Hypobaric ropivacaine (0.1%) in spinal anesthesia with or without low-dose clonidine or fentanyl for anorectal surgery

BackgroundPerineal and anorectal surgeries performed on an outpatient basis under spinal block lead to a shorter postoperative hospital stay. Spinal anesthesia has better cost efficacy and is very well accepted by patients. Ropivacaine is less toxic with rapid motor recovery. Clonidine provides dose-dependent analgesia. Intrathecal opioids decrease nociceptive afferent input without affecting dorsal root axons.ObjectiveThe aim of this study was to compare the onset, the level, and the duration of sensory and motor blockade occurring after the administration of low-dose hypobaric ropivacaine (0.1%) either alone or with clonidine or fentanyl as adjuvants in spinal anesthesia for anorectal surgeries in the jack-knife position.Study designA prospective, randomized, double-blind, comparative, case-control study. A total of 75 ASA grade I-III patients were randomized into three groups.ResultsThere was a significant difference in the heart rate among the three groups. The plain ropivacaine group had a significantly higher heart rate. The addition of fentanyl resulted in a stable heart rate, but with the addition of clonidine, there was a decrease in the heart rate from the baseline. Mean arterial pressure (MAP) in the ropivacaine group was significantly higher in comparison with the clonidine or the fentanyl groups. None of the patients in any of the groups had complete motor blockade (Bromage score ≥ 3) at any time. After 2 h, there was complete regression (Bromage score = 1) in all the patients in all the groups. The majority of cases, irrespective of their group, achieved a T10 level of sensory blockade. The time taken for two-segment regression of sensory block and the time required for the first analgesic dose was significantly higher (P < 0.001) in the clonidine group.ConclusionHypobaric ropivacaine provides adequate surgical conditions for anorectal surgeries. Also, intrathecal clonidine with 0.1% hypobaric ropivacaine is a better adjuvant than fentanyl as it prolongs the duration and improves the quality of the sensory block and provides postoperative analgesia for longer periods.