A 62-year-old man, who had a myocardial infarction three years ago, complicated by congestive heart failure and renal failure, is undergoing a colectomy. A pulmonary artery catheter demonstrates a cardiac output higher than measurements recorded during a cardiac catheterization two months after the infarction. Which of the following most likely contributes to the increased cardiac output?
(A) Creation of an arteriovenous fistula
(B) Increased hemoglobin concentration from 10 to 12 g/dl
(C) Stimulation of carotid body receptors
(D) Transcutaneous nitroglycerin
(E) Use of a beta-adrenergic blocker to prevent myocardial reinfarction
A Fluotec vaporizer is set to administer halothane 4% using a fresh gas flow of 4 L/min. If the diluent gas flow is increased to 8 L/min, and at the same time the room temperature increases from 20 to 25°C, the approximate concentration of halothane delivered to the patient would be
A 72-year-old man has ST-segment depression of 2 mm in ECG lead II immediately after suprarenal aortic clamping. Which of the following is the most likely cause?
(A) Decreased left ventricular stroke volume
(B) Decreased venous return
(C) Increased left ventricular wall tension
(D) Reflex tachycardia
(E) Release of epinephrine from hypoperfused adrenal medulla
C
In an adult undergoing laparotomy, which of the following is the most effective means of maintaining body temperature during the first hour of anesthesia?
(A) Increasing ambient temperature
(B) Using a warming blanket
(C) Warming inspired gases
(D) Warming intravenous fluids
(E) Warming irrigating fluids
A
Which of the following muscle relaxants is most likely to result in histamine release following administration of a bolus dose sufficient to facilitate rapid endotracheal intubation?