[Caffeine skinned fiber tension test: application to the diagnosis of susceptibility to malignant hyperthermia].
OBJECTIVE
To assess the reactivity of sarcoplasmic reticulum to caffeine, using the skinned muscle fibre tension test and to compare it with the reference in vitro contracture test in the diagnosis of malignant hyperthermia (HM) susceptibility.


METHODS
Laboratory investigation.


METHODS
Muscle biopsies from 63 patients, including 29 classified as susceptible to MH (MHS) and 34 classified as non-susceptible (MHN) according to criteria of the European and the North American MH groups.


METHODS
The reactivity to caffeine and halothane of skinned muscle fibres was compared, according to the type of fibres, with the data of the in vitro contracture test. The type of fibres (type I: oxidative, slow; type II: glycolytic, fast) were determined with strontium dose-response curves.


RESULTS
The reactivity to caffeine was significantly lower in the MHS group, for both type I and type II skinned fibres. However, in comparison with the data of the in vitro contracture tests, using the ROC curve analysis, the best sensitivity-specificity compromise was 90%-71% and 74%-84% for type I and type II skinned fibres respectively.


CONCLUSIONS
The skinned muscle fibre tension test cannot be used instead of the in vitro contracture test for the diagnostic of MHS. However, it may strengthen the data of the latter.
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Service d'accueil et d'urgences, hôpital Roger Salengro, CHU, Lille.
Börtlein
M L
ML
Tavernier
B
B
Nivoche
Y
Y
Etchrivi
T
T
Krivosic-Horber
R
R
Haudecoeur
G
G
D002110:Caffeine / Q000494:pharmacology; D004198:Disease Susceptibility / Q000175:diagnosis; D006801:Humans; D066298:In Vitro Techniques; D008305:Malignant Hyperthermia / Q000175:diagnosis* / Q000503:physiopathology*; D009119:Muscle Contraction / Q000187:drug effects; D018485:Muscle Fibers, Skeletal / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology / Q000503:physiopathology*; D012372:ROC Curve; D012016:Reference Values; D015203:Reproducibility of Results; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000502:physiology; D012680:Sensitivity and Specificity
D002110:Caffeine