Lack of bronchodilator effect after administration of subanaesthetic concentration of isoflurane in mild asthmatic subjects challenged with methacholine.
Volatile anaesthetics used in high concentrations are potent bronchodilators. The effect of lower subanaesthetic concentrations is less documented, particularly in humans with provoked bronchial obstruction. We have studied seven mild asthmatic subjects twice, 1 week apart, during an asymptomatic period. A provocative test with methacholine was performed to produce a decrease in forced expiratory volume in 1 s (FEV1) of at least 20%. The subjects then inhaled either 100% oxygen or 0.75% isoflurane in oxygen for 8 min, via a face mask. During isoflurane inhalation, the subjects lost consciousness but recovered quickly. There was no significant improvement in FEV1 and maximum expiratory flow at 50% vital capacity (MEF50) recorded 3, 6, 9, 14 and 19 min after the end of isoflurane inhalation compared with time-control values. We conclude that lung function in mild asthmatic subjects challenged with methacholine was not improved after administration of a low subanaesthetic concentration of isoflurane. This may be important during recovery from general anaesthesia.
Mercier
F J
FJ
Département d'Anesthésie, Hôpital Antoine Béclère, Clamart, France.
Benhamou
D
D
Denjean
A
A
D000328:Adult; D001249:Asthma / Q000503:physiopathology*; D001980:Bronchi / Q000187:drug effects* / Q000503:physiopathology; D001985:Bronchial Provocation Tests; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D016210:Methacholine Chloride; D011446:Prospective Studies; D014797:Vital Capacity / Q000187:drug effects
D016210:Methacholine Chloride; D007530:Isoflurane