Low Doses of Ketamine and Postoperative Quality of Recovery

There are evidences that intraoperative administration of low doses of ketamine may contribute to control the postoperative pain by acting on the N-methyl-D-aspartate (NMDA) channel, reducing the effects related to the tolerance and hyperalgesia induced by opioids. This study aims to evaluate the effects of administration of this agent not only as an analgesic but also its role in the quality of recovery from anesthesia, which includes observation of emotional, psychological and physical aspects. Patients who were scheduled to undergo total intravenous anesthesia (TIVA) for laparoscopic cholecystectomy will be enrolled in this clinical study. After induction of anesthesia, patients will receive one of three solutions according to the randomly selected group: ketamine 0,2 mg/kg; ketamine 0,4 mg/kg or saline. In the recovery room and on the ward, data related to the presence of pain, analgesic consumption, the incidence of nausea and vomiting, dizziness or hallucinations will be recorded. The next day, the quality of recovery will be evaluated by application of the questionnaire QoR40 (Quality of Recovery Questionnaire-40).