Use of sodium nitroprusside induced hypotensive anaesthesia for reducing blood loss in patients undergoing lienorenal shunts for portal hypertension.

A randomized study was performed on 18 patients to determine whether hypotensive anaesthesia, induced by sodium nitroprusside (SNP), would reduce blood loss during elective proximal lienorenal shunt operations for portal hypertension which was due to extrahepatic obstruction or non-cirrhotic portal fibrosis. Eight patients received SNP intraoperatively to reduce the systolic blood pressure to below 95 mmHg, and there were 10 control patients. Blood loss, the number of units of blood transfused, and urine output during surgery were measured together with the postoperative drainage from the abdominal and chest tubes over the first 24 h. There was a significantly lower blood loss (mean +/- s.d. 517 +/- 220 versus 1286 +/- 523 ml; P less than 0.01) and number of units of blood transfused was less (0.9 +/- 0.9 versus 3.0 +/- 1.2; P less than 0.01) in the SNP patients than in the controls. The urine output was greater in the SNP group (606 +/- 211 versus 399 +/- 139 ml, n.s.). Postoperative drainages from the chest and abdomen were similar. Hypotensive anaesthesia with SNP reduces operative blood loss and transfusion requirement in patients with good liver function undergoing proximal lienorenal shunts for portal hypertension.