Laparoscopic inguinal hernia repair and laparoscopic cholecystectomy are well known to cause chronic post-operative pain. Ketamine has proven to reduce acute post-operative pain in multiple procedures. Our hypothesis was that low dose ketamine infusion could play a role in preventing chronic post-operative pain following laparoscopic hernia repair and laparoscopic cholecystectomy. Forty five patients scheduled for laparoscopic inguinal hernia repair and laparoscopic cholecystectomy were randomly divided into two groups, Ketamine (n:22 patients) and placebo (n:23 patients) groups. 0.5 mg/kg bolus followed by 0.2 mg/kg/hr infusion of ketamine was given before surgical incision till one hour after surgery. An equal amount of saline was given to the placebo group. Pain scores were taken at Post Anesthesia Care Unit (PACU), after 24 hours, after 1, 2 and 3 months using Visual Analogue Scale (VAS) pain score for both groups. A significant reduction in VAS pain scores were seen in Ketamine group in PACU and after 24 hours with P value of 0.000 and 0.023 respectively. After 1 and 2 months, there was 15% reduction in the incidence of pain though this was statistically not significant with P value of 0.054 and 0.054 respectively. At the end of 3 months the reduction in pain incidence reached 50% in ketamine group but again it was statistically not significant (P value 0.055). Our statistical significance cut off value of P was <0.05. in conclusion, low dose ketamine infusion not only reduces acute postoperative pain but also plays a substantial role in reducing 15-50% of the incidence of chronic pain state lasting 1-3 months after laparoscopic hernia repair and laparoscopic cholecystectomy.

Laryngeal mask airway, induction technique, propofol, sevoflurane

Propofol, ketamine, pain, Patient’s heart, anaesthesia.

Anesthesia: general; anesthesia: coexisting disease; hypokalemia: Gitelman’s syndrome.