A Double-blinded, Randomized, Placebo Controlled Study of the Effect a Small Dose of Ketamine has on Postoperative Pain of Sevoflurane-remifentanil Anesthesia.

Lee,  Eui Min; Lee,  Heeseung; Kim,  Chi Hyo; Lee,  Guie Yong

doi:2008.54.2.146

Original Article

Korean Journal of Anesthesiology 2008;54(2):146-151.
DOI: https://doi.org/10.4097/kjae.2008.54.2.146

A Double-blinded, Randomized, Placebo Controlled Study of the Effect a Small Dose of Ketamine has on Postoperative Pain of Sevoflurane-remifentanil Anesthesia.

Eui Min Lee, Heeseung Lee, Chi Hyo Kim, Guie Yong Lee

Department of Anesthesiology and Pain Medicine, School of Medicine, Ewha Womans University, Seoul, Korea. leehee@ewha.ac.kr

Abstract

BACKGROUND
Remifentanil is a useful and relatively safe opioid, but acute tolerance to it frequently develops, as patients who have received remifentanil based anesthesia often suffer postoperative hyperalgesia.This study investigated whether a small dose of ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, can attenuate postoperative pain suffered with remifentanil anesthesia.
METHODS
32 patients who were scheduled to undergo laparoscopic cholecystectomy were randomly assigned to two groups: a ketamine group (group K) and a control group (group C).All patients were given remifentanil by target controlled infusion (TCI) to the effect site (concentrations:4.0-6.0 ng/ml).Just before incision patients in group K received 0.15 mg/kg ketamine intravenously and patients in group C received the same volume, but only of normal saline.Pain scores measured by Numerical Rating Scale (NRS) and additional use of analgesics were immediately recorded by a blinded investigator at the post-anesthesia care unit (PACU) and general ward up to 24 hours after surgery.
RESULTS
The average NRS scores upon arrival to PACU, 5, 10, 15 and 30 min in PACU, and 5 hours after discharge from PACU were significantly lower in group K than group C.The frequency of additional analgesics use was also significantly lower in group K.
CONCLUSIONS
It is suggested that a small dose of ketamine attenuates the postoperative pain felt with remifentanil anesthesia. This finding also suggests that ketamine may decrease the possible acute tolerance developed with remifentanil anesthesia.

Key Words: acute opioid tolerance; hyperalgesia; ketamine; remifentanil