A comparative study of intrathecal ropivacaine with fentanyl and L-bupivacaine with fentanyl in lower abdominal and lower limb surgeries

Abstract

Background: Subarachnoid block (SAB) is the anesthesia of choice and is the gold standard for lower abdominal and lower limb surgeries. SAB, a popular and common anesthetic procedure practiced worldwide. Today heavy bupivacaine, 0.5% is most commonly used for spinal anesthesia. Levo-bupivacaine, new long-acting local anesthetic, has a pharmacological activity very similar to that of racemic bupivacaine. Due to lesser cardiovascular side-effects and central nervous system toxicity, use of levo-bupivacaine, a pure S (−) enantiomer of bupivacaine has progressively increased. Ropivacaine has a less systemic toxicity, especially cardio toxic profile than both racemic and levo-bupivacaine. Though less potent, even 50% higher dose is still less toxic than bupivacaine. So, intrathecal ropivacaine may prove useful than that of bupivacaine or levo-bupivacaine when anesthesia of a similar quality and shorter duration is desired. Methods: This study was conducted in 60 adult patients aged between 18 and 60 years, who underwent elective lower abdominal and lower limb surgeries under spinal anesthesia. They were distributed in two groups. Group R: 30 patients were given injection ropivacaine 3 ml (0.75%) + injection fentanyl 0.5 ml (25 µg). Group L: 30 patients were given injection L-bupivacaine 3 ml (0.5%) + injection fentanyl 0.5 ml (25 µg). Hemodynamic parameters such as pulse rate, blood pressure, and respiratory rate, sensory and motor blockade were assessed at 0, 5, 10, 15, 30, 45, 60, 90, and 120 mins following the block. Thereafter, observation was continued at 30 mins intervals until the motor block regressed completely as defined by modified Bromage score. Time of two segment regression, duration of complete and effective analgesia, and time to first analgesic dose, side effects, and complications were studied. Results: Statistical analysis was done using SPSS software 16.0. Data obtained is tabulated in the excel sheet and analyzed. Chi-square test for proportion and t-test for quantitative data were done. Block characteristics were compared using Mann–Whitney U-test. Both the groups were comparable with respect to age, sex, height, weight, body mass index, level of SAB, American Society of Anesthesiologist score (p>0.05). The mean time for onset of sensory block with p=0.49 which was clinically and statistically not significant for both groups. The mean time for onset of motor block (Bromage 3) with p=0.16 was clinically and statistically not significant. The time taken for two segment regression of sensory block was p=0.22 statistically not significant. There was no clinical or statistical significance in the incidence of side effects in both groups. Conclusion: This study revealed that the intrathecal ropivacaine with fentanyl provided adequate anesthesia for lower abdominal and lower limb surgeries. Ropivacaine achieved a shorter duration of sensory and motor blockade, and a lesser degree of motor blockade when compared to L-bupivacaine. Thus, ropivacaine was justified for short duration ambulatory surgeries of lower abdominal and lower limb surgeries. Furthermore, fentanyl as an adjuvant to both ropivacaine and L-bupivacaine enhanced the duration of the sensory block. Hence, ropivacaine with fentanyl in spinal anesthesia for lower abdominal and lower limb surgeries is a better alternative compared to L-bupivacaine with fentanyl favoring day care ambulatory surgeries.