Background and objective: Levobupivacaine is the most recently introduced local anaesthetic into clinical practice. In a randomized double-blinded study, the onset, intraoperative tolerance, postoperative analgesic effect, motor blockade and any adverse reactions produced by levobupivacaine were compared with ropivacaine.
Methods: Sixty children, ASA I-II, 2-6 yr old, undergoing elective minor surgery, received a single caudal injection of 1 mL kg(-1) of either levobupivacaine 0.25% or ropivacaine 0.25%. Caudal blocks were performed after induction of inhalation general anaesthesia using sevoflurane; anaesthesia was maintained via a laryngeal mask airway using a mixture of sevoflurane, oxygen and air.
Results: Onset time, intraoperative tolerance, postoperative analgesic effect and motor blockade were comparable between the two groups. The mean onset of the block was 8.2 +/- 2.2 min for levobupivacaine and 8.5 +/- 3.0 min for ropivacaine (P = 0.66). Additional analgesics during operation were not required in any of the children. No significant difference was found for mean time to requirement of additional analgesia with rectal acetaminophen (paracetamol) (302 +/- 29 min for the levobupivacaine group and 230 +/- 38 min for the ropivacaine group (P = 0.32)). During the first 4 h after placement of caudal block, the pain assessment score (according to the Children Hospital Eastern Ontario Pain Scale) was comparable for the two groups. No motor block was observed in any group on awakening, nor during the observation period.
Conclusions: We conclude that levobupivacaine 0.25% 1 mL kg(-1) provides caudal block of comparable onset and duration, as produced by the same volume and concentration of ropivacaine.