Low Doses of Ketamine and Postoperative Quality of Recovery

Postoperative Pain Clinical Trial

Official title: Effects of Low Doses of Ketamine on Postoperative Quality of Recovery After Total Intravenous Anesthesia

Status Recruiting

Clinical Trial Summary

There are evidences that intraoperative administration of low doses of ketamine may contribute to control the postoperative pain by acting on the 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 apllication of the questionnaire QoR40.

Clinical Trial Description

Introduction It is known that nociceptive stimuli, triggered by surgery and tissue inflammation can cause peripheral sensitization and primary hyperalgesia, increases spinal responsiveness to stimuli, whether harmful or not, due to the wind-up phenomenon, and other mechanisms, with induction central sensitization. Additionally, opioids commonly employed during general anesthesia may activate, both, the antinociceptive system and the pro-nociceptive system which can lead to acute tolerance and hyperalgesia. There is evidence that NMDA receptors are involved in the development of these changes and that low doses of ketamine (< 1mg/kg) may control of postoperative pain to bind to the receptor phencyclidine the NMDA channel and inhibit the activation of the channel by glutamate non-competitively. Recently, there has been a change in pain management, which includes the observation of non-traditional variables such as those related to the concepts of satisfaction and quality of life related to health. To this end, a growing number of authors went on to assess the opinion of patients as a way to determine the quality of recovery from anesthesia, meaning the observation not only of pain intensity, but also aspects related to emotional state, comfort and independence physical. The QoR-40 questionnaire (Quality of recovery-40), a validated instrument for this purpose, allows an objective approach of these factors that can influence the perception of the patient and allows you to compare different therapeutic ways. There are no recent data on the application of this instrument to assess the effects of giving, or not, of low doses of ketamine on the quality of recovery of patients undergoing total intravenous anesthesia.

Methods After arrival in the operating room, standard ASA monitors will be applied. Midazolam 0.06 mg/kg and 1% lidocaine (30 mg) will be administered intravenously immediately after venoclysis. After anesthesia induction, capnographic monitoring will be added and the neuromuscular blockade will be evaluated using acceleromyography (TOF Watch SX, Bluestar Enterprises, Inc., Omaha, NE). Induction and maintenance of anesthesia will be performed as follows: remifentanil, induction dose 0.5 μg/kg/min, followed by a maintenance dose of 0.3 μg/kg/min. Propofol, initial bolus (2.0 mg/kg) followed by infusion at 4 to 6 mg/kg/h. Each patient will receive rocuronium (0.6 mg/kg) before tracheal intubation. Ventilation will be controlled by adjusting the flow volume and respiratory rate to keep the end-tidal CO2 level between 30 and 40 mmHg. In the case of inadequate depth of anesthesia (movements, sweating, tachycardia, blood pressure increase >10% of the pre-induction value), propofol infusion or sevoflurane rate will be increased (by 1%); if this was not sufficient, the remifentanil infusion rate will be also increased (by 0,1 μg/kg/min). Patients who exhibit reductions in systolic arterial pressure (SAP) greater than 30% or heart rate (HR) reductions to less than 50 bpm will be given ephedrine (10 mg) and atropine (0.5 mg), respectively. After induction patients will receive one of three intravenous solutions: ketamine 0.2 mg/kg - diluted in saline until the volume of 5 ml (k2 group); ketamine 0.4 mg/kg diluted in saline until the volume of 5 ml (k4 group) or 5mL of 0.9% normal saline (K0 group). Hydration will be maintained with 0.9% normal saline 2 ml/kg/h. All of the participants were given dexamethasone (8 mg) and ketoprofen (100 mg) at the onset of surgery and dimenhydrinate (30 mg), dipyrone (1 g) and morphine (0.1 mg/kg) 15 minutes prior the end of the procedure. Atropine (0.01 mg/kg) and neostigmine (0.05 mg/kg) were used to achieve T4/T1>0.9 on the TOF monitor. Extubation was performed after awakening. When stable vital signs and respiration was confirmed, all patients were transferred to the post-anesthesia care unit (PACU). Data related to the occurrence of pain, nausea, vomiting, dizziness or hallucinations at the PACU will be recorded as will be the length of stay in the PACU. Pain will be assessed every 15 minutes using a 0-10 numeric pain rating scale, where zero meant no pain and 10 the worst imaginable pain. Morphine (1 to 2 mg) will be administered intravenously every 10 minutes to maintain the pain score below 4 (1 mg when the pain score was <7 and 2 mg when it was ≥7). Following discharge from the PACU (minimum stay 60 minutes and Aldrete & Kroulik index >9), all of the participants will be given ketoprofen (100 mg) every 12 hours and dipyrone (30 mg/kg, maximum 1 g) every six hours intravenously. Whenever patients judged that their analgesia was insufficient, tramadol (100 mg) will be administered intravenously at eight-hour minimum intervals as needed. Postoperative nausea and vomiting (PONV) will be treated with dimenhydrinate (30 mg) intravenously. Pain score, use of analgesics, and the occurrence of nausea, vomiting, and other complications during the hospital ward stay will be recorded.

QoR40 The quality of postoperative functional recovery will be assessed by the QoR-40 questionnaire, which assesses five dimensions of recovery (physical comfort - 12 items; emotional state - 7 items; physical independence - 5 items; physiological support - 7 items; and pain - 7 items). Each item is rated on a five-point Likert scale: none of the time, some of the time, usually, most of the time, and all the time. The total score on the QoR-40 ranges from 40 (poorest quality of recovery) to 200 (best quality of recovery). The QoR-40 will be administered by a blind investigator 24 hours after surgery. ;

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Prevention

Related Conditions & MeSH terms

• Pain, Postoperative
• Postoperative Nausea and Vomiting
• Postoperative Pain

• NCT number: NCT02571153
• Study type: Interventional
• Source: Pontificia Universidade Catolica de Sao Paulo
• Contact: Eduardo T Moro, PhD
• Phone: +55-15-997728015
• Email: eduardo_moro@terra.com.br
• Status: Recruiting
• Phase: Phase 4
• Start date: September 2015
• Completion date: May 2016