Comparative study of intrathecal hyperbaric versus isobaric ropivacaine: A randomized control trial

BACKGROUND: Hyperbaric ropivacaine produce more reliable sensory and motor block, with faster onset, better quality of muscles relaxation than isobaric ropivacaine. So, this study was designed to compare the efficacy of hyperbaric ropivacaine with isobaric ropivacaine in patients undergoing lower abdominal surgery. METHODS: A randomized controlled double blind study in two groups of patients. group A (n=35) received 3 ml of isobaric ropivacaine 6 mg/ml (18 mg). Group B (n=35) received 3 ml of hyperbaric ropivacaine 6 mg/ml (18 mg). The onset and duration of sensory block at dermatome level T10, maximum upper and lower spread of sensory block, intensity, and duration of motor block were recorded. STATISTICAL ANALYSIS: Block characteristics were compared using the two-tailed Mann – Whitney U-test. The proportion of side effects was compared using the Chi-square test. RESULTS: The median time of onset of sensory block at the T10 dermatome was 4.4±1.3 min in group B and 6.0±1.03 min in group A. The median time to maximum block height was 16.7±3.7 min in group A and 12.03±1.96 min in group B. The median duration of complete motor recovery (B0) was significantly shorter in the heavy ropivacaine group (166.5±11.7 min) compared with the isobaric ropivacaine group (192.9±9.6 min). CONCLUSIONS: Intrathecal hyperbaric ropivacaine provides more rapid, adequate, and good quality of sensory and motor block with rapid post-operative recovery as compare to isobaric ropivacaine.