Comparison Of Onset And Duration Of Sensory And Motor Blockade Between Intrathecal 0.5% Isobaric Bupivacaine With 25 Micrograms Fentanyl And 0.5% Hyperbaric Bupivacaine With 25 Microgrms Fentanyl For Infraumbilical Surgeries - A One Year Hospital Based Randomised Controlled Trial

Abstract

Background and Aims: There are two forms of commercially available bupivacaine; isobaric bupivacaine and hyperbaric bupivacaine. Opioids like fentanyl are used as adjuvants with local anaesthetics to improve analgesic intensity and to achieve faster onset and prolonged duration. This study aims at comparing isobaric bupivacaine -fentanyl and hyperbaric bupivacaine-fentanyl primarily, in terms of onset and duration of sensory and motor blockade and secondarily, in terms of hemodyamic changes and associated complications. Methods: Eighty patients belonging to American society of Anaesthesiologists I and II undergoing infraumbillical surgeries under spinal anaesthesia were randomised into two groups. Group A received 3ml of 0.5% isobaric bupivacaine with 25 micrograms fentanyl, while Group B received 3ml of 0.5% hyperbaric bupivacaine with 25 micrograms fentanyl . Student’s unpaired t test and the χ2 test were used to analyse the results, using the SPSS version 11.5 software. Results: The mean onset of sensory block was significantly faster in Group B (3.55 ± 0.96 min) than in Group A (5.70 ± 0.69 min). The mean duration of sensory block was significantly longer in Group B (189.65 ± 9.58 min) than in Group A (129.08 ± 3.47 min). The mean onset of motor block was significantly faster in Group B (4.78 ± 0.80 min) than in Group A (7.83 ± 0.78 min).The mean duration of motor block was significantly longer in Group B (204.55 ± 12.46 min) than in Group A (171.18 ± 4.31 min). Isobaric bupivacaine-fentanyl mixture was associated with better hemodynamic stability as compared with hyperbaric bupivacaine-fentanyl mixture. Conclusion: Intrathecal isobaric bupivacaine-fentanyl mixture is associated with lesser duration of both sensory and motor blockade, thereby enabling quicker recovery from anaesthesia and also better haemodynamic stability as compared with hyperbaric bupivacaine fentanyl mixture for infraumbilical surgeries