A 50-year-old man with an 80 pack-year history of cigarette smoking has a forced expiratory volume in one second of 1.5 L and a forced vital capacity of 3.5 L. Which of the following statements concerning intraoperative anesthetic management is true?
(A) An I:E ratio of 1:1 will improve carbon dioxide removal more than an I:E ratio of 1:2.5
(B) Antagonism of neuromuscular block will most likely trigger acute bronchospasm
(C) Functional residual capacity will increase during an acute exacerbation of bronchospasm
(D) Induction with ketamine will increase airway resistance
Which of the following statements concerning pressure support ventilation is true?
(A) Continuous positive airway pressure is provided during inspiration and expiration
(B) Delivered tidal volume remains the same with decreasing lung compliance
(C) Inspiratory effort less than -2 cmH20 is not assisted
(D) The overall work of breathing decreases when weaning from mechanical ventilation
(E) The patient will need more sedation than during intermittent mandatory ventilation
D
An anesthesia machine is set to deliver oxygen 2 L/min, nitrous oxide 2 L/min, and sevoflurane. After 30 minutes of stable anesthesia, which of the following, is the most likely cause of a decrease in the oxygen analyzer reading from 50% to 30%?
(A) A leak in the ventilator bellows
(B) Accumulation of water on the oxygen sensor membrane
(C) Calibration at 100% oxygen using less than 100% oxygen
(D) Disconnection of the wall oxygen hose
(E) Presence of the oxygen analyzer in the expiratory limb
Prior to occlusion of any major pulmonary blood vessels during a thoracotomy, applying positive end-expiratory pressure to ventilation through the dependent lumen of a double-lumen tube and occluding the upper lumen of the tube will
(A) increase blood flow to the dependent lung
(B) increase the alveolar-arterial oxygen tension difference
A 34-year-old man is undergoing appendectomy during spinal anesthesia with T2 sensory blockade. Approximately 15 minutes after the injection of bupivacaine 15 mg, heart rate decreases to 34 bpm and blood pressure decreases to 70/40 mmHg. Which of the following is the most likely cause?
(A) Baroreceptor stimulation
(B) Bupivacaine cardiotoxicity
(C) Hypovolemia
(D) Thoracic sympathetic blockade
(E) Vasovagal reflex
B
In a patient with severe mitral stenosis, induction of anesthesia must include avoidance of increased
(A) airway pressure
(B) heart rate
(C) myocardial contractility
(D) right ventricular preload
(E) systemic vascular resistance
B
A 45-year-old woman with mitral stenosis is scheduled for elective mitral valve replacement. Two minutes after tracheal intubation, she develops atrial fibrillation with a ventricular response rate of 150 bpm and a decrease in blood pressure to 75/45 mmHg. Which of the following is the most appropriate first step in management?
(A) Increasing the concentration of enflurane
(B) Increasing the infusion rate of lactated Ringer's solution