Truelearn Questions 2 Flashcards

Question

Brachial Artery Cannulation is Most likely to injure what nerve?

Answer 1

**Median Nerve**

Answer 2

Heparin, Insulin, Nondepolarizing muscle relaxants, Glycopyrrolate, and Succinylcholine. Additionally **phenylephrine** does not cross the placental barrier.

Answer 3

* Cryoprecipitate contains **von Willebrand factor (vWF), fibrinogen, fibronectin, factor VIII, and factor XIII.**

Answer 4

* *Hemodynamic effects of aortic cross clamping include:** 1) Increased arterial blood pressure above the level of the clamp 2) Increased coronary artery blood flow 3) Increased left ventricular wall stress 4) Increased central venous pressure 5) Increased pulmonary artery wedge pressure 6) Decreased arterial blood pressure below the clamp 7) Decreased cardiac output 8) Decreased renal blood flow

Answer 5

* **Acute Tubular Necrosis**: "muddy brown casts"; Excretion of sodium FENA \>1%; Uosm \<350 * **Pre renal:** hypovolemia issue, urine is concentrated, osmolarity HIGH Uosm \>500. BUN:Cr \>20

Answer 6

* **50 mm Hg above the systolic** pressure of upper extremity surgery * **100 mm Hg above systolic** pressure of lower extremity surgery.

Answer 7

1. **Decreased total-body oxygen consumption** 2. Decreased total-body carbon dioxide production 3. **Increased mixed venous oxygen saturation** 4. Decreased total-body oxygen extraction 5. Increased epinephrine and norepinephrine 6. Respiratory alkalosis 7. Metabolic acidosis

Answer 8

**Pericardial Effusion** Pericardial tamponade can be differentiated from myocardial failure by the presence of **pulsus paradoxus** (a drop of at least 10 mm Hg (or \>9%) in systolic arterial blood pressure on inspiration)

Answer 9

Atropine Associated with High T5 Spinal Blockade

Answer 10

* Type 1: Acute Thrombus * d/t plaque rupture, stress on atheroma etc. * Type 2: Demand ischemia * **MOST Common type of MI to occur in OR** * Myocardial oxygen demand exceeds oxygen supply d/t factors such as tachycardia, anemia, hypoxemia, hypotension * Manage w/ rapid revascularization, aspirin, heparin.

Answer 11

Troponin * Serum troponin levels are elevated in 80% of patients within 2 to 3 hours of MI. * CK-MB may be elevated after only 2-3 hours but often does not peak for several hours after ischemia. * The sensitivity of troponins is nearly 50% within 3 hours, 75% by 6 hours, and nearly 100% by 12 hours. * Troponin may also be elevated in other disease states like renal failure, sepsis, and congestive heart failure. Elevated troponin from any cause is a sign of poor prognosis and should be considered equivalent to cardiac injury until proven otherwise.

Answer 12

**Acute intermittent porphyria** * An **autosomal dominant** condition that results from an error in **porphobilinogen deaminase,** an enzyme involved in heme synthesis * Symptoms are vague and include: abdominal pain, diarrhea, constipation * Attacks a precipitated b conditions that increase **amnolevulinic acid (ALA)** * **Ie Inducers of P450 system:** alcohol, benzodiazepines, nifedipine, glucocorticoids. * Important to maintain normothermia and hydration.

Answer 13

Think "60, 70. 80, 90" **60** ml/kg- adult female **70** ml/kg - anyone after age 3 months **80** ml/kg - full term newborn **90** ml/kg - premature infant

Answer 14

1. Hyponatremia 2. Hyperkalemia 3. Hyperchloremia 4. Hypercalcemia

Answer 15

* MA value decreased -\> platelets. ("Ma Platelets) * K value prolonged -\> cryoprecipitate. ("Kryoprecipitate) * R value prolonged -\> FFP. ("RLASMA" - theres a P in the R) * Teardrop configuration -\> antifibrinolytics.

Answer 16

* Both are pumps used to circulate blood between the CPB machine and the patient. * Both can deliver pulsatile flow * Key Difference: Centrifugal require flowmeters on the arterial portion of the CPB circuit since **flow can vary from alterations in pump preload and afterload** * **Roller pump flow is essentially only dependent on the speed of the rollers** * **Due to compressive forces, roller pumps have higher incidence of blood element destruction, creation of plastic microemboli, inflow/outflow obstruction.** * Centrifugal pumps rotate about a magnetically controlled impeller associated with an electric motor. Centrifugal pumps are often favored over roller pumps due to less blood element destruction, lower line pressures, lower risk of air emboli, and elimination of tubing wear and spallation.

Answer 17

Vital Capacity is Unchanged

Answer 18

* Most common cause of jaundice in the adult population in the USA caused be decreased activity of enzyme **bilirubin glucuronyltransferase.** * Autosomal dominant; Decreased ability to uptake unconjugated bilirubin * A large unconjugated bilirubin load, such as from multiple packed red blood cell (PRBC) transfusions, overwhelms the limited enzyme activity resulting in clinically evident jaundice. Jaundice is typically noticeable with serum bilirubin levels above 2-2.5 mg/dL

Answer 19

* Forms inside PSOAS MAJOR MUSCLE from Anterior Rami of L1 to L4 * 6 MAIN NERVES; mnemonic: "**I** (twice) **G**et **L**aid **O**n **F**ridays" * iliohypogastric * ilioinguinal * Genitofemoral * Lateral Femoral Cutaneous * Obturator * Femoral * All the nerves except Genitofemoral and Obturator emerge lateral to psoas major; "they GO anterior and medial"

Answer 20

* Arises from anterior and posterior divisions of spinal nerves of **L4 to S3**; Supplies posterior compartment of thigh, leg and foot * Courses beneath **piriformis muscle** and **exits through greater sciatic foramen**, travels deep to gluteus maximus and into posterior compartment of thigh where it innervates Semimembranosus, Semitendonosus, Biceps femoris * **Branches at popliteal fossa** to become **tibial nerve** and **common peroneal nerve**

Answer 21

* It can worsen **respiratory acidosis** * Causes **extracellular alkalosis, which will shift the oxygen-hemoglobin dissociation curve to the left making unloading of oxygen more difficult**. * Produces **hypernatremia and hyperosmolarity.** * May **inactivate administered catecholamines** such as epinephrine by exacerbating venous acidosis. Bicarbonate may **compromise cerebral perfusion pressure (CPP) by reducing systemic vascular resistance**. * **_2 Circumstances where giving Bicarbonate may be appropriate_** * _Known Hyperkalemia_ * _Known TCA overdose_

Answer 22

* TNF alpha * Interferon Gamma * IL-1 * IL-2 * IL-6 * IL-8 * IL-10

Answer 23

**Iatrogenic Antithrombin 3 Deficiency** **Administer FFP or AT 3 concentrates**

Answer 24

Measure Creatinine Clearance * Creatinine Clearance = (Urine creatinine x Urine volume)/Plasma Creatinine

Answer 25

**Fractional excretion of sodium** * **Used to determine cause of an established AKI**; can identify wheather injury is caused by prerenal, intrinsic, or postrenal etiology' * **FENa = (Urine sodium \* Plasma creatinine) / (Urine creatinine \* Plasma sodium)** * ****FENa \< 1% = Prerenal * FENa \> 1% = Intrinsic (e.g. acute tubular necrosis) * FENa \> 4% = Postrenal

Answer 26

* Eyes; 4 * Verbal; 5 * Motor; 6

Answer 27

Musculocutaneous nerve * Musculocutaneous nerve (**C5,6,7**) * Axillary nerve (C5,6) * Radial nerve (C5,6,7,8,T1) * Median nerve (C5,6,7,8,T1) * Ulnar nerve (**C7,8,T1**)

Answer 28

TRUE: Factors predicting increased efficacy of ESI include * Patients with recent onset of symptoms * Absence of psychopathology * Those with herniated disc associated with nerve root irritation or compression. Factors predicting decreased efficacy include * Chronic radiculopathy * Presence of psychopathology * Degenerative bony disease * Previous back surgery.

Answer 29

1. Age \<40 years 2. Prior PDPH 3. BMI \<30 4. History of air travel 5. Multiple dural attempts 6. Quincke needle (only cutting needle) Key point: **midline vs paramedian approach & air vs saline LOR technique do not alter PDPH incidence.**

Answer 30

TRUE: Obese (BMI \> 30) patients tend to be less susceptible to PDPH which is attributed to increased abdominal pressures which may reduce CSF leakage

Answer 31

**_Acetylsalicylic acid toxicity_** ABG shows **Mixed Respiratory acidosis and metabolic acidosis** * Acute overdoses cause harm by i**nterfering with the Krebs 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 to increase the respiratory drive leading to a respiratory alkalosis** **Arterial Blood Gas** * **Classic ABG** * ****pH: 7.43/PaCO2: 25/ PO2: 81/ HCO3 16/ SpO2 99%

Answer 32

6 months of age then begins to decline

Answer 33

0.2 to 0.4 miliamps

Answer 34

A: Cardiovascular disease ## Footnote Maternal mortality in the U.S. has steadily increased from 7.2 deaths per 100,000 live births in 1987 to 18.0 deaths per 100,000 live births in 2014. This is a high number for a developed country, and the U.S. is one of the few countries where maternal mortality has increased in recent years. Globally, the causes of maternal mortality are usually separated into direct causes (e.g., hemorrhage, hypertensive disorders of pregnancy, infection) and indirect causes (non-obstetric conditions that may be exacerbated by pregnancy, e.g. cardiovascular disease). While direct causes make up the majority worldwide, in developed countries direct causes have been dropping for decades to the point that indirect causes may be the majority.

Answer 35

**Prematurity** * **The younger the patient, the more likely they are to develop post operative apnea.** * Infants are at a higher risk if they also have multiple congenital anomalies, a history of apnea or bradycardia, and chronic lung disease. Other contributing factors include hypothermia and anemia. * Risk of postoperative apnea decreases to less than 5% when postconeptual age is 48 weeks

Answer 36

* Orthodeoxia related to **Hepatopulmonary Syndrome** * ****HPS Is defined as **intrapulmonary vascular dilatations** and **increased alveolar-arterial (A-a**) **oxygen gradient,** in the setting of **end-stage liver disease**. * 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 37

Mid Esophageal Aortic Valve Short Axis View

Answer 38

* Oliguria is defined as urine output less than **0.5 mL/kg/hr or less than 400 mL per day.** * In the average adult, u**rine output should be between 0.5-1.0 mL/kg/hr.** * Anuria is defined as urine output that is **less than 50 mL per day.** Note that this is different from oliguria.

Answer 39

* **Hypokalemic, Hypochloremic metabolic alkalosis** * This is often accompanied by a **compensatory respiratory acidosis.** Bicarbonate produced in the pancreas is exchanged in the stomach by chloride ions. Chloride-rich gastric fluids are lost in pyloric stenosis, and serum bicarbonate levels are elevated due to increased gastrointestinal absorption. Hypokalemia occurs through gastric losses, secretion of aldosterone, and H+/K+ exchange within the kidneys. *

Answer 40

* Foreign bodies in eye ie. welders * Implanted pacemakers & AICDs * Cochlear implats * Tissue Expanders * Intracranial coils and stents may contain ferrous material * Coronary stents are non-ferromagnetic and considered MRI safe

Answer 41

* Sphenopalatine ganglion block

Answer 42

Hyperchloremic, Hypokalemic, Metabolic Acidosis

Answer 43

1. 10 2. 10 3. 3

Answer 44

* *Underestimation of the TDCO:** 1) Injectate bolus volume is greater than the programmed volume 2) Large volume of fluid is administered during a CO reading 3) Injectate solution’s actual temperature is colder than the preprogrammed Ti 4) Self-measuring Ti probe is warmer than the actual injectate temperature * *Overestimation of the TDCO:** 1) Injectate bolus volume is less than the programmed volume 2) Injectate solution's actual temperature is warmer than the preprogrammed Ti 3) Self-measuring Ti probe is colder than the actual injectate temperature The thermodilution CO (TDCO) technique is the most commonly utilized invasive method for assessing CO. The basis for measurement rests on determining temperature as a function of time. Assuming correct positioning of the pulmonary artery catheter (PAC), two specific temperatures are utilized in this assessment: (1) the programmed temperature of the injectate solution, Ti, and (2) the temperature of the patient’s blood within the main PA, Tb. A bolus of injectate solution (room temperature or colder) is injected into the right atrium. Prior to injection, the temperature of the injectate is programmed into the CO computer. After injection, the temperature change at the thermistor, located at the tip of the PAC, is then measured and integrated over time by the computer. Cardiac output and cardiac index (CI = CO ÷ body surface area) are inversely proportional to the area under the curve. The faster the Tb returns to its baseline, the higher the cardiac output reading. The slower the Tb returns to its baseline, the lower the cardiac output reading.

Answer 45

* While spinal cord injuries are associated with an upregulation of nicotinic acetylcholine receptors, this is typically not evident until **at least beyond 24 hours and usually peaks at 7-10 days beyond the injury date.**

Answer 46

The Ten Major DMGs: - MAP 60-120 mmHg - CVP 4-12 - **Final Na ≤ 155, or 135-160 mmol/L. (MOST IMPORTANT)** - Pressors \< 1 ideal, or low dose pressor - PaO2/FiO2 ratio \> 300 (PaO2 \> 300 on 100% FiO2, 5 PEEP) - pH on ABG 7.25-7.5 - Glucose \< 150 - Urine Output 0.5-3 mL/kg/h - LV EF (%) \> 50 - Hgb \> 10 mg/dL

Answer 47

Use of neuraxial anesthesia is generally not recommended because it can exacerbate disease. The exact mechanism is not clear, and it may be secondary to local trauma from the needle or local anesthetic effects near the nerves.

Answer 48

Hypertension Bradycardia Irregular Respirations

Answer 49

Atrial Fibrillation

Answer 50

Helpful mnemonic: "Syndrome of INAPPropriate ADH: Increased Na (sodium) in PP (urine)."

Answer 51

**SET D** ## Footnote a) **Prolonged emesis or excessive diuretic therapy** can cause a metabolic alkalosis. Respiratory compensation for metabolic events occurs more quickly than renal metabolic compensations for respiratory events. Therefore, patients with metabolic alkalosis decrease their respiratory drive to achieve a PaCO2 increase of 0.5-0.6 mm Hg per 1 mEq/L increase in bicarbonate. b) Patients with **chronic respiratory acidosis,** such as those with chronic hypercarbia from chronic obstructive pulmonary disease (COPD), have a relatively normal pH, an elevated PaCO2, and a serum bicarbonate level that reflects a 4-5 mEq/L increase per 10 mm Hg increase in PaCO2. c) Patients with **metabolic acidosis compensate by increasing respiration to remove carbon dioxide.** The Winter formula is used to determine the appropriate PaCO2 response for a metabolic acidosis: PaCO2 ≈ [HCO3-] \* 1.5 + 8 ± 2. Therefore, an acidemic patient with a serum bicarbonate level of 14 mEq/L would be expected to increase ventilatory drive to achieve a PaCO2 of 29 ± 2 mm Hg e) Although unusual, it is also possible to have a **concurrent metabolic and respiratory acidosis** (or concurrent alkalosis). For example, a patient may have diabetic ketoacidosis, uremia, or diarrhea resulting in a metabolic acidosis coupled with a respiratory acidosis from COPD or hypopnea due to postoperative pain. These patients can experience severe, life-threatening acidemia if not promptly treated

Answer 52

* Intercostal * Subcostal * Iliohypogastric * Ilioinguinal

Answer 53

Landmarks for TAP block ## Footnote The lumbar triangle of Petit - its inferior edge the iliac crest, the posterior edge the latissimus dorsi, and the anterior edge the external oblique. The tip of the triangle of Petit is the rib cage.

Answer 54

* Internal Oblique and Transverse Abdominis

Answer 55

Right ventricle followed by left ventricle

Answer 56

* **Neuraxial administration** of opioids results in analgesia primarily by action in the dorsal horn of the spinal cord in the **substantia gelatinosa** where they inhibit release of excitatory neurotransmitters such as substance P and glutamate and inhibit afferent neural transmission to the brain from incoming peripheral pain neurons. * In the brain, exogenous and endogenous opioids work in the area of the **periaqueductal gray matter of the midbrain and rostral ventromedial medulla** and modulate descending inhibitory pain pathways. * Remember: **Opioids activate G-protein coupled inhibitory receptors both pre and postsynaptically to inhibit the release of excitatory neurotransmitters** (presynaptic) and hyperpolarize postsynaptic neurons to inhibit neuronal transmission.

Answer 57

**The most common being type C (occurs about 84% of the time)**

Answer 58

Middle Cerebral Artery

Answer 59

The quick sequential organ failure assessment (qSOFA) can be used to identify adult ICU patients with a suspected infection that are likely to have a prolonged ICU stay or poor outcome. It may also be used in adult out-of-hospital, emergency room, and general ward patients with suspected infection to identify those that are more likely to have poor outcomes typical of sepsis. It is scored 0-3 with one point each for **altered mental status (GCS \< 15), respiratory rate ≥22, and systolic blood pressure ≤100 mm Hg. A score ≥2 indicates a worse prognosis.**

Answer 60

The dial should read 2 percent! If EtCO2 reads 1% patient is only receiving 1/2 MAC. Explanation 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.** The potency of volatile anesthetics is commonly thought of as relating to the percent concentration delivered to the patient. For example, 1 minimum alveolar concentration (MAC) of isoflurane is approximately 1.1% compared to approximately 2% for sevoflurane. However, these percentages only apply when the barometric pressure is 1 atm or 760 mm Hg (sea level). Most commercially-available variable-bypass vaporizers are designed to deliver fixed partial pressures of volatile anesthetics based on their dialed settings, though they are calibrated by percent concentrations at sea level. For example, an isoflurane variable-bypass vaporizer is designed to deliver isoflurane at a partial pressure of approximately 7.6 mm Hg when the dial is set at 1%. When the vaporizer is at sea level, (1 atm or 760 mm Hg barometric pressure), the partial pressure of 7.6 mm Hg corresponds to a concentration of 1% (7.6 mm Hg / 760 mm Hg) as dialed. Even after bringing the same vaporizer with the same dialed 1% to 5500 meters (barometric pressure of 0.5 atm or 380 mm Hg), the vaporizer is designed to compensate for the change in barometric pressure and continue to deliver isoflurane at nearly the same partial pressure of 7.6 mm Hg. It does this by increasing the vaporizer output such that the delivered concentration increases to approximately 2% (7.6 mm Hg / 380 mm Hg) despite still being dialed at 1%. When at high altitudes, care must be taken when dosing volatile anesthetics based on end-tidal percent concentration as measured by gas analyzers. As barometric pressure decreases, the same end-tidal percentage corresponds to a lower partial pressure of volatile anesthetic. This is due to Dalton’s law of partial pressures which says the total pressure exerted by a mixture of gases is the sum of the individual gases’ partial pressures. Therefore, at an altitude of 5500 m, if end-tidal isoflurane reads 1%, the patient will really only receive the partial pressure equivalent of 0.5 MAC. Similarly, if the vaporizer dial is set to deliver 1%, the end-tidal gas monitor should read approximately 2% isoflurane, but the patient is still receiving the partial pressure equivalent of 1 MAC.

Answer 61

* The incidence of gastroschisis is 0.4-3 per 10,000 births, compared to the more common omphalocele, occurring in 1.5-3 per 10,000 births. * Gastroschisis lesions are comprised of an abdominal wall defect, typically to the right of the umbilical cord, through which small and large bowel are exposed outside of the body. * A omphalocele lesion is a central defect of the umbilical ring and the abdominal contents (stomach, loops of bowel, and possibly the liver) are protruded outside the abdomen, yet enclosed in an amniotic membrane sac externally and peritoneal membrane internally. * Gastroschisis tends to be an isolated lesion while omphalocele is often associated with other anomalies and/or chromosomal abnormalities including Beckwith-Wiedemann, Reiger, and prune belly syndromes and trisomy 13, 18, and 21

Answer 62

Use of fetal heart rate monitoring (FHR) is feasible beginning at **18-20 weeks gestation**

Answer 63

* **Transvalvular pressure = 4 x Peak velocity²** * Using the Doppler function on the echocardiography, one is able to measure the velocity of blood flow. Peak velocity refers to the highest value measured, while the mean velocity refers to the average of all the values measured. Velocity is related to pressure and this principle was first described by the physicist Bernoulli. The Bernoulli equation is based on the principle of conservation of energy, which states that energy is neither created nor destroyed. In a given system, the total energy (sum of potential and kinetic energy) must remain the same. The potential energy is manifested as pressure, while the kinetic energy is manifested as velocity. Based on this principle, the Bernoulli's equation states: P1\*V1 = P2\*V2 When blood flows through a narrow orifice, the velocity increases, but the pressure decreases (to maintain equal energy). By measuring the velocity across a region (e.g. aortic valve), one can calculate the change in pressure. The pressure gradient correlates with the degree of narrowing. ``` The Bernoulli equation that is used in echocardiography is a simplified version: Pressure Gradient (P2 - P1) = 4 \* (Velocity)^2 ```

Answer 64

Root cause analysis is **a focused examination of the root cause(s) of an unforeseen consequence.** This is a structured approach via a preset procedural policy within the institution to examine the cause, timing, nature, and magnitude of an event in order to prevent future events from occurring. There is no universally accepted comprehensive methodology to root cause analysis but common endpoints have been consistent within the literature. All of the following are considered fundamental endpoints or goals of a root cause analysis effort: 1) Establishing a root cause analysis policy along with a trained team of analysts 2) Correctly defining the event and the consequences of the event 3) Correctly determining the situational awareness and reasoning behind why a decision was made 4) Appropriate evidence collection to support or nullify cause-and-effect theories 5) Tracking results of implanted changes 6) Changes instituted following a root cause analysis should be given “high-priority”

Answer 65

The Parkland formula for the total fluid requirement in 24 hours is as follows: 4ml x TBSA (%) x body weight (kg); 50% given in first eight hours; 50% given in next 16 hours.

Answer 66

* Visual evoked potentials (VEP) are the MOST SENSITIVE to anesthetic technique and are rarely ever used. * 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 67

* Subdural injection should be considered when subarachnoid or epidural block does not behave as expected. * Often the symptoms are variable but classically they are: * **minimal or variable motor blockade** * **excessive sensory blockade** * **excessive sympatholysis.** Patients that have experienced a subdural block in the past appear to have a higher incidence of it reoccurring, and these patients may prove to be more difficult for neuraxial placement.

Answer 68

* **pH is increased by 0.015 for each degree below 37 °C.** * **PaCO2 is decreased by 2 mm Hg for each degree below 37 °C. ** Remember: **As temperature decreases, gases become more soluble in solution, leaving less in gaseous form.** Since the partial pressure is a measurement of gas in gaseous form, the partial pressure of a gas decreases as temperature decreases. Therefore, when corrected for colder temperatures, an arterial blood gas will show decreased partial pressures of oxygen and carbon dioxide (PaO2 and PaCO2). **It is important to note that only the partial pressures of gases change as temperature changes. The total amount (content) of the gases does NOT change.**

Answer 69

Four main factors promote faster inhalational induction in infants and children compared to adults by allowing a more rapid rise in FA:FI: 1. Increased minute ventilation relative to FRC (most important) 2. Increased blood flow to vessel-rich organs 3. Decreased blood:gas partition coefficients 4. Decreased tissue:blood partition coefficients

Answer 70

* Volume resuscitation with normal saline and initiation of **D5 1/2 NS at 1.5 times maintenance fluid (4:2:1 rule) is the most appropriate initial medical therapy**. * Remember urine output is KEY; do not ADD potassium until urine output improves

Answer 71

ATRIAL SEPTAL DEFECT, NOT Ventricular septal defect.

Answer 72

1. 100% O2 and hyperbaric O2 2. N acetylcysteine 3. NaHCO3 4. Potassium Iodide 5. Ammonium chloride 6. Atromine + Pralodoxime 7. Pralidoxime 8. Physostigmine 9. Narcan 10. Flumazenil 11. Glucagon 12. Beta blockers 13. Digitalis Ab + Lidocaine + Mg 14. Methylene blue + vitamin C 15. Vitamin K + FFP or Prothrombin Complex Concentrate 16. Protamine 17. Ethanol IV or Fomepizol 18. Anti-venim

Answer 73

Patients who have been receiving echothiophate eye drops are at **risk for significant prolongation of succinylcholine's effects for up to 2 weeks after therapy is discontinued.**

Answer 74

* Early: methicillin-sensitive Staphylococcus aureus (MSSA), Haemophilus influenzae, Streptococcus pneumoniae (Pneumococcus), as well as Proteus, Klebsiella, and Enterobacter species. * Late: methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Acinetobacter species. * E-Coli is more associated with neonates

Answer 75

Distilled water

Answer 76

Sodium Deficit = (140 - Serum sodium) x Total Body Water TBW = Weight in Kg x 0.6 Free water deficit = Total Body water ([Serum Na - 140]/140 Ideal body weight = 50 (male) or 45.5 (female) + 2.3 kg per inch of 5 ft

Answer 77

**- Perimembranous VSD:** Perimembranous VSDs occur in the upper ventricular septum, close to the aortic and/or mitral valve. They account for 70-80% of all VSDs and are the most common congenital anomaly recognized at birth. Perimembranous VSDs shunt blood across the left ventricle outflow tract into the right ventricle at the level of the tricuspid valve. **- Muscular VSD:** Muscular VSDs occur lower in the ventricular septum in the more muscular portion of the septum, closer to the apex of the heart. They account for 20-30% of all VSDs.

Answer 78

Lipophilicity! ## Footnote As opioids cross the dura and enter the CSF, **highly lipophilic drugs will remain primarily at the level of injection.** However, opioids with a low lipid solubility, like morphine, will diffuse greatly and have a widespread in the CSF.

Answer 79

* A magnet over a permanent pacemaker with an asynchronous magnet setting will induce one of the following modes: AOO, VOO, or DOO. Which of these settings is activated depends on the patient's original programming for their underlying pathology. Pacemakers are inserted for several reasons including symptomatic sinus or atrioventricular nodal disease, long QT syndrome, hypertrophic obstructive cardiomyopathy, and dilated cardiomyopathy. There are multiple ways to provide pacemaker capabilities and hundreds of possible devices. When a patient with a pacemaker presents for surgery, evaluation should occur first to determine the reason for pacemaker placement and to determine the patient's other comorbid conditions. Determining if the patient is pacemaker dependent is vital and can usually be ascertained from history or documentation. If not, an electrocardiogram should be obtained to see if every P-wave or QRS complex is preceded by a pacemaker spike. If possible, device interrogation should occur as this gives the best evaluation of pacemaker settings, function, battery life, lead integrity, and device history. Often, programmers (pacemaker technicians) can help guide perioperative management of the pacemaker. In addition, checking serum electrolytes (especially serum potassium) should occur because alterations can make capturing of the pacemaker easier (hyperkalemia) or more difficult (hypokalemia). A pacemaker set in DDD mode will ensure that each spontaneous atrial depolarization is followed by a ventricular depolarization. This will allow AV sequential pacing or "physiologic pacing" because the ventricular rate tracks the atrial rate. These pacemakers usually have a lead in the right atrium and the right ventricle – occasionally in severe disease, there will be three pacemaker wires (one in the right atrium and biventricular leads). The atrial lead fires leading to atrial contraction, followed by a preset interval and then the ventricular lead will follow causing ventricular contraction, resulting in "normal" atrioventricular contraction sequence. It allows sensing and pacing of both chambers along with inhibition of pacing in both chambers. This is important in patients who rely on the atrial kick contribution to cardiac output. It is a versatile mode that is commonly used, however, the development of pacemaker-mediated tachycardia can occur. A major concern in the intraoperative period with pacemakers is **electrocautery interference,** also known as electromagnetic interference (EMI). **EMI may result in oversensing by the pacer causing inappropriate inhibition on the pacing function.** If electrocautery is required, a bipolar cautery device should be used if possible else the grounding pad should be placed as far away from the pacemaker as possible without the electrical pathway going through the pacemaker. **If feasible, bursts should be limited to less than 10 seconds.** Reprogramming of the device may be the best way to avoid intraoperative problems if monopolar electrocautery is planned. **Most clinicians will place the patient into an asynchronous mode (AOO, VOO, DOO), this causes the pacemaker to fire at a fixed preset rate, independent of the patient's underlying cardiac activity.****The rate will need to be higher than the patients underlying rhythm to try to ensure that an R-on-T phenomenon does not occur, protecting the patient from arrhythmias.**This is crucial for patients that are not pacemaker dependent.**Setting the patient in asynchronous mode can result in competition with the patient's intrinsic rhythm and may result in the development of a malignant arrhythmia, thus appropriate means to treat this should be available (namely a defibrillator and appropriate antiarrhythmic and blood pressure support medications).**In addition,**if the patient has an automated implantable cardioverter defibrillator (AICD), this needs to be deactivated if electrocautery is planned under certain circumstances.**Tachyarrhythmia therapies, such as overdrive pacing, also need to be disabled. This may also be completed with a magnet in modern devices. Of note,**a magnet does not affect pacemaker function for modern AICDs. Rather, magnets inhibit defibrillation in those devices.** In the perioperative period, placement of a magnet over the pacemaker may have variable results. Nearly all modern pacemakers will switch to a continuous asynchronous mode at a preset heart rate – the exact mode is variable (and maybe unknown without interrogation). Generally, DDD pacemakers switch to DOO, VVI switches to VOO, and AAI switches to AOO. **If switched to asynchronous mode, the pacemaker will shut down the demand (inhibition) function allowing protection of pacemaker-dependent patients during electrocautery. Placing a magnet is not without risk since asynchronous pacing may trigger ventricular asynchrony in patients with hypoxia, electrolyte imbalances, and myocardial ischemia.** It is useful to know the pacemaker model and what will happen when a magnet is placed (if an electrophysiologist or device specialist is unavailable, calling the manufacturer can be invaluable in helping to determine this).

Answer 80

* Stage I of labor analgesia requires sensory blockade of uterine contractions **(T10-L1 alone)**. * The **T12-L1 and S2-4 dermatomes** need to be covered during the second stage of labor for a patient to remain comfortable.

Answer 81

15 minutes

Answer 82

1. Renal tubular acidosis type 1 is seen with **Sjogren syndrome** and is caused by dysfunction in the alpha cells of the collecting tubule. 2. Renal tubular acidosis type 2 is associated with **Fanconi syndrome** and is caused by defects of the proximal tubule, leading to bicarbonate wasting. 3. Renal tubular acidosis type 4 is caused by **aldosterone deficiency or resistance.**

Answer 83

* The **ischial tuberosity, greater trochanter of the femur, and sciatic groove** are all anatomic landmarks for an infra-gluteal sciatic nerve block.

Answer 84

It is reduced * Key point: In the setting of hyperchloremia (from large saline infusion) the plasma Cl- concentration increases which results in a **decrease in HCO3- to maintain net neutrality.** The decrease in HCO3- reduces the SID.

Answer 85

* NO * BMI has not been shown to be a risk factor for developing GERD during pregnancy (B). Risk factors for developing GERD during pregnancy include: **gestational age, GERD symptoms prior to pregnancy, and multiparity.** Maternal age has an inverse correlation with development of GERD symptoms.

Answer 86

**Scenario C** * When a patient’s intrinsic heart rate is greater than the set pacemaker rate along with a pacemaker in an asynchronous mode, an **R-on-T phenomenon may occur leading to ventricular tachycardia or ventricular fibrillation.** * As long as the patient’s intrinsic heart rate is less than the pacemaker rate setting, complications are unlikely. However, **if the patient’s intrinsic heart rate increases above the pacemaker rate, the pacemaker will still continue to pace and the potential for an R-on-T phenomenon develops.** This is **where a ventricular depolarization (represented by the R wave) initiated by the pacemaker occurs during the relative refractory period of the cardiac conduction cycle (represented by the T wave).** An R-on-T phenomenon can lead to life-threatening ventricular tachycardia and/or ventricular fibrillation. Accordingly, if a patient’s pacemaker is changed to an asynchronous mode perioperatively, it should be changed back to its original setting as soon as possible after the surgery is complete.

Answer 87

* **Sodium bicarbonate (mEq) = 0.2 \* patient weight (kg) \* base deficit (aka base excess)**

Answer 88

There is a clear correlation between CK-MB and 6-month mortality rates, with values ≥20 ng/ml corresponding to 20.2% mortality. Troponins have also been used to monitor post-cardiac surgery myocardial injury, with increased troponin I (\>3.5 ng/ml) having predictive and prognostic value for cardiac-associated death and major postoperative complications such as malignant ventricular arrhythmia, myocardial infarction, congestive heart failure, and the need for myocardial revascularization within 1 year following CABG. Troponin is integral to cardiac and skeletal muscle contraction. It acts by binding to the protein tropomyosin. Tropomyosin is an inhibitory molecule that prevents the actin-myosin fiber cross-bridge. After calcium binds to troponin, troponin inhibits tropomyosin via reversible conformational change. This allows actin and myosin to bind and muscle contraction to occur. Troponin is not found in smooth muscle.

Answer 89

The list of patients who should receive prophylaxis is below: - Patients with a **prosthetic cardiac valve** - Patients who have **previously had IE** - Patients with **unrepaired cyanotic congenital heart disease (including palliative shunts/conduits)** - Patients with **congenital heart defects which were repaired with prosthetic material within 6 months of the procedure** - Patients with **repaired congenital heart disease with residual defects at the site, or adjacent to the site, of a prosthetic patch or device** - **Cardiac transplantation recipients who develop cardiac valvulopathy** (substantial leaflet pathology and regurgitation) Of note, **prophylaxis only applies to certain surgical procedures:** - **Dental procedures t**hat involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa - **Invasive respiratory tract procedures** that involve incision or biopsy of the respiratory mucosa (e.g. tonsillectomy, adenoidectomy) - **Infected skin, skin structure, or musculoskeletal tissue** Antibiotics are **no longer recommended for endocarditis prophylaxis for patients undergoing genitourinary or gastrointestinal tract procedures.** The preferred prophylactic regimen is Amoxicillin 2 g given as a one time oral dose 30-60 min before the procedure.

Answer 90

1. At least **60 days should pass after a myocardial infarction (MI)** before noncardiac surgery is performed in the absence of any coronary intervention. 2. Wait **14 days after balloon angiography** (without coronary stenting) for elective surgery. 3. Wait **30 days after BMS implantation** for elective surgery and continue dual-antiplatelet therapy (DAPT) until that point. 4. Wait **180 days after DES implantation for elective surgery** and continue dual-antiplatelet therapy (DAPT) until that point. KEY POINT: The recommended duration of dual antiplatelet therapy (DAPT) varies: in the setting of **PCI for ACS the** **current recommendation is for 12 months of DAPT regardless of the type of stent implanted**, while for PCI in the non-ACS setting at least 12 months of DAPT is recommended for patients receiving DES and **at least 1 month** and up to 12 months for patients **receiving BMS.** Earlier discontinuation of DAPT in patients at high risk of bleeding is reasonable if this risk exceeds the perceived benefit.

Answer 91

**Diluting 7.5 mL of 2% lidocaine into a total volume of 30 mL will produce a 0.5% lidocaine solution.** An upper extremity Bier block can be performed using a wide range of local anesthetic (most commonly lidocaine) volumes and concentrations. Some practitioners prefer smaller volumes of concentrated lidocaine solution (e.g. 10-15 mL of 2% lidocaine) while others prefer larger volumes of dilute lidocaine (e.g. 30-40 mL of 0.5% lidocaine). Recall that in order to minimize the risk of local anesthetic systemic toxicity, no more than 5 mg/kg of lidocaine (without epinephrine) should be administered. In order to dilute a concentrated drug, the following equation (proportion calculation) is used: V1 x C1 = V2 x C2 Where: V1 = volume of initial drug needed, C1 = concentration of initial drug, V2 = desired volume of dilute drug, C2 = desired concentration of dilute drug By rearranging the equation, this question can be solved: V1 = (V2 x C2) / C1 V1 = (30 mL x 5 mg/mL) / 20 mg/mL V1 = 150 mg / 20 mg/mL **V1 = 7.5 mL (D)** **Note: the percent concentration (i.e. 0.5 and 2) can be used instead of mg/mL.**

Answer 92

**Oxygen consumption in an adult is approximately 3-4 mL/kg/min and functional residual capacity (FRC) is 30 mL/kg.** Therefore, in this patient O2 consumption is approximately 210 mL/min (assuming 3 mL/kg/min) and FRC is 2100 mL. Since oxygenation is solely dependent on the FRC during apnea, the following equation gives time until hypoxemia: Minutes until hypoxemia = [FRC (ml) ÷ O2 consumption (mL/min)] \* %O2 in FRC. Therefore, in this patient: 2100 mL ÷ 210 mL/min \* 100% O2 in the FRC = 10 minutes. The assumption would be FiO2 = 21% if the clinical scenario did not indicate preoxygenation (or denitrogenation) for 10 minutes with FiO2 = 1.0. Desaturation would occur in 1/5th of the time on room air, which would be about 2 minutes in this scenario. Reduced FRC and increased O2 consumption are the reasons why morbidly obese patients quickly desaturate when apneic. Also, note that FRC is reduced by 10-15% when going from upright to supine, and the FRC is reduced another 10% with induction of general anesthesia. Children, especially infants, desaturate quickly due to increased oxygen consumption (up to 7-8 mL/kg/min).

Answer 93

Predicts an increased incidence of **obstructive sleep apnea and potential difficulty with mask ventilation and intubation.**

Answer 94

* **α1:** Positive inotropy * **β1:** Positive chronotropy, **dromotropy (conductivity of a nerve),** lusitropy (myocardial relaxation), and inotropy * **β2:** Positive chronotropy \> inotropy

Answer 95

* The fresh gas inlet should not be positioned between the patient and the inspiratory or expiratory valves in a traditional circle system.

Answer 96

TRUE ## Footnote **Hepatocytes, most immune cells, erythrocytes, and brain neurons** utilize insulin-independent glucose transporters for the majority of their glucose uptake. The insulin receptor is a **tyrosine kinase receptor composed of α and β subunits.** When insulin binds to the insulin receptor, the receptor phosphorylates and activates several downstream proteins, which in turn activate several different cellular pathways. Important downstream effects of insulin receptor activation include, but are not limited to: 1) Activation of glycogen synthase which converts glucose to glycogen (myocytes and hepatocytes) 2) Activation of lipid synthesis pathways (adipocytes and hepatocytes) 3) Translocation of GLUT4 transporters from storage vesicles to the cell membrane. The GLUT4 transporter is a high-affinity glucose transporter that mediates transfer of glucose from plasma into the cell membrane. It is especially plentiful on myocytes and adipocytes.