Study On Low-dose Ketamine To Prevent The Pain Of Propofol Injection In Children

ObjectiveTo evaluation the effect of low-dose ketamine in reducing propofol injection pain in children and determine the best administration method.MethodsTwo hundred forty patients presenting for elective surgery were randomly allocated into six groups of 40 each; four groups during trialⅠof the study and three groups during trialⅡ(One group in trialⅡis Group K300 of trialⅠ).In trialⅠ,patients received 0.9% saline(Group S),ketamine 100μg/kg(Group K100),200μg/kg (Group K200) or 300μg/kg(Group K300),all pretreatment drugs were made in 2 ml, followed by administration a 2 mg/kg bolus of propofol. In trialⅡ,the minimum effective dose of ketamine (300ug/kg) was administered 2min before propofol(Group P),mixed with propofol solution (Group KP), administered immediately before propofol(Group K300).An anesthesiologist blinded to the study group monitored each patient's pain score at 2-s intervals.ResultsIn trialⅠ,the incidence and intensity of pain were the lowest in the Group K300.In trialⅡ,the patients in the Group K300 had significantly lower pain scores compared with the KP and P groups(P＜0.05).During induction, there were significant differences in arterial blood pressure between Group K300 and Group S.ConclusionAdministration of ketamine 300μg/kg immediately before propofol injection which is the best method can be effective in preventing propofol injection pain.