90 mL/kg

Answer 467

70-75 ml/kg

Answer 468

MABL = Estimated Blood Volume \* [(*_Starting Hct - Guarded Hct_*) / Starting Hct]

Answer 469

Recurrent laryngeal nerve (CN Branch)

Answer 470

**The superior laryngeal nerve** (**CN X Branch**) can be blocked by either injection at the horn of the hyoid bone or by placing a pledget in the pyriform sinus

Answer 471

superior laryngeal nerve has 2 branches, an **internal and external.** The **internal** branch provides **sensation** above the trachea (laryngeal mucosa) while the *_external*_ branch provides muscular _*innervation to the cricothyroid muscle_* **A mnemonic to help remember this is "SIME",** for sensory = internal, motor = external.

Answer 472

The **cricothyroid** **muscle** is the only intrinsic muscle of the larynx not innervated by the recurrent laryngeal nerve.

Answer 473

Increased PTH Decreased Calcium

Answer 474

***_normal_*** PaO2 and a ***_falsely elevated_*** calculated SaO2 and SpO2

Answer 475

**Two-wave pulse oximetry is unable to properly determine SpO2 level and inappropriately reads 85-88%** in the setting of methemoglobinemia, regardless of the true SaO2.

Answer 476

1 = Trivial or no injury 2 = Traumatic Injury

Answer 477

Superclavicular Block

Answer 478

**Benzodiazepines** | (All opthalmic cases should get Versed)

Answer 479

Retrobulbar hemorrhage is characterized by closing of the upper eyelid, proptosis, and an **INCREASE in intraocular** pressure, which is often palpable. Further effects of this complication depend on the degree of hemorrhage Posterior globe puncture after retrobulbar block typically presents as immediate **ocular pain *_WITHOUT_*an increase in intraocular pressure**. Myopia (nearsightedness) is a risk factor for inadvertent globe puncture during a retrobulbar block.

Answer 480

1. The β-adrenergic antagonism from labetalol can cause **unpredictable, unopposed α-receptor agonism from circulating catecholamines.** 2. Labetalol may **also cause persistent bradycardia and hypotension following removal of the tumor**. Despite that labetalol has alpha-adrenergic blocking activity, it is not an agent of choice in these patients. Other beta-blockers, particularly those without alpha-adrenergic activity, would be worse choices.

Answer 481

The **blood:gas partition coefficients of inhalation anesthetics are higher** in adults than in infants which leads to a *_slower rise of the FA:FI ratio (see below) and therefore a slower induction._*

Answer 482

**Soluble agents** such as halothane (blood:gas coefficient 2.4 which is high) will lead to a slower induction because the agent will easily dissolve into blood from the alveoli and therefore lead to a slower rise in FA. (FA = [gas at the alveoli]) **Less soluble agents** such as desflurane (blood:gas partition coefficient 0.42) dissolve much less readily in blood which results in quicker equilibration of partial pressures in the alveoli and blood.

Answer 483

Infants and children have faster inhalation inductions primarily because they have **increased minute ventilation** relative to **functional residual capacity**. This creates a faster rise in FA:FI and therefore a quicker induction. FA is wicked high because you have a high concentration of gas at the alveoli

Answer 484

1. Increased minute ventilation relative to FRC (most important) 2. Increased blood flow to ***_vessel-rich organs_*** (infants have less muscle mass than adults) 3. Decreased blood:gas partition coefficients 4. Decreased tissue:blood partition coefficients

Answer 485

The absence of consciousness, motor activity, and movement in response to painful stimuli indicates cessation of ***_cerebral cortical function_***.

Answer 486

The absence of **pupillary, vagal, oculocephalic, oculovestibular, and respiratory reflexes** indicates cessation of brainstem function.

Answer 487

**Hypercarbia**

Answer 488

*_Other clinical tests for brain death include:_* 1. **Two isoelectric EEG** tracings 24-hours apart 2. The **absence of cereral blood flow** as evidenced by cerebral angiography, transcranial Doppler ultrasonography, or MRI/MRA.

Answer 489

The acidosis can occur with as little **as 3 liters of normal saline.**

Answer 490

The obturator nerve provides sensory innervation to the **medial thigh skin and posterior knee joint.** ## Footnote **Yellow in photo**

Answer 491

Furosemide is a loop diuretic that promotes sodium and water loss in the loop of Henle in the kidneys. This causes a decrease in overall circulatory volume which **moves the end-diastolic volume left on the Frank-Starling curve without changing its contractility.**

Answer 492

PAO2 = FiO2 (Patm - Pwater) \* (PaCO2 / RQ) RQ goal = Little CO2 production RQ 1 = Carbs RQ 0.8 = Proteins \* Carbs **RQ 0.7 = Lipids** **Switch to lipids = Answer**

Answer 493

**RSBI = Rapid Shallow Breathing Index** (breaths/min/L) = f/VT, where *_f is respiratory rate*_ and _*VT is tidal volume in Liters_* **RSBI \<105** Likely successful wean to extubation (97% sensitive, original study), "positive" **RSBI \>105** Likely to fail extubation, "negative"

Answer 494

**Methylene** blue treats symptomatic methemoglobinemia Methemoglobin is formed when the iron in normal Hb is oxidized from the Fe2+ to the Fe3+ form. It impairs oxygen delivery to tissues with symptoms appearing when metHb levels reach \>30% of total Hb. Methylene blue treats symptomatic methemoglobinemia by reducing metHb back to Hb. **Methylene blue reduces metHb back to Hgb**

Answer 495

1. **Hydroxycobalamin** 2. **Amyl Nitrate** 3. **Sodium Nitrite**

Answer 496

Hydroxocobalamin is similarly used to treat cyanide toxicity. It is a form of **vitamin B12 that binds cyanide** to form *_cyanocobalamin, another nontoxic form of vitamin B12 that is then renally excreted._*

Answer 497

Both amyl nitrate and sodium nitrite are used to treat cyanide toxicity by purposefully **causing methemoglobinemia since metHb avidly binds cyanide, removing it from cytochrome c oxidase.**

Answer 498

\>50% of total Hgb

Answer 499

\>30% of total Hgb

Answer 500

Treatment of symptomatic methemoglobinemia is with methylene blue **(1-2 mg/kg IV infused over 3-5 minutes).** Although the first dose is usually effective, it may be **repeated every 30 minutes to a total dose of 7-8 mg/kg.**

Answer 501

Excessive administration can actually lead to **paradoxical methemoglobinemia.**

Answer 502

Methylene blue acts as an ***_electron acceptor for NADPH methemoglobin reductase and enhances the enzyme’s effects up to 5-fold, leading to rapid reduction of metHb to normal Hb_***.

Answer 503

It is important to note that this enzyme works via the G6PD system so symptomatic patients with ***_congenital G6PD deficiencies_*** can be treated with ascorbic acid (vitamin C) or exchange transfusions.

Answer 504

Treatment of AT3 deficiency includes the administration of: 1. **Antithrombin 3** and/or 2. **FFP**, which includes Antithrombin 3.

Answer 505

[*_Serum Creatinine_* \* *_Urine Na*_] / [_*Serum Sodium_* \* *_Urine Creatinine_*]

Answer 506

Urine osmolality is normally **300-900 mOsm/kg**

Answer 507

Whenever **minute ventilation \>\>\>** *_fresh gas flow_*, rebreathing of exhaled gases will occur, leading to a lower FiO2, compared to the dialed O2 concentration.

Answer 508

**Pleural effusions** are the most common pulmonary manifestation.

Answer 509

Cardiac manifestations include: 1. **Restrictive pericarditis** 2. Possible **cardiac tamponade**

Answer 510

Anterior subluxation of C1 on C2 (A) may **occur in up to 40% of patients with RA**

Answer 511

Anterior subluxation of C1 on C2 (A) may occur in up to 40% of patients with RA – if the **subluxation is greater than 3mm**, one should consider an awake flexible laryngoscopic ("fiberoptic") intubation *_Radiology pearls (See image attached)_* - anterior border of the dens and the posterior border of the anterior tubercle of C1 (blue line) from ligamentous laxity caused by rheumatoid arthritis. The "pre-dentate space," as this is called, should be less than 3 mm in the adult.

Answer 512

Wide complex tachycardia with evidence of cardiopulmonary compromise should be treated with synchronized cardioversion ***_(0.5-1 J/kg)._***

Answer 513

Wide complex QRS is defined as ***_\>0.09 seconds'_*** duration in children. ## Footnote *_(This is a lower cutoff than adults which is 0.12 seconds)_*

Answer 514

Schedule 3

Answer 515

The **esophageal detector device** is generally reliable in patients with both a perfusing and a nonperfusing rhythm

Answer 516

***_Partial bilateral recurrent laryngeal nerve_*** injury results in complete obstruction (unopposed adduction of vocal cords). Caveat: When abductor fibers are damaged bilaterally (incomplete bilateral damage to the recurrent laryngeal nerve), the adductor fibers draw the cords toward each other and the glottic opening is reduced to a slit, resulting in severe respiratory distress. However, with a complete palsy each vocal cord lies midway between abduction and adduction, and a reasonable glottic opening exists. ***_Thus, bilateral incomplete palsy is more dangerous than complete palsy._***

Answer 517

**Complete bilateral Recurrent Laryngeal Nerve injury** results in the vocal cords being in a paramedian position causing aphonia and aspiration risk (both abduction and adduction affected).

Answer 518

It provides motor function to **all of the intrinsic muscles of the larynx except the cricothyroid (superior laryngeal nerve) including adduction and abduction of the vocal cords.**

Answer 519

Recurrent Laryngeal Nerve

Answer 520

Superior Laryngeal Nerve *_Tenses and ADDucts the vocal cords_*

Answer 521

The RLN also provides sensation to the ***_larynx from the glottis and below._***

Answer 522

Internal Branch of the Superior Laryngeal Nerve

Answer 523

**Anticholinergic Symptoms** mydriasis (Pupillary dilation), nystagmus, QT prolongation, tachycardia, hypotension, flushing, dry mouth, and urinary retention. **Anticholinergic symptoms** include tachycardia, altered level of consciousness, hyperthermia (“atropine fever”), flushing, dry mouth, mydriasis, constipation, and urinary retention. Recall: “dry as a bone, mad as a hatter, blind as a bat, and hot as a hare.”

Answer 524

The **Galen anastomosis (also called the ramus anastomoticus or Ansa of Galen)** is a connection between the RLN and the internal branch of the SLN.

Answer 525

***_High-dose glucocorticoids_*** should not be administered in patients with traumatic brain injury. Strategies for decreasing ICP include, but are not limited to, head elevation, hyperventilation, barbiturate coma, neuromuscular blockade, and decompressive craniectomy.

Answer 526

***_Succinylcholine dosage will likely need to be increased (1.5-2 mg/kg)_*** for proper intubating conditions secondary to a decreased number of functional acetylcholine receptors.

Answer 527

Recall that cerebral perfusion pressure is mean arterial pressure minus ICP (CPP = ***_MAP – ICP_***)

Answer 528

The most common complications of peripheral TPN administration are ***_infection (#1)_*** and ***_thrombophlebitis (#2)_***

Answer 529

1. If the patient is **fluid resuscitated** 2. ***_Continues to require vasopressors_*** to maintain a MAP ≥65 mm Hg 3. ***_Lactate of \> 2 mmol/L,_*** they are considered in septic shock.

Answer 530

SBP increases DBP decreases

Answer 531

– The dicrotic notch is **positioned further down the pressure curve.** – Rather than being a sharp interruption in the pressure descent, the dicrotic notch becomes more of a *_dicrotic wave_*.

Answer 532

**Pulse Pressure widens (increases) you go farther from aorta** Why? Normally, as a pressure wave travels down a straight tube, the wave dissipates over time and distance. However, in the arterial blood system, the introduction of branches and the increase in resistance as blood flows peripherally causes the arterial pulse wave to be reflected centrally. These reflections effectively “add” to the arterial pulse wave, raising primarily the systolic blood pressure (relative to the diastolic blood pressure) which accordingly widens the pulse pressure. Therefore, a more *_peripherally obtained invasive blood pressure will typically have a higher systolic blood pressure and a wider pulse pressure than one obtained more centrally._*

Answer 533

"CD plays your BIS" **Creatinine** **Dialysis (Hemodialysis)** **Bilirubin** **INR** **Sodium**

Answer 534

"Think **AEI**OU but cut off OU and replace with **B"** ## Footnote **Albumin, Ascites** **Encephalopathy** **INR** **Biliruin**

Answer 535

***_15_*** (3 points for 5 categories) Albumin Ascites Encephalopathy INR Bilirubin

Answer 536

A score of **5-6** is associated with a **10% mortality** whereas a score **greater than 10 is associated with a greater than 60% mortality.**

Answer 537

When using a DLT placed in the contralateral lung, **continuous positive airway pressure (CPAP) will not improve oxygenation** to the operative lung if a BPF is present.

Answer 538

**If there is a chest tube in place, it should be on water seal** at the time of induction because a chest tube to suction will divert each breath administered through the chest tube and compromise positive-pressure ventilation (PPV). ## Footnote *_If pleur-evac disconnected from **wall suction**, it is on water seal (Gravity) and will allow for one way flow of air out of the chest_*

Answer 539

In neonates, heat generation by shivering is somewhat limited during the first three months of life. This makes ***_nonshivering thermogenesis, which consists of metabolism of brown fat, a primary means of heat production in this population._*** Neonates are largely dependent on nonshivering thermogenesis via the metabolism of brown fat, which uncouples oxidative phosphorylation in the mitochondria to generate heat.

Answer 540

**Increased CVP** Central venous pressure does not decrease with aortic cross-clamping. This occurs because with **increased catecholamine levels there is increased venoconstriction distal to the clamp driving central venous pressure higher.**

Answer 541

***_Decreased_*** cardiac output

Answer 542

Stimulation of carotid sinus -\> ***_glossopharyngeal nerve -\>_*** ***_inhibits sympathetic tone/stimulates vagal nucleus_*** -\> hypotension and bradycardia.

Answer 543

Hyperalimentation is commonly associated with **hypophosphatemia** **hypo or hyperglycemia** acute liver injury therefore **coagulopathic**

Answer 544

For healthy pediatric patients undergoing elective surgeries, the current perioperative fluid guidelines recommend a **20-40 mL/kg bolus of isotonic fluid administered over 2 to 4 hours.**

Answer 545

**Postoperative infusion rates:** *_2 mL/kg/h x first 10 kg_* + *_1 mL/kg/h x second 10 kg_* + *_0.5 mL/kg/hr for \>20 kg_* + Daily serum sodium check

Answer 546

An adult (living) liver donor may undergo the less technically challenging ***_left hepatectomy when donating to a child._*** An ***_adult liver recipient_*** requires a larger donor-liver volume, which generally requires the donor to undergo a ***_right hepatectomy._*** ***_Children = Left (2, 3 and maybe 4)_*** ***_Adults = Right (5 - 8)_***

Answer 547

\>250 seconds

Answer 548

CO \* ((SaO2 \* Hgb \* 1.36) + (PaO2 \* 0.003))

Answer 549

Rightward shift

Answer 550

Norepinephrine

Answer 551

1. **Lithotomy** Position 2. **Positioning** for **total knee arthroscopy** 3. **Outpatient** status

Answer 552

*_pain and dysesthesia in the buttocks, thighs, and legs_* without other neurologic symptoms after an uncomplicated spinal anesthetic. ***_Motor weakness and bladder/bowel dysfunction are not signs of TNS._*** Therefore, if motor weakness and bladder/bowel dysfunction are present, this should prompt the consideration of an alternative diagnosis, such as cauda equina syndrome, which may present in up to one-third of patients receiving intrathecal lidocaine, but the precise etiology is unknown

Answer 553

12 - 24 hours after surgery

Answer 554

3 days after surgery (Rarely beyond a week)

Answer 555

**Haemophilus influenza type B** **Staphylococcus aureus** **Group A beta-hemolytic Streptococci**

Answer 556

***_Hypotension_*** & ***_Diarrhea_*** Otheer less common ones are hiccups, pleurisy, retroperitoneal bleeding, abdominal aortic dissection, transient motor paralysis, and paraplegia.

Answer 557

Huge Vagal Response

Answer 558

**Cardiac arrhythmias** may occur during laparoscopic surgery and the clinician must be aware of the physiologic basis. ***_Tachycardia and ventricular extrasystoles_*** may occur following the release of catecholamines. Carbon dioxide may produce or worsen arrhythmias since it is a cardiac irritant. More dangerous *_bradyarrhythmias_* such as severe bradycardia, nodal rhythms, atrioventricular dissociation, and even asystole can occur. These are often secondary to vagal nerve stimulation following acute stretching of the peritoneum.

Answer 559

Most carbon dioxide that enters the circulation will not cause any effect because it is ***_very soluble and will be excreted through the lungs._***

Answer 560

1. **Acute** Symptoms 2. ***_Absence_*** of **psychopathology** 3. **Herniation** + Nerve root irritation/compression

Answer 561

- Young age (incidence peaks in the early 20s) - Pregnancy - History of headaches - Smaller gauge (larger bore) cutting needles - Greater number of dural punctures - Skill of the operator

Answer 562

Macroglossia Large organs Hypoglycemia

Answer 563

A normal **SvO2 is approximately 75%**, which is essentially the *_amount of oxygen “left over” after the body has extracted what it needs_*

Answer 564

1. Increased oxygen consumption 2. Decreased oxygen delivery (CO, Hgb, or SpO2)

Answer 565

1. **Decreased oxygen consumption** (*_Reduced VO2_* as in cyanide, sepsis, CO posioning, MetHgb) 2. **Increased oxygen delivery** (CO, Hgb, or SpO2)

Answer 566

**Staphylococcus aureus** **Streptococcus pyogenes** **S. pneumoniae** **Nontypeable Haemophilus influenza** Before routine vaccination against Haemophilus influenzae type B, *_the incidence of epiglottitis was much higher and Haemophilus influenzae type B was by far the most common pathogen._*

Answer 567

Hyperventilation leads to **hypocapnia**, which *_reduces ICP via a reduction in cerebral blood flow (CBF)._*

Answer 568

See photo ***_Radial_*** nerve = Most posterior ***_Median_*** nerve = Anterolateral to the artery and found in 9 oclock position ***_Ulnar_*** nerve = Anteromedial positon to artery and found 3 oclock position ***_Musculocutaneos_*** nerve = In corocobrachialis

Answer 569

1. Disease \> 6 years 2. Chronic respiratory illness unrelated to myasthenia gravis 3. Vital capacity of \< 2.9 L 4. Daily pyridostigmine dose \> 750 mg (New studies say 250) 5. Intraoperative blood loss \> 1,000 mL 6. Serum anti-acetylcholine receptor titer \> 100 nmol/mL 7. Pronounced decremental response (18-20%) on low-frequency repetitive nerve stimulation

Answer 570

**Von Willebrand Disease** As many as 1/100 people

Answer 571

*_VWF is a plasma protein that:_* 1. **Assists platelets to adhere to sites of vascular injury** 2. **Stabilizes the clotting factor VIII** The vWF plays important roles in platelet adhesion by forming linkages between platelets and subendothelial structures and also as a carrier for coagulation factor VIII.

Answer 572

Type 1 VWD: **partial quantitative decrease** in VWF concentrations Type 2 VWD: *_qualitative_* defect in VWF Type 3 VWD: **total depletion of VWF**

Answer 573

Main goal is to ***_increase circulating functional VWF_***. *_This is accomplished by:_* 1. Administration of **VWF concentrates** 2. **Desmopressin** (**DDAVP**) 3. **Cryoprecipitate** when the former options are not available in an emergency. VWF concentrates are the primary treatment of major bleeding in VWD. VWF concentrates can be plasma-derived, which include factor VIII and VWF, or recombinant, which only include VWF.

Answer 574

If a recombinant VWF concentrate is used during major bleeding, you must also administer ***_factor VIII concentrate._***

Answer 575

Cryoprecipitate contains ***_factor VIII, VWF,_*** factor XIII, and fibrinogen. It can be used to replete VWF in emergencies when VWF concentrates are not available.

Answer 576

DDAVP acts on V2 receptors on endothelial cells, ***_stimulating them to secrete VWF_*** and is used for minor procedures or minor bleeding. It is best utilized in the pre-operative phase

Answer 577

DDAVP is not very effective in Type 2 VWD because the issue is **qualitative defects.** desmopressin is contraindicated in type 2B vWD as ***_administration may lead to significant thrombocytopenia._***

Answer 578

In acute respiratory acidosis, serum bicarbonate levels ***_increase 1 mEq/L for each 10 mm Hg rise in PaCO2_***

Answer 579

If the respiratory acidosis is chronic, bicarbonate levels increase between ***_4-5 mEq/L for each 10 mm Hg rise in PaCO2_***

Answer 580

***_Functional Adrenal Insufficiency_*** Functional adrenal insufficiency (FAI) is associated with increased mortality and is defined as subnormal cortisol production during acute severe illness.

Answer 581

The major adrenocortical hormone secreted is cortisol which is a hydrophobic hormone that circulates bound to proteins with a ***_half-life of 60 to 120 minutes_***

Answer 582

Adrenal insufficiency occurs when the HPA fails to provide sufficient amounts of appropriate hormones. This can be termed primary adrenal insufficiency when the ***_adrenal gland is unable to produce hormones when stimulus from the pituitary gland is adequate._***

Answer 583

Secondary adrenal insufficiency is caused by impairment of the ***_pituitary gland or hypothalamus._*** Its principal causes include pituitary adenoma (which can suppress production of adrenocorticotropic hormone (ACTH) and lead to adrenal deficiency unless the endogenous hormones are replaced; secondary adrenal insufficiency can be caused by steroids, inhaled steroids such as Flovent; and Sheehan's syndrome, which is associated with impairment of only the pituitary gland.

Answer 584

Tertiary adrenal insufficiency is due to **hypothalamic disease and a decrease in the release of corticotropin releasing hormone (CRH).** Causes can include brain tumors and sudden withdrawal from long-term exogenous steroid use (which is the most common cause overall).

Answer 585

When the body is stressed, the central nervous system activates the sympathetic system and the hypothalamic-pituitary axis (HPA) to help deal with the changes required to attenuate the stress. The sympathetic nervous system will release catecholamines and the HPA will respond with an increase in hormone production. When the stress becomes chronic, as is often seen in patients in the intensive care unit, ***_the system can become depleted particularly the HPA axis and adrenal glands._*** ***_Replete what could be exhausted!_***

Answer 586

30-90 days

Answer 587

***_Increase_*** The only SVR drop is Distributive shock

Answer 588

Initial compensation occurs though ***_plasma protein buffers_*** and is followed hours to days later by the ***_renal response._***

Answer 589

Type 1 = Most common | (Partial quantitative defect)

Answer 590

Factor 8 - vWF contentrate for ***_2a and 2b_*** Factor 8 - vWF contentrate and desmopressin for ***_2m and 2n_***

Answer 591

Elevated peak pressures with a large difference between peak and plateau pressures suggest ***_increased airway resistance._*** Ex: **- bronchospasm** **- kinked endotracheal tube** **- mucus plugging**

Answer 592

Elevated plateau pressures (without a significant difference between peak and plateau pressures) suggest decreased **respiratory compliance.** If the peak and plateau pressure ***_are not significantly different (normal is 4-10 cm H2O_***), it suggests an issue with respiratory compliance such as: *_Poor positioning_* *_Pulmonary fibrosis_* *_Pneumothorax_* *_Obesity_* *_Chest wall deformity_* *_Compression._* Efforts to fix these problems (if modifiable) should be sought.

Answer 593

**Ptosis** **Anhydrosis** **Miosis (Constricted Pupil)** - Sympathectomy = Pupil cannot dilate

Answer 594

Chassaignac's tubercle (the **anterior tubercle of the transverse process of the C6 vertebra)**

Answer 595

**A normal A-a gradient is 5 - 10 mm Hg** for a young adult nonsmoker. The *_A-a gradient increases about 1 mm Hg per decade of life, so a 40-year-old would have a normal A-a gradient of \< 14 mm Hg._* A conservative estimate of A-a gradient can be calculated with the same equation as pediatric endotracheal tube size: *_(Age / 4) + 4._*

Answer 596

VQ Mismatch

Answer 597

***_50 to 75 mg/kg/day_*** in children OR *_2.6 grams per day max_*

Answer 598

The half-life is approximately ***_2 to 3 hours_***

Answer 599

NAC provides cysteine for the ***_replenishment and maintenance of hepatic glutathione stores which enhances the elimination pathway and may reduce the hepatic toxicity of acetaminophen_***.

Answer 600

NAC is most effective when administered ***_within the first 8-10 hours after an overdose_*** however it should be provided to patients outside this window according to the above nomogram or if toxicity is ever suspected

Answer 601

The popliteal fossa is bordered by the **semitendinosus**, **semimembranosus**, **biceps femoris**, and **gastrocnemius** muscles.

Answer 602

Female 8:1

Answer 603

The most commonly encountered defect is a **left-sided (75% of cases**) posterolateral herniation of the abdominal visceral contents through the “**foramen of Bochdalek"** This is most likely due to the *_absence of the majority of the liver under the left side of the diaphragm. _*

Answer 604

**_Low V/Q ratio_** AKA ***_Shunt_***

Answer 605

***_Vascular access in the lower extremities should be avoided_*** because the inferior vena cava may become compressed after the reduction of the hernia

Answer 606

**Mild**: PaO2/FiO2 ratio of **201-300 mm Hg** **Moderate**: PaO2/FiO2 ratio of **101-200 mmHg** **Severe**: PaO2/FiO2 ratio **≤100 mmHg**

Answer 607

Improved V/Q Mismatch Justification for this method centers around the idea that there is A) less alveolar collapse due to gravity and B) more even distribution of perfusion in the prone position as compared to the supine position

Answer 608

Systemic hypotension from *_mast cell degranulation and histamine release_* caused by rapid administration. It is the polycationic structure of protamine that triggers this reaction.

Answer 609

Anaphylaxis from ***_IgE-mediated dose-independent reaction_***. Previous exposure to protamine or a similar protein (such as neutral protamine Hagedorn found in NPH insulin) is **required for anaphylaxis to occur.**

Answer 610

**Pulmonary hypertensive crisis causing pulmonary hypertension, vasoconstriction, and possible right heart failure.** The mechanism for this reaction is thromboxane A2 released from platelets and macrophages stimulated by protamine-heparin complexes.

Answer 611

Type 1 ## Footnote Systemic hypotension from mast cell degranulation and histamine release caused by rapid administration. It is the polycationic structure of protamine that triggers this reaction.

Answer 612

The uterus receives ***_up to 20%_*** of maternal cardiac output at term.

Answer 613

**Uterine arteries supply about 85%** of blood flow and *_ovarian arteries supply up to 15%_*.

Answer 614

***_Erection = Parasympathetic_*** ***_Ejaculation = Sympathetic_*** \*CRPS Lumbar Plexus blocks cant ejaculate due to sympathectomy\*

Answer 615

SID = [strong cations] - [strong anions] = [**Na+ + K+ + Ca2+ + Mg2+**] - [**Cl- + lactate-**].

Answer 616

Any process that ***_increases the SID increases plasma pH_*** and causes alkalosis Any process that ***_decreases the SID lowers plasma pH_*** leading to acidosis.

Answer 617

In normal human plasma, the ***_SID is 40-42 mEq/L_*** due to the greater concentration of strong cations, especially sodium

Answer 618

The intrapulmonary vascular dilations cause increased perfusion relative to ventilation. Standing further ***_worsens this ventilation-perfusion mismatch_*** since gravity causes increased perfusion and pooling in the less-ventilated lower lung segments.

Answer 619

The presence of IPVDs is confirmed if contrast enhanced agitateed saline shows agitated saline bubbles in the left atrium ***_after at least 3-6 cardiac cycles have passed following IV administration._*** If saline bubbles appear in the left atrium after 1-2 cardiac cycles, the presence of intracardiac shunts (e.g. PFO) cannot be ruled out.

Answer 620

If the CEE is positive but there are confounding factors such as cardiopulmonary disease, then a: ***_1. technetium-99m-labeled lung perfusion scan_*** ***_2. pulmonary arteriography_*** may help confirm the diagnosis.

Answer 621

Normal PVR is 100 – 200 dynes/sec/cm

Answer 622

**Nimodipine** is the most appropriate therapy to reduce the rate of vasospasm following clipping of a ruptured berry aneurysm.

Answer 623

Vasospasm occurs in 70% of patients following SAH.

Answer 624

Cerebral vasospasm may **occur 2-14 days** following subarachnoid hemorrhage (SAH) due to the breakdown products of blood causing local vascular irritation (e.g. oxyhemoglobin).

Answer 625

“Triple-H” therapy is initiated to treat cerebral vasospasm and is comprised of: **1. Hypertension** **2. Hypervolemia** **3. Hemodilution** There is no benefit to prophylactic Triple H therapy in patients with SAH.

Answer 626

**pulsus paradoxus (a drop of at least 10 mm Hg (or \>9%) in systolic arterial blood pressure on inspiration** The normal fall in pressure is less than 10 mmHg

Answer 627

Hirudin is a ***_recombinant antithrombin_*** that has been used to anticoagulate patients undergoing bypass, but it would not be recommended in this situation.

Answer 628

The pulsatility index (PI) is a ***_dimensionless index that reflects the degree of native pulsatility of the left ventricle in real time._*** It is calculated from flow (Which in turn, is a calculated number)

Answer 629

higher number means that the left ventricle is pushing more blood via pulsatile flow.

Answer 630

Below-normal PI providing evidence of **hypovolemia** or **impaired cardiac function**

Answer 631

The incidence of nausea and vomiting ***_is the same for intrathecal/epidural and intravenous administered opioids, approximately 30%._***

Answer 632

Higher in neuraxial

Answer 633

Opioid-induced pruritus (off-label use): IV infusion: ***_0.25 mcg/kg/hour_*** (Gan 1997) to ***_max of 2 mcg/kg/hour._*** Doses up to ~3 mcg/kg/hour have been employed (Kendrick 1996). However, doses *_\>2 mcg/kg/hour are more likely to lead to reversal of analgesia and are not recommended_* (Kjellberg 2001; Miller 2011). Note: Monitor pain control; verify that the naloxone is not reversing analgesia.

Answer 634

Ischemia is generally absent if TCD shows a mean flow velocity **\>40% of the preclamped value** **Mild to moderate if 15-40%** of the preclamped value **Severe if \< 15%** of the preclamped value.

Answer 635

***_Beta-blockers_*** should be used cautiously as they can worsen reflexive bradycardia and, if given in the setting of unopposed α-stimulation, may lead to severe vasoconstriction, hypertensive crisis, and congestive heart failure.

Answer 636

Autonomic immature **Parasympathetic dominates**

Answer 637

The cardiac output of the neonate is determined primarily by heart rate and their cardiac myocytes are relatively insensitive to catecholamines. Neonatal myocytes have ***_poor lusitropy and cannot accommodate increasing preloads with increasing stroke volume._***

Answer 638

Decreased maximum amplitude (MA) primarily provides evidence of quantitative (thrombocytopenia) and/or qualitative platelet dysfunction or, to a lesser extent, inadequate fibrinogen ## Footnote **Platelets and possibly fibrinogen (Cryo)**

Answer 639

Prolonged K values provide evidence of deficiencies of **thrombin formation or generation of fibrin from fibrinogen/inadequate fibrinogen**.

Answer 640

A **decrease \>10 mm Hg of systemic blood pressure** during ***_inspiration_*** is called pulsus paradoxus and is characteristic of cardiac tamponade. Said Another Way Pulsus paradoxus is a ***_greater than normal decrease in the systolic blood pressure during inspiration_*** secondary to *_impaired left ventricular filling_*.

Answer 641

Right atrial pressure is ***_lowest during late diastole and early systole_***, therefore this is when an increase in the surrounding pericardial pressure would cause collapse.

Answer 642

**Early diastole** represents the time of lowest pressure in the right ventricle and collapse will occur if the pressure in the pericardial sac increases enough.

Answer 643

The presence of lupus anticoagulant: **Prolongs activated partial thromboplastin time (aPTT)**, but *_not prothrombin time (PT)_*. The phospholipid used as an activator for the aPTT measurement binds with the lupus anticoagulant and results in a **prolonged aPTT.**

Answer 644

Infants have a CSF volume of 4 mL/kg Children have a CSF volume of 3 mL/kg Adults have a CSF volume of 1.5-2 mL/kg

Answer 645

Sites Correlating With Core Temperature: * *1) Esophageal 2) Tympanic 3) Pulmonary artery 4) Nasopharyngeal**

Answer 646

Back pain following injection of large volumes of 2-chloroprocaine can cause muscle spasms. 2-chloroprocaine may contain the preservative disodium **ethylenediaminetetraacetic acid (EDTA). EDTA is a known chelator of calcium.** Larger volumes of 2-chloroprocaine chelate the calcium of nearby muscle, which causes local muscle spasms. **These spasms are transient and self-relieving. There is no need for treatment or imaging** unless other signs and symptoms are present. However, there are preservative free formulations of 2-chloroprocaine readily available so this side effect is less commonly seen.

Answer 647

***_Distributive (66%):_*** severe sepsis, anaphylaxis, neurogenic (spinal shock), endocrinologic (adrenal crisis), toxic. ***_Hypovolemic (16%): hemorrhage_*** ***_Cardiogenic (16%)_***: acute myocardial infarction, end-stage cardiomyopathy, advanced valvular heart disease, cardiac arrhythmias, prolonged cardiopulmonary bypass, fulminant myocarditis, blunt myocardial trauma, medication induced (anthracycline toxicity). ***_Obstructive (2%):_*** pulmonary embolism, cardiac tamponade, tension pneumothorax, constrictive pericarditis, acute pulmonary hypertension, aortic dissection.

Answer 648

**\>18 mmHg**

Answer 649

25 - 30 seconds

Answer 650

Propofol (0.75 mg/kg) may be a useful induction agent in ECT patients with a ***_history of seizures lasting greater than 100 seconds_*** as it will shorten the seizure duration.

Answer 651

a – atrial contraction

Answer 652

c – tricuspid valve bulging into right atrium during right ventricle isovolemic contraction

Answer 653

x – tricuspid valve descends into right ventricle with ventricular ejection

Answer 654

RA fills againist closed Tricuspid Valve

Answer 655

y – atrial emptying into right ventricle through open tricuspid valve

Answer 656

\<100 mg/dL This is because the brain needs time to compensate for change in serum osmolarity and will correct slower. **If correction occurs too rapidly cerebral edema may result.**

Answer 657

1. Potent selective pulmonary vasodilator that ***_decreases pulmonary artery pressure_*** 2. ***_Reduces right ventricle (RV) afterload_***

Answer 658

1. **Endothelin Pathway** (Endothelin Receptor Antagonists) 2. **Nitric Oxide Pathway** (Nitrous Oxide) 3. **Prostacyclin Pathway** (Epoprostenol pathway)

Answer 659

1. Higher oxides of nitrogen (**Pulmonary edema anad chemical pneumonitis**) 2. **Methemoglobinemia** 3. **Platelet aggregation**

Answer 660

Psoas Major

Answer 661

The incidence of inhibitors for factor VIII and factor IX is increasing in the population leading to ‘refractory hemophilia’. It is possible for an anesthesiologist to encounter one of these patients and prompt hematology consultation is warranted. In patients with hemophilia A and factor VIII inhibition, the most common treatment is with: ***_1. PCC = Prothrombin complex concentrates_*** ***_2. Recombinant factor VII._*** Why? In approximately 10-25% of patients, an alloantibody develops that inactivates replacement factors administered (in hemophilia A it would be factor VIII). This results in inadequate coagulation and can be a major problem in the perioperative period thus surgery in these patients should proceed with only extreme caution. Generally, these antibodies are IgG and they are poorly removed by plasmapheresis

Answer 662

In patients with hemophilia B and factor IX inhibition, treatment with ***_recombinant factor VIIa_*** is preferred as there is less of a risk of anaphylactoid reactions when compared with **PCCs.** **Recombinant Factor 7a \>\> is better \>\> PCC**

Answer 663

**What is the coags for Hemophilia** PTT - Prolonged PT, BT, Platelet Count - All normal

Answer 664

**What is the coags for Von Willebrand disease?** PTT - Prolonged PT - Normal BT - Prolonged Platelet Count - Normal

Answer 665

All prolonged - PTT, PT, BT Platelet count - Decreased

Answer 666

PTT and PT - Prolonged BT and Platelets are normal

Answer 667

Carbamazepine inhibits **sodium channels** in neuronal cells *_inhibiting excitability and conduction._* Used for Trigeminal Neuralgia = First Line Therapy

Answer 668

***_Anterior Parts of Body_*** (Cardiac Surgery is most common amongst anterior)

Answer 669

**Posterior aspect of body** (Spine surgery)

Answer 670

painless visual loss Visual field deficits Sluggish pupils

Answer 671

***_Prognathia_*** - Extension or bulging out (protrusion) of the lower jaw (mandible) ***_Retrognathia_*** - refers to a facial malformation characterized by abnormal development of the mandible with an abnormal position in relation to the maxilla ***_Micrognathia_*** - refers to a facial malformation characterized by mandibular hypoplasia causing a small receding chin

Answer 672

**Sensitive** = Screen = IGF1 **Specific** = Lack of GH suppression following oral glucose load

Answer 673

***_Cholestasis is a major complication of parenteral_***, not enteral, nutrition because there is no stimulus for the release of cholecystokinin to promote gall bladder contraction and thus stasis occurs.

Answer 674

Cardiac Myxoma

Answer 675

**Left Atrium (70%)** Right Atrium (30%)

Answer 676

**Metastatic**

Answer 677

Ventricular Fibroma

Answer 678

***_Systemic Resistance_*** increases significantly Closes the foramen ovale

Answer 679

Clostridium botulinum toxin **destroys SNARE (soluble N-ethylmaleimide-sensitive attachment protein receptors) proteins** which are required to *_facilitate the release of acetylcholine (ACh) from storage vesicles_* into the neuromuscular junction.

Answer 680

Neuraxial opioids provide analgesia via ***_inhibition of excitatory neurotransmitters and hyperpolarization of postsynaptic neurons_*** in the substantia gelatinosa of the dorsal horn of the spinal cord.

Answer 681

LQT1 (K+) LQT2 (K+) LQT3 (Na+)

Answer 682

ongenital LQTS may occur with deafness ## Footnote ***_(Jervell, Lange-Nielsen syndrome)_***

Answer 683

Congenital LQTS may occur without deafness ***_(Romano-Ward syndrome)._***

Answer 684

The main goal is ***_heart rate control_*** thus patients should be adequately beta-blocked and sympathetic surges should be avoided. Adrenergic stimulation, even auditory stimulation (LQT1 and 2), can worsen the syndrome.

Answer 685

***_Cryoprecipitate contains:_*** ***_"8, 13, VWD and Fibrinogen"_*** 1. *_Von Willebrand factor (vWF)_* (VWD disease) *_2. Fibrinogen_* (Coagulopathies) 2. Fibronectin 3. *_Factor VIII_* (Hemophilia A) 4. *_Factor XIII_* (Christmas Disease)

Answer 686

Hemophilia A and von Willebrand disease can alternatively be treated with: 1. ***_Virally inactivated factor VIII_*** concentrates as they contain vWF.

Answer 687

It binds and inhibits the **alpha2-delta subunit of the voltage-gated calcium channel**. This results in a decreased release of the excitatory neurotransmitter glutamate.

Answer 688

Ataxia Nystagmus Peripheral Edema

Answer 689

13 - 50 hours

Answer 690

4 - 8 hours

Answer 691

Methadone is a full agonist at mu receptors (it does also act as an NMDA receptor antagonist and as a monoamine transmitter reuptake inhibitor). **Because it is a full agonist, there is no "ceiling dose" beyond which there is no further analgesic effect.**

Answer 692

Methadone is especially useful in patients with: 1. **Opioid tolerance** (due to NMDA blockade) and 2. Those with **neuropathy** (due to monoamine reuptake inhibition).

Answer 693

***_You dump Sodium + Bicarbonate so these serum levels drop_*** *_Cl goes up_* K & Phos goes down

Answer 694

PAO2 = (FiO2 x (Patmosphere - PH20)) - (PaCO2/RQ) RQ = 0.8 Patm = 760 Pwater = 47

Answer 695

**vWD is divided into 3 major categories:** (1) Partial quantitative deficiency (type I) (2) Qualitative deficiency (type II) (3) Total deficiency (type III)

Answer 696

**Types I autosomal dominant** **Type II autosomal dominant** Type III is autosomal recessive

Answer 697

Type 1 (75%)

Answer 698

**Desmopressin** increases the release of von Willebrand factor, is the primary treatment for **vWD type I**, and should be administered prior to surgery.

Answer 699

30 minutes

Answer 700

Individuals with vWD type III have a *_virtually complete deficiency_* of vWF. Thus, the fact that DDAVP, an agent that causes the release of stored vWF, **has no effect in patients with vWD type III is not surprising (No stores)**

Answer 701

Type II: **trial of DDAVP, avoid if known type IIB** DDAVP trials may be contraindicated in patients with type IIB, because of thrombocytopenia and possible thrombotic complications. DDAVP is probably not effective in patients with type IIM and is rarely effective in patients with type IIN.

Answer 702

Type III: ***_vWF concentrate_*** (DDAVP has no effect)

Answer 703

**General treatment guidelines:** Type I: trial of DDAVP Type II: trial of DDAVP, avoid if known type IIB Type III: vWF concentrate (DDAVP has no effect) * _Acquired vWF Deficiency_*: trial of DDAVP, switch to vWF concentrate if not responding * _Antibody-Mediated Acquired vWF Deficiency_*: IVIG * *Minor Bleeding/Surgery**: DDAVP, follow clinically, vWF concentrate if bleeding continues * *Major Bleeding/Surgery**: use vWF concentrate and continue in the perioperative period

Answer 704

**Upper extremity = 50 mmHg above SBP** ## Footnote *_Lower Extremity = 100 mmHg above SBP_*

Answer 705

***_Treatment of salicylate toxicity includes:_*** 1) **Supportive** care (beginning with the ABC’s of airway and circulatory support) 2) Activated **charcoal** and/or gastric lavage if recent ingestion 3) **Dextrose** to avoid CSF hypoglycemia 4) **IV fluids** to replace losses from tachypnea and vomiting 5) **Bicarbonate** administration - Raises systemic pH, decreases tissue distribution of salicylate - Raises urine pH, increases the rate of renal clearance 6) **Hemodialysis** if severe symptoms

Answer 706

The shunt fraction can be easily calculated by using the simplified shunt equation: ***_Qs / Qt = (1 − SaO2) / (1 − SvO2)_*** Qs = pulmonary physiologic shunt Qt = cardiac output SaO2 = arterial oxygen saturation Sv02 = venous oxygen saturation

Answer 707

Anatomic shunts naturally occur in the body and contribute to approximately **5% of the overall shunt total** **S**uch as the *_thespian veins_* (valveless veins in the walls of the cardiac chambers that drain directly into the cardiac chambers they overlie) & *_bronchial veins_* (veins that can drain directly into pulmonary veins)

Answer 708

Pathological shunts include **right-to-left shunts** such as ventricular septal defects, patent foramen ovale, *_pneumonia*_, _*pulmonary edema_*, and vascular tumors.

Answer 709

Steroid therapy to decrease ICP is effective for space-occupying lesions with surrounding edema. By decreasing the inflammation, ICP will decrease. However, this patient has an acute traumatic injury and therefore would not benefit from dexamethasone. Further, ***_steroids have been shown to be ineffective in traumatic injury and can worsen outcomes by increasing hyperglycemia._***

Answer 710

1) **Heart rate** 2) **Coronary perfusion pressure**: CPP = AoDP - LVEDP 3) **Coronary vascular resistance (CVR)**: Vasospasm or atherosclerosis worsens myocardial oxygen supply. Providing vasodilation with medications such as nitroglycerin improves CBF.

Answer 711

CBF = **Cerebral Perfusion Pressure / CVR** or CBF = **(AoDP – LVEDP) / CVR.**

Answer 712

Hyperbaric chambers allow the delivery of 1 MAC of N2O but this is not without consequence as: 1. **Decompression sickness** 2. **Diffusion hypoxia** 3. Induction reactions such as **opisthotonos, hypertension, tachycardia, and muscular rigidity** can occur.

Answer 713

A restrictive defect is a proportional decrease in all lung volumes; thus *_VC, FVC and FEV1 are all reduced_* but **FEV1/FVC remains normal.**

Answer 714

*_Superficial_* = Saphenous, Superficial Peroneal, Sural *_Deep_* = Deep Peroneal and Posterior Tibial ***_ALL NERVES_*** **1. Saphenous** **2. Peroneal - Common/Superficial** **3. Peroneal - Deep** **4. Sural** **5. Posterior Tibial**

Answer 715

First-line pharmacologic treatments for neuropathic pain are **1. TCAs** **2. Serotonin-norepinephrine reuptake inhibitors (SNRI) -** *_duloxetine and Venlafaxine_* **3. Gabapentinoids - Gabapentin, and pregabalin.**

Answer 716

*_Second-line pharmacologic treatments for neuropathic pain are_* 1. Oral **tramadol** 2. 8% **capsaicin** patches 3. 5% **lidocaine** patches.

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