PREOPERATIVE VALPROATE ADMINISTRATION DOES NOT INCREASE BLOOD-LOSS DURING TEMPORAL LOBECTOMY

Surgical treatment is increasingly used for patients with medically re fractory seizures. Valproate (VPA) is an effective, widely used antico nvulsant in this patient population, but believed by some researchers to increase surgical bleeding because of quantitative thrombocytopenia and functional defects in platelet aggregation. Because we have obser ved no clinical evidence that perioperative administration of VPA incr eases blood loss or complications related to postoperative bleeding in patients undergoing temporal lobectomy at our institution, we sought to test this hypothesis. We made a retrospective review of the medical records of all patients who underwent epilepsy surgery at the Univers ity of California, San Francisco Medical Center, from September 1986 t hrough January 1993. Patients who had a temporal lobectomy and whose m edical records documented preoperative platelet counts and pre- and po stoperative hematocrit and hemoglobin values were included. We exclude d patients who had cranial surgery before temporal lobectomy and those with intracranial neoplasms or vascular malformations. Patients were divided into two groups: those who received VPA in the immediate preop erative period and those who had not received VPA recently. We compare d the estimated surgical blood loss and the estimated change in red bl ood cell (RBC) volume between groups by unpaired t tests, The charts o f 87 consecutive patients qualified for inclusion in the study. Patien ts in the VPA group had relative (but not absolute) thrombocytopenia p reoperatively (235 +/- 64 vs. 277 +/- 69 k in the No-VPA group). There were no differences in the estimated blood loss, RBC volume, or in th e incidence of postoperative transfusion. VPA apparently does not incr ease complications of hemostasis during therapeutic surgical resection s for epilepsy. Therefore, we do not recommend routinely discontinuing VPA before craniotomy.