During exploration of the posterior fossa with the patient in the sitting position, blood pressure decreases from 120/70 to 70/40 mmHg, central venous pressure increases from 6 to 16 mmHg, oxygen saturation decreases to 88%, nitrogen is detected by the mass spectrometer, and premature ventricular contractions appear on the ECG. The most appropriate management is to
A 120-kg 56-year-old man undergoing gastrectomy during anesthesia with fentanyl and isoflurane has a PetCO2 of 35 mmHg and a PaCO2 of 50 mmHg. His FEV,/FVC ratio is 80% of predicted. Heart rate is 120 bpm and arterial blood pressure is 80/40 mmHg. Which of the following is the most likely cause of the difference in PaCO2 and PetCO2?
A 2500-g, 12-hour-old infant is tracheally intubated and mechanically ventilated at a rate of 20/min with an FiO2 of 0.4 and peak inspiratory pressure of 25 cmH2O. At birth, amniotic fluid was meconium stained and Apgar scores were 2 and 7. The most recent arterial blood gas levels are PaO2, 50 mmHg, PaCO2, 55 mmHg, and pH 7.20. The most appropriate management is to
(A) administer sodium bicarbonate
(B) begin intravenous infusion of prostaglandin E,
A 76-year-old patient is restless and hallucinating in the preoperative holding area. He received morphine 5 mg and scopolamine 0.4 mg intramuscularly as premedication and is now breathing oxygen 2 L/min through nasal prongs. SpO2 is 98%. Which of the following is the most appropriate next step?
(A) Administration of naloxone
(B) Administration of physostigmine
(C) Induction of general anesthesia
(D) Determination of serum electrolyte concentrations
A 37-year-old woman with pregnancy-induced hypertension develops oliguria two hours after cesarean delivery during epidural .anesthesia. Despite infusion of 2000 mL of crystalloid solution, urine output remains 10 mL/hr. Which of the following laboratory findings is most suggestive of acute tubular necrosis?
(A) Blood urea nitrogen level of 30 mg/dL
(B) Serum creatinine level of 1.2 mg/dL
(C) Urinary/plasma osmolality of 1:1
(D) Urinary sodium level of 10 mEq/L
(E) Urinary specific gravity of 1.024
C
Preoperative evaluation of a patient who has marked malnutrition will demonstrate each of the following EXCEPT
A 157 cm (5 ft 2 in), 180-kg, 40-year-old woman has a PaO2 of 65 mmHg, a PaCO2 of 38 mmHg, and a pH of 7.43 while breathing room air preoperatively. The most likely cause of these values is
(A) decreased hypoxic ventilatory drive
(B) higher than normal oxygen extraction from blood
(C) lower than normal cardiac output
(D) lower than normal functional residual capacity