For any given FiO2 and PaCO2, the PaO2 is lower in a healthy paralyzed patient anesthetized with isoflurane than in the same patient unanesthetized and breathing spontaneously. The primary cause of this difference is
(A) controlled ventilation
(B) increased airway resistance
(C) inhibition of hypoxic pulmonary vasoconstriction
A 20-kg, 6-year-old boy is undergoing strabismus surgery under anesthesia with sevoflurane, nitrous oxide, and oxygen. The heart rate suddenly decreases from 85 to 40 bpm. Which of the following is the most appropriate first step in management?
A patient undergoes axillary block for placement of an arteriovenous shunt in the forearm. Blockade of the musculocutaneous nerve is not achieved. Injection of a local anesthetic at which of the following sites will provide the required sensory block?
(A) Between the tendon of the palmaris longus and flexor carpi radialis
(B) Body of coracpbrachialis muscle
(C) Medial to the brachial artery at the elbow
(D) Proximal to the medial epicondyle against the medial surface of the humerus
(E) Superficial to the pulse of the axillary artery
A 100-kg, 42-year-old woman received enflurane and oxygen for clipping of an intracranial aneurysm lasting eight hours. In the first two postoperative hours, urine output is 2 liters. Serum sodium concentration is 152 mEq/L. Urine osmolality and central venous pressure are low. Which of the following is best used to establish the diagnosis?