A comparative study of intrathecal low dose bupivacaine with fentanyl and low dose levobupivacaine with fentanyl in transurethral resection of prostate: Randomized, double blind, prospective study

Objective: Isobaric levobupivacaine has been recently introduced for intrathecal use and there are very few studies comparing it with widely used hyperbaric bupivacaine. So this randomized trial was planned to study the effectiveness of intrathecal low dose isobaric levobupivacaine with fentanyl and compare it with low dose hyperbaric bupivacaine with fentanyl in transurethral resection of prostate. Materials and Methods: This prospective, randomized, double blinded study was conducted in 60 ASA physical status I and II patients, aged between 50-80 years and posted for transurethral resection of prostate under subarachnoid block. Enrolled patients were divided into two groups of 30 each. Patients in Group B received 7.5mg, 0.5% hyperbaric bupivacaine with 25mcg fentanyl intrathecally while patients in Group L received 7.5mg, 0.5% isobaric levobupivacaine with 25mcg fentanyl intrathecally. Time to achieve sensory block to T10 level, max spread of sensory block, time to two-segment regression and time to S1 regression were recorded. Motor blockade was assessed at every 2 minute for 20 minute, at the end of the surgery and in recovery room. Onset time of motor block, maximum motor block and duration of motor block were also recorded. Results: A total of 60 subjects were enrolled. Baseline parameters were comparable. Onset of sensory block was significantly faster in group B compared to group L. The mean time of onset in Group B was 4.75±0.79 min. and in Group L was 6.60±0.61 min. Both group had statistically significant difference in onset and duration of motor block. The mean time of onset of motor block in Group B was 6.4±1.6 min and in Group L was 9.9±2.3 min. The mean duration of motor block in Group B was 164.17±22.8min and in Group L was 138.27±23.5min. Group B had statistically significant dense block compared to group L. The median MBS in Group B was 1(95% C.I. 1.18-1.68) and in Group L was 2 (95% CI 2.13-2.86). In group B, 20 patients had complete motor block while in group L number of patient with complete motor block was only 4. Conclusion: Our results, suggest that subarachnoid low-dose isobaric levobupivacaine fentanyl provides lesser degree of motor block & for short duration when compared with heavy bupivacaine.