Induction dose of propofol in children

Abstract

SummaryIn II study of144 children aged 1-12 years, astempts were made to ussess the ED,, und ED,, o Key wordsAnae.~thrtics. intruvetzous; propofol. Aniirsth~sia; paediatric.Propofol i n an emulsion formulation that contains soyabean oil and a puritied egg phosphatide has been available for clinical evaluation since July 1983. Pharmacokinetic studies o f propofol in adults have demonstrated its high plasma ~l e a r a n c e l -~ and short elimination half-life. which suggests its suitability for daycase anaesthesia. Clinical studies have confirmed rapid postoperative recovery and it appears to be superior to m e t h~h e x i t o n e~-~ in this respect. Thc dose required in adults to induce anaesthesia in 95% of hcalthy, unprcmcdicated paticnts is 2.5 mg/kg.' However, there are very few published studies on the usc of propofol as an induction agcnt in ~h i l d r e n .~ Thc aim of this study was to dctcrmine the cffcctive dose of propofol for induction in premedicated and unpremcdicatcd children. Opportunity was taken to make general observations of efficacy and side effects of thc drug in this respect. MethodForty-six children were used in a pilot study to determine the range of doses which would be appropriate for use in a formal study to detect ED,, and ED,, (the ED,, was taken as that dose which would abolish the eyelash reflex in 50% of the studied subjects). It also became clear from this study that an unacccptably high proportion of children experienced severe pain on injection. Thereforc lignocainc was mixed with the propofol for the formal study. The dose uscd was 2% lignocainc 0.5 ml added to propofol 20 ml, according to the rccommendations of Brooker and Redfern.g The prepared mixture was uscd within 25 minutes of preparation.Inrormed parental consent and approval from the District Ethics Committee was obtained Tor both the pilot and definitive studies. In the definitive study 144 mentally normal children in ASA grades 1 and 2 and betwccn 1 and I2 years of age, were evaluated. The study split them into two groups. Group A consisted of 72 children who were premedicatcd with trimcprazinc 3.0 ingjkg up to a maximum of 100 mg. They also received atropine 30 pgjkg orally 2 hours pre-operatively. Group B's 72 children received no premcdication. The majority were undergoing surgery as day cases. Both groups had EMLA cream applied over a vcin on the dorsum of one hand 2 hours before operation. Each child was allocated randomly to one of the six dose rangc groups on arrival in the anaesthetic room. These were 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5 mgikg for the premedicated group A and 1.5. 2.0, 2.5, 3.0, 3.5 and 4.0 mgikg for the unpremedicated group B.The allocated dose was administered over approximately 20 seconds through a 25-gauge indwelling needle in the dorsum of the hand. Twenty seconds after the injection two reactions were assessed. Firstly, an attempt was made to elicit the eyelash reflex and if it was lost, the patient was considered a responder. If not, increments of propofol 5-10 mg were given. If no e...

The Effect of Obesity on the ED95 of Propofol for Loss of Consciousness in Children and Adolescents

“…22 Hannallah et al found that the ED 95 of propofol was 2.0 (95% CI, 1.7-2.6) mg/kg, and attributed the difference to waiting 50 seconds before assessment. 23,24 It is possible that our results were influenced by the decision to use the 20-second mark to judge the effectiveness of the administered dose of propofol.…”

“…20 Two published pediatric studies used the same endpoint of loss of lash reflex at 20 seconds as in our study. 22,23 In one study by Patel et al, the ED 90 for propofol was 2.8 (95% CI, 2.3-3.5) mg/kg, 23 and the other study by Aun et al estimated the ED 95 as 2.14 mg/kg (95% CI, 1.98 -2.38 mg/kg) in children ages 2 to 12 years. 22 Hannallah et al found that the ED 95 of propofol was 2.0 (95% CI, 1.7-2.6) mg/kg, and attributed the difference to waiting 50 seconds before assessment.…”

“…Logistic regression analysis was used in 3 pediatric studies of the ED 95 of propofol for loss of eyelash reflex. [22][23][24] In this method, the ED 95 value is extrapolated from the doseresponse curve, and the 95% CI of ED 95 values are dependent on the steepness of the curve. In contrast, the 95% CI of the ED 50 is usually narrower, permitting more reliable comparisons of drug potency.…”

Deep sedation with propofol in preschool children undergoing radiation therapy

“…For rapid and safe induction of anaesthesia with propofol in children usually a loading dose of 2.5 mgkg-' has to be administered intravenously (7). The dose must be increased in unprernedicated children (8) and therefore a mean induction dose of 3.6mg.kg-' was necessary for our patients. All children had fallen asleep after administration of the induction dose.…”

A CLINICAL COMPARATIVE STUDY OF EFFECTIVENESS OF MIDAZOLAM 0.05mg.kg - 1 AS CO - INDUCTION AGENT WITH PROPOFOL 2.5mg. k g - 1 AND PROPOFOL 3.5mg.kg - 1 ALONE FOR LARYNGEAL MASK AIRWAY INSERTION IN CHILDREN

“…kg -1 . Patel DK et al 12 found that propofol in a larger dose of 2.5-3.5 mg. kg -1 is an effective induction agent in children aged 1-12yrs to achieve satisfactory anaesthesia in both premedicated and unpremedicated children. Saint-Maurice C et al 13 reported that higher induction dose of propofol is required in children consistent with the larger value of V α .…”