Addition of intrathecal fentanyl to bupivacaine clonidine mixture effect on quality of subarachnoid block and postoperative analgesia

CONTEXT: This study was undertaken in 100 patients scheduled for lower limb orthopaedic surgeries. AIM: The objective of this study was to study the effect of addition of intrathecal fentanyl to bupivacaine clonidine mixture on the quality of subarachnoid block and compare it with intrathecal bupivacaine clonidine mixture without fentanyl. SETTINGS AND DESIGN: In this prospective and double blind randomized controlled study, one hundred patients, between 20-40 years of age, of either sex, weighing between 40-65 Kg, measuring more than 150 cm in height, of ASA Grade I and II who were undergoing orthopaedic lower limb surgeries were selected in order to study the quality of subarachnoid block and post-operative analgesia produced by a combination of bupivacaine clonidine and fentanyl in comparison with bupivacaine clonidine. MATERIALS AND METHODS: The patients were randomly divided in two groups of 50 each: Group BC: 2.4 ml of 0.5% hyperbaric bupivacaine (12 mg) + 0.2 ml (30 μg) clonidine + 0.4 ml of 0.9% NaCl. Group BCF: 2.4 ml of 0.5% hyperbaric bupivacaine (12 mg) + 0.2 ml (30 μg) clonidine + 0.4 ml (20 μg) of fentanyl. The total volume of solution in both the groups was 3.0 ml. The quality of subarachnoid block and post-operative analgesia were studied. STATISTICAL ANALYSIS USED: The data thus obtained was statistically analysed using the following tests: Unpaired student's t-test. Average % change in data over baseline values to detect trends. A ‘P’ value of <0.05 was considered to be statistically significant. RESULTS: There was no significant difference in duration of sensory and motor blockade in group BCF compared to BC. The duration of analgesia as assessed by, either VAS score of >5 or demand of additional analgesia was > 524.6 ± 32.21 mins in group BC and > 774.4 ± 59.59 mins in group BCF. This prolongation of duration of analgesia in group BCF compared to group BC has statistical significance. Blood pressure and heart rate changes were not significantly different among groups, whereas sedation and pruritus were significantly more frequent in Group BCF. CONCLUSIONS: In conclusion, this study has demonstrated that addition of 20 μg fentanyl to intrathecal 30 μg clonidine and 12 mg bupivacaine enhanced the duration of post-operative analgesia with moderately increased sedation and was not associated with hemodynamic instability or other complications.