Advanced True Learn #2 Flashcards
(229 cards)
1
Q
Hoow do gabapentoids create relief on a molecular level?
A
The gabapentinoids (gabapentin and pregabalin) result in a
- Decreased release of glutamate*, *norepinephrine*, and *substance P (all chemicals that are considered pronociceptive) via their binding to voltage-gated calcium channels within the central nervous system.
2
Q
The most common cause of death from subarachnoid hemorrhage (SAH) within the first 24 hours?
A
Rebleeding (Peaks at 24 hours)
3
Q
When does vasospasm events occur most commonly after SAH?
A
Vasospasm typically develops by the third day and peaks within 5-10 days, resolve over 10-14 days
2/3 of SAH patients vasospasm
4
Q
What blood product should be used to minimize dilutional coagulopathy?
A
Fresh frozen plasma should be used to reduce the risk of dilutional coagulopathy during massive transfusion.
5
Q
With obstructive disease, who responds the most to bronchodilator therapy?
A
Moderate disease
Healthy, severe, and mild disease = Mild Response to bronchodilators
6
Q
The most common cause of sudden stridor 24 to 96 hours post thyroidectomy is what?
A
The most common cause of sudden stridor 24 to 96 hours post thyroidectomy is hypocalcemia.
7
Q
Post Op Thyroidectomy
Stridor and difficulty with phonation.
Diagnosis?
A
Damage to the recurrent laryngeal nerve is more likely to cause early stridor and difficulty with phonation.
8
Q
Post Op Thyroidectomy
Change in Pitch of Voice noted on extubation
Diagnosis?
A
Damage to the superior laryngeal nerve would cause a change in the pitch of the patient’s voice as the superior laryngeal nerve innervates the cricothyroid muscle.
9
Q
Why does phosphorous and glucose levels drop with TPN?
A
Total parenteral nutrition carries a significant glucose load that increases the pancreatic secretion of insulin.
Insulin causes several metabolic effects, including the cellular uptake of glucose and phosphate
10
Q
What are 3 scenarios that low phosphate levels are encountered?
A
- Refeeding syndrome
- Diabetic ketoacidosis
- Large decreases in PCO2 (e.g., hyperventilation during hypercarbic respiratory failure)
11
Q
What is Refeeeding Syndrome?
A
Refeeding syndrome is a term that refers to various metabolic abnormalities that may complicate carbohydrate administration in subnourished patient populations.
Refeeding syndrome (a constellation of fluid and electrolyte disorders, most notably severe hypophosphatemia) after starting TPN occurs frequently in patients who have had poor or no nutritional intake for >72-96 hours. Patients at high risk for refeeding syndrome also have reduced levels of prealbumin (< 10 mg/dL).
Hypophosphatemia is the most well known, and perhaps most significant, element of the refeeding syndrome, and may result in sudden death, rhabdomyolysis, red cell dysfunction, and respiratory insufficiency.
12
Q
Hypokalemic periodic paralysis:
Inheritance pattern?
What channel is affected?
A
Hypokalemic periodic paralysis is a rare autosomal dominant disorder resulting in an abnormal dihydropyridine sensitive calcium channel
13
Q
Gastroschis vs. Omphalocele
Which is more common?
A
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
14
Q
What is the Pentalogy of Cantrell?
A
1) Omphalocele
2) Ectopia cordis (heart partially or completely outside thorax)
3) Ventricular septal defect or ventricular diverticula
4) Sternal cleft
5) Anterior diaphragmatic hernia
15
Q
What is the best test for carcinoid syndrome diagnosis?
A
urine 5-hydroxyindoleacetic acid. (Urine 5-HIAA)
16
Q
What is the formula for determining how much sodium bicarbonate to give?
A
Initial sodium bicarbonate (mEq) =
[0.3 * patient weight (kg) * (24 – patient HCO3 mEq/L)]/2
OR
The amount of sodium bicarbonate that will normalize the pH in most patients can be approximated using the formula:
Sodium bicarbonate (mEq) = 0.2 * (kg) * base deficit
17
Q
Butorphanol mechanism?
A
Butorphanol is a mixed opioid agonist-antagonist with partial agonism of the mu and kappa opioid receptors.
If it is used with opioid full agonists, the partial agonist properties of butorphanol will behave as an antagonist. The effect of butorphanol leads to pain relief but does not lower the seizure threshold.
18
Q
What are the absolute contraindications to ECT?
A
pheochromocytoma
Recent stroke
Recent intracranial surgery
Intracranial mass lesion
Recent MI
Unstable cervical spine
19
Q
What physiological changes are seen in ECT?
A
The first 5-10 second tonic phase of the seizure is characterized by parasympathetic activity with bradycardia and hypotension.
The second clonic phase of the seizure lasts up to 10 minutes and is characterized by sympathetic activation with hypertension and tachycardia.
20
Q
How soon do you have to wait after an MI to have ECT?
A
American College of Cardiology-American Heart Associate guidelines suggest a 4-6 week delay in elective surgery, such as ECT, after an uncomplicated myocardial infarction
21
Q
What is the osmolarity difference of LR and Plasmalyte?
A
The osmolarity of Plasmalyte is 294 mOsm/L, which is iso-osmolar compared to the lactated Ringer solution, which is hypoosmolar (273 mOsm/L).
22
Q
How do you identify the Lateral Femoral Cutaneous nerve by landmark technique?
A
The LFCN may be anesthetized by injecting local anesthetic:
2-2.5 cm medial and 2-2.5 cm inferior to the ASIS and above and below the fascia lata.
23
Q
What position do you put the patient should you suspect you have an air lock on TEE for Venous Air Embolism?
A
Left Lateral Decubitus Position
Place surgical site below heart (if able)
Lower the head position & compress the jugular veins (if surgical site above the neck)
Reposition the patient into left lateral decubitus, trendelenberg, or left lateral decubitus head down position (controversial - poor evidence & often impractical to do in the OR)
24
Q
What are the benefits to adding Epinephrine in Locals Anesthetics?
A
- Increases the block duration and intensity
- Decreases systemic absorption due to its vasoconstrictive properties
- Direct analgesia via its α2-adrenergic agonist properties
25
What is the max dose of Mepivacaine with and without epinephrine?
5 mg/kg without epi
7 mg/kg with epi
26
What is the max dose of Ropivacaine with and without epinephrine?
3 mg/kg without epinephrinie
3.5 mg/kg with epinephrine
27
Tracheoesophageal fistulas (TEFs) are the result of a midline defect during the development of the fetus.
Other defects occur as part of the VACTERL association: Vertebral, Anal, Cardiac, Tracheal, Esophageal, Renal, and Limb.
Of these associatons, which is most common?
The most common defect associated with TEF is a ***_cardiac defect._***
## Footnote
***_20-35% of the time_***
28
What physiological derangements can be found to negative affect SSEP?
Evoked potentials are sensitive to physiologic changes including:
***_hypotension_***
*_**Temperatue -** **hypothermia** + **h****yperthermia**_*
***_hypoxia_***
***_anemia_***
**\*\*Bad SSEP --\> Fix one of these if you can\*\***
*_Acid-base balance has not been shown to negatively impact SERs._*
29
**When do neurological findings of evoked potential monitoring become clinically signficant (Flow / mass)?**
_What critical value can anesthesia drop this to?_
*SSEP above what value may not be clinically affected?*
**Clinical neurologic findings become abnormal below a cortical blood flow of 25 ml/min/100g of brain tissue.**
_Anesthesia may lower this critical value to as low as 15 ml/min/100g of brain tissue._
Somatosensory evoked potential recordings are not affected until cortical blood flow falls below ***_20 ml/min/100g of brain tissue._***
30
What is a positive apnea test utilized in the ICU?
To determine whether or not there is spontaneous ventilation, an apnea test is performed. This is done by removing the patient from the ventilator while providing oxygen insufflation at the level of the carina. **If the patient does not take a spontaneous breath by the time their PaCO2 reaches 60mmHg (or 20 mmHg above baseline),** the apnea test is declared positive.
31
What is the pathology associated with malignant hyperthermia?
Malignant hyperthermia-susceptible patients have ***_RYR1 defects_*** that, in the presence of a triggering agent (succinylcholine or any volatile anesthetic), cause prolonged opening of the channel which leads to sustained muscle contraction.
32
What anti-arrythmics are contraindicated in the setting of Malignant Hyperthermia?
Antiarrhythmics may be necessary, but ***_CCBs_*** are contraindicated when a patient has been treated with dantrolene.
Although the exact mechanism for interaction is unknown, *_dantrolene can decrease the release of calcium from the SR resulting in an additive or synergistic effects with calcium channel blockers._*
Arrhythmias, myocardial depression, worsening hyperkalemia, and severe cardiovascular collapse have all been reported in animal models and humans.
33
Each 20 mg vial of dantrolene contains *_how many grams_* mannitol?
each 20 mg vial of dantrolene contains ***_3 g_*** of mannitol.
34
What is the dose of Dantrolene to treat malignant hyperthermia?
Assign several people to prepare **2.5 mg/kg IV Dantrolene** or
Initial: 2.5 mg/kg
Monitor patient continuously
**Give repeat doses of 1 mg/kg** until symptoms subside or a cumulative dose of **10 mg/kg is reached**
35
Symptomatic patients with serum Na+ = 120 mEq/L should have the serum osmolality corrected with *_what therapies?_*
1. **3% hypertonic saline** (not normal saline)
2. **Loop diuretics** (Furosemide, are utilized to eliminate excess free water and treat the sodium deficit.)
36
What is the dose of hypertonic saline?
**Asymptomatic**: IV: Hypertonic saline: 3% NaCl: *_50 mL bolus over at least 5 minutes_*
**Symptomatic**: IV: Hypertonic saline: 3% NaCl: *_100 mL over 10 minutes_*; if symptoms persist, may repeat up to a total of 3 doses over a period of 30 minutes (Sterns 2019; Verbalis 2013).
Alternatively, some experts recommend *_150 mL over 20 minutes up to a total of 2 doses while measuring serum sodium between infusions_* (ESE/ESICM/ERAEDTA [Spasovski 2014]).
37
What is anesthesia dolorosa?
Anesthesia dolorosa is pain in an area that lacks sensation, often involving the face.
38
When is anesthesia dolorosa most seen?
Anesthesia dolorosa is a **feared complication of neurolytic blocks for the treatment of trigeminal neuralgia** (eg, radiofrequency rhizotomy).
It can also be in the distribution of one of the divisions of the trigeminal nerve or the occipital nerve. **Anesthesia dolorosa is difficult to treat and is generally considered to be nonreversible.**
Anticonvulsants, antidepressants, opiates, and psychological support are the mainstays of management. Motor cortex stimulation has been shown to, have some promise in preliminary studies. **Anesthesia dolorosa after the neurolytic treatment of trigeminal neuralgia is often accompanied by eye pain.**
39
The majority of patients with myelomeningocele also have what pathology?
**Chiari II**
**Hydrocephalus**
The majority of patients with myelomeningocele also have Chiari II malformation, which involves herniation of the brainstem through the foramen magnum and frequently hydrocephalus secondary to blockage of the fourth ventricle.
40
What are the three phases to Liver Transplantation?
The **preanhepatic** stage begins with *_incision and ends with cross-clamping of the major vessels of the liver_* (portal vein, hepatic artery, inferior vena cava, or hepatic vein).
The **anhepatic** stage starts with *_cross clamping and continues until anastomosis are mad_*e and perfusion restarts – in other words from occlusion of vascular inflow to start of graft reperfusion.
The **neohepatic** phase begins with *_unclamping of the portal vein when reperfusion_* of the donor liver starts and continues during hepatic artery, biliary duct anastomosis, and abdominal closure.
41
What is the blood flow & Oxygen contents of portal vein and hepatic artery for liver?
* *Oxygen:**
* _50% Portal Vein & 50% Hepatic Artery_*
## Footnote
**Blood flow:**
*_1. 75% Portal Vein_*
*_2. 25% Hepatic Artery_*
42
What enzyme is defective in Gilbert's Disease?
Gilbert syndrome is the most common cause of jaundice in the adult population of the United States and is characterized by a decrease in the activity of the hepatic enzyme
***_bilirubin glucuronyltransferase_***
Patients with Gilbert syndrome are said to only have about 1/3 of the normal enzyme activity.
43
What is the gold standard medication and dose for ECT?
The gold standard induction agent is ***_methohexital (1-1.5 mg/kg)_*** because it has less anticonvulsant activity compared with other anesthetic agents.
44
What does Etomidate do to seizure duration for ECT?
Etomidate ***_increases the seizure duration_*** for ECT
45
What does Methohexital effects have on hemodynamics?
*_Methohexital_* does have:
1. **Cardiovascular depressant effects**
2. **Lower SVR**
- but the cardiovascular effects occur in a dose-dependent manner
46
How does Methohexital affect seizure duration?
Methohexital ***_does not prolong the seizure duration_***
47
A blood gas taken from a patient in DHCA shows pH 7.25 and PaCO2 60 mm Hg when run at 37 °C.
## Footnote
**If the patient’s temperature is 18 °C, which of the following would be the expected temperature-corrected values?**
1. pH is increased by 0.015 for each degree below 37 °C
2. PaCO2 is decreased by 2 mm Hg for each degree below 37 °C
***_pH = 7.535_***
***_PaCO2 = 22_***
48
Why are PaO2 leves normal in Severe Anemia, CO poisoning and Methemoglobinemia?
PaO2 is not a function of hemoglobin content or of its characteristics, but only of the ***_alveolar PO2 and the lung architecture (alveolar-capillary interface)_***.
This explains why patients with severe anemia, carbon monoxide poisoning, or methemoglobinemia can (and often do) have a normal PaO2.
49
**How do volatile anesthetics affect cerebral parameters?**
CMRO2, CBF, ICP
**Decrease** CMRO2
*_increase_* CBF
*_Increase_* ICP
50
Past 1 MAC how do volatile anesthetics behave on cerebral parameters?
In general, volatile agents produce increases in CBF and ICP with reduction in CMRO2 when given at \> 1.0 MAC.
51
For an epidurarl, which has least amount of placental transfer?
***_2-chloroprocaine_*** has the least amount of placental transfer of all local anesthetics because it is rapidly metabolized in the plasma by plasma cholinesterase.
52
What type of local anesthetic is 2-chloroprocaine?
Ester (One "i")
53
How do you dose single-shot caudal epidural blocks?
For most standard concentrations of local anesthetics (e.g. **0.125-0.25% bupivacaine or 0.2-0.3% ropivacaine)**
Dosing of single-shot caudal epidural blocks in infants and young children is done on a **ml/kg basis**.
(Dosing for a single-shot block in infants and young children is done on a ml/kg basis since it is volume of local anesthetic that affects the height of the block, not the mg of drug)
Using **0.5 mL/kg** of local anesthetic will cover the **sacral dermatomes**
**1 mL/kg** will cover up to the **low thoracic dermatomes**
**1.25 mL/kg** will cover up to the **mid thoracic dermatomes**
54
In newborns, the dural sac typically ends at ***_"A"_*** and the conus medullaris at ***_"B"_***. ?
In adults, the dural sac typically ends at ***_"C"_*** and the conus medullaris at ***_"D"?_***
In newborns, the dural sac typically ends at ***_S3_*** and the conus medullaris at ***_L3_***
In adults, the dural sac typically ends at ***_S1-S2_*** and the conus medullaris at ***_L1-L2_***
55
What is the treatment for active bleeding for a Hemophilia A patient?
In the event of active bleeding, cryoprecipitate is typically the product of choice as it contains high concentrations of:
## Footnote
***_1. factor VIII (Cryo, FFP or Recombinant)_***
***_2. fibrinogen_***
56
**HIT Type 1:**
Timing?
Clinical picture?
Mechanism?
**2-5 days of heparin.**
**Mild thrombocytopenia & no thrombosis**. It is generally not considered clinically significant.
The mechanism behind Type I thrombocytopenia is **heparin binding to platelets at GPIb receptors causing the release of ADP, which results in platelet aggregation.**
57
***_HIT Type 2_***
Timing?
Clinical picture?
Mechanism?
***_5-9 days_*** after heparin
**Severe thrombocytopenia**, with platelet counts \< 100k or a fall of \>30-50% from baseline values over several days.
**The mechanism is via IgG-, IgA-, and IgM-mediated antibodies towards heparin and platelet factor 4 (PF4)** complexes, which results in platelet activation and clot formation.
About 20% of patients with Type II thrombocytopenia will develop **thrombosis due to massive thrombin generation** (HIT with thrombosis or HITT)
58
How do you diagnose HIT Type 2?
1) **Heparin-induced serotonin release assay (SRA).** This is considered the GOLD STANDARD for diagnosis.
2) **Enzyme-linked immunosorbent assay (ELISA) specific for heparin and PF4 complexes.** Although these patients may have a positive test they do not always go on to develop thrombosis.
3) **Heparin-induced platelet activation assay.** The table below may serve as a primer for serologically diagnosing HIT type II:
59
*_What is the half life of Bivalirudin?_*
**Dosing for CPB?**
*_24 minutes_*
Typical CPB dosing is a **1 mg/kg bolus** followed by a **2.5 mg/kg/hr infusion.**
60
What does the CAM-ICU questions ask?
The CAM-ICU asks the following:
Is there an **acute change in mental status** or fluctuating course? (yes/no)
Is the patient **inattentive** or easily distracted? (yes/no)
Is there an **altered level of consciousness** or RASS other than zero? (yes/no)
Does the patient experience **disorganized** thinking? (yes/no)
61
**List the confirmatory tests for Brain Death** when you cannot perform apnea test or contraindications to apnea test.
1. Crebral angiography
2. Transcranial Doppler
3. Magnetic resonance angiography
4. Computed tomographic angiography
5. Radionuclide brain imaging
6. Electrophysiology such as electroencephalography
62
**Phentolamine**
Mechanism? (Receptors, Selectivity)
Phentolamine is a ***_short-acting non-selective alpha-1 and alpha-2 antagonist_***
63
**Phentolamine**
Duration of action?
10-15 minutes
64
**Phenoxybenzamine**
Mechanism? (Receptors and Selectivity)?
Half Life?
Phenoxybenzamine is a **long-acting non-selective alpha-1 and alpha-2 antagonist**
*_Elimination half-life of 24 hours_*
It is commonly used in the preoperative treatment of pheochromocytoma. It should be noted that the alpha-2 effects can potentially worsen tachycardia and hypertension (opposite effects of dexmedetomidine).
65
**Mirtazapine**
Mechanism?
Indication?
**Mirtazapine** is a ***_selective alpha-2 blocker_*** that is used in the treatment of **depression**.
66
**Prazosin**
Mechanism? (Selective? Receptors?)
Prazosin and other drugs in the same class (e.g. terazosin, doxazosin) are **selective alpha-1 antagonists** with varying lengths of action
67
How do you determine atlantoaxial instability/injury radiographically?
AADI: anterior atlantodental interval
The anterior atlantodental interval is the distance between the atlas and the dens in the midsagittal view.
***_Greater than 2-3 mm is considered abnormal and is suggestive of atlantoaxial instability or injury._***
If instability at the atlantoaxial joint is present, widening will be seen with flexion, as seen in these images.
68
What is ankyloglossia?
***_Ankyloglossia, or "tongue-tie"_*** is a congenital defect that limits tongue movement.
(See photo)
69
What is the treatment for Pneumocephalus?
Pneumocephalus after craniotomy is a common occurrence with resolution generally occurring at about *_2-3 weeks._*
***_Treatment:_***
1. Supportive/Conservative
2. Bed rest in an upright position
3. High concentration oxygen
4. Avoidance of maneuvers that might increase intrasinus pressure (such as nose-blowing or valsalva maneuver)
5. Antibiotics if there is evidence of meningism.
6. Aspiration of air loculi by neurosurgery (Defintive and if there is tension)
70
What is the risk factors for Acute MR following MI?
1. **Advanced age**
2. **Prior myocardial infarction**
3. **Infarct extension**
4. **Inferior or posterior MI** (Severe MR is ten times more likely to occur after posterior or inferior wall compared with anterior wall myocardial infarction)
5. **Multiple vessel CAD**
6. **Recurrent ischemia**
71
The spread of neuraxial opioids is predicated on what?
The spread of opioids is related to the h**ydrophilicity and lipophilicity of the opioid**.
Fentanyl is very lipid soluble and remains near the spinal level it is injected at, whereas morphine has a wide spread in the CSF.
72
What is pKA influence on onset?
When considering pKa, it is often associated with the **speed of onset of the drug, especially local anesthetics**.
This is why sodium bicarbonate may be added to some local anesthetic mixtures.
73
What determines **duration** of action of local anesthetics?
**Protein binding** is related to the duration of action of LA
74
What determines **potency** of action of local anesthetics?
Lipid Solubility
75
How does 2,3 DPG affect oxy-hemoglobin curve shifts?
Decreased = Left Shift
Increased = Right shift
76
For pyloric stenosis, what should be your bolus rate for a 4 week old 3 kg neonate?
***_10 to 20 mL/kg/hr_*** of normal saline with 20 mEq/L of potassium.
For a 3-kg infant, this includes an infusion rate in the range of ***_30 to 60 mL/hr._***
77
How quickly does the temperature change in Malignant Hyperthermia?
The temperature rise in malignant hyperthermia can be as high as ***_1°C every 5 minute_***s accompanied by an increase in end-tidal CO2
78
How long will a Bier Block last?
It can provide complete motor and sensory anesthesia for up to ***_approximately 90 minutes_*** with a success rate of 94-98%.
79
After injection for Bier Block, what is the minimum time you must wait?
Following the procedure (***_or after 20-30 minutes_*** after the local anesthetic was injected if the procedure is short), the tourniquet is then released
80
What medications and doses you use for Bier Block?
Lidocaine is most commonly used; 15-20mL of 2% lidocaine is a fairly standard dose
- Also can use 30-40 mL of 0.5% (More volume but lower concentration)
- Ropivacaine has been described (1.2 and 1.8 mg/kg)
81
Mechanism of how a Bier Block works
1. **Blockade** of distal nerves is achieved via diffusion of local anesthetic across the vascular bed from veins into capillaries surrounding peripheral nerves and then into vasa nervorum which then produce nerve conduction block
2. **Diffusion** of local anesthetic into local tissues
3. **Tissue acidosis**
4. **Hypothermia**
5. **Distal Ischemia** - contributes to a degree of anesthesia and analgesia by impairing nerve conduction and motor end plate function. Even without any local anesthetic injection, after 20 minutes of tourniquet time, there is analgesia to pinprick sensation. Local anesthetic, therefore, significantly improves the speed of onset and density of anesthesia but is not the sole cause.
82
Retrobulbar vs. Peribulbar Blocks:
Which is higher incidence of retrobulbar hematoma?
Retrobulbar is higher incidence than peribulbar
83
Retrobulbar vs. Peribulbar Blocks:
Which is higher incidence of globe rupture?
**Retrobulbar** has higher incidence of globe rupture
84
What is the downside of peribulbar blocks compared to retrobulbar blocks?
Peribulbar blocks have a higher incidence of **chemosis** but a lower incidence of retrobulbar hematoma when compared with the retrobulbar block.
Chemosis is swelling of the tissue that lines the eyelids and surface of the eye (conjunctiva). Chemosis is swelling of the eye surface membranes because of accumulation of fluid. This symptom is often related to an allergic response.
85
What is the ideal leak pressure of an uncuffed ETT tube in a pediatric patient?
The ideal leak pressure of an uncuffed ETT in pediatric patients is ***_20-30 cm H2O_***.
86
If a leak pressure *_of what level_* H2O is measured during pediatric case, the ETT should be replaced with a smaller size.
If a leak pressure ***_\>40 cm_*** H2O is measured, the ETT should be replaced with a smaller size.
87
A leak pressure *_of what value_* H2O may indicate an inadequate seal and may result in an increased risk of aspiration, difficulty providing positive pressure ventilation, and/or inaccurate EtCO2 monitoring\>
A leak pressure ***_\< 10-20 cm_*** H2O may indicate an inadequate seal and may result in an increased risk of aspiration, difficulty providing positive pressure ventilation, and/or inaccurate EtCO2 monitoring.
88
How do NSAIDS like ketorolac work?
Administration of NSAIDs results in the reversible inhibition of prostaglandin synthesis, which is vital for maintaining renal perfusion.
Normal = Prostaglandins vasodilate the afferent arterioles maintaining renal perfusion.
With the **inhibition**, **the afferent arterioles vasoconstrict, decreasing renal perfusion.**
89
What is the gold standard for pulmonary fibrosis diagnosis?
Pulmonary fibrosis requires a ***_biopsy_*** for definitive diagnosis.
A lung biopsy remains the gold standard for diagnosis of IPF. In order to obtain adequate samples, ***_surgical biopsies_*** via thoracotomy or VATs are needed because larger pieces of tissue from multiple sites are required.
***_Transbronchial biopsies obtained via bronchoscopy are not large enough_*** and can only rule out other causes of similar presentations (e.g. infection, cancer, sarcoidosis).
90
What is the difference in increased Airway resistance vs. Increased Pulmonary Compliance?
Both ***_peak inspiratory and plateau pressure increase when elastic resistance (compliance) increases_***.
***_Only peak inspiratory pressure increases when airway resistance increases._***
91
What is the differential for elevated peak airway pressures but unchanged plateau pressures?
*_(Think of obstruction prior to the main bronchioles)_*
Airway compression
**Bronchospasm (Not the tube but the circuit)**
Foreign body
Kinked endotracheal tube
Mucus plug
Secretions
92
What is the differential for elevated peak airway pressures and elevated plateau pressures?
Abdominal insufflation
Ascites
Intrinsic lung disease
Obesity
Pulmonary edema
Tension pneumothorax
Trendelenburg position?
93
What two metals are considered MRI safe?
**Aluminum** and **brass** are the two metals considered MRI safe.
94
What is the mechanism of Phenoxybenzamine?
Phenoxybenzamine is a ***_non-specific irreversible alpha blocker,_*** thus blockade of alpha-2 receptors can cause increased heart rate and blood pressure.
95
What constellation make up Tetralogy of Fallot?
Tetralogy of Fallot is the most common and prototypical cyanotic congenital heart disease. Associated defects include:
## Footnote
**1. VSD**
**2. Overriding aorta (Aorta sits on top of VSD)**
**3. Infundibular pulmonic stenosis**
**3. RVH as a result of RVOT obstruction**
96
What is the half life of Phenoxybenzamine?
irreversible alpha blocker with a ***_half-life of approximately 24 hours_***
97
What is the anesthetic goals of a Tetralogy of Fallot patient?
The goals of anesthetic management include:
## Footnote
**1. Maintaining SVR**
**2. Reducing heart rate**
**3. Reduce contractility**
**3. Ensuring adequate oxygenation**
**4. Normocarbia**
98
A steeple sign can be found on frontal neck radiographs of patients with *_what pathology?_*
## Footnote
*_What does the image indicate?_*
A steeple sign can be found on frontal neck radiographs of patients with ***_laryngotracheobronchitis (croup)_*** and is indicative of *_tracheal mucosal edema causing tracheal narrowing._*
99
Retropharyngeal soft tissue widening is a common (80-90%) radiographic finding in patients with a *_what pathology?_*
Retropharyngeal soft tissue widening is a common (80-90%) radiographic finding in patients with a ***_retropharyngeal abscess_***. It is also a sign of cervical spine trauma.
100
A lateral neck radiograph will demonstrate a thumbprint sign in what pathology?
A lateral neck radiograph will demonstrate a thumbprint sign due to the **swelling of the epiglottis (Epiglottitis)**
101
What blood dyscrasia can occur with nitric oxide?
Inhaled nitric oxide (NO) can result in **methemoglobinemia** resulting in a left shift in the oxyhemoglobin curve and a decrease in the P50.
102
What is the formula for predicted body weight?
* *Males**: 50 + 2.3 \* (height in inches - 60)
* *Females**: 45.5 + 2.3 \* (height in inches - 60)
103
What is the expert opinion on where you should keep the Hematocrit level in a sickle cell patient?
30-40%
104
What is the recommended precurarization dosage for a nondepolarizing agent?
The recommended precurarization dosage for a nondepolarizing agent is ***_10% of the ED95_***, given about 3-5 minutes prior to succinylcholine.
105
What is the precurariation dose of rocuronium when giving succinylcholine?
Rocuronium
0.3 mg/kg (ED95)
**.03 mg/kg (Pre-curarization dose)**
106
What is the reasoning if giving precurarization dose of Rocuronium with Succinylcholine?
Normally the difference between intragastric pressure (typical mean value of 10 cmH2O) and lower esophageal sphincter pressure (normal value 36 cmH2O) prevents reflux of gastric contents into the esophagus.
When succinylcholine is given, the increase in intragastric pressure due to fasciculations can reach levels as high as 40 cmH2O, which may lead to aspiration of gastric contents into the esophagus and potentially the pulmonary tree.
Precurarization with a ***_small dose of nondepolarizing neuromuscular blocking agent has been proposed to help decrease muscle fasciculation and the subsequent rise in intraabdominal pressure._***
107
What are the downsides of precurarization?
1. **Reduces** **potency** of **succinylcholine**
2. **Delays the onset of action.**
3. Dose for **succinylcholine has to be increased to 1.5 mg/kg** to antagonize the nondepolarizing agent.
108
What does the ED95 for NDNB drugs mean?
How does the intubating dose differe from ED95?
The ED95 for nondepolarizing neuromuscular blocking drugs is the dose that causes 95% twitch suppression in 50% of the population.
Intubating dose is double the ED95 dose (Typically)
109
The mainstay of treatment for botulism for \<1 year old is?
The mainstay of treatment for botulism includes ***_human-derived_*** ***_immune globulin_*** in patients \< 1 year of age
110
What is the treatment for botulism in \>1 year old?
**(Horse) Equine-derived antitoxin** in patients \> 1 year of age.
111
What is the mechanism for Botulism toxin?
This neurotoxin causes the **inhibition of exocytosis of acetylcholine at the peripheral cholinergic, motor, and autonomic nerve terminals.**
Thus, acetylcholine is not released into the synapse (exocytosis). Decreased acetylcholine at the motor nerve terminals leads to a chemical paralysis that can be partial or complete, depending on the amount of neurotoxin.
112
Radiation intensity (exposure) with respect to distance decreases according to *_What equation?_*
*_I.e. If you double the distance from a radiation source, by what factor do you decrease radiation exposure?_*
Radiation intensity (exposure) with respect to distance decreases according to the inverse square law:
**I ∝ 1 / r^2.**
Accordingly, doubling the distance from a radiation source decreases exposure by a factor of 4.
113
What is the average ***_stroke volume_*** and ***_stroke volume index_***?
Stroke Volume (SV) **60 - 100 mL/beat**
Stroke Volume Index (SVI) **33 - 47 mL/m^2/beat**
114
Can roller pumps for CPB deliver pulsatile flow?
There are commercially available pumps that can also deliver pulsatile flow, for both rollers and centrifugal.
115
What are the two most common complications of celiac plexus blocks?
1. Orthostatic hypotension = #1
2. Diarrhea
116
What causes improvements in a patients pain diagnosed with spinal stenosis?
Pain is improved by **walking uphill or squatting (Think about them going to the gym)**
## Footnote
**(Think about spinal flexion)**
117
What causes worsening in a patients pain diagnosed with spinal stenosis?
Spinal Extension
118
Bare-metal cardiac stents require ***_what length_*** dual antiplatelet therapy (aspirin and adenosine diphosphate [ADP]-receptor antagonist) before stopping the ADP-receptor antagonist prior to a scheduled surgery?
Bare-metal cardiac stents require ***_1 month_*** of dual antiplatelet therapy (aspirin and adenosine diphosphate [ADP]-receptor antagonist) before stopping the ADP-receptor antagonist prior to a scheduled surgery
119
Dual antiplatelet therapy should continue for ***_how long_*** in the case of drug-eluting stent placement?
Dual antiplatelet therapy should continue for ***_6 months_*** in the case of drug-eluting stent placement, with continuation of aspirin perioperatively.
120
What is the mechanism of action of Aspirin?
Acetylsalicylic acid (ASA) blocks prostaglandin synthesis.
It is ***_non-selective for COX-1 and COX-2 enzymes_***
Inhibition of COX-1 results in the inhibition of platelet aggregation for about 7-10 days (average platelet lifespan). The acetyl group of acetylsalicylic acid binds with a serine residue of the cyclooxygenase-1 (COX-1) enzyme, leading to irreversible inhibition. This prevents the production of pain-causing prostaglandins. This process also stops the conversion of arachidonic acid to ***_thromboxane A2 (TXA2), which is a potent inducer of platelet aggregation_***.
Platelet aggregation can result in clots and harmful venous and arterial thromboembolism, leading to conditions such as pulmonary embolism and stroke.
121
What are the side effects of PGE-1 given to ductal dependent lesions?
Apnea
Hypotension, fevers, and CNS irritability.
122
How does hyperbaric oxygen therapy affect CO poisoning?
1. **Increasing the O2 dissolved in plasma**
2. **Decreases the half-life of carbon monoxide** bound to hemoglobin. Increased Partial pressure pushes CO off the Hgb molecule
3. Half-life of carboxyhemoglobin is normally **4 to 6 hr**
- FiO2 of 1.0 = Half Life decreases to **40 to 80 min.**
- Hyperbaric oxygen therapy, the half-life becomes **15 to 30 min.**
123
Should Torsades be cardioverted or defibrillated?
Defibrillated
124
What situation is activated charcoal ineffective?
Even in the setting of recent ingestion (\< 4 hrs), activated charcoal is ***_ineffective for methanol poisoning since it does not absorb alcohols._***
125
What is the fire triangle or triad?
Operating room fires traditionally require three components, known as the “fire triad”:
* *1) An oxidizer
2) An ignition source
3) A fuel source**
126
What is the glucose level in CSF?
Glucose is present in the CSF at ***_40-70 mg/dL_*** and is not present in normal saline.
127
What is important to know about the Nd:YAG laser?
What color eye glasses should be worn?
The Nd-YAG laser is a general-purpose laser that thermally coagulates several millimeters of tissue upon exposure. **The light passes through the cornea but can permanently damage the retina within milliseconds of exposure.**
Protective eyewear with *_green filters_* should be worn to prevent eye damag
128
In multisystem trauma, what dose of Scopalamine is given IV?
In extreme hemodynamic instability, such as multi-system trauma with refractory shock, scopolamine ***_5 mcg/kg IV (0.2-0.4 mg for an adult)_*** is an option to provide amnesia
129
What is the half life of IV Scopalamine?
5-11 hours
130
What are the risk factors for post operative apnea?
GA
IV sedation
Anemia
131
What is the qSOFA criteria?
qSOFA criteria are scored from 0-3 with one point for each of the following:
## Footnote
**1. Altered mental status (GCS \< 15)**
**2. Respiratory rate ≥ 22**
**3. Systolic blood pressure ≤ 100 mm Hg.**
132
Poor pneumonectomy outcomes are associated with:
1. What PVR cutoff?
2. What VO2 cutoff?
3. A decrease in arterial oxygen saturation (SaO2)?
1) **PVR \>190 dynes/sec/cm^5**
Normal = 100 – 200 dynes/sec/cm
2) **Maximum VO2 \< 15 mL/kg/min**
average sedentary male will achieve a VO2 max of approximately 35 to 40 mL/kg/min.
3) A decrease in **arterial oxygen saturation (SaO2) \> 2-4 %**
133
Treatment of myotonia or myotonic crises includes what 3 medications?
Treatment of myotonia or myotonic crises includes **phenytoin**, **quinine**, and **procainamide**.
The drugs work by *_decreasing sodium influx into skeletal myocytes and delaying the return of membrane excitability following an action potential_*
134
What are the 4 ways that positive pressure ventilation decreases UOP?
Positive pressure ventilation increases intrathoracic pressure which can decrease urine output through four main effects:
1) **Impaired renal perfusion and renal venous drainage**
2) **Decreased preload** and **increased right ventricular afterload**
3) **Stimulation** of the **sympathetic nervous system**
4) **Release of inflammatory cytokines**
135
What evoked potentials are best to monitor brainstem ischemia?
**BAERs**
**Brainstem *_auditory_* evoked potentials** are the best monitor for brainstem ischemia with posterior fossa craniotomy due to proximity to the surgical site as well as the relative resistance to anesthetic used, therefore eliminating other confounding variables in ischemia evaluation.
136
When unfractionated heparin or low–molecular-weight heparin is administered for \>4 days, the American Society of Regional Anesthesia and Pain Medicine (ASRA) guidelines recommend checking *_what lab_* before neuraxial placement?
***_Platelet Counts_***
137
**When you start TPN, what are the expected electrolyte changes:**
Phosphate?
Potassium?
Magnesium?
All Hypo
138
What other nerve needs to be blocked during TURP under spinal?
Transurethral surgery of the bladder usually can be performed with spinal anesthesia without further consideration. If the tumor is along the lateral aspect of the bladder then the obturator nerve may be stimulated and the jerk reflex initiated even under spinal anesthesia.
***_An obturator nerve block_*** should be performed to help prevent this.
Alternatively, general anesthesia with muscle relaxation can also be performed to prevent the reflex. If neuromuscular blocking agents are not used during general anesthesia, the ***_obturator nerve block_*** will still need to be performed.
139
Tigecycline covers what organisms?
Tigecycline is a glycylcycline antibiotic that covers:
## Footnote
**1. MRSA**
**2. Gram-negative organisms**
140
What does Daptomycin cover?
Daptomycin is a lipopeptide antibiotic used in the treatment of systemic and life-threatening infections caused by:
**1. Gram-positive organisms**.
2. It is useful for **MRSA**, but does not cover Gram-negative organisms.
141
What does Linezolid cover?
Linezolid is an oxazolidinone antibiotic. Linezolid is bacteriostatic by inhibition of bacterial protein synthesis. Linezolid inhibits the 50S subunit of the bacterial ribosome.
Linezolid is effective against a wide variety of **Gram-positive organisms**, including **MRSA** and **vancomycin resistant enterococcus (VRE)**. However, linezolid is not effective against Gram-negative bacteria.
142
What is necessary to diagnose Fat Embolism?
Diagnosis of FES using the Gurd criteria requires:
**1. At least one major criterion**
- respiratory insufficiency
- Petechial rash
- CNS involvement
- Hypoxemia)
**2. At least four minor criteria**
- tachycardia
- fever
- unexplained drop in hematocrit or platelets
- elevated erythrocyte sedimentation rate
- retinal fat emboli
- fat in urine
- fat in sputum)
**3. Presence of fat macroglobulinemia.**
143
A classic triad of symptoms for fat embolism is?
A classic triad of symptoms has been described consisting of:
1. **Petechiae** (mostly around the head, neck, and axillae)
2. **Hypoxemia**
**3. Neurologic abnormalities** (e.g., altered level of consciousness or seizure).
144
What is the treatment for cyanide toxicity who do not have IV access?
**Amyl nitrite** is an inhaled nitrite that is oftentimes used to treat cyanide toxicity in patients who do not have established IV access. I
t is an older drug that has many more side effects than hydroxocobalamin and thus has fallen out of favor as first-line therapy
145
Other than hydrocobalamin which is gold standard for cyanide, what are the 3 options?
**Amyl Nitrate**
**Sodium Nitrite**
**Sodium Thiosulfate**
146
What is the maximum epinephrine for tumescent lidocaine?
0.07 mg/kg (1:1,000,000)
147
What is required to diagnose idiopathic intracranial hypertension?
A lumbar puncture is used to confirm an **elevated opening pressure (\>25 cmH2O).**
148
When is the peak plasma lidocaine concentrations for tumescent lidocaine?
Patients must be informed of the potential signs and symptoms of local anesthetic toxicity because peak plasma lidocaine concentrations ***_occur 12 to 16 hours after initial injection_*** for tumescent liposuction. If tumescent liposuction is performed in an outpatient setting, the patient will most likely be at home during this time.
149
What are the 4T scoring system for HIT?
What scores indicate low probability and what are high probability?
**Thrombin level or activity is not a component of the 4T scoring system for heparin-induced thrombocytopenia (HIT).**
The 4T clinical scoring system is used to clinically diagnose HIT prior to laboratory confirmation. The 4Ts include:
* *1) Thrombocytopenia
2) Timing of the reduced platelet count
3) Presence of Thrombosis
4) The exclusion of other causes for thrombocytopenia**
*_A score of 0-3 suggests a low probability_*
Whereas
*_Ascore of 6-8 indicates high probability for clinically-relevant HIT._*
150
What is the best option for idiopathic intracranial hypertension in labor?
Pregnant patients with idiopathic intracranial hypertension presenting for labor analgesia are an interesting dilemma. If the patient has symptoms, an ***_intrathecal catheter_*** may be a great option to allow for removal of CSF if symptoms worsen during labor.
\*\*I disagree with this\*\*
151
The femoral triangle is bordered by what three structures?
The femoral triangle is bordered by the:
1. **Inguinal ligament** superiorly
2. **Adductor longus** muscle medially (**AL**abama)
3. **Sartorius** muscle laterally.
152
How does Dantrolene block calcium release from skeletal muscle Sarcoplasmic retriculum?
Dantrolene blocks calcium release from skeletal muscle sarcoplasmic reticulum by **interfering with the ability of calcium and calmodulin to activate the voltage-gated ion channels (RYR1 and the L-type calcium channel).**
153
According to MHAUS, dantrolene should be administered as in acute phase as what dose?
After acute phase?
According to MHAUS, dantrolene should be administered as a rapid **2.5 mg/kg IV bolus** which can be repeated every 5-10 minutes as necessary up to 10 mg/kg.
After the acute phase has resolved, dantrolene should be **continued for 24-48 hours either as a 1 mg/kg bolus every 4-6 hours**
or
As an infusion of ***_0.25 mg/kg/hr_*** to prevent recrudescence.
154
PaO2 decreases by *_what amount_* per year after 20 years of life?
PaO2 decreases by ***_0.5 per year_*** after 20 years of life.
155
The NIMS tube uses what technology during thyroid and parathyroid surgery?
***_EMG - Electromyography_***
Classically, the gold standard for monitoring the RLN was direct visualization by the surgeon. While this is still important, it lacks the functional information provided by intraoperative nerve monitoring (IONM). IONM is done using a specialized endotracheal tube which has electrodes sitting on the bilateral vocal cords.
During surgery, a surgeon uses a **stimulator probe to touch the RLN and surrounding tissues while a neurophysiologist monitors the EMG trends detected by the electrodes on the endotracheal tube. Changes in trends can alert the surgeon of potential nerve injury.**
Described here is intermittent IONM. While intraoperative nerve monitoring (as opposed to direct visualization) can give real-time information about nerve function, it is controversial whether employing such an adjunct is able to reduce the number of RLN injuries from thyroid surgery.
156
What is the difference in Lambert Eaton vs. Myasthenia Gravis with anticholinesterases?
Lambert Eaton = Poor response to anticholinesterases
MG = Good response to anticholinesterases
157
What is the benefit of a fructosamine test?
Fructosamine testing in diabetes measures a shorter time interval than hemoglobin A1c and is **typically used for patients who have reduced red blood cell lifespans** (e.g., in those with hemolytic anemia, sickle cell disease). A
## Footnote
**HgA1c level of ≥ 6.5% is diagnostic for diabetes mellitus.**
158
What pain modality is utilized when thoracic epidural placement or paravertebral blocks are contraindicated?
**TENS - *_A transcutaneous electrical nerve stimulation_*** is an effective modality in pain management of post-thoracotomy pain and can be especially useful in patients in whom neuraxial anesthesia is contraindicated.
With regards to patients on antithrombotic agents, paravertebral blocks follow the same guidelines as neuraxial anesthesia.
159
How does Methylene blue mechanically act for vasoplegia?
Methylene blue **can block the vasodilatory effect of nitric oxide by inhibiting guanylate cyclase**.
However, it is usually considered a *_last-line medication for vasoplegic shock_*.
Also it is contraindicated in patients receiving **SSRIs because it is a MAO inhibitor and can cause serotonin syndrome.**
160
Why should you not give Succinylcholine to Strabismus patients?
Children with strabismus who receive succinylcholine for general anesthesia are **4 times more likely to experience *_MMR (Masseter Muscle Rigidity)_***
161
How should you dose Propofol infusions?
Total Body Weight
162
How should you dose induction doses of Propofol?
Lean Body Weight (75-80%)
163
How should you dose induction doses of Fentanyl?
Lean Body Weight
164
How should you dose induction doses of Non-depolarizing paralytics?
Ideal Body Weight (Same as tidal volume)
165
How does the IABP decrease afterload?
In addition, and perhaps more importantly, IABPs improve the myocardial oxygen supply/demand ratio. Because the balloon inflates during diastole, it increases coronary perfusion pressure (increases supply), and because it ***_deflates suddenly right when the ventricle is about to eject blood, it decreases afterload_*** (decreased wall tension -\> decreased oxygen demand).
166
**SIADH**
Serum Level Na?
Serum osmolality?
Urine Na?
Urine Osmolality?
Fluid status?
Serum Level Na - Low
Serum osmolality - Low
Urine Na - High
Urine Osmolality - High
Fluid status - Euvolemic or Hypervolemic
167
What type of cautery should be used when a patient has an uninterrogated pacemaker/defibrillator?
**Bipolar** - Less energy used
Monocautery is bad
168
With an uninterrogated AICD, where should the dispersive pad be placed?
The dispersive pad should be placed ***_near the surgical field_*** to prevent electrical energy from affecting the AICD.
169
What does a magnet due to an implanted device?
If the operation is an emergency, a magnet can be placed over the device.
The ***_magnet will disable anti-tachyarrhythmia_*** therapy in general, although there is some variability.
170
How does hydrocortisone affect nitric oxide?
Hydrocortisone **inhibits nitric oxide synthesis.**
171
How do ultrasounds have different penetration and resolution?
*_Increased wavelength (decreased frequency_*) ultrasound probes provide better tissue penetration (depth) at the cost of resolution.
**Higher frequency means better resolution**, but **worse penetration.**
172
Comment on vessel rich blood flow and how this affects induction of pediatric patients.
***_Peds have increased proportion of cardiac output_*** going to the vessel-rich groups in infants.
173
What are the diagnostic signs of compartment syndrome?
Include:
**1. Compartment Pressure?**
**2. CK level?**
**3. Dopplers?**
**4. Distal pulses?**
**5. Compartment Perfusion Pressure?**
Pulse oximetry and pain are unreliable signs/symptoms of acute compartment syndrome. Diagnostic signs of compartment syndrome described in the literature include:
compartment pressure \>30 mmHg
creatine phosphokinase level \>5000 U/ml (possibly as little as \>1000 U/ml
Loss of normal phasic patterns of tibial venous blood flow
Loss of distal pulses in the setting of closed extremity injury
And compartment perfusion pressure \< 21 mmHg.
174
What is the IM dose of phenylephrine?
An ***_IM dose of 2-5 mg_*** will raise blood pressure and lower heart rate typically within 10-15 minutes from injection.
175
What is the IM dose of epinephrine?
An ***_IM dose of 0.1 - 0.5 mg_*** increases heart rate, blood pressure, and produces bronchodilation within 5 minutes from injection.
176
What dose of Phentolamine would you use if you have extravasation?
Should this occur, the degree of necrosis can potentially be decreased by infiltration of the affected area with a ***_phentolamine solution (5-10 mg in 10-15 mL saline)._***
177
What dose of Ephedrine would you use for IM injectons?
***_An IM dose of 0.5-0.6 mg/kg (35 mg for 70 kg adult)_*** will produce modest increases in blood pressure and heart rate within 10-15 minutes from the time of injection.
178
Where does Herpes zoster affect most nerve roots?
1. Thoracic nerve roots
2. Ophthalmic division of the trigeminal nerve (V1)
3. Maxillary division of the trigeminal nerve (V2)
4. Cervical spinal roots
5. Sacral spinal roots
179
How is Bicarbonate levels in pyloric stenosis before resuscitation?
**Elevated serum bicarbonate** is often present along with increased urine specific gravity and decreased urine chloride.
180
How do you diagnose abdominal compartment syndrome?
Abdominal compartment syndrome is diagnosed by observing a tense, distended abdomen and by obtaining bladder pressure readings ***_\> 20-25 mm Hg via a urinary catheter._***
181
What is the defintion of Heparin resistance?
Heparin resistance is defined as an activated clotting time (ACT) of \< 480 seconds after ***_500 U/kg of IV heparin_*** has been administered or an ACT \< 400 seconds at any time during the course of cardiopulmonary bypass (CPB) and heparin administration.
182
What is the dose of antithromobin III levels?
Thrombate III: IV: ***_Initial: 500 units once_*** (dose can be rounded to the nearest vial size)
A repeat dose of 500 units may be considered if activated clotting time remains subtherapeutic after the initial dose.
183
What are the symptoms of Anticholinergic syndrome?
Anticholinergic syndrome:
1. Blind as a bat (**cycloplegia** and **mydriasis**)
2. Mad as a hatter (**delirium** and **hallucinations**)
3. Red as a beet (**skin flushing**)
4. Hot as hell (**fever**)
5. Dry as a bone (**anhidrosis**)
6. Full as a flask (**urinary retention**)
184
What is the treatment for anticholinergic syndrome?
**Physostigmine** (Acetylcholinesterase Inhibitor)
185
What size defib pads should be used?
Defibrillation using *_Smaller 4.3-cm electrodes can cause damage to the patient including possible myocardial necrosis._*
Electrodes that are **12-cm** are more effective than smaller electrodes to deliver a shock. Paddle/pad size is inversely proportional to transthoracic resistance.
Paddles of **13-cm** diameter reduce transthoracic resistance by 21% as compared with 8.5-cm diameter paddles. Current recommendations by the American Heart Association (AHA) state electrode size of 8-12 cm is reasonable for use in adults. The use of smaller electrodes can injure the patient.
186
What is the treatment for central DI?
Desmopressin
187
What is demeclocycline used for?
Demeclocycline, derived from the tetracycline class of antibiotics, is used in the treatment of the syndrome of inappropriate antidiuretic hormone secretion (***_SIADH_***) by actually inducing diabetes insipidus (C) and reducing ADH effects in the collecting duct.
188
What is the American Spinal Injury Association Impairment Score?
A - Complete injury with complete motor and sensory
B - Incomplete - Sensation preserved below injury
C - Incomplete - \<3/5 motor strenth in 1/2 of motor groups
D - Incomplete - \>3/5 motor strength in 1/2 major groups
E - No evidence of cord injury. Intact motor and sensory innervation
189
What are the labs for primary hyperaldosteronism?
Na?
K?
renin?
High sodium
Low potassium
Reduced renin activity
Metabolic alkalosis
190
What is the ***_thyroid hormone binding ratio_*** in hyperthyroidism vs. hypothyroidism?
T**hyroid hormone binding ratio** high hyperthyroidism and low in hypothyroidism
191
What is usually the difference between ScvO2 and SvO2?
In normal settings, the **ScvO2 is approximately 5% greater** than the SvO2 due to the coronary sinus contribution of deoxygenated blood for SvO2.
**ScvO2** = Central venous sample
**SvO2** = Mixed venous in the Pulmonary Artery
192
What does Dibucaine do?
Dibucaine **inhibits normal pseudocholinesterase to a far greater extent than the abnormal enzyme.**
193
Understandardized test conditions, dibucaine inhibits the normal enzyme what percent?
dibucaine inhibits the abnormal enzyme what percent?
Under standardized test conditions, **dibucaine inhibits the normal enzyme about 80 percent** and the *_abnormal enzyme about 20 percent_*, thus the DN is the percent of PChE enzyme activity that is inhibited by dibucaine.
194
Normal Dibucaine number?
70-80
195
Heterozygote for Atypical Pseudocholinesterase enzyme Dibucaine number?
heterozygous atypical yields a DN of 50-60
196
Homozygous Atypical Pseudocholinesterase Enzyme Dibucaine number?
Homozygous atypical yields a DN of 20-30
197
When should specimens should be collected 48 hours after the administration of succinylcholine to test for dibucaine number?
Specimens should be collected **48 hours *_after_* the administration of succinylcholine**
198
***_Mivacurium_***
What class?
Metabolism?
Mivacurium, a **benzylisoquinolinium** short-acting nondepolarizing skeletal muscle relaxant, is also **metabolized via hydrolysis by pseudocholinesterase.**
199
90-95% of an intravenous dose of succinylcholine occurs *_when?_*
The remaining 5-10% of the succinylcholine dose acts where?
Pseudocholinesterase hydrolyzes succinylcholine to succinylmonocholine and then to succinic acid. In individuals with normal plasma levels of normally functioning pseudocholinesterase enzyme, ***_hydrolysis and inactivation of approximately 90-95% of an intravenous dose of succinylcholine occurs before it reaches the neuromuscular junction_***.
**The remaining 5-10% of the succinylcholine dose acts as an acetylcholine** receptor agonist at the neuromuscular junction, causing prolonged depolarization of the postsynaptic junction of the motor-end plate.
200
What organisms are most commonly seen in Ventilator Associated Pneumonia?
antibiotic-sensitive flora
## Footnote
**1. methicillin-sensitive Staphylococcus aureus**
**2. Haemophilus influenzae**
**3. Streptococcus pneumoniae**
**4. Proteus, Klebsiella, and Enterobacter species**
201
What are the main differences between coma vs. Persistent Vegetative State?
They may have **spontaneous eye movement**
They may have **sleep-wake cycle**
They may **vocalize** or have **non-purposeful sound**
202
What are similar between coma vs. persistent vegetative state?
Cannot follow commands
Cannot communicate
Cannot have purposeful movement
203
How does reducing contractility help with SAM / HOCM / LVOTO pathologies?
*_Reducing cardiac contractility:_*
**1. Improves diastolic filling**
**2. Increases LV end diastolic volume**
**3. Increases LV chamber size**
ALL = reduces LVOT obstruction.
204
How does increasing afterload help in SAM/LVOTO/HOCM?
Maintaining or increasing the afterload on the left heart l***_engthens the systolic ejection time, therefore reducing the incidence of coaptation between the mitral valve leaflets and the ventricular septum_***.
Incidentally, SAM may occur due to coaptation of both MV leaflets or only the anterior MV leaflet with the septum; this is dependent on the spatial relationship between the MV apparatus and the LVOT during systole.
205
How would dual chamber sensing help a HOCM patient's hemodynamics?
The mechanism likely involves the ***_paradoxical motion of the ventricular septum during systole_***, which serves to reduce coaptation with the mitral valve leaflet(s).
206
Can you use succinylcholine in cerebral palsy patients?
Yes
Succinylcholine has been used in children with CP for more than 50 yr without a single report of a hyperkalaemic response.
207
What pulm and GI considerations need to be in place for cerebral palsy cases?
CP patients have an ***_increased incidence of gastroesophageal reflux and esophageal dysmotility. Pulmonary aspiration is increased_*** in CP patients and places them at a greater risk for postoperative pulmonary complications.
208
How do Spinal Cord Stimulators work?
Spinal cord stimulators activate the **larger Aα and Aβ fibers** to a greater degree compared with the smaller nociceptive Aδ and C fibers.
**Directly acts at dorsal horn of the spinal cord (Ascending)**
**This closes the gate in** and impedes conduction of pain sensation past the substantia gelatinosa of the dorsal horn of the spinal cord.
209
For metabolic acidosis, how would you predict compensatory change in PaCO2?
Winter formula to predict the compensatory change in PaCO2.
*_**Expected PaCO2 = (1.5 \* [HCO3]) + 8 +/- 2**_*
**If Measured \> Expected = Then respiratory acidosis also**
**If measured \< expected = Respiratory alkalosis compensating**
If the PaCO2 is significantly different then expected, suspect a mixed disorder.
210
How does the upslope change in different arterial line waveforms?
Steeper upstroke the more distal you go
211
How does mixed venous oxygen saturation change with hyperdynamic state?
Increases
212
How does the dicrotic notch change as arterial line changes?
Dicrotic notch later the more peripheral you go
213
What are the mechanisms of high frequency jet ventilation?
**Cardiogenic mixing** describes the movement of lung tissue directly surrounding the pumping heart results in further molecular diffusion and mixing of gases.
**Pendelluft ventilation** involves the redistribution and mixing of gas as a result of local differences in airway and alveolar resistance and compliance.
**Venturi effect** describes the entrainment of room air along with each delivered jet ventilation cycle. In the setting of supraglottic jet ventilation, this will always result in the delivered gas containing less than 100% oxygen.
**Taylor Dispersion**
214
How does the appearance of dicrotic notch change the more peripheral you go?
Later and less sharp
215
What is lid lag? When is it seen?
Patients can also have lid lag which is due to a**drenergic hyperactivity** leading to spasming of the levator palpebrae superioris muscle.
Seen in **Hyperthyroidism**
216
How does TLC (Total Lung Capacity) change in restrictive lung diseases
Drops
217
Why can myotonic dystrophy patients not receive Neostigmine?
Neostigmine inhibits acetylcholinesterase, thereby increasing acetylcholine at the neuromuscular junction. This increase in ***_acetylcholine causes increased muscle activation and has been associated with myotonias._***
218
What is SpO2 during 1st minute of life?
10 minutes of life?
***_60-65%_*** by 1 minute of life
***_85-95%_*** by 10 minutes of life.
219
Is nasal congestion or rhinoorhea with stellate ganglion block?
Nasal congestion
220
How will temperature change in stellate ganglion block?
**A temperature increase in the ipsilateral arm** is evidence of a successful stellate ganglion block. Temperature increases in the leg can be seen with a lumbar sympathetic block.
221
How will low phosphate shift the Oxy-Hemoglobin curve?
Shift to left (Decreased 2,3 DPG)
222
What is the metabolite of **cisatracurium**?
What is the **clinical significance** of this?
Cisatracurium (and atracurium) is primarily metabolized (80%) to **laudanosine**.
This renally-cleared excitatory amine ***_can precipitate seizures_***, but does not have neuromuscular blocking activity.
The clinical significance of laudanosine was more important with atracurium since it is much less potent than cisatracurium, and thus more of the metabolite is produced.
223
What end organ does vecuronium have clinical signficance and why?
**Vecuronium** has an active metabolite, **3-desacetyl-vecuronium**, that has 80% of the potency of vecuronium. Accumulation of this renally-cleared metabolite can significantly prolong the duration of action of the drug, particularly when an infusion is used in a patient with ***_renal failure._***
224
When do you see alpha effects from Dopamine?
\>10 mcg/kg/min
225
What is the genetics of Malignant hyperthermia?
MH is often caused by a **mutation in the ryanodine receptor (RYR1)** of skeletal muscle found on **chromosome 19**
226
_WHAT_ is the treatment of choice for methemoglobinemia in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency?
***_Ascorbic acid_*** is the treatment of choice for methemoglobinemia in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency.
227
What are the indications for Fenoldopam?
**Severe hypertension**: Short-term treatment of severe hypertension (up to 48 hours in adults while in hospital), including patients with malignant hypertension with deteriorating end-organ function
AND
Short-term (up to 4 hours while in hospital) blood pressure reduction in pediatric patients while in hospital
228
What is the equation for Wall Tension?
Wall tension = (**LVEDP** x **radius**) / (2 x LV wall thickness)
T = P \* R / LVH
229
When does the RV recevive its greatest perfusion peak in the cardiac cycle?
The right ventricle is perfused throughout the cardiac cycle but receives its greatest perfusion during **peak/late systole** and **early diastole**.
