While checking an anesthesia machine, opening the oxygen flow-control valve yields no oxygen flow, although the wall-mounted oxygen pipeline supply gauge reads 50 psig. Opening the backup oxygen cylinder results in normal oxygen flow. The most likely cause is
(A) failure of the oxygen pipeline supply
(B) failure of the second-stage oxygen pressure regulator
(C) a malfunctioning check valve in the oxygen pipeline supply inlet
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 full-term newborn has marked respiratory distress in the delivery room. Breath sounds are asymmetric and the abdomen is scaphoid. Which of the following maneuvers is most appropriate?
(A) Hyperventilation with bag and mask
(B) Intubation and ventilation with positive end-expiratory pressure
(C) Intubation and ventilation with zero end-expiratory pressure
During induction of anesthesia, a 56-year-old man with small bowel obstruction vomits a large quantity of undigested food particles and presumably aspirates. After instituting ventilation with pure oxygen, the most appropriate management is to
(A) administer dexamethasone
(B) administer penicillin G
(C) perform bronchoscopy
(D) ventilate with positive end-expiratory pressure 15 cmH2O
(E) proceed with the anesthesia plan if the tracheal pH is greater than 2.5
Compared with general anesthesia, epidural anesthesia for hip arthroplasty is associated with
(A) decreased incidence of perioperative myocardial ischemia
(B) decreased intraoperative blood loss
(C) decreased risk for acute renal failure
(D) increased risk for stress-induced hyperglycemia
(E) increased thromboembolic complications
B
Three hours after total thyroidectomy, a 33-year-old man develops inspiratory stridor. The most likely cause is
(A) hematoma formation
(B) tracheomalacia
(C) tetany
(D) recurrent laryngeal nerve injury
(E) superior laryngeal nerve injury
A
Massive venous air embolism occurs in a patient who is undergoing craniotomy in the sitting position with nitrous oxide, oxygen, fentanyl anesthesia. Which of the following changes in end-tidal (ET) concentrations of carbon dioxide, nitrogen, and nitrous oxide are most likely in this patient? (ETCO2, ETN2, ETN2O)