Spinal Anaesthesia for Ambulatory Perianal Surgeries: A Comparison between Short Acting and Long Acting Local Anaesthetics

Introduction: Chloroprocaine (ester group) is a preservativefree local anaesthetic which is available as isobaric solution. It is being recently popularised in spinal anaesthesia for its shorter duration of action which plays a significant role in the early ambulation and voiding functions, which is the primary essence in ambulatory surgery. Intrathecal Bupivacaine is the most commonly used drug for its block characteristics, taking into account not only the fast initiation of sensory and motor blockade but also faster sensory and motor regression. Aim: To compare the block characteristics between 1% Chloroprocaine and 0.5% Bupivacaine in patients undergoing perianal surgeries under spinal anaesthesia. Materials and Methods: This randomised, interventional double blinded study was carried out in Chettinad Hospital and Research Institute, Kelambakkam, Chennai, Tamil Nadu, India, from April 2020 to August 2021. The patients were split into two groups of 34 each. Group 1: Patients received 30 mg of 1% Chloroprocaine intrathecally. Group 2: Patients received 10 mg of 0.5% Bupivacaine intrathecally. In both the groups the onset, duration of both sensory and motor blocks, intraoperative haemodynamic, two segment regression time, time to ambulation and micturition, the time to eligibility for discharge from hospital was evaluated. Independent sample t -test, Chi-square test and Fisher's-Exact test were employed to compare the distribution of qualitative variables between the groups. Results: Total of 68 participants 31 (45.6%) males and 37 (54.4%) females), 34 in each group 1 and group 2 were analysed. Both groups contained maximum patients in >45 years age group, 12 (35.2%) in each group. Demographic and anthropometric parameters of patients in both the groups were comparable. Mean time of ambulation after spinal anaesthesia in the Group 1 was 137.65 +/- 9.15 minutes and in Group 2 was 193.38 +/- 8.14 minutes (p-value <0.05). Mean time taken to return of voiding function the Group 1 was 157.06 +/- 16.05 minutes and in Group 2 was 213.53 +/- 10.26 minutes (p-value <0.05). Mean time taken for Post-Anaesthetic Discharge Scoring System (PADSS) score >9 in Group 1 was significantly less (165.29 +/- 13.59 minutes) than Group 2 (219.41 +/- 9.52 minutes). Mean time duration for request of first rescue analgesic in Group 1 was significantly faster (104.71 +/- 8.69 minutes) than Group 2 (157.79 +/- 8.81 minutes). There was no significant difference in haemodynamic changes between the study groups. Conclusion: Chloroprocaine has proved to be better than Bupivacaine. It has proven to provide adequate surgical anaesthesia, it leads to early regression of motor and sensory blocks, faster un-assisted ambulation and micturition. Time to rescue analgesia was earlier in the Group 1 when compared to Group 2.