ABSTRACT
After approval by the local ethics committee sixty ASA 1 and 11 children, undergoing tonsillectomy surgery by dissection technique were included into the study. The parents of all children had been informed to the nature of the study and a written informed consent was obtained. The children who fulfilled our inclusion criteria were classified into three equal groups according to the timing of dexamethasone administration: Group I: Received dexamethasone 8mg IV one hour before induction of anesthesia. Group II. Received dexamethasone 8mg IV at the end of anesthesia. Group III: Received placebo [2 ml saline]. Anesthesia was managed in a standardized manner in the three groups. Postoperative pain was assessed by questioning the children on a visual analogue toy at one, two and, six hours postoperatively. Nausea and vomiting were assessed by 3 point ordinal scale: 0 = none. 1 = Nausea. 2 = Vomiting. Vomiting was assessed immediately after operation and was defined as forceful expulsion of gastric contents. Leach vomiting episode was counted in the operating room after the tracheal tube was removed. No distinction was made between vomiting and retching, [defined as active efforts without expulsion of gastric contents], and retching was graded as a vomiting event. The severity of vomiting episodes was recorded as: None [no emetic episode], Mild [1-3 episodes], Moderate [4-6 episodes], or Severe [> 7 episodes]. Vomiting was classified according to its time of occurrence after recovery as: none, early [within the first 180 minutes after the end of anesthesia], or delayed [after 180 minutes]. No vomiting and no rescue antiemetic medication during the 24 hour postoperative period were defined as successful protection. Surgery time, anesthesia time, need for rescue antiemetics, quality of oral intake in the PACU were recorded for each patient. Paracetamol suppositories 10 mg/kg 4-hourly were described for postoperative analgesia and on request of the patient, the total dose of paracetamol consumption was recorded. Our results showed that, at 0-2 hour postoperatively: Patients in group I reported a significantly less frequent incidence of PONV than those in group II and III with frequencies of 20%, 60% and 70% in group 1, II and III respectively. At 2-6 h postoperatively, no patient [0%]. Two patients]10%] and three patients [15%] suffered form vomiting in group I, II and III respectively. At 0-2h postoperatively, four patients [20%] in group I, and 12 patients [60%] in group II, and 14 patients [70%] in group III suffered vomiting early within 180 minutes after the end of anesthesia. At 2-6 hours postoperatively, no patient in group I suffered from vomiting, one patient [5%] in group II suffered vomiting early within 180 minutes after the end of anesthesia, and one patient [5%] in group II and 3 patients [15%] in group III had delayed vomiting after 180 minutes from the end of anesthesia. There were no children in group I who required antieienietic rescue while 4 patients [20%] in group II and 5 patients [25%] in group III required treatment with metoclopramide. Children in group I achieved early oral intake than the other two groups. We concluded that 8 mg IV dexamethasone, when administered 1 hour before the induction of anesthesia provided an effective antiemetic therapy throughout the first six hours of the postoperative period. On the other hand, dexamethasone when administred at the end of anesthesia, failed to provide an effective antiemetic therapy during the immediate postoperative period in children after tonsillectomy surgery