Subcutaneous ketamine prolongs the analgesic effect of local infiltration of plain Bupivacaine in children undergoing inguinal herniotomy

Background: Inguinal herniotomy is one of the commonest paediatric surgical procedures at the University of Benin Teaching Hospital. Incisional infiltration with plain bupivacaine has been used to provide postoperative analgesia for this procedure but with a short duration of action, 4- 6hours.
Aims/Objectives: The aim of this study therefore was to evaluate the efficacy of subcutaneous ketamine on post-operative analgesia in children undergoing unilateral inguinal herniotomy
Methods: Forty-six (46) ASA I or II patients aged three to seven years scheduled for unilateral inguinal herniotomy were recruited. The patients were randomized to receive surgical wound site infiltration with plain bupivacaine plus subcutaneous injection of ketamine for group I or surgical wound site infiltration plain bupivacaine plus 2ml of saline subcutaneously for group II at the end of surgery. Data obtained were analyzed using SPSS version 20. Continuous data were compared using student t-test while categorical data were compared using Chi-square or Fisher's exact test. P- value <0.05 was considered statistically significant.
Results: In group, I, the mean time to first analgesic request was 667.7 minutes (11.12hours) and in group II, it was 371.3minutes (6.2 hours) with p<0.001. The pain scores were better and more favourable in group I from the 8th hour and above of the assessment period. The mean post-operative analgesic consumption in 24 hours was less in group I (19.35±5.4mg) than in group II (27.32±5.8 mg) with p-value <0.001.
Conclusion: The study showed that subcutaneous ketamine prolonged the analgesic effect of plain bupivacaine surgical wound site infiltration in children undergoing unilateral inguinal herniotomy.

Keywords
Subcutaneous ketamine; inguinal herniotomy; children; postoperative analgesia.