Patients undergoing anesthesia are at high risk of postoperative nausea and vomiting. Despite its prophylaxis, many patients suffer from postoperative nausea and vomiting and express this symptom as the worst or one of the worst experiences they had after the surgery.
1) Objectives: to study the effect of Opioid Free Anesthesia in reducing the incidence and severity of postoperative nausea and vomiting in comparison to conventional balanced anesthesia.
2) Design: prospective, randomized study
3) setting & conduct: Patients who are candidates for elective transurethral resection of bladder tumor and transurethral resection of prostate surgery, will be enrolled in this study. There will be two groups of patients. The first group will get Opioid-Free Anesthesia and the second one will receive conventional balanced anesthesia using opioids. Patients will be blind to their group assignment and consent forms will be obtained before the randomization. The hemodynamic changes will be perfectly managed by Trinitroglycerin and labetalol and the satisfactory pain management will be accomplished by non-opioid analgesics like paracetamol, ketorolac, ketamine and lidocaine. Nurses on the recovery unit and the ward and the investigator evaluating the patients and anesthesia outcome will be blinded to the group assignment. All patients will receive postoperative nausea and vomiting prophylaxis (ondansetron) if needed. The patients in both groups will also get paracetamol, ketorolac, ketamine and lidocaine for their pain management during the surgery. Paracetamol and ketorolac will be continued in the recovery unit and ward every 6 hours. Patients are also free to get morphine for breakthrough pain if needed in recovery unit or the surgery ward.
The severity of postoperative nausea and vomiting will be assessed using a 4-points verbal rating scale (none, mild, moderate, and severe). The pain intensity will be recorded by an 11-points numeric rating scale. We will also evaluate, record and analyze the following data that will be obtained from the study: Height, weight, Body Mass Index, hemodynamic data, Bispectral index, and also trinitroglycerine, Labetalol, opioids consumption, arrhythmia, and quality of recovery. The statistician will be also blinded to the group assignment of patients.
4) Participants including major eligibility criteria: Candidates for transurethral resection of bladder tumor and transurethral resection of prostate surgery, Opioid naïf patients; Patients with American Society of Anesthesiologists class I – III.
Exclusion criteria: Age <18 or >75 years old; Usage of High doses of opioids before the operation; Patients with allergy to any medication used in the study; Patients with hypertension or ischemic heart disease even if perfectly controlled; Patients who need to get any corticosteroids or any pro-kinetic medication; Patients with history of snoring or sleep apnea.
5) Interventions: In study group we will not use any opioid including fentanyl during the anesthesia; however, in control group we will provide the balanced anesthesia which contains opioids in the medications patients receive.
6) main outcome measures: The incidence and severity of postoperative nausea and vomiting will be assessed as the main outcome of this study. The outcome will be measured by using a 4-points verbal rating scale (none, mild, moderate, and severe).