Pre-emptive Analgesia: The Effect of Low-Dose Ketamine on the Postoperative Pain after Circumcision with Unilateral Hydrocelectomy in Children

Lee, Il Ok

Abstract

Background
s: Brief noxious stimuli are found to produce long-lasting neuronal sensitization. This cumulative depolarization results from the activation by glutamate of N-methyl-D-aspartic acid (NMDA) receptor. Ketamine at subanesthetic doses blocks the channel associated with the NMDA receptor. The aim of this study was to investigate the pre-emptive effect of ketamine in children after circumcision with unilateral hydrocelectomy.
MATERIALS AND METHODS
We have compared the effect of preoperative ketamine (0.3 mg/kg) in a double-blind, randomized study, which was approved by the local Ethics Committee. Informed consents were obtained from their parents. After induction of anesthesia, patients were allocated randomly to receive a ketamine (n=20) or placebo (n=20) intravenously before surgery. Postoperative pain was rated on a faces scale for the first 24 hours. If pain occurred, children received tiaprofenic acid in a dose related to body weight. The cumulative pain score, the time of the first requirement of analgesics, and total requirement of analgesics for 24 hours were also checked.
RESULTS
The pain scores at 4, 5, 6, 7, 8, 9, and 12 hours after operation were significantly low in ketamine group. The cumulative pain scores for the first 8 hours and the total requirements of analgesics were significantly low in ketamine group. The time of the first requirement of analgesic was significantly delayed in ketamine group.
CONCLUSIONS
Preoperative ketamine in the pediatric circumcision with unilateral hydrocelectomy is effective on the reducing the intensity of the postoperative pain. The results of this study support the theory of pre-emptive analgesia of ketamine.