Lumbar Wedge versus Pelvic Wedge in Preventing Hypotension following Combined Spinal Epidural Anaesthesia for Caesarean Delivery

Aortocaval compression is a major cause of maternal hypotension. A randomised controlled clinical trial was designed to compare two wedged supine positions for prevention of hypotension following combined spinal epidural anaesthesia for caesarean delivery. Sixty parturients undergoing elective caesarean delivery were randomly assigned to two different wedged supine positions. After the completion of subarachnoid injection, parturients were placed with either a wedge under the right pelvis (group P, pelvic wedge) or under the right lumbar region (group L, lumbar wedge). Systolic blood pressure and heart rate were recorded every minute for 20 minutes from the subarachnoid injection. Hypotension, defined as systolic blood pressure <100 mmHg or 80% of the baseline, was treated with intravenous ephedrine 5 mg. The incidence of hypotension, ephedrine use and neonatal Apgar scores and umbilical arterial pH were recorded. The incidence of hypotension was significantly higher in group P than that in group L (23/30 [77%] vs. 14/30 [47%], P=0.016). Systolic blood pressure decreased significantly in both groups at seven, eight and nine minutes (P <0.001); moreover it was lower at seven, eight and nine minutes in group P than in group L (P <0.01). Heart rate did not change significantly in either group. There were no significant differences between the two groups for Apgar score and umbilical arterial pH. A lumbar wedge is more effective than a pelvic wedge in preventing hypotension following combined spinal epidural anaesthesia for caesarean delivery, although it does not eliminate hypotension.