Clinical experience with adenosine for controlled hypotension during cerebral aneurysm surgery.

The cardiovascular effects of adenosine-induced hypotension were studied in 47 patients undergoing intracranial vascular surgery under neurolept anesthesia. Adenosine infusion (214 +/- 18 micrograms X kg-1 X min-1) decreased mean arterial pressure (MAP) by 42 +/- 1% from 80 +/- 1 to 46 +/- 1 mm Hg for an average of 29 +/- 5 min of hypotension. Hypotension was associated with a minor increase in heart rate (13 +/- 2%) and with prolongation of the PR interval (9 +/- 2%). ST-T depression did not occur except in one patient with a previous history of myocardial infarction. The adenosine-induced increase in cardiac index (42 +/- 9%, n = 7) was associated with a 63 +/- 10% decrease in systemic vascular resistance index (n = 7) while the pulmonary capillary wedge pressure remained unchanged. Adenosine metabolism was limited and there was no accumulation of the end metabolite, uric acid. Serum creatinine levels were normal in all patients postoperatively. We conclude that adenosine rapidly induces a stable and easily controlled hypotension in man without tachyphylaxis or rebound hypertension. There were no signs of renal or myocardial dysfunction except for dysrhythmias that occurred in two patients with a history of myocardial infarction.