Randomised controlled trial of combined spinal epidural vs. spinal anaesthesia for elective caesarean section: vasopressor requirements and cardiovascular changes.

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.

A comparison of levobupivacaine 0.5% and racemic bupivacaine 0.5% for extradural anesthesia for caesarean section.

BACKGROUND AND OBJECTIVES: Bupivacaine is available as a racemic mixture of its enantiomers, dextrobupivacaine and levobupivacaine. Both in vitro and in vivo studies show that dextrobupivacaine has a greater inherent central nervous system (CNS) and cardiovascular toxicity than levobupivacaine. Clinical studies show levobupivacaine to have similar local anesthetic potency to the racemate. The aim of this study was to investigate the clinical efficacy and safety of levobupivacaine compared with racemic bupivacaine for extradural anesthesia. METHODS: We studied 62 patients undergoing elective caesarean delivery who received 25 mL of either levobupivacaine 0.5% or bupivacaine 0.5%, extradurally, in a randomized, double-blind study. RESULTS: The 2 groups were similar in terms of time to block suitable for surgery, segmental spread, and duration of sensory block. However, lower-limb motor block was significantly longer in the levobupivacaine group but of significantly less intensity. CONCLUSIONS: Levobupivacaine produces an extradural block that is similar to bupivacaine, and is a suitable local anesthetic agent for caesarean delivery.