Controlled hypotension with adenosine or sodium nitroprusside during cerebral aneurysm surgery: effects on renal hemodynamics, excretory function, and renin release
Zäll, S.; Edén, E.; Winsö, I.; Volkmann, R.; Sollevi, A.; Ricksten, S.E.
Anesthesia and Analgesia 71(6): 631-636
1990
ISSN/ISBN: 0003-2999 PMID: 2240636 Document Number: 354737
Adenosine, a potent vasodilator both in animals and in humans, has been used to produce controlled hypotension in patients, especially during cerebral aneurysm surgery. However, in animals adenosine by intrarenal infusion decreases renal blood flow (RBF), glomerular filtration rate (GFR), urine flow, and causes an inhibition of renin secretion. In this study we evaluated the effects of adenosine on RBF in patients (n = 15) scheduled for cerebral aneurysm surgery who had been anesthetized with a modified neurolept-anesthesia during controlled hyperventilation. Perioperative hypotension was achieved with infusion of adenosine (252.8 .+-. 55.8 .mu.g.cntdot.kg-1.cntdot.min-1) (n = 8) or sodium nitroprusside (2.5 .+-. 0.8 .mu.g.cntdot.kg-1.cntdot.min-1) (n = 7). Mean arterial pressure was lowered by 25%-30%, to approximately 60-70 mm Hg, in both groups. Glomerular filtration rate and RBF were measured using standard renal clearance methods for 51Cr-ethylenediaminetetraacetic acid and paraaminohippuric acid. Urine and blood samples were collected during normotension before and after a bolus dose of hypertonic mannitol, during hypotension, and during normotension after clipping of the aneurysm. Adenosine induced a marked decrease in GFR (-91%) and RBF (-92%), and a pronounced increase in renal vascular resistance. Sodium nitroprusside caused a significantly (P < 0.01) less pronounced decrease in GFR (-24%) and RBF (-36%), but did not affect renal vascular resistance. After discontinuation of the hypotensive agents, GFR returned to baseline levels in both groups. Renal blood flow, however, increased above baseline after discontinuation of adenosine (+93%) but not after sodium nitroprusside. Sodium nitroprusside increased renin secretin, which was not seen with adenosine. Four patients in the adenosine group developed reversible atrioventricular conduction disturbances. We conclude that adenosine-induced hypotension during cerebral aneurysm surgery prevents renin release and induces a reversible renal vasoconstriction mainly involving preglomerular resistance vessels and thereby decreasing RBF and GFR.