[Sevoflurane augments the degree and speeds the onset of rocuronium evoked neuromuscular blockade in children].
BACKGROUND
In adults, sevoflurane augments the intensity of rocuronium evoked neuromuscular blockade. However, in children effective doses and onset of action of rocuronium have not been reported during sevoflurane anaesthesia. To test in children the hypothesis that sevoflurane speeds the onset and potentiates the degree of rocuronium induced neuromuscular blockade we studied 50 children aged 2 - 7 years following approval by the local ethics committee.


METHODS
After induction and maintenance of anaesthesia with either 2 % endtidal sevoflurane in 60 % N(2)O/O(2) (n = 30) or with propofol (3 mg small middle dot kg(-1) and 10 mg small middle dot kg(-1)h(-1), n = 20) and 60 % N(2)O/O(2) for 17 +/- 1 min, we injected either 0.15, 0.22, or 0.3 mg small middle dot kg(-1) rocuronium and quantified by mechanomyography the evoked (0.1 Hz ulnar nerve stimulation) response of the adductor pollicis muscle. Dose-response relationships of rocuronium under both anaesthetic regimes were assessed using a generalised linear model based on the maximum-likelihood-technique. Data were compared by analysis of covariance, F-test, and Mann-Whitney-U-test as indicated, p < 0.05, mean +/- SD, (95% confidence interval).


RESULTS
The degree of neuromuscular blockade was greater (p < 0.05) during sevoflurane (estimated ED 50: 0.15 (0.076 - 0.177) mg small middle dot kg(-1)) than propofol (ED 50: 0.25 (0.15 - 0.35) mg small middle dot kg(-1)) anaesthesia. Furthermore, onset time was significantly faster under sevoflurane/N(2)O compared to propofol/N(2)O anaesthesia (110 +/- 31 versus 230 +/- 52 s, p < 0.01, after rocuronium 0.3mg small middle dot kg(-1)).


CONCLUSIONS
In young children during steady state anaesthesia onset of action of rocuronium is halved and the degree of neuromuscular blockade is markedly augmented during sevoflurane/N(2)O anaesthesia compared to propofol.
Eikermann
M
M
Abteilung für Anästhesiologie und Intensivmedizin, Universitätsklinik Essen. matthias.eikermann@uni-essen.de
Renzing-Köhler
K
K
Peters
J
J
D000732:Androstanols; D018685:Anesthetics, Inhalation; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005260:Female; D006801:Humans; D008297:Male; D008738:Methyl Ethers; D009126:Muscle Relaxation / Q000187:drug effects; D009213:Myography; D019148:Neuromuscular Blockade; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium; D000077149:Sevoflurane
D000732:Androstanols; D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D003473:Neuromuscular Nondepolarizing Agents; D000077149:Sevoflurane; D000077123:Rocuronium