Effects of intraoperative low dose ketamine on remifentanil-induced hyperalgesia in gynecologic surgery with sevoflurane anesthesia

Abstract

BackgroundRemifentanil is useful during general anesthesia because of its rapid onset and short acting time. However, some studies report that due to opioid-induced hyperalgesia (OIH) and tolerance, remifentanil also increases early postoperative pain. The occurrence of OIH and opioid-induced tolerance is mainly thought to be due to central sensitization by the activation of NMDA receptors. Therefore, we investigated the effects of continuous infusion of ketamine, an NMDA receptor antagonist, on postoperative pain and the quantity of opioids used.Methods40 patients scheduled to undergo laparoscopic gynecologic surgery were randomly allocated into two groups. Anesthesia was equally maintained with sevoflurane and 4 ng/ml of remifentanil in all patients. Ketamine (0.3 mg/kg) was injected and followed with a continuous dosage of 3 µl/kg/min in the ketamine group (n = 20) while the control group was injected and infused with an equal amount of normal saline. We compared postoperative VAS up to 7 hours and morphine demand through PCA.ResultsPostoperative VAS and morphine demand was significantly lower in the ketamine group 2 and 3 hours after surgery, respectively.ConclusionsWhen general anesthesia is maintained with sevoflurane and remifentanil in patients undergoing laparoscopic gynecologic surgery, continuous infusion of low dose ketamine decreased early postoperative pain and the quantity of opioids used.

Avaliação do efeito da cetamina associada à remifentanila na dor pós-operatória

“…Analgesic potency of S(+) ketamine is two times that of racemic mixture 15 . We observed preemptive analgesic effect of S(+)ketamine and reduction of the hyperalgesia phenomenon induced by remifentanil, using low-dose infusion intravenously 7,16,17 . When administered both prior to anesthesia induction and throughout the perioperative period, ketamine is able to promote signifi cant reduction in the consumption of anesthetic agents during surgical anesthetic procedure, exerting an "opioid sparing" effect, aside from promoting adequate postoperative analgesia 18 .…”

Opioid-free anaesthesia in three dogs

“…It is thought to provide less intense analgesia than pure-µ opioids and is often used in combination with an opioid for multimodal analgesic effects (Carstensen and Moller, 2010;Gutierrez-Blanco et al, 2015). Ketamine is a common component of OFA in people and has even been shown to reduce the development of OIH if administered prior to opioid treatment in animals (Celerier et al, 2000) and humans (Hong et al, 2011;Kaur et al, 2015). The dysphoria reported for Case 2 after premedication was believed to be secondary to ketamine administration.…”

Hiperalgesia asociada al tratamiento con opioides

“…Un pequeño número de estudios ha evaluado la HiO producida por exposición a altas dosis de opioides en el contexto del tratamiento perioperatorio, mostrando en estos pacientes un aumento del dolor postoperatorio y un mayor consumo de opioides (34). También se ha visto que cuanto más corto es el periodo de acción de los opioides utilizados, como en el caso del remifentanilo, más rápida y frecuentemente se produce la hiperalgesia (36).…”