Preemptive peritonsillar ketamine infiltration: postoperative analgesic efficacy versus meperidine.

OBJECTIVES The current study was planned to assess post-tonsillectomy analgesic efficacy of pre-emptive peritonsillar ketamine infiltration with or without bupivacaine in comparison to meperidine alone or in combination with bupivacaine. PATIENTS & METHODS The study included 100 patients with mean age of 10.5 +/- 2.3 years assigned for adenotonsillectomy. Patients were randomly allocated into 4 groups (n = 25): Group K1: received peritonsillar infiltration of ketamine (0.5 mg/kg), Group M1: received peritonsillar infiltration ofmeperidine (1 mg/kg), and groups K2 and M2 received either ketamine (0.5 mg/kg) or meperidine (1 mg/kg) in combination with bupivacaine (5 mg/ml). All medications were prepared as 2 ml in volume and were applied as 1 ml per tonsil 3 min prior to tonsillectomy. On admission to the post-anesthesia care unit (PACU) pain was assessed using the objective pain scale (OPS) score which evaluates 5 parameters each was scored from 0 to 2 for a collective score ranged from 0 = best to 10 = worst. OPS score was assessed at time of admission to PACU and every 15 min for one hour and every 30 minutes till patients were ready for discharge from PACU at an Aldrete score of 9. Rescue analgesia with morphine 0.05 mg/kg i.v. was administered, after operation; for OPS score > or = 5 and time elapsed till first request of rescue analgesia was determined. Upon patient discharge, parents were asked to rate their satisfaction with patient analgesia on 7-point scale; 1 = extremely dissatisfied and 7 = extremely satisfied. RESULTS All enrolled patients passed smooth intraoperative course without complication. Mean duration ofPACU stay was significantly shorter in group K2 compared to the other 3 groups and in group K1 compared to groups M1 and M2. Moreover, total hospital stay was significantly shorter in group K2 compared to groups M1 and M2 but was non-significantly shorter compared to group K1. Both duration of PACU and hospital stay showed a non-significant difference between groups M1 and M2. In group K1 number of patients who had short hospital stay was significantly higher compared to groups M1 and M2. Number of patients in group K2 and had short hospital stay was significantly higher compared to groups M1 and M2. Mean recorded OPS scores showed progressive increase in all patients reaching a peak at 90-min after PACU admission in groups K1, M1 and M2 and at 120-min in K2 group. At 60- and 90-minutes after admission to PACU patients enrolled in group K2 had a significantly lower OPS scores compared to groups K1 and M1 but non-significantly lower scores compared to group M2. Mean parents' satisfaction scores reported in group K2 were significantly higher compared to groups K1 and M1 and were non-significantly higher compared to group M2 with non-significant difference among the other three groups despite being in favor of group M2. CONCLUSION Peritonsillar injection of a combination of bupivacaine and ketamine provided efficient postoperative analgesia after adenotonsillectomy and achieved higher parents' satisfaction for the outcome of surgery. The used drugs' combination and volume could be recommended as a routine preemptive analgesic policy for children assigned for adenotonsillectomy.