Controlled hypotensive anesthesia during spinal surgery. A retrospective study.

A retrospective study has been made of 264 posterior spinal fusions performed between 1972 and 1978 at the Good Samaritan Hospital in Cincinnati. Two hundred ten of the procedures were performed under hypotensive anesthesia. Blood loss and total blood replacement were related to the mean arterial pressure (MAP) during surgery. A 42% reduction in total intraoperative loss and a 28%reduction in total blood requirements were demonstrated. The results were significantly different when patient age was considered in adults maintained below 80 mmHg MAP, blood loss was decreased by 33%, but the total blood requirement was decreased by only 6%; in children under 18 years of age maintained below 90 mmHg MAP, the blood loss was decreased by 49% and the blood requirement by 42%.