Evaluation of low dose hyperbaric bupivacaine with or without fentanyl in perianal surgeries: A prospective randomized double blind trial

Abstract

Spinal anaesthesia should be ideal for perianal surgeries due to its quick onset, reliable anaesthesia with minimal supplies making it cost-effective technique with rapid turnover time. 90 patients of ASA grade I-II scheduled for perianal surgeries divided into three groups of 30 each according to intrathecal dose of local anaesthetic: Group LB (Low dose bupivacaine): 0.6 ml of 0.5% hyperbaric bupivacaine (3mg), Group ULBF (ultralow dose bupivacaine plus fentanyl): 0.4 ml of 0.5% hyperbaric bupivacaine (2 mg) + 0.2 ml of fentanyl (10 µg) and Group ULB (ultra low dose of bupivacaine): 0.4 ml of 0.5% hyperbaric bupivacaine (2 mg) + 0.2 ml of normal saline. Three groups were compared in terms of success of block, time to first rescue analgesic from time of block, total rescue analgesic (tramadol) needed in 8 hours since time of block, visual analogue score (VAS) and patient satisfaction score. Successful saddle block was achieved in all patients in Group ULBF, 27 patients in Group LB and none in Group ULB. Group ULBF showed significantly lower mean VAS score when compared to Group ULB and Group LB, and Group LB when compared to Group ULB. Thus the group using fentanyl intrathecally had significantly lesser pain, so the requirement for the first dose of rescue analgesic was significantly earlier in Group ULB and delayed in Group ULBF. Patient satisfaction score was significantly higher in Group ULBF as compared to Group LB and Group ULB and in Group LB as compared to Group ULB. Use of hyperbaric bupivacaine in dose of 3 mg and 2 mg with fentanyl (10 μg) in saddle block are an effective method of achieving successful surgical anaesthesia in patients undergoing perianal surgeries. Hyperbaric bupivacaine (2mg) with fentanyl (10µg) is better than other in providing postoperative analgesia.