Effect of Acute Preoperative Stress Assessed With Salivary Amylase on the Severity of Maternal Hypotension After Spinal Anesthesia for Planned Cesarean Section

Salivary amylase, heart rate variability, Spielberger state-trait inventory are assessed on the morning of surgery, on the surgical ward, and repeated in the operating room, before performing spinal anesthesia. Spinal anesthesia use hyperbaric bupivacaine (11 mg), sufentanil (5 µg) and morphine (100 µg). Prophylactic treatment of hypotension uses a continuous infusion of ephedrine (0.6 mg/ml) and phenylephrine (10 µg/ml). Rate of the continuous infusion is adapted to keep maternal systolic blood pressure between 95-105% of preinduction values. Total dose of ephedrine and phenylephrine infused from spinal anesthesia to delivery of the newborn is recorded (about 20 minutes for the estimated time frame). Association between stress markers and total dose of vasoactive drugs will be tested with the Spearman's correlation coefficient.

The study is observational. The subjects do receive a therapeutic intervention but the investigator does not assign patients to this intervention since this intervention is a routine care (spinal anesthesia for planned cesarian section) that would have been performed in the absence of the study.