A comparison of acceleromyography and mechanomyography for determination of the dose-response curve of rocuronium in children.
In order to compare an acceleromyograph (TOF-Guard) with a mechanomyograph (Grass FT03), the dose-response relationship of rocuronium was simultaneously determined in both arms of 15 children aged 3-11 years during anaesthesia with thiopentone, alfentanil and nitrous oxide. Three subgroups of five children received rocuronium 120, 180 or 240 micrograms.kg-1 randomly. The effective doses to produce 50% and 95% depression of the first twitch of the train-of-four determined by acceleromyography were 206 and 337 micrograms.kg-1, respectively, while these values determined by mechanomyography were 151 and 331 micrograms.kg-1, respectively. The dose-response curve obtained by acceleromyography was steeper and shifted to the right compared with that obtained by mechanomyography (p < 0.0001). The difference between the effective dose producing 50% twitch depression determined by the two devices was highly significant (p < 0.0001). In 13 out of 15 children, the acceleromyograph control train-of-four ratio was significantly greater than unity. Although there was a good correlation (r = 0.85) between simultaneous pairs of measurements of neuromuscular block, the acceleromyograph exhibited a bias of -25% relative to the mechanomyograph with wide limits of agreement (-62 to +12%). We conclude that acceleromyographic and mechanomyographic measurements should not be used interchangeably when determining the potency of muscle relaxants.
McCluskey
A
A
Royal Manchester Children's Hospital, Pendlebury, UK.
Meakin
G
G
Hopkinson
J M
JM
Baker
R D
RD
D000732:Androstanols / Q000494:pharmacology*; D000768:Anesthesia, General; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D006801:Humans; D009213:Myography / Q000379:methods*; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D000077123:Rocuronium; D009435:Synaptic Transmission / Q000187:drug effects
D000732:Androstanols; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium