Elective repeat cesarean section was scheduled for a 28-year-old woman, 39 weeks' pregnant. She had undergone her first section eight years ago for cephalopelvic disproportion and had had two subsequent transabdominal deliveries, the most recent 14 months ago. The antenatal course of this pregnancy was uneventful, and the patient's physical status was within normal limits.
The patient was given atropine, 0.4 mg, preoperatively. On arrival in the operating room, she was lying comfortably on her back; blood pressure was 105/60 mm Hg; pulse rate, 92 beats per minute. An intravenous infusion was started and 800 ml of lactated Ringer's solution with dextrose were administered within 20 minutes. At this time blood pressure was 110/70 mm Hg and pulse rate, 88 beats per minute. A spinal block (8 mg tetracaine [Pontocaine]) was given with the patient in the lateral decubitus position. After the patient was returned to the supine position, blood