No difference between bupivacaine in 0.9% and 8% glucose for spinal anaesthesia in small children

Baricity is one of the most important factors to influence the characteristics of distribution of the local anaesthetic and hence success and spread of the blockade. Bupivacaine is rendered hyperbaric by adding glucose. The effect of differing degrees of hyperbaricity remains to be evaluated.

Two hyperbaric bupivacaine solutions, in 0.9% and in 8% glucose, for spinal anaesthesia were investigated in 60 children, aged 1-7 years, in a double-blind, randomised, parallel group, prospective study. The children were premedicated with diazepam orally. Bupivacaine 5 mg ml(-1) in either 0.9% or 8% glucose was injected in a dose of 0.4 mg kg(-1). Maximum cephalad extent and regression of sensory block were tested by transcutaneous electrical stimulation.

Success rate, spread and duration of sensory block were similar in both groups. Only one child required a single dose of fentanyl during surgery. The highest median level of sensory block was T3 (T2-T7) (median (10th/90th percentiles)) in both groups. Time to reach T10 did not differ between the groups. The incidence of adverse effects was similar. Atropine was administered to one child in each group to treat bradycardia and 6 children (10%) experienced shivering. One child in each group vomited once.

These results demonstrate that bupivacaine in 0.9% glucose and in 8% glucose solutions are equally suitable for spinal anaesthesia in small children. Similar success rate, spread and duration of the sensory and motor block are achieved with both baricities of bupivacaine.