title: Hypertension during anesthesia on discontinuation of sodium nitroprusside-induced hypotension.
abstract: The authors had observed that on intraoperative discontinuation of sodium nitroprusside being administered to induce hypotension, mean arterial pressure increased to above the pre-hypotension level. Twelve patients who recieved hypotensive anesthesia for surgical correction of cerebral aneurysms were studied to evaluate the role of the renin-angiotensin system in this phenomenon. In the awake state, mean arterial pressure was 100 +/- 2 torr and plasma renin activity 3.0 +/- 0.1 ng/ml/hr. Thirty minutes after the establishment of stable halothane-nitrous oxide anesthesia, mean arterial pressure decreased to 85 +/- 1 torr and plasma renin activity increased to 4.4 +/- 0.1 ng/ml/hr. No appreciable change in either occurred over the next two hours of operation. During sodium nitroprusside-induced hypotension, mean arterial pressure decreased to 49 +/- 2 torr and plasma renin activity increased to 15.2 +/- 0.2 ng/ml/hr. Thirty minutes after discontinuation of sodium nitroprusside administration, mean arterial pressure increased to 112 +/- 2 torr, which was not only higher than the prehypotension level, but also significantly higher than that recorded in the awake state. Plasma renin activity at that time was 10.9 +/- 0.1 ng/ml/hr. As the half-life of plasma renin is 15 min, the data suggest that the persistently increased plasma renin activity is probably responsible for the increase of arterial pressure following sodium nitroprusside-induced hypotension.
mesh_terms: D000293:Adolescent; D000328:Adult; D000768:Anesthesia, General; D001794:Blood Pressure / Q000187:drug effects*; D005292:Ferricyanides / Q000494:pharmacology*; D006221:Halothane; D006801:Humans; D006973:Hypertension / Q000209:etiology*; D007023:Hypotension, Controlled / Q000009:adverse effects*; D007275:Injections, Intravenous; D002532:Intracranial Aneurysm / Q000503:physiopathology; D008875:Middle Aged; D009599:Nitroprusside / Q000008:administration & dosage / Q000494:pharmacology*; D009609:Nitrous Oxide; D012083:Renin / Q000097:blood*; D013874:Thiopental
chemical_list: D005292:Ferricyanides; D009599:Nitroprusside; D012083:Renin; D013874:Thiopental; D009609:Nitrous Oxide; D006221:Halothane