Résumé
Spinal anaesthesia for caesarean section exposes to high incidence of arterial hypotension which can result in maternal and neonatal morbidity. We hypothesized that the reduction of this dose from 10 mg to 7.5 mg would minimize hypotension without altering pain relief. In this double-blind prospective study, 80 ASA1 women scheduled for elective caesarean section were randomized into two groups A and B receiving respectively 10 and 7.5 mg of isobaric bupivacaine both with 25 micro g of fentanyl and 100 micro g of morphine in spinal anaesthesia. Intravenous ephedrine was administered for each episode of hypotension. We recorded sensory and motor block, intraoperative pain, nausea and vomiting. In postanaesthesia care unit, sensory and motor recoveries were measured and maternal satisfaction rate was assessed. In group A, a larger dose of ephedrine was needed [32 +/- 23 vs 19 +/- 16 mg; p=0.004]. Incidence of sensory block above T4 [52 vs 10%; p<0.001], nausea [52 vs 22%; p=0.005] and vomiting [25 vs 8%; p=0.03] were all higher than in group B. Arterial hypotension was less frequent in group B [68 vs 88%; p=0.03]. The time required for recovery to T10 sensory level and motor regression were shorter than in group A [p<0.001] and the satisfaction rate was higher than in group A [excellent and good in 90% vs 67%; p=0.03]. There was no difference in pain relief. A dose of 7.5 mg of isobaric bupivacaine reduced incidence of hypotension, nausea and vomiting and improved patient satisfaction