Hypotensive anesthesia, thromboprophylaxis and postoperative thromboembolism in total hip arthroplasty

A prospective study was performed in 120 patients undergoing total hip arthroplasty. The patients were randomly allocated to four groups. The first two groups had nitroprusside-induced hypotensive anesthesia with either a fixed combination of sodium heparin and dihydroergotamine mesylate (HDHE) or dextran 70. The other two groups had normotensive halothane anesthesia with either HDHE or preoperative hemodilution with dextran 70. Hypotensive anesthesia reduced surgical bleeding. Blood loss was increased in patients undergoing preoperative hemodilution as compared to thromboprophylaxis with HDHE, whereas no difference was found between conventional administration of dextran and HDHE. Deep vein thrombosis, diagnosed with ascending phlebography of the operated leg, was registered in 48% of the patients. There was no difference between the techniques of anesthesia and thromboprophylaxis. Pulmonary embolism, studied with perfusion-ventilation scintigraphy, was diagnosed in 19% of the patients. No significant difference was found between hypotensive and normotensive anesthesia, or between thromboprophylaxis with conventional dextran and HDHE. There was a lower incidence of pulmonary embolism in patients with HDHE and normotensive anesthesia. Major wound hematomas were noted postoperatively in 12% of the patients receiving HDHE, whereas no major hematomas developed following dextran prophylaxis. No anaphylactic reaction was noted from dextran 70, using hapten-dextran prophylaxis.