Objective: To date, racemic bupivacaine is the most popular local anaesthetic for spinal anaesthesia in parturients undergoing elective Caesarean delivery. However, data suggests that S-enantiomers like levobupivacaine may produce differential sensory and motor blockade. The aim of the present study was to compare fixed doses of intrathecal hypertonic levobupivacaine 0.5% (10 mg) and bupivacaine 0.5% (10 mg) combined with either intrathecal fentanyl (10 and 20 microg), or sufentanil (5 microg) in terms of sensory and motor block characteristics.
Research design and methods: 60 parturients with singleton pregnancy and > 34 weeks of gestation who underwent elective Caesarean delivery participated in this randomized, double-blinded clinical trial. They received spinal anaesthesia with either levobupivacaine or bupivacaine and the above mentioned opioids added (n = 10 parturients/group). Sensory block was assessed bilaterally by loss of cold sensation, and the degree of motor block was determined according to the Bromage scale every minute until delivery, subsequently at 5-min intervals until the end of surgery, and at 15-min intervals thereafter until complete resolution of spinal anaesthesia. A visual analogue scale was used postoperatively to measure duration of analgesia at 15-min intervals.
Main outcome measures: Levobupivacaine produced a significantly shorter and less pronounced motor blockade than racemic bupivacaine regardless of the kind and dose of opioid added. Duration of motor block Bromage 3 was 53 +/- 14 min, 23 +/- 18 min and 41 +/- 8 min compared to 65 +/- 25 min, 70 +/- 19 min and 65 +/- 22 min in the bupivacaine groups. Also, only n = 5/30 parturients reached Bromage 3 in the levobupivacaine groups versus n = 21/30 parturients in the bupivacaine groups. No parturient experienced intraoperative pain. Adding sufentanil 5 microg to either local anaesthetic significantly prolonged duration of effective analgesia compared to supplemental fentanyl 10 or 20 microg.
Conclusions: Based on our data, 10 mg of hypertonic levobupivacaine 0.5% combined with sufentanil 5 microg was the most appropriate anaesthetic regimen in parturients undergoing elective Caesarean delivery in spinal anaesthesia.