MCQ 1 Flashcards
A 40-year-old woman with Graves’ disease is undergoing thyroidectomy with 1% isoflurane, 60% nitrous oxide, and oxygen. During surgical manipulation of the thyroid, temperature increases to 38.5°C, heart rate to 160 bpm, and blood pressure to 150/100 mmHg. The most appropriate initial treatment is to
(A) administer dantrolene sodium
(B) administer potassium iodide
(C) administer propranolol
(D) administer propylthiouracil
(E) increase the concentration of isoflurane
C
Six hours after coronary artery bypass grafting, a pulmonary artery catheter oximeter shows a mixed venous hemoglobin oxygen saturation of 50%. This value may result from each of the following EXCEPT
(A) anemia
(B) fever
(C) hypovolemia
(D) respiratory alkalosis
(E) shivering
D
A 75-year-old man is confused, restless and disoriented two days after an aortic aneurysm repair. Serum sodium concentration is 112 mEq/L, serum osmolality is low, and urine is hypertonic. The most appropriate treatment is
(A) restriction of fluid intake
(B) administration of isotonic saline solution
(C) administration of hypertonic (3%) saline solution
(D) administration of spironolactone
(E) infusion of mannitol 25 g
C
patient is undergoing thoracotomy in the lateral position. Five minutes after initiation of one-lung ventilation using a double-lumen tube and 100% oxygen, SpO2 decreases from 100% to 65%. Which of the following is the most appropriate initial step in management?
(A) Adding continuous positive airway pressure to the nondependent lung
(B) Adding positive end-expiratory pressure to the dependent lung
(C) Increasing the tidal volume to the dependent lung
(D) Resuming two-lung ventilation
(E) Verifying the position of the double-lumen tube
D
A patient who is paraplegic secondary to spinal cord transection at T3 develops bradycardia and facial flushing during a nephrectomy under general anesthesia with nitrous oxide, fentanyl, and atracurium. The most likely cause of this response is
(A) release of histamine
(B) stimulation of the carotid sinus
(C) release of prostaglandins
(D) vagal response to peritoneal traction
(E) release of epinephrine
B
Which of the following statements concerning awareness (recall) during opioid anesthesia is true?
(A) It is usually not associated with pain
(B) It correlates well with intact auditory evoked responses
(C) It is prevented if the dose of opioid blocks the hemodynamic response to stimuli
(D) It is prevented if the dose of opioid is adequate to prevent movement without muscle relaxants
(E) It is predicted by a specific EEG pattern
A
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) cardioversion
(B) esmolol
(C) fluid bolus
(D) phenylephrine
(E) verapamil
D
Which of the following processes is primarily responsible for the decrease in core body temperature that occurs during the first hour of general anesthesia?
(A) Decreased production of heat
(B) Convective heat loss caused by cutaneous vasodilation
(C) Evaporative heat loss during skin preparation
(D) Heat loss from the respiratory tract
(E) Redistribution of core body heat to the periphery
D
As part of a preoperative evaluation, a patient had a thallium scan showing a ‘cold spot’ over the left ventricle that occurs with moderate exercise and disappears at rest. This most likely indicates
(A) moderate-sized aneurysm of the left ventricle
(B) acute myocardial ischemia
(C) recent myocardial infarction
(D) old myocardial infarction
(E) Prinzmetal’s variant angina
B
Reduction of fire hazards during laser surgery of the airway is best accomplished by use of
(A) continuous mode laser emissions
(B) a nitrous oxide/opioid/relaxant anesthetic technique
(C) a polyvinylchloride endotracheal tube and cuff
(D) topical lidocaine
(E) saline-filled sponges over exposed tissues
E
A 26-year-old patient with multiple trauma is admitted to the intensive care unit postoperatively. The early development of polyuria, hypotension, low urine sodium excretion, high serum osmolality, and normal serum creatinine concentration is best explained by
(A) adrenal insufficiency
(B) fluoride-induced high-output renal failure
(C) inappropriate ADH secretion
(D) intraoperative fluid overload
(E) posterior pituitary insufficiency
E
After the first 70 minutes of a transurethral resection of the prostate, a 70-year-old man becomes confused and has tachycardia, hypertension, and shortness of breath. Serum sodium concentration is 116 mEq/L. After informing the surgeon that the procedure should be terminated as soon as possible, the most appropriate next step would be to
(A) administer furosemide
(B) administer labetalol
(C) administer 3% sodium chloride
(D) change the irrigating solution to normal saline
A
A 57-year-old man has back pain, a heart rate of 90 bpm, decreased pulse in the left arm, and blood pressure of 200/110 mmHg. During infusion of nitroprusside, heart rate increases to 115 bpm and blood pressure decreases to 140/80 mmHg. The most appropriate management at this time is administration of
(A) droperidol
(B) nifedipine
(C) normal saline solution
(D) propranolol
(E) verapamil
D
Each of the following would be expected in an otherwise healthy 165-kg woman undergoing cholecystectomy EXCEPT
(A) decreased functional residual capacity
(B) decreased ventilatory response to carbon dioxide
(C) increased cardiac output
(D) increased gastric fluid volume
(E) increased metabolism of volatile anesthetics
B
A 50-year-old patient undergoes subtotal thyroidectomy for Graves’ disease. In the immediate postoperative period, he has marked hoarseness but no stridor. The most likely cause of the hoarseness is trauma to the
(A) external branch of the superior laryngeal nerve
(B) internal branch of the superior laryngeal nerve
(C) recurrent laryngeal nerve
(D) glossopharyngeal nerve
(E) vocal cords
C
In patients with head trauma, which of the following factors results in a return of arterial pH toward normal levels after two days of mechanical hyperventilation?
(A) Decreased renal absorption of hydrogen ions
(B) Decreased renal blood flow
(C) Increased PaCO2 with constant minute ventilation
(D) Increased renal excretion of bicarbonate ions
(E) Normalized cerebrospinal fluid pH
D
Preoperative administration of an alpha-adrenergic blocker for 10 days to patients with pheochromocytoma will decrease
(A) episodic tachycardia
(B) hyperglycemia
(C) hypovolemia
(D) nasal stuffiness
(E) postural hypotension
C
When used for irrigation during transurethral resection of the prostate, glycine 1.5% is associated with each of the following EXCEPT
(A) hemolysis
(B) hyperammonemia
(C) cerebral edema
(D) hypofibrinogencmia
(E) visual disturbances
A
Following pneumonectomy, a paralyzed patient being mechanically ventilated has the following arterial blood gas values: PaO2 71 mmHg, PaCO2 55 mmHg, pH 7.29. SvO2 is 45%. The most likely explanation for this SvO2 is
(A) decreased red cell mass
(B) high cardiac output
(C) hypothermia
(D) peripheral left-to-right arteriovenous shunt
(E) ventilation / perfusion mismatch
A
(Lifl) Low SvO2
decreased O2 delivery:
1. decreased Hb (anaemia, haemorrhage, dilution)
2. decreased SaO2 (hypoxaemia)
3. decreased Q (any form of shock, arrhythmia)
increased O2 demand (hyperthermia, shivering, pain, seizures)
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
A
Autoregulation is the intrinsic capacity of resistance vessels in end organs, such as heart, kidney, and brain, to dilate and constrict in response to dynamic perfusion pressure changes, maintaining blood flow relatively constant.
Perfusion pressures below the lower limit result in initially increased oxygen extraction from hemoglobin and, subsequently, global ischemia. Pressures above the upper bound may result in breakthrough edema, hemorrhage, seizures, and posterior leukoencephalopathy (ie, hypertensive encephalopathy). The normal autoregulatory curve may be right shifted in chronically hypertensive patients, although the magnitude and duration over which this occurs cannot be determined on an individual basis.
Which of the following findings on the left is most likely to be associated with an increased risk of complications with cannulation of the left internal jugular vein compared with cannulation of the right internal jugular vein?
(A) Longer recurrent laryngeal nerve
(B) Lower location of the cupola of the pleura
(C) More acute angle between the internal jugular and innominate veins
(D) More anterior location of the phrenic nerve
(E) Presence of the thoracic duct
E
(Miller’s)
Left internal jugular vein cannulation may be accomplished reliably and safely, although several anatomic
details make the left side less attractive than the right.
The cupola of the pleura is higher on the left, theoretically increasing the risk of pneumothorax.
○ The thoracic duct may be injured during the procedure as it enters the venous system at the junction of the left internal jugular
and subclavian veins. ○ The left internal jugular vein is often smaller than the right and demonstrates a greater
degree of overlap of the adjacent carotid artery.
○ Most important, any catheter inserted from the left side of the patient must traverse the innominate (left brachiocephalic) vein and enter the superior vena cava perpendicularly. As a result, the catheter tip may impinge on
the right lateral wall of the superior vena cava, increasing the risk of vascular injury. This anatomic disadvantage pertains to all left-sided catheterization sites and
highlights the need for radiographic confirmation of
proper catheter tip location.
○ Finally, most operators
have less experience performing left internal jugular vein cannulation, which leads to more adverse events and morbidity.
Each of the following is an effect o electroconvulsive therapy EXCEPT
(A) increased intracranial blood volume
(B) increased oxygen consumption
(C) inhibition of parasympathetic activity
(D) retrograde amnesia
(E) stimulation of the sympathetic nervous system
C
Which of the following statements regarding carbon monoxide poisoning is true?
(A) Breathing 100% oxygen at 1 atmosphere reduces the carboxyhemoglobin half-life
(B) Effective treatment includes administration of methylene blue
(C) It is commonly associated with respiratory acidosis
(D) It is incompatible with a normal Sp02 while breathing room air
(E) The oxyhemoglobin dissociation curve is shifted to the right
A
A 35-year-old woman undergoes a one-hour abdominal liposuction procedure under general anesthesia. During the procedure, 2000 ml of crystalloid is administered and 800 ml of fatty tissue is extracted. Thirty minutes postoperatively, blood pressure is 75/40 mmHg and heart rate is 100 bpm; SpO2 is 94% on room air. Which of the following is the most likely cause of these findings?
(A) Acute systemic vasodilation
(B) Circulating free fatty acids
(C) Hypocalcemia
(D) Inadequate intravascular volume replacement
(E) Venous fat embolism
D
A 35-year-old woman undergoes a one-hour abdominal liposuction procedure under general anesthesia. During the procedure, 2000 ml of crystalloid is administered and 800 ml of fatty tissue is extracted. Thirty minutes postoperatively, blood pressure is 75/40 mmHg and heart rate is 100 bpm; SpO2 is 94% on room air. Which of the following is the most likely cause of these findings?
(A) Acute systemic vasodilation
(B) Circulating free fatty acids
(C) Hypocalcemia
(D) Inadequate intravascular volume replacement
(E) Venous fat embolism
D
A patient undergoes thoracotomy in the lateral decubitus position. Which of the following maneuvers is most likely to increase PaO2 during one-lung ventilation?
(A) Applying continuous positive airway pressure to the nondependent lung
(B) Applying positive end-expiratory pressure to the dependent lung
(C) Increasing inspiratory flow rate
(D) Increasing the tidal volume
(E) Increasing the ventilatory rate
A
A patient who had liver transplantation two years ago now requires general anesthesia for ENT surgery. Minimal rejection has occurred on a regimen of cyclosporine and prednisone. Which of the following is most likely?
(A) Hypoalbuminemia
(B) Hypocalcemia
(C) Episodic hypoglycemia
(D) Increased serum creatinine concentration
(E) Prolonged prothrombin time
D
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
A
The most likely cause of this capnographic tracing obtained just after laryngoscopy and intubation is

(A) esophageal intubation
(B) partial obstruction of the endotracheal tube
(C) pulmonary embolus
(D) insertion of an endotracheal nasogastric tube
(E) mild bronchospasm
A
