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Anesthesiology Research and Practice
Volume 2016, Article ID 6918327, 6 pages
Clinical Study

Efficacy of Continuous S(+)-Ketamine Infusion for Postoperative Pain Control: A Randomized Placebo-Controlled Trial

1Department of Anesthesiology, Centro Médico Campinas, Rua Edilberto Luis Pereira da Silva 150, Campinas, SP, Brazil
2Department of Pharmacology, Universidade de Campinas (UNICAMP), Centro Médico Campinas, Rua Edilberto Luis Pereira da Silva 150, 13083-190 Campinas, SP, Brazil

Received 21 September 2015; Accepted 10 January 2016

Academic Editor: Jean Jacques Lehot

Copyright © 2016 Luiz Eduardo de Paula Gomes Miziara et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Aim. A double-blind, randomized, placebo-controlled trial was designed to evaluate the efficacy of continuous intraoperative infusion of S(+)-ketamine under intravenous anesthesia with target-controlled infusion of remifentanil and propofol for postoperative pain control. Methods. Forty-eight patients undergoing laparoscopic cholecystectomy were assigned to receive continuous S(+)-ketamine infusion at a rate of 0.3 mg·kg−1·h−1 (, intervention group) or an equivalent volume of saline at the same rate (, placebo group). The same target-controlled intravenous anesthesia was induced in both groups. Pain was assessed using a 0 to 10 verbal numeric rating scale during the first 12 postoperative hours. Pain scores and morphine consumption were recorded in the postanesthesia care unit (PACU) and at 4 and 12 hours after surgery. Results. Pain scores were lower in the intervention group at all time points. Morphine consumption did not differ significantly between groups during PACU stay, but it was significantly lower in the intervention group at each time point after PACU discharge (). At 12 hours after surgery, cumulative morphine consumption was also lower in the intervention group () than in the placebo group (). Conclusions. Continuous S(+)-ketamine infusion during laparoscopic cholecystectomy under target-controlled intravenous anesthesia provided better postoperative pain control than placebo, reducing morphine requirement. Trial Registration. This trial is registered with NCT02421913.