The effect of intravenous pre-emptive versus postoperative paracetamol on postoperative nausea and vomiting in patients undergoing strabismus surgery: A prospective randomised study

This prospective randomised study was approved by the Ethics Committee of Ataturk University, Medical Faculty, Erzurum, Turkey. Ninety-six patients, between the ages of 2 and 14 years, ASA (the classification of the American Society of Anesthesiologists) physical status I-II who underwent elective strabismus surgery under general anaesthesia were included. Written informed consent was obtained from the parents. Basic data including patients’ age, weight and height were recorded. All patients were pre-medicated with midazolam (0.5 mgkg-1, orally) before the procedure of anaesthesia. Before transfer to the operating room, patients were randomly divided into 3 equal groups (n=32): In the preemptive paracetamol group (n = 32), IV infusion of paracetamol 15 mgkg-1 (1.5 mlkg-1) (Perfalgan Registered Trademark, Bristol-Myers Squibb, France) was administered one hour before operation over 20 minutes and IV infusion of saline (1.5 ml kg-1) administered at recovery room after full consciousness. Patients in the postoperative paracetamol group (n = 32) received IV infusion of saline (1.5 ml kg-1) one hour before operation over 20 minutes and paracetamol postoperatively at recovery room after full consciousness at the same dose as the preemptive paracetamol group. A standardized general anaesthesia regimen was provided for all patients enrolled in the study. Standard monitoring including non-invasive arterial pressure, electrocardiography and pulse oximetry was established in the operating room. General anesthesia was induced with propofol 3–5 mgkg-1 and lidocaine 0.1 mgkg-1 and a laryngeal mask airway (LMA) was inserted. Maintenance of anaesthesia was achieved with sevoflurane 2–3% and N2O/O2 (FiO2, 50%). At the end of the surgery, LMA was removed and patients were transferred to the post-anaesthesia recovery room. Intravenous metoclopramide 0.15 mgkg-1 were used in case of two or more vomiting episodes. The number of the orbital muscles requiring surgery, duration of anaesthesia, duration of surgery, the number of patients who experienced oculocardiac reflex (OCR) requiring treatment with atropine were recorded. In the recovery room, an independent observer blinded to the group assignment recorded the pain score, complaints of nausea and vomiting, the need for rescue analgesics and the need for antiemetic drug during 24 hours postoperatively. Nausea was defined as only retching and vomiting was defined as a forceful expulsion of the gastric contents through the mouth or the nose. Postoperative pain condition during the first 24 hours was evaluated using the Faces Pain Scale. This scale includes six faces reflecting the severity of pain and every facial expression has a numerical score. The selected face by the children or their parents and the numerical score of selected face was recorded. In control group, postoperative analgesia was provided with oral Ibuprofen suspension 5 mgkg-1 (IbufenRegistered Trademark, Abbott, Istanbul, Turkey) in the event of Faces Pain Scale score greater than or equal to 3. In preemptive and postoperative paracetamol groups, postoperative analgesia was provided with oral paracetamol suspension 5 mgkg-1 (CalpolRegistered Trademark, GlaxoSmithKline, Istanbul, Turkey) in the event of Faces Pain Scale score greater than or equal to 3.