Common features associated with spinal-anesthesia-induced hypotension: a retrospective study.

A retrospective study investigated features common to 85 documented cases of spinal-anesthesia-induced hypotension. Low preoperative systolic blood pressure and anemia were the most predictive features. Physical status was less important, with the exception of emergency surgeries. An association was found between preoperative medication--especially narcotics--and hypotension. Other variables found to have a high frequency among hypotensive patients were known preexisting pathologic conditions, increasing concentrations of anesthetic used at the time of surgery, and increasing levels of anesthesia achieved. The study is weighted toward obstetric/gynecologic cases.