Background and objectives: Combined spinal and epidural anaesthesia (CSEA) has previously been shown to result in a higher sensory block than equivalent single shot spinal anaesthesia (SSSA). In nonpregnant patients, hypotension was also more pronounced in the CSEA group. The aim of this randomized trial was to compare the haemodynamic stabilities of CSEA and SSSA during elective caesarean section when the same dose of anaesthetic was administered. This was studied directly by measuring the noninvasive arterial blood pressure (BP) and indirectly by the amount of ephedrine required to maintain baseline BP. Systemic vascular resistance index (SVRI) and cardiac index (CI) were also measured using thoracic impedance cardiography.
Methods: Seventy women received hyperbaric bupivacaine (12.5 mg) and diamorphine (0.3 mg) intrathecally via either CSEA or SSSA. Noninvasive arterial BP, CI and SVRI were measured every 2 min. The total ephedrine used was calculated.
Results: There were no significant differences between the groups in ephedrine requirements (P = 0.38), intraoperative mean arterial pressure (P = 0.77), CI (P = 0.17) or SVRI (P = 0.10).
Conclusion: CSEA placement appears to offer no haemodynamic benefits compared with SSSA when the same dose of local anaesthetic is administered.