Assessment of the efficacy of intravenous propactamol versus morphine in reducing post operative pain and vomiting in paediatric strabismus surgery

ABSTRACT

Post operative pain has been considered to be a major cause of post operative vomiting after corrective strabismus surgery in children 1. Many factors are known to influence the incidence of pain and vomiting in paediatric strabismus surgery including the use of opioid analgesia, the use of antiemetics, and anaesthetic technique. There has been an increasing interest in the use of propacetamol, an injectable water soluble prodrug of paracetamol [acetaminophen] which can be parenterally administered as analgesic for the treatment of post operative pain 2. This study was designed to assess the efficacy of injectable propacetamol versus morphine in reducing post operative pain and vomiting in paediatric strabismus surgery. After approval of our local ethical committee and obtaining written informed consents from the parents, 60 ASA I, II children 4-16 ys of age were included in our study. The study was conducted in a double blind randomized fashion. The children were randomly divided into 2 equal groups. Group I Patients received propacetamol in 30 mg/kg/dose as l.V in fission. Group II Patients received morphine in 0.1 mg/kg/dose. Anaesthesia was induced and maintained with propofol. Pain was assessed every 20 minutes on arrival to PACU using pain behaviour score. Incidence of postoperative vomiting was assessed by measuring the frequency of vomiting [0-2 h, 2-6 h, 6-24h]. Cortisol and epinephrine plasma levels were evaluated before the start of surgery and 2 hours post operative to assess the efficacy of propacetamol in obtunding hormonal stress response. In the propacetamol group I the incidence of vomiting during the first 24h was 16.6% [of which one child had severe vomiting]. The incidence of post operative vomiting in morphine group II was much higher 80% [P<0.01]. There was no difference as regards pain score between the two groups. Also, there was no statistical significant difference as regards the rise of post operative [2 h after operation] plasma level of cortisol and epinephrine between the 2 groups [p >0.05 = non significant]. No adverse effects were observed on using propacetamol. Propacetamol parenterally administered is an effective safe analgesic for paediatric strabismus surgery and gives less post operative vomiting than morphine i.v