A 54-year-old man receives 25 ml of a 50% alcohol and 0.25% bupivacaine solution for celiac plexus block. During the next 20 minutes, blood pressure decreases from 130/75 mmHg to 85/55 mmHg. Which of the following is the most likely cause?
A 32-year-old man with acute aortic regurgitation is scheduled to undergo emergency aortic valve replacement. Heart rate is 110 bpm, blood pressure is 90/35 mmHg, and pulmonary artery occlusion pressure is 14 mmHg. Cardiac index is 2.2 L/min/m2. Which of the following is the most appropriate management?
(A) Administration of esmolol
(B) Administration of a fluid bolus before induction
(C) Infusion of dobutamine
(D) Infusion of phenylephrine
(E) Induction of anesthesia
E
An 8-kg, 1-year-old child has a measured blood loss of 50 ml during the first two hours of a rectal pull-through operation. Preoperative hematocrit was 31%. Balanced saline solution 150 ml has been administered for replacement. Urine output has been 2 ml for the last hour, heart rate is 160 bpm, and blood pressure is 40/15 mmHg. The most appropriate fluid therapy is,
An 87-kg 64-year-old woman in good general health is undergoing a right knee arthroplasty while in the supine position with general anesthesia consisting of enflurane 2% and nitrous oxide 50% in oxygen. She is breathing spontaneously through a 7-mm endotracheal tube. During the first 30 minutes of the procedure, the arterial oxygen saturation measured by pulse oximetry decreases from 98% to 92%. The most likely cause of the desaturation is
(A) decreased functional residual capacity
(B) diffusion hypoxia
(C) hypercarbia
(D) increased airway resistance produced by the endotracheal tube
(E) inhibition of hypoxic pulmonary vasoconstriction
A
An oxygen-driven anesthesia ventilator with a bellows that ascends during exhalation develops a small hole in the bellows. Which of the following is the most likely effect?
(A) Alveolar hyperinflation
(B) Decreased inspiratory flow rate
(C) Decreased inspired oxygen concentration
(D) Increased concentration of inhalational agent
(E) Rebreathing of exhaled gases
A
Which of the following is an advantage of a circle system over a Mapleson D system?
(A) Better anesthetic conservation
(B) Lower dead space
(C) Lower circuit resistance
(D) More efficient scavenging
(E) More rapid changes in inspired gas concentration