Comparison of Peritonsillar Infiltration of Ketamine and Dexamethasone for Postoperative Pain Relief in Children Following Adenotonsillectomy

The immediate postoperative period after tonsillectomy, , is often difficult. These children frequently have severe pain but postoperative airway edema along with increased sensitivity to the respiratory-depressant effects of opioids may result in obstructive symptoms and hypoxemia. Opioid consumption may be reduced by non-steroidal anti-inflammatory drugs, but these drugs may be associated with increased bleeding after this operation.

Methods: One hundred sixty ASA I-II children 3-12 were randomized four groups of 40 each. Group P received a local peritonsillar infiltration of 2 ml saline, group D dexamethsone (0.2 mg/kg)) , group K ketamine (0.5 mg/kg) and group KD combination of ketamine0.5mg/kg dexamethasone 0.2mg/kg. All medications were 2 ml in volume which was applied 1 ml per tonsil 3 min prior to tonsillectomy. Study drugs were marked only with a coded number label. A computer-generated table of numbers guided randomization. Modified Hannallah pain scale [observational pain scores (OPS)], nausea, vomiting, bleeding, rescue analgesia, sedation and Aldrete scores were recorded at first, 15th, 30th and 60th min postoperatively. Patients were interviewed on the day after surgery to assess the postoperative pain, nightmares, hallucinations, vomiting and bleeding. All the children were premedicated with midazolam hydrochloride 0.3 mg/kg) and fentanyl 1micro g/kg intavenously. Anesthesia was induced with thiopental 5mg/kg and atracurium0.3mg/kg. Anesthesia was maintained with isoflurane 1.5% and nitrous oxide 30% in oxygen. The two surgeon used the same dissection and snare technique for all cases and hemostasis done with bipolar cutter. At the end of the surgery neuromuscular blockade was reversed by neostigmine 0.03 mg/kg) and atropine 0.01 mg/kg intravenously), anesthesia was discontinued and the tracheal tube removed in the operating room when patients were deep. After extubation the patients were taken to the postanesthesia care unit (PACU) where an nurse who were unaware of the study drug observed the patients. The pain scoring observer nurse in PACU was consistent. Time to awaken (from the end of anesthesia until the patients opened their eyes on command) and time to the first administration of postoperative analgesia were recorded. Pethidine in a titrated dose (total 1 mg/kg) was administered intravenously for rapid pain relief to patients with a OPS score > 4 or who were crying during two consecutive five minute observation periods until the child was comfortable. Postoperative pain during the first 24 h was assessed using a four-point scale: 0 no pain, 1 mild pain, 2 moderate pain, 3 severe pain by questioning their parents. In the ward the standardized postoperative analgesic technique was with acetaminophen supp (40 mg/kg followed by three doses of 20 mg/kg at 6-hour intervals to be given as needed for pain. Pethidine in a titrated dose (total 1 mg/kg) was administered intravenously for rapid pain relief to patients who had pain scale >3.Any supplementary analgesia , nausea and vomiting, bleeding, sleep disturbance and nightmares that the child might have had as surgery were assessed during a telephone follow up 24 h later.