A 4-month-old child undergoing a craniectomy for craniosynostosis is anesthetized with nitrous oxide and halothane. Suddenly the systolic blood pressure decreases from 75 to 30 mmHg, and the PetCO2 decreases from 35 to 6 mmHg. Which of the following maneuvers is LEAST likely to have a beneficial effect?
(A) Administration of a fluid bolus
(B) Administration of a vasopressor
(C) Application of positive end-expiratory pressure
(D) Discontinuation of nitrous oxide
(E) Flooding the surgical wound with saline solution
During insufflation of the peritoneal cavity with carbon dioxide at the start of laparoscopy, heart rate increases to 140 bpm, blood pressure decreases to 70/40 mmHg, and a loud murmur is heard through the esophageal stethoscope. The most appropriate immediate step is to
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?
Which of the following findings necessitates the preoperative insertion of a ventricular pacemaker in a 48-year-old man scheduled to undergo cholecystectomy?
(A) Atrial flutter with 3:1 atrioventricular block
(B) Bifascicular (right bundle branch block and left anterior hemiblock) block
(C) Left bundle branch block with first-degree atrioventricular block
A patient undergoes differential spinal block for evaluation of persistent foot pain. If the pain returns coincident with a decrease in skin temperature, which of the following is the most appropriate conclusion?