A healthy, but obese, 110-kg woman is scheduled for gastric stapling. Compared with that required at her ideal weight, the dose of thiopental required for anesthetic induction would likely be increased because of changes in
In a patient who is receiving nitroglycerin intravenously after a coronary artery operation, peripheral oxygen saturation is 85% and PaO2 is 200 mmHg. The most appropriate management is administration of
During anesthesia with nitrous oxide 65% in oxygen, fentanyl, and pancuronium, nitroprusside is administered to decrease arterial pressure to 85/50 mmHg. A decrease in PaO2 from 120 to 65 mmHg is most likely caused by
A patient with metastatic carcinoma and chronic renal failure has tremors, fasciculations, mydriasis, and hyperreflexia after several days of therapy with high doses of meperidine for analgesia. Which of the following is most likely to occur if the meperidine is continued?
(A) Disappearance of the symptoms as tolerance to meperidine develops
One week after sustaining third-degree burns over 40% of his body surface area, a patient requires general anesthesia for debridement and skin grafting. Which of the following responses to neuromuscular blockers is most likely?
(A) Clinically insignificant increases in serum potassium concentration after administration of succinylcholine 1 mg/kg
(B) Increased risk of hyperkalemia after administration of succinylcholine 1 mg/kg
(C) Increased sensitivity to vecuronium
(D) Laudanosine toxicity after administration of atracurium 0.4 mg/kg
(E) Normal serum potassium concentration if administration of succinylcholine is preceded by d-tubocurarine 3 mg
An obese patient and a lean patient receive halothane for the same duration and at the same inspired tension. Postoperatively, the obese patient would demonstrate
Compared with the response of a normal patient, administration of a bolus dose of pancuronium (0.15 mg/kg) to a patient with cirrhosis and ascites would be associated with
A 68-year-old man who is scheduled for outpatient cystoscopy has non-insulin-dependent diabetes mellitus controlled with glipizide (Glucatrol) 5 mg twice daily. He has had nothing to eat since awakening this morning and has not taken glipizide today. His blood glucose level is 185 mg/dl. Before proceeding, the most appropriate management is to administer
Ninety minutes after administration of succinylcholine 1 mg/kg to a 28-year-old woman, the train-of-four shows a T4:T1 ratio of 25%. This is most consistent with
When antagonizing neuromuscular block produced by pancuronium, the combination of simultaneously administered anticholinergic and anticholinesterase drugs that is most likely to produce bradycardia is
A 16-year-old girl is receiving isoflurane, nitrous oxide, oxygen, and pancuronium for insertion of a Harrington rod. In order to perform a "wake-up test" the muscle relaxant was antagonized with neostigmine 2.5 mg and atropine 1 mg. The patient abruptly moved all extremities and was given thiopental 100 mg and succinylcholine 100 mg rapidly. Forty-five minutes later no twitch could be elicited with a nerve stimulator. The most likely explanation is
(A) a dibucaine number of 20
(B) incomplete antagonism of pancuronium
(C) prolongation of the action of succinylcholine by neostigmine
(D) spinal cord damage caused by the abrupt arousal
(E) synergism between succinylcholine and pancuronium
During pulmonary artery catheterization, a 65-year-old man receives morphine 6 mg and scopolamine 0.4 mg intravenously. The pulse oximeter indicates desaturation, which quickly resolves with stimulation. When the drapes are removed, he has unilateral eye pain, decreased visual acuity, and dilated and irregular pupils. These eye symptoms are most likely caused by
A patient receiving monoamine oxidase inhibitor therapy for depression undergoes an emergency cholecystectomy. Which of the following is the best means of providing postoperative analgesia in this patient?
(A) Epidural analgesia using 0.25% bupivacaine
(B) Intravenous meperidine
(C) Epidural analgesia using meperidine
(D) Epidural analgesia using 1% lidocaine with epinephrine
(E) Intercostal analgesia using 1% lidocaine with epinephrine
A 70-year-old man who has just undergone an abdominal aortic aneurysm repair under halothane anesthesia develops hypertension, dyspnea, and cyanosis shortly after awakening in the recovery room. Administration of furosemide 20 mg intravenously improves the cyanosis within 10 minutes. This immediate effect of furosemide is best explained by
Following antagonism of a nondepolarizing muscle relaxant with neostigmine, twitch height is normal. To achieve this effect, the percentage of the acetylcholine receptor pool that must be free of muscle relaxant is
Ten days after sustaining burns over 40% of his body surface area, a patient requires greater than expected doses of vecuronium for adequate relaxation of skeletal muscle. The primary cause is increased
To predict the requirement for isoflurane in milliliters of vapor per minute during closed circuit anesthesia, each of the following is necessary EXCEPT
A 72-year-old woman with stable angina is undergoing bowel resection. Anesthesia is induced with etomidate. Five minutes after starting isoflurane 1% in nitrous oxide 50%, her blood pressure decreases from 110/84 to 70/40 mmHg. The most likely cause is
(A) coronary steal produced by isoflurane
(B) direct myocardial depression produced by isoflurane
(C) vasodilation produced by isoflurane
(D) adrenocortical suppression produced by etomidate
Preoperative evaluation shows a serum sodium concentration of 140 mEq/L, serum chloride concentration of 90 mEq/L, PaCO2 of 46 mmHg, and arterial pH of 7.50. These findings are most indicative of prior treatment with
For 30 minutes, a patient has been receiving oxygen 2 L, nitrous oxide 2 L, and halothane from an agent-specific vaporizer set at 1%. A mass spectrometer sampling gas from the patient's airway shows an end-tidal halothane concentration of 0.7%. The most likely explanation for this difference is
A patient with jaundice who has a minimally elevated SGOT (AST), markedly elevated alkaline phosphatase, and normal prothrombin time is to receive a muscle relaxant. Which of the following is most likely in this patient?
A patient has severe hypotension, bronchospasm, and edema of the upper airway after injection of radiocontrast medium during cerebral angiography. The most appropriate immediate treatment is administration of
A patient has tonic movements of the head and neck, nystagmus, and slurred speech after receiving metoclopramide for nausea after nitrous oxide-opioid anesthesia. The most appropriate pharmacologic treatment is
Anesthesia is induced with halothane in a 3-year-old girl. Sixty seconds after administration of succinylcholine 1 mg/kg intravenously, heart rate decreases rapidly from 120 to 60 bpm. The most likely cause is
(A) acute hyperkalemia
(B) failure to pretreat with a nondepolarizing relaxant
A previously healthy 28-year-old woman scheduled for laparoscopic tubal ligation becomes, agitated and refuses to undergo the procedure after being brought to the operating room. This behavior most likely resulted from preoperative administration of
A 70-kg, 20-year-old athlete receives nitrous oxide and oxygen, thiopental, and fentanyl 1.25 mg (25 ml) during a knee reconstruction procedure lasting three hours. Postoperatively, he does not awaken or resume spontaneous breathing for three hours. The most likely explanation for the prolonged effect of fentanyl is
(A) dose-dependent elimination half-life
(B) genetically slow biotransformation
(C) large volume of distribution
(D) presence of an active metabolite in high concentration
The following hemodynamic values are obtained two hours after coronary artery bypass surgery: Cardiac index 1.7 L/min/m2; Pulm Art. Occ. Pressure 22 mmHg; MAP 60 mmHg; Urine volume 0.2 ml/kg/hr. The most appropriate management is
During an otherwise uneventful nitrous oxide-sevoflurane anesthetic in a spontaneously breathing patient, 85% nitrous oxide is accidently administered, resulting in a PO2 of 48 mmHg. Which of the following would be expected?
A 45-year-old man is scheduled for exploratory laparotomy. Six months ago, he received doxorubicin (Adriamycin) therapy for testicular cancer. This patient is at increased risk for
Which of the following would be most likely to increase the duration of seizures during electroconvulsive therapy using a barbiturate and succinyleholine for general anesthesia?
(A) Administration of atropine prior to therapy
(B) Changing to a benzodiazepine for induction
(C) Changing to etomidate for induction
(D) Adding phenytoin to preoperative medications
(E) Decreasing the dose of barbiturate used for induction
A 15-kg, 3-year-old child is anesthetized for an inguinal hernia repair with halothane and nitrous oxide. The trachea is intubated after administration of succinylcholine 30 mg. At the conclusion of the 45-minute procedure, the child is not breathing; a peripheral nerve twitch monitor indicates no response to a train-of-four stimulus. Further investigation is most likely to show
(A) abnormal response to nondepolarizing muscle relaxants
(B) a low dibucaine number
(C) a low plasma cholinesterase concentration
(D) an underlying myopathy
(E) a positive halothane-caffeine contracture test
A 70-kg patient experiences pain on incision of a thigh abscess. The area around the abscess had been infiltrated with 30 ml of 1% lidocaine in 1:200,000 epinephrine. The local anesthetic was most likely ineffective because of
(A) acidosis at the site of the injection
(B) epinephrine-induced limitation of drug diffusion
During induction of anesthesia in a 70-year-old man with aortic stenosis, the blood pressure decreases from 140/ 80 to 70/45 mmHg as the cardiac rhythm changes from normal sinus at 70 bpm to junctional at 120 bpm. The most appropriate initial therapy would be
A 73-year-old woman with a preoperative serum creatinine concentration of 2.1 mg/dl develops oliguria during enflurane anesthesia. Urine sodium concentration is 10 mEq/L and urine osmolality is 450 mOsm/L. The most likely cause of these findings is
A 100-kg, 42-year-old woman received enflurane and oxygen for clipping of an intracranial aneurysm lasting eight hours. In the first two postoperative hours, urine output is 2 liters. Serum sodium concentration is 152 mEq/L. Urine osmolality and central venous pressure are low. Which of the following is best used to establish the diagnosis?
A 76-year-old patient is restless and hallucinating in the preoperative holding area. He received morphine 5 mg and scopolamine 0.4 mg intramuscularly as premedication and is now breathing oxygen 2 L/min through nasal prongs. SpO2 is 98%. Which of the following is the most appropriate next step?
(A) Administration of naloxone
(B) Administration of physostigmine
(C) Induction of general anesthesia
(D) Determination of serum electrolyte concentrations
A 25-year-old man requires exploratory laparotomy following a motor vehicle accident. He is acutely intoxicated with alcohol. Which of the following is the most likely result of the alcohol ingestion?
(A) Hyperdynamic circulation
(B) Hyperglycemia
(C) Hyperthermia
(D) Increased respiratory depression from opioids
(E) Increased sensitivity to neuromuscular blocking drugs
A 66-year-old man with chronic obstructive pulmonary disease who underwent colectomy 12 hours ago has been receiving an epidural infusion of fentanyl at a rate of 100 mcg/hr. Which of the following is LEAST likely to develop?
In a 35-year-old patient, which of the following is associated with an increased duration of clinical narcosis following infusion of a total dose of 10 mg/kg thiopental over three hours?
A 24-year-old woman requires anesthesia for emergency repair of open fractures of the tibia and fibula. She used cocaine two hours ago. Blood pressure is 170/110 mmHg. Each of the following is useful in managing the hypertension EXCEPT
A 40-year-old woman receives alfentanil 75 mcg/kg followed by an infusion of 1.5 mcg/kg/min for a one-hour cholecystectomy and cholangiogram. This regimen could be associated with each of the following EXCEPT
A 62-year-old man is scheduled for coronary artery bypass grafting. During induction of anesthesia with fentanyl, high peak inspiratory pressures occur with manual ventilation, and peripheral oxygen saturation decreases from 100% to 94%. The most appropriate management is administration of
A 95-kg, 65-year-old woman receives sevoflurane and pancuronium during a laparoscopic cholecystectomy. Three minutes after administration of neostigmine 5 mg and atropine 1.2 mg, the twitch height returns to normal. Spontaneous tidal volume is 500 ml when the endotracheal tube is removed. In the PACU she reports dyspnea and appears distressed. Which of the following is the most likely cause of the respiratory distress?
A 75-year-old woman with significant carotid artery stenosis is scheduled for general anesthesia for repair of a fractured hip. Which of the following is the greatest disadvantage of using propofol as an induction agent in this patient?
After termination of cardiopulmonary bypass, a patient who is chronically digitalized receives digoxin 0.5 mg in error. An ECG shows sinus bradycardia with intermittent sinus arrest; blood pressure is 90/60 mmHg. Which of the following drugs is contraiindicated in this patient?
Prolonged respiratory depression following administration of morphine is more likely in patients with chronic renal faillure than in patients with normal kidney function because of
A 20-year-old man with a history of substance abuse is undergoing preoperative evaluation. Which of the following findings suggests current use of cocaine?
A 60-kg, 38-year-old woman undergoes laparoscopic tubal ligation. Paralysis is maintained for one hour with infusion of succinylcholine at a rate of 10 mg/min. At the end of the procedure, respirations are shallow and tetanic fade is noted on neuromuscular stimulation. In addition to continued mechanical ventilation, which of the following is the most appropriate next step in management?
(A) Observe until the patient recovers spontaneously
A newly developed inhalational anesthetic has a blood-gas partition coefficient of 0.2. Which of the following statements best describes this drug compared with isoflurane?
(A) MAC is lower
(B) The difference between Fa and Fl during maintenance of anesthesia is greater
(C) Time to emergence is shorter
(D) Rapid induction requires greater overpressure
(E) Equilibrium in a circle system with the same flow of fresh gas is slower
A 55-kg, 70-year-old woman with mild chronic renal failure is unresponsive 20 hours after an uneventful coronary artery bypass grafting procedure. Anesthetic drugs included fentanyl 3000 mcg, diazepam 35 mg, and pancuronium 20 mg. Which of the following is the most appropriate next step in management?
A 40-year-old man requires brief surgical relaxation after administration of neostigmine and glycopyrrolate for reversal of vecuronium-induced neuromuscular blockade. Succinylcholine 1 mg/kg is administered intravenously. Compared with a patient who has not had prior reversal of neuromuscular blockade, which of the following characterizes the succinylcholine blockade in this patient?
(A) Greater antagonism with calcium chloride
(B) Slower onset
(C) Less profound
(D) Less likelihood of phase II neuromuscular blockade
A 69-year-old man is confused and agitated one hour after preoperative intramuscular administration of scopolamine for awake fiberoptic laryngoscopy. SpO2 measured by pulse oximetry is 97%. Which of the following drugs is most appropriate for treatment of the change in mental status?
A 72-year-old patient who takes levodopa and carbidopa is undergoing colon resection. Metoclopramide is administered preoperatively and anesthesia is maintained with proposal, fentanyl, and nitrous oxide, with vecuronium for muscle relaxation. Fifteen minutes after reversal of muscle relaxation with neostigmine and atropine and tracheal extubation, the patient has dyspnea and muscular rigidity. Which of the following is the most likely cause?
(A) Central anticholinergic syndrome
(B) Fentanyl-induced rigidity
(C) Inhibition of methionine synthetase by nitrous oxide
A 32-year-old patient with end-stage renal failure has irreversible neuromuscular blockade two hours after tracheal intubation with a muscle relaxant. Which of the following is the most likely cause?
A previously healthy 46-year-old woman has severe substernal chest pain one hour after receiving morphine sulfate 10 mg intramuscularly for an elective cholecystectomy. Vital signs, SpO2, and findings on a five-lead ECG on the operating room monitor are within normal limits. Which of the following is the most appropriate next step?
A 68-year-old woman who is receiving urokinase for deep venous thrombosis and pulmonary emboli requires emergency laparotomy for a bleeding gastric ulcer. Which of the following agents is most appropriate to reverse the effects of urokinase?
Which of the following is the most likely effect of intramuscular ketamine used for induction of anesthesia in a 2-year-old child undergoing elective surgery?
A 19-year-old woman has severe nausea and vomiting following laparoscopy. After intramuscular administration of prochlorperazine 10 mg, she has muscle spasms in the face, neck, and tongue. Which of the following is the most appropriate management?
A 23-year-old man who is receiving his first anesthetic has not resumed spontaneous ventilation two hours after receiving succinylcholine. The train-of-four monitor shows no twitch response. Which of the following is the most likely cholinesterase genotype in this patient?
Administration of succinylcholine 1 mg/kg to a pregnant woman rarely causes fetal neuromuscular blockade. Which characteristic of succinylcholine best explains this phenomenon?
To predict the requirement for isoflurane in milliliters of vapor per minute during closed circuit anesthesia, each of the following is necessary EXCEPT
A patient has severe pain after total knee arthroplasty. Systemic opioids are most likely to modify the pain through action at which of the following sites?
A 70-kg 78-year-old man undergoing small-bowel resection during anesthesia with isoflurane in oxygen becomes hypotensive and develops frothy pink sputum in the endotracheal tube. Heart rate is 50 bpm, blood pressure is 75/60 mmHg, pulmonary artery occlusion pressure is 22 mmHg, and cardiac output is 1.7 L/min. The most appropriate initial step in management is administration of which of the following?
A 64-year-old man with diabetes mellitus well controlled with NPH insulin undergoes lower extremity revascularization. Following administration of protamine 10 mg, the patient has facial flushing and blood pressure of 60/30 mmHg. The most appropriate initial step in management is administration of which of the following drugs?
A 30-year-old woman has an abrupt change from sinus to nodal rhythm with unchanged heart rate on ECG during induction of halothane anesthesia. Which of the following is the most likely result of this change?
A 35-year-old woman with a grade III subarachnoid hemorrhage is undergoing clipping of a middle cerebral artery aneurysm 48 hours after initial hemorrhage. Which of the following drugs used to induce hypotension is LEAST likely to affect intracranial pressure?
Which of the following muscle relaxants is most likely to result in histamine release following administration of a bolus dose sufficient to facilitate rapid endotracheal intubation?
A patient develops jaundice one week after undergoing laparoscopic cholecystectomy during halothane anesthesia. Laboratory studies show an increased serum alkaline phosphatase concentration, a mildly increased serum aspartate aminotransferase concentration, and a markedly increased conjugated bilirubin fraction. Which of the following is the most likely diagnosis?
During induction of anesthesia for cesarean delivery, pancuronium is inadvertently substituted for succinylcholine. The neonate shows no clinical signs of muscle relaxation because pancuronium is
A 64-year-old, 70-kg woman treated with lithium for manic-depressive psychosis is given methohexital 90 mg and succinylcholine 35 mg intravenously for electroconvulsive therapy. Ten minutes later she remains sedated and the peripheral nerve stimulator shows a decreased twitch response. The most likely explanation is
The EKG rhythm shown developed during cholecystectomy in a 62-year-old man who had a myocardial infarction and is taking atenolol. The drug of choice for treating this arrhythmia is
In the diagram, point "X" represents a patient with severe left ventricular dysfunction. The points labeled 1, 2, and 3 each represent the results of a different therapeutic intervention. Which of the following represents the most likely intervention at each point?
The figure describes the uptake of nitrous oxide 75% by individual tissue groups (VRG = vessel-rich group, MG = muscle group, FG = fat group) and their sum (total uptake, TU). Which set of labels accurately describes the curves?
The five curves shown represent the uptake of enflurane, desflurane, halothane, isoflurane, and nitrous oxide. Which uptake curve best depicts desflurane?