ABSTRACT
Objective To investigate the efficacy of two low doses of ketamine for postoperative pain relief in children following adenotonsillectomy.Methods Ninety ASA physical status Ⅰ patients,aged 2-9 years,scheduled for adenotonsillectomy were enrolled in this randomized,double-blinded study.Patients were divided into three groups of 30 each and received an intravenous injection of 0.9％ saline (group C),ketamine 0.2mg/kg (group K1),or ketamine 0.5mg/kg (group K2).FLACC scores were used to evaluate pain levels during 12h after surgery.Tramadol and diclofenac potassium suppositories were provided for pain relief if FLACC ＞ 4.The operating time(OT),anesthesia duration(AT),extubation time(ET) and awaking time(AWT) were recorded.Adverse reactions such as nausea,vomiting,headache,abdominal pain and the requirement of rescue analgesic was recorded.Results Group C had significant higher FLACC scores than group K1 and K2 during the first 30min after operation.The requirement of analgesics was also higher in the control group(P ＜ 0.05).No significant difference of FLACC scores was found between group K1 and K2.However,children in K2 group have longer awaking time (P ＜ 0.05).There was no significant difference among three groups in the FLACC score after 2 hours.Conclusion A 0.2 or 0.5mg/kg dose of ketamine given before surgery by intravenous injection provides efficient pain relief in the early period after surgery.0.2mg/kg may be preferable for its low incidence of deep sedation.