Comparison of dexmedetomidine and clonidine as an adjuvant to intrathecal bupivacaine in lower limb surgery: a randomised, double-blind, place controlled trial

ABSTRACT

We compared the duration of analgesia and adverse effects along with the hemodynamic changes, following intrathecal administration of dexmedetomidine or clonidine with bupivacaine. Seventy five patients of ASA grade I or II, ages between 20-50 years, were enrolled in the study. Patients were randomly allocated to three equal groups, Group B received hyperbaric bupivacaine [0.5%] 12.5 mg with normal saline as a placebo, group D received bupivacaine with 3 micro/g of dexmedetomidine and Group C received bupivacaine with 30 fig of clonidine. All solutions were made up to 3 rnl with addition of normal saline and injected at L3-L4 using a 25G spinal needle. The onset and duration of sensory and motor blockade, time to reach peak sensory and motor level and the sensory and motor regression times were recorded. Hemodynamic changes and time to use first rescue analgesia, diclofenac sodium 75 mg IM, were also recorded. In post anaesthesia care unit [PACU], pain scores were recorded using visual analogue scale [VAS], initially every 30 minutes for 8 hours, then every 2 hours till 24 hours. Descriptive statistics was used tor describing frequencies, mean and standard deviation. Analysis of variance [ANOVA] test was used to compare the quantitative variables in between the three groups which were independent of each other. Chi square test was used to compare categorical variables. All the data was analysed using SPSS vs. 17. P value < 0.05 was considered statistically significant. There was no significant difference in patients demographics or duration of surgery, in the time to onset of sensory block but motor block was early in Group D and Group C as compared to Group B. Duration of sensory and motor blockade was prolonged in Groups C and D, compared with Group B. The mean regression time to SI segment was 306.6 +/- 52 min in Group D, 278.6 +/- 27 min in Group C and 199.8 +/- 33 min in Group B. The regression of motor block to Bromage zero was 253.2 +/- 38.40 min in Group D, 229.00 +/- 42.57 min in Group C and 175.00 +/- 29 min in Group B. The time to analgesia was significantly prolonged in Group D compared with Group C the latter being longer than Group B. The addition of dexmedetomidine to intrathecal bupivacaine prolongs the motor and sensory block and postoperative analgesia when compared to bupivacaine with or without clonidine, with preserved hemodynamic stability in lower limb surgeries