A 14-year-old girl with status asthmaticus is receiving oxygen 3 L/min through nasal prongs. Heart rate is 110 bpm. Arterial blood gas values are PaO2 90 mmHg, PaCO2 32 mmHg, and pH 7.46. If ventilation appears unchanged, which of the following is the most reliable sign of impending respiratory failure?
A 70-kg, 22-year-old man who is unconscious after a closed head injury is to undergo emergency splenectomy. He is anesthetized with thiopental, given pancuronium for paralysis, and started on nitrous oxide and oxygen 50% each with controlled ventilation (tidal volume 700 ml, rate 10/min). Pulse is 70 bpm, blood pressure is 160/100 mmHg, PaO2 is 65 mmHg, PaC02 is 45 mmHg, and pH is 7.30. In adjusting the ventilator at this time, which of the following is most appropriate?
An 18-month-old child with tetralogy of Fallot is anesthetized with halothane and nitrous oxide. Following intubation, oxygen saturation decreases abruptly from 85% to 45%. The most effective treatment is
During frontal craniotomy for removal of an astrocytoma, the surgeon notes that the brain is "tight." The patient is receiving nitrous oxide 50% in oxygen, isoflurane 0.5%, fentanyl, and pancuronium. Heart rate is 92 bpm, blood pressure is 110/60 mmHg, end-tidal carbon dioxide tension is 31 mmHg, and oxygen saturation is 98%. The most appropriate initial treatment is to
Two opened oxygen cylinders, one full and one empty, are attached to an anesthesia machine. The check valve to the empty cylinder fails. This is expected to result in
Each of the following contributes to hypotension following induction of anesthesia with propofol EXCEPT
An 8-year-old child with chronic renal failure is scheduled for an operation to create an arteriovenous fistula. Laboratory studies include: Hemoglobin 6.5 g/dl, Blood gases (breathing air) : PaO2 97 mmHg, PaCO2 29 mmHg, pH 7.30 Sodium 129 mEq/L Potassium 5.5 mEq/L Chloride 101 mEq/L Bicarbonate 15 mEq/L. Before inducing general anesthesia, which of the following abnormalities should be corrected?
A 68-year-old woman is scheduled for a mastectomy. She has not taken prescription medications for 24 hours. Preoperative examination shows a heart rate of 104 bpm and blood pressure of 200/105 mmHg. The most likely cause of these findings is omission of which of the following drugs?
Which of the following additives accelerates the onset of lidocaine axillary block without shortening duration?
A patient is undergoing exploration of a stab wound to the left side of the neck. On awake laryngoscopy, the left vocal cord is in midposition and the right vocal cord is abducted during inspiration. The most likely cause of these findings is trauma to which of the following structures on the left?