10 Random Questions
An 87-kg 64-year-old woman in good general health is undergoing a right knee arthroplasty while in the supine position with general anesthesia consisting of enflurane 2% and nitrous oxide 50% in oxygen. She is breathing spontaneously through a 7-mm endotracheal tube. During the first 30 minutes of the procedure, the arterial oxygen saturation measured by pulse oximetry decreases from 98% to 92%. The most likely cause of the desaturation is
- (A) decreased functional residual capacity
- (B) diffusion hypoxia
- (C) hypercarbia
- (D) increased airway resistance produced by the endotracheal tube
- (E) inhibition of hypoxic pulmonary vasoconstriction
Compared with healthy nonhypertensive patients, in patients with untreated hypertension undergoing anesthesia and operation,
- (A) cerebral ischemia may occur at higher blood pressures
- (B) intravenous fluid should be restricted before induction
- (C) left ventricular hypertrophy enhances compensation for intraoperative fluid loss
- (D) responses to sympathetic stimulation are decreased
- (E) the incidence of intraoperative hypotension is lower
The preanesthetic ECG trace (lead II) shown from a 32-year-old woman suggests
- (A) potential for tachyarrhythmia
- (B) need for preanesthetic atropine
- (C) myocardial ischemia
- (D) left bundle branch block
- (E) right ventricular hypertrophy
During ligation of a patent ductus arteriosus, a newborn infant receives a total gas flow of 5 L/min through a nonheated Jackson-Rees system. Operating room temperature is maintained at 30°C. The primary cause of a rapid decrease in rectal temperature from 36.8°C to 35°C is
- (A) absence of the central temperature control mechanism
- (B) conductive heat loss
- (C) convective heat loss
- (D) evaporative heat loss
- (E) radiant heat loss
A 72-year-old woman is somnolent one day after left carotid endarterectomy. She has smoked 2 packs of cigarettes daily for 50 years. Six weeks ago, she underwent right carotid endarterectomy. At this time, arterial blood gases while breathing room air are PO2, 45 mmHg, PCO2, 60 mmHg, and pH 7.30. Which of the following is the most likely cause of the increased PCO2?
- (A) Bilateral vocal cord paralysis
- (B) Cerebral infarction
- (C) Congestive heart failure
- (D) Denervation of the carotid bodies
- (E) Phrenic nerve injury
Which of the following is the most reliable indicator of antagonism of nondepolarizing neuromuscular block sufficient for airway protection?
- (A) Clinically assessed ulnar nerve train-of-four ratio of 0.75
- (B) Peak negative pressure of 25 cmH2O
- (C) End-tidal PC02 of 40 mmHg during spontaneous ventilation
- (D) Sustained head lift for 5 seconds
- (E) Vital capacity of 15 ml/kg
A patient has decreased lung compliance and hypoxemia after a 30-minute episode of laryngospasm following extubation. The most likely cause is
- (A) allergic reaction to the anesthetic
- (B) altered alveolar-capillary membrane permeability
- (C) anesthetic-induced lymphatic dysfunction
- (D) increased pulmonary capillary pressure
- (E) negative pulmonary interstitial hydrostatic pressure
Properly performed local anesthetic block of the celiac plexus
- (A) requires that the needle tip be positioned anterior to the vertebral body of LI
- (B) preserves efferent parasympathetic outflow
- (C) produces urinary retention
- (D) is not associated with hypotension
- (E) produces truncal cutaneous hypesthesia
A neurologically intact 48-year-old woman is scheduled for removal of a parietal lobe arteriovenous malformation. The relative risk for complete resection is to be determined by a test occlusion of the feeding artery. Which of the following intraoperative monitoring techniques is most appropriate for this test?
- (A) Brain stem auditory evoked potentials
- (B) Cerebral blood flow using radioactive xenon
- (C) EEG
- (D) Evoked potentials elicited by stimulating the posterior tibial nerve
- (E) Transcranial Doppler
During cardiopulmonary bypass, the perfusionist notes that the mixed venous oxygen saturation has decreased from to 55%. Which of the following is the most likely cause?
- (A) Administration of a nitroprusside bolus
- (B) Administration of a thiopental bolus
- (C) Decrease in rectal temperature from 34°C to 28°C
- (D) Inadequate muscle relaxation
- (E) Increase in pump flow