ACE 2013 10A Flashcards
What does placing a magnet to an ICD-pacemaker do to it generally?
Disables the anti-tachycardia features (cardioversion and defibrillation) while not changing the pacemaker settings
How should you manage a patient who is going to undergo surgery who is on IM depot naltrexone?
Have them stop the medication 6-8 weeks before surgery
Which of the following is best dosed using total body weight in the morbidly obese population: rocuronium, succinylcholine, vecuronium, cisatracurium
Succinylcholine; morbidly obese patients have increased concentrations of plasma pseudo-cholinesterase and may require more depolarizing NMB
Which of the following viruses has the highest risk of transmission following a stick: HIV, Hep A, Hep B, Hep C
Hep B (19-37%); Hep C is about 1.9% and HIV is 0.3%. Hep A is transmitted fecal-orally
How much does a full cylinder of O2 contain and what pressure reading does it read?
660L, 2000psi
What are the general goals for anesthesia in patients with pulmonary hypertension?
- Maintenance of preload
- Maintenance of afterload (avoid hypotension)
- Maintenance of NSR and adequate HR (optimize CO)
- Avoid hypoxia, hypercapnia, acidemia (increases PA pressures)
What is the diagnosis of a patient with ascending weakness after a URI?
Guillian-Barre Syndrome
What is the most common complication seen in Guillian-Barre syndrome patients?
Hypotension (changes in catecholamine levels and impaired baroreceptor function) - 75% of patients
SIADH - >40% of patients
Respiratory failure - <20% of patients
What factors increase the risk of PA catheter-induced endobronchial hemorrhage?
- Female
- Mitral stenosis
- Pulmonary HTN
- Advanced age
- Coagulopathy
- Distal placement of PAC or hyperinflation
What is the most common nerve affected by the lithotomy position and how does it present?
Common peroneal nerve
Inability to dorsiflex the foot (foot drop)
What nerve is affected if you have paresthesias along the medial thigh? Lateral thigh? Inability to flex the hip?
- Obturator nerve
- Lateral femoral cutaneous nerve
- Femoral nerve
What does the superior laryngeal nerve provide sensation to?
Inferior aspect of epiglottis to the vocal cords
What does the glossopharyngeal nerve provide sensation to?
Posterior 3rd of the tongue, superior surface of epiglottis, and the pharynx
What does the recurrent laryngeal nerve provide sensation to?
Sensation below the vocal cords
Which volatile anesthetic in use today leads to the highest increase in serum fluoride levels?
Sevoflurane
What is a common risk seen with first-generation devices during extracorporeal shock wave lithotripsy? How can you avoid this?
Cardiac dysrhythmias; try to time the shocks after the R wave (refractory period so a new AP does not fire)
What is the mechanism of action for methylene blue?
Selective inhibitor of guanylate cyclase (NO-mediated vasodilation)
What is methylene blue used for?
Reduction of methemoglobinemia, treatment for vasoplegic syndromes (including refractory hypotension after bypass), possible benefit in Alzheimer’s disease
What is medication is contraindicated with concurrent use of methylene blue?
Serotonin reuptake inhibitors; methylene blue inhibits monoamine oxidase
In what surgeries do you worry about venous air embolisms?
- Posterior fossa in sitting position
- Tumors near posterior sagittal sinus
- Craniosynostosis procedures
- Uterine externalization during C-sections (rare)
What is the most sensitive test for diagnosing VAE?
TEE
Why do elderly patients have more intraoperative hemodynamic lability?
- Reduced compliance of blood vessels
2. Reduction of beta-receptor responsiveness
Which local anesthetics are patients more likely to be allergic to and why?
Esters; metabolized by plasma cholinesterases and RBC esterases to para-aminobenzoic acid (PABA) which is a known allergen
Which local anesthetics have the quickest onset of action?
Chloroprocaine and Lidocaine
Which local anesthetic is the most potent?
Tetracaine
What is the treatment for cocaine-induced chest pain?
- Benzos
- Nitroglycerin
- CCBs
How much (%) does each unit of FFP increase coagulation factors?
3-6%
How quickly must FFP be used after being thawed if kept at 1-6 degrees C?
Within 5 days
What coagulation factors are generally diminished after thawing FFP?
Factor V and VIII
Who is the universal plasma donor for FPP?
AB: no anti-A or anti-B antibodies (opposite of RBC type)
Is citrate concentrations higher in pRBCs or FFP?
FFP (about 5x higher)
How does etomidate cause adrenal suppression?
Inhibits 11-beta-hydroxylase
What are some side effects of etomidate?
Adrenal suppression, PONV, thrombophlebitis, myoclonic activity
What does a FeNa < 1% suggest? What urine sodium level would you expect? BUN/creatinine? Urine osmolality?
Prerenal etiology
Urine sodium < 20mEq/L
BUN/Creatinine >20:1
Urine osmolality: >500mOsm/kg
What renal pathology do you expect with a urine sodium > 40 mEq/L?
Acute tubular necrosis
What condition(s) would you expect an increased DLCO: polycythemia, PE, CF, emphysema, morbid obesity, pulmonary hemorrhage, anemia, exercise
Polycythemia, morbid obesity, pulmonary hemorrhage, exercise
During an episode of bronchospasm in an asthmatic, what nervous system and nerve is responsible?
PSNS, vagus nerve
What do you expect if you see pink frothy sputum?
Pulmonary edema
How would you manage the airway for a patient with neurofibromatosis and a hx of seizures with mild mental retardation?
Worry about neurofibromas obstructing the airway; avoid RSI, consider fiberoptic with spontaneous ventilation
Should you apply cricoid pressure with a patient who has a Zenker’s diverticulum?
No, it might express contents of the diverticulum and cause aspiration
What do you worry about in patients with SLE and positive antiphospholipid antibodies?
Venous or arterial thrombosis
What is the maximum recommended exposure during pregnancy?
5 mSv total for the pregnancy
What happens when an MRI needs to quench and what should you do?
Quench: MRI’s stored energy is released as heat and leads to the vaporization of helium (which cools the MRI)
You should make sure the patient and yourself have oxygen to avoid asphyxia
How does the percentage of body surface area affected by a burn affect the hyperkalemic response seen with succinylcholine?
No correlation
What time frame should you avoid succinylcholine in burn patients?
24 hours to 1 year
What factor is dysfunctional in hemophilia A and what percentage activity level characterizes that as severe?
Factor VIII, <1% is severe (1-5% is moderate and 6-40% is mild)
How is hemophilia A transmitted?
X-link recessive
What factors are tested by prothrombin time?
I, II, V, VII, and X
What factors are tested by partial thromboplastin time?
All factors except for factor VII and XIII
What is the half life of factor VIII?
12 hours (that’s why we repeat doses of factor VIII every 12 hours)
What is an acceptable predicted post-operative FEV1% for patients undergoing lobectomies? ppoDLCO?
> 40% for both (low risk for perioperative respiratory complications)
What is the most useful predictor of post-thoracotomy outcome?
Preoperative maximum oxygen consumption (<15 mL/kg/min is high risk)
What do we use droperidol for and how does it work?
Anti-nausea; anti-DA effects at the chemoreceptor trigger zone
At what temperature do our bodies start shivering? What about in the elderly?
A full degree Celsius lower than the vasoconstriction threshold; elderly are less likely to shiver (reduced ability to thermoregulate)
Would severe hypercalcemia cause hypertension or hypotension? Would it cause bronchospasms?
Hypotension (associated with acute renal failure -> calcium-induced polyuria and associated hypovolemia)
Hypocalcemia is associated with bronchospasms
What do you suspect if a patient who had an aorto-femoral procedure with epidural develops fecal incontinence and paraplegia, loss of pain and temp of lower extremities, and preservation of vibration and proprioception?
Anterior spinal artery syndrome: ischemia of the ventral spinal cord -> motor tracts and spinothalamic tracts -> bilateral motor deficits + loss of pain and temp with preservation of vibration/proprioception (dorsal column)
What test would you use to test for a nonrandom association between sex and eye color to see if women have blue eyes in a population?
Chi-square test: association between two categorical variables (NOT continuous like a T-test)
Which of the following is associated with a type A aortic dissection: bicuspid aortic valve, MVP, dilated cardiomyopathy, rheumatic heart disease
Bicuspid aortic valve (also Marfan’s syndrome)
What are some common drugs to avoid in patients with myasthenia gravis or Lambert-Eaton syndrome?
Aminoglycosides (gentamicin), Macrolides (azithromycin), Quinolones (ciprofloxacin), H2 receptor blockers, anticonvulsants, CCB, magnesium salts
What are the 5 measures used to diagnose metabolic syndrome?
- Elevated waist circumference
- Elevated TG
- Decreased HDL
- Elevated BP
- Elevated fasting glucose
What is the pathophysiology of metabolic syndrome?
Production of pro-inflammatory cytokines (TNF-alpha and IL-6) by visceral adipose tissue leading to insulin resistance and oxidative stress to CV system and other systemic disorders
What causes an underdamped A-line tracing? Overdamped?
Under: Increased vascular resistance, over-stiff tubing
Over: air bubbles, compliant tubing, kinks
How many oscillations on an A-line tracing is considered optimally damped?
1.5-2 oscillations before returning to tracing
What happens to the SBP, DBP, pulse pressure, and MAP in an overdamped a-line tracing? Underdamped?
Over: SBP decreases, DBP increases, low PP, normal MAP
Under: SBP increases, DBP decreases, increased PP, normal MAP
Is MAC increased or decreased with pregnancy, anemia, acute EtOH, chronic EtOH, hyperthermia?
- Decreased
- Decreased
- Decreased
- Increased
- Increased
Why would sevoflurane anesthesia cause an OR fire?
If you have a desiccated soda lime CO2 absorbent (rapidly degrades, producing heat, CO and methanol)
What is the initial response in hemodynamics to a loading dose of dexmedetomidine?
Increased BP (first 5-10 minutes) from peripheral vasoconstriction -> then decreased BP with decreased HR
What would you expect on an ABG in a patient who has obesity hypoventilation syndrome?
Near normal pH, increased PaCO2, decreased PaO2, increased HCO3 (compensated)
Which would you find in patients with obesity hypoventilation syndrome: MVP, RV failure, aortic stenosis, aortic dissection
RV failure: hypercapnia and hypoxia causes pulmonary vasoconstriction -> pulmonary HTN -> RV failure (cor pulmonale) -> TV regurgitation + LV hypertrophy + diastolic dysfunction
What do you worry about in patients with chronic benzo use who has a suspected benzo overdose being given flumazenil?
Precipitation of seizures and benzo withdrawals
What is the Budapest criteria and what is it used for?
Diagnosis of CRPS 1. Disproportionate pain 2. 1+ symptom (patient reported) 3. 1+ signs (exam) 4. No other diagnosis (sensory - hyperesthesia/allodynia, vasomotor - temp asymmetry/skin changes, edema or sweat changes, motor - weakness, tremor, dystonia or hair changes)
What is the most common serious adverse event of a neurolytic celiac plexus block?
Paraplegia (1 in 700 blocks)
Which is most likely to be decreased in clinically relevant hyperthyroidism: SVR, PVR, blood volume, CO
SVR (the rest are increased)
In abdominal compartment syndrome, which would be decreased: HR, PAOP, GFR, SVR
GFR (also hepatic and splanchnic blood flow)
How does tidal volume and respiratory rate change during pregnancy? How is PaCO2 affected? FRC? FEV1?
Increased both -> increased MV
PaCO2 is decreased slightly (slightly decreased bicarb)
FRC is decreased (~20%)
FEV1 is unchanged
How is SVR affected by pregnancy?
SVR is decreased (~20%)
How is blood volume and RBC volume affected by pregnancy? Why are pregnant women slightly anemic?
BV increases 45%
RBC volume increases 30%
Although RBC volume increases, plasma volume increases by 55% causing the anemia
How is coagulation affected by pregnancy?
Hypercoagulable (increased factors)
How is GFR affected by pregnancy? Creatinine? BUN?
GFR is increased
BUN and creatinine are decreased
What nerve is commonly missed in the axillary approach to a brachial plexus block?
Musculocutaneous (lateral aspect of forearm)
What electrolyte abnormality is common in patients with diagnosed brain death?
Hypernatremia from DI -> central DI (lack of production of ADH) -> polyuria
What is the mechanism of action of nicardipine and what is a common side effect?
Dihydropyridine CCB -> arterial vasodilation that mostly affects the periphery
Headache (21% pf patients), N/V (7%), peripheral edema (8%)
What would you find on TEE in a patient with PE?
Dilated RV, hypokinetic RV, D-shaped septum (all indicative of RV pressure overload)
What would you use to stabilize a patient with a significant PE: esmolol, milrinone, dobutamine, epinephrine
Epinephrine: need to maintain CO, increased SVR for coronary blood flow and reduce the leftward shift of the septum (esmolol will kill the patient, milrinone decreases SVR, dobutamine decreases SVR)
What is magnesium used for in pregnant women?
- Seizure ppx in preeclampsia
- Tocolytic agent for preterm labor but has recently shown to be ineffective
- Effect fetal neuroprotection (decreased risk of cerebral palsy in early preterm birth)
What is a serious adverse side effect of magnesium?
Pulmonary edema and hypotension
How does magnesium affect muscle relaxants?
Potentiates the effects of non-depolarizing NMB
Does not potentiate succinylcholine
Rank the effects of volatile anesthetics on spinal cord evoked potentials: SSEP, MEP, BAER, VEP
VEP > MEP > SSEP > BAER
Where should you measure oxygen in a newborn?
Right hand; the ductus arteriosus is still open and can affect values in the left hand
What should you avoid during resuscitation of a newborn?
100% oxygen (decreased survival compared to room air)
What C-spine level is the location of the larynx in a full term infant? Adult?
Infant: C3-C4
Adult: C4-C5
What is the minimum amount of time before epidural placement in a patient on therapeutic lovenox? Ppx lovenox?
24 hours
10-12 hours
How long does it take for transdermal fentanyl to become therapeutic in the blood? How long after can you have respiratory depression?
13 hours
3 days after patch is removed
What happened to your epidural if you have patchy motor blockade and high sensory level?
Subdural injection of local anesthetic
What metabolic abnormality can you see with furosemide use?
Hypochloremic metabolic alkalosis (inhibits Na/K/2Cl in distal loop of the loop of Henle)
What is the formula for oxygen delivery?
DO2 = CO * CaO2 * 10 CaO2 = (1.39 * Hgb * SaO2) + (0.003 * PaO2)
How dose Dopamine increase BP?
- Nonselective alpha, beta 1 and beta 2
2. Indirect effect of releasing NE and epi (precursor)
What is the first line treatment for acute migraines? Prophylaxis?
Tx: Triptan and NSAID combo
PPx: Carbamazapine (TCA), divalproex sodium, propranolol
What medications treat bradycardia in a patient who has had a heart transplant in the past?
Direct actors: epinephrine, dobutamine, isoproterenol
What is the most common cause of late death in heart transplant recipients?
Coronary allograft vasculopathy (involves all 3 arterial layers, multi-vessel involvement, rapid progression)
What is the Apfel score?
Approximates PONV: 1. Female 2. Periop opioid use 3. Non-smoker 4. Hx of motion sickness Points: 0 = 10%, 1 = 20%, 2 = 40%, 3 = 60%, 4 = 80%
What type of surgeries have a higher risk of PONV?
ENT, GYN, ophthalmic, abdominal
What is the diagnosis: hyponatremia + urine sodium 80mEq/L + serum osmolality 250 mOsm/L
SIADH
What is the treatment for SIADH?
Symptomatic: hypertonic saline with lasix
Asymptomatic: fluid restriction + salt intake
Consider “vaptan” drugs + demeclocycline
What is the treatment for diabetes insipidus?
Desmopressin
In patients with A. fib, what are the strongest predictors of increased risk of thromboembolic stroke intraoperatively?
- Mitral stenosis
- Hx of stroke or TIA
Others include DM, HTN, CHF, and >70 yo
An injury at or above what level puts you at an increased risk of autonomic hyperreflexia?
T6
What are the symptoms of autonomic hyperreflexia?
Hypertension, bradycardia, vasodilation above the level of the lesion, vasoconstriction below level of the lesion, headache or AMS, sweating
Why would you prefer a spinal over an epidural to avoid autonomic hyperreflexia?
Epidurals can have sacral sparing and may not be fully reliable
What nerve is innervated if you see isolated inversion and plantarflexion of the foot?
Tibial nerve
What nerve is innervated if you see isolated eversion and dorsiflexion of the foot?
Common peroneal nerve
If doing a sciatic nerve block at the popliteal fossa, what area of the leg/foot is commonly missed?
Medial aspect of leg and ankle (saphenous nerve from the femoral nerve)
What nerve supplies sensation to the lateral aspect of the foot and lower leg?
Sural nerve (from popliteal nerve)
