Comparative Evaluation of Three Different Doses of Spinal Isobaric Ropivacaine in Patients Undergoing Day Care Perineal Surgeries: A Randomized Double-blind Study

BACKGROUND AND OBJECTIVE: Ropivacaine owing to its propensity of causing motor blockade of reduced duration, is preferred for ambulatory day care surgery. Intrathecal ropivacaine has shown effective analgesia for lower limb surgery. Our study plans to evaluate spinal ropivacaine in three different doses in patients undergoing day care perineal surgery. METHODOLGY: 90 ASA-I patients scheduled to undergo day care perineal surgery were randomized to receive intrathecal ropivacaine. Group I (n=30) received 15mg of intrathecal ropivacaine, Group II (n=30) received 18.75 mg of intrathecal ropivacaine and Group III (n=30) received 22.5 mg of intrathecal ropivacaine. Onset of sensory block at T 10, peak sensory block level, duration of sensory block, onset and duration of motor block and relevant safety data were recorded. RESULT: Onset of analgesia was significantly shorter in Group III (3.5 min ; P <0.0001). However, time taken for peak sensory blockade was comparable in group II and III (12.76 and 11.93 mins). Duration of analgesia was longer and statistically significant in Group III (201.6 mins: P <0.0001) when compared to Group I and II. Onset of motor block was observed to be shortest in Group III (6.7 mins) and duration of motor block was longest in Group III (153.73 mins). These two parameters were statistically significant than Group I and II (P <0.0001). CONCLUSION: Intrathecal ropivacaine in a dose of 18.75 and 22.5 mg were observed to be equally effective in providing satisfactory analgesia. However, higher dose was associated with profound sensory and motor block.