Dexamethasone as an Additive to Heavy Bupivacaine in Unilateral Spinal Anaesthesia for Lower Limb Open Reduction and Internal Fixation

Abstract

Background: An ideal additive should shorten the speed of onset of action of the local anaesthetic drug and also reduce its dosage along with providing better hemodynamic changes. Therefore, the aim of this study was to determining the onset of action of unilateral spinal anaesthesia when intrathecal dexamethasone is added to heavy Bupivacaine for lower limb open reduction and internal fixation (ORIF).

Materials and methods: The study was carried out in Anaesthesia Department, Federal Teaching Hospital Gombe, Gombe State. It was a prospective experimental study in which patients were recruited using simple random sampling technique and balloted for the intervention given. The minimum sample size (n) for this study was calculate and resulted in a total number of 68 subjects for the entire study. Data was collected using modified questioner. Dependent variables; onset time, level of the block, HR, SBP, DBP, MAP and while the independent variables; height, age, weight. All the data obtained were analyzed using statistical package for social sciences (SPSS Chicago, USA). Student T test was used to compare the quantitative variables; age, height, weight, BMI, haemodynamic changes and the onset time. While Chi-squared (X²) test was used to compare the qualitative variables; sex, ASA. Results were presented in the form of tables and p < 0.05 was regarded as statistically significant.

Results: The mean onset time for sensory block were 4.48 ± 1.44 minutes and 4.44 ± 0.88 minutes in groups BA and BD respectively, p=0.92, while the mean onset time for the motor block were 7.24 ± 2.09 minutes and 6.59 ± 1.56 minutes for groups BA and BD respectively, p=0.16 which were all not statistically significant.

Conclusion: this study revealed that, addition of 4mg dexamethasone to 10 mg of 0.5% heavy Bupivacaine intrathecally does not affect both sensory and motor onset of action anaesthesia.

Key words: Unilateral spinal anaesthesia, heavy bupivacaine, dexamethasone