We are going to assess the effect of intravenous paracetamol on postoperative nausea and vomiting during the first 24 hr after strabismus surgery in pediatric patients aged between 2-12 years in Farabi hospital. After approval by the University Research Ethics Committee and obtaining written informed consent from the parents, 120 children scheduled for strabismus surgery under general anesthesia will be included in this prospective, randomized, double-blind clinical study. Children with hepatic or renal failure, allergy to study drugs, history of motion sickness, previous severe postoperative nausea and vomiting and current use of antiemetic drugs will be excluded from the study.
Age, sex, weight and height will be recorded. Induction of general anesthesia will be done with fentanyl 1µ/kg, sodium thiopental 3-5mg/kg, lidocaine 1mg/kg, and a laryngeal mask airway (LMA) will be inserted. All patients will receive intravenous dexamathasone 0.1 mg/kg after induction and then will be studied in two groups. Anesthesia will be maintained with isoflurane 1-1.5% and O2/air (FiO2=50%) and half saline solution with a rate of 10cc/kg/hr will be infused. At the end of the surgery intravenous infusion of paracetamol 15mg/kg (1.5ml/kg of 1 gram paracetamol in 100 cc normal saline) or nomal saline with the same volume (1.5cc/kg) will be performed in 20 minutes in intervention or control group respectively . Two or more vomiting episodes will be treated with ondansetrone 0. 1mg/kg.
The Facial Pain Scale will be used to measure postoperative pain after surgery and if the pain score to be measured is 3 or more, the patient will receive acetaminophen with a dose of 10mg/kg.
Nausea and vomiting and pain score will be assessed in post-anesthesia care unit and in ward in 6-12 and 24 hours after surgery.