Two days after coronary artery bypass grafting, a 62-year-old man remains sedated, tracheally intubated, and mechanically ventilated with full neuromuscular block. Over the next three hours, Pa02 decreases from 90 to 70 mmHg at an Fl02 of 0.7, peak inspiratory pressure measured proximally in the ventilatory circuit increases from 40 to 66 cmH20, and plateau pressure remains unchanged at 30 cmH20. Which of the following is the most likely cause of these changes?
(A) Adult respiratory distress syndrome
(B) Bronchial mucus plugging
(C) Left ventricular failure
(D) Lobar pneumonia
(E) Tension pneumothorax
B
A 30-year-old man has had burning pain, allodynia, and edema of the hand for six weeks after sustaining a forearm fracture. Appropriate treatment includes each of the following EXCEPT
(A) physical therapy, employing stress loading
(B) oral prazosin
(C) intravenous regional sympathetic block with guanethidine
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?
Compared with the demand-flow intermittent mandatory ventilation (IMV) system, the continuous-flow IMV system has which of the following characteristics?
(A) It cannot be used with positive end-expiratory pressure
(B) It permits monitoring of exhaled tidal volume
(C) It decreases waste of medical gases
(D) It decreases the work of breathing
(E) It synchronizes mechanical and spontaneous breaths
D
Which of the following findings is most likely in patients with acute transection of the spinal cord at the level of C6?
(A) Autonomic hyperreflexia
(B) Hyperkalemia with administration of succinylcholine
Five minutes after initiating one-lung ventilation using a double-lumen endobronchial tube, a 70-year-old patient has a decrease in Sp02 from 99% to 90%. Tidal volume and respiratory rate are unchanged. Fiberoptic bronchoscopy verifies appropriate positioning of the tube. Which of the following is the most likely cause of the desaturation?
(A) Blood flow to the nondependent lung
(B) Failure of hypoxic pulmonary vasoconstriction in the dependent lung
(C) Inadequate filling of the bronchial cuff
(D) Inadequate minute ventilation
(E) Surgical manipulation of the nondependent lung