Effect of premedication on the induction dose of thiopentone in children

Abstract

SummaryThe ef'ective dose qj' thiopentone in 90% (ED,,) of unpremedicated children is 10.5 mglkg. This is significantly greater (p < 0.01) than in premedicated children. The ED,, in children premedicated with TDP ( a mixture of trimeprazine, droperidol and physeptone with atropine) is 4.2 mglkg which is significantly less (p < 0.05) than with trimeprazine and atropine (ED,, 5.2 mglkg) or papaveretum and hyoscine (EDpo 5.0 mglkg). Key wordsInduction; anaesthesia. Premedication.It has been known for some time that premedication affects the induction dose of thiopentone in There is little information on the effect of premedication on the dose requirement of thiopentone in children although recent work indicates that children require less thiopentone than adults for induction of anae~thesia.~ Beeby and Morgan Hughes4 have shown that the frequency of satisfactory behaviour in unpremedicated children is similar to that in published trials of sedative premedication, using the same method of assessment., It is becoming fashionable to encourage the presence of a parent in the anaesthetic room. Many anaesthetists now prefer to anaesthetise unpremedicated children accompanied by a parent particularly as more day case surgery is done. The aim of this study was to compare the effect of different premedicants on the dose requirement of thiopentone and to determine the ED,, and ED,, for thiopentone with and without premedication. MethodObservations were made on 490 mentally normal children aged 1-12 years in the American Society of Anesthesiologists Physical Status grades 1-2. Children with needle phobia were excluded. There were four groups for premedication: trimeprazine 3 mg/kg and atropine 0.03 mg/kg orally I f hours pre-operatively (group I); T D P (trimeprazine 6 mg, droperidol 0.6 mg and physeptone 0.32 mg per ml) 0.25 ml/kg arid atropine 0.03 mg/kg orally 1+ hours preBarbara B

Comparison of the Induction Characteristics of Thiopentone and Propofol in Children

“…Although these two patients received 2.22 and 2.52 mg kg" 1 of propofol, this was thought to be insufficient. Increased dose requirements have been noted in children compared with adults when using etomidate, Althesin and thiopentone (Keep and Manford, 1974;Kay, 1976;Duncan et al, 1984). This would also appear to be the case with propofol.…”

Oral Premedication in Children

“…Other centres have pre-anaesthetic rooms adjacent to the operating theatres which overcomes this problem. 4 The method of assessing waking times in the recovery room (response to verbal command) provides a very definite end-point and protective airway reflexes may well have returned sooner. The differences in mean waking times (Table 1 d) of Groups A (20 min), B (23 min) and C (26 min) are small and not clinically important.…”

“…However, both drugs have deficiencies which might be improved by the addition of droperidol. 4 Postoperative pain is badly treated in adults 5 and children. I Often adequate postoperative analgesia is achieved at the expense of an increased incidence of vomiting.…”

Regarding sevoflurane and emergence agitation…again!

“…We note that the majority of patients in Meyer’s study were induced with thiopentone – 27/29 isoflurane group and 26/30 in the sevoflurane group. The induction dose (8–12 mg·kg −1 ) is significantly higher that that traditionally used, particularly in the setting of premedication (7) and with the concomitant use of alfentanil. Given the dosage used and considering the long half‐life of thiopentone, we feel that this could easily have led to a decreased incidence of EA/ED in both groups.…”