Effect of hyperoxia on bronchial response to inhaled methacholine.
Bronchial reactivity to methacholine (MCH) under normoxic and hyperoxic conditions was studied in a double-blind controlled study in 10 normal subjects and nine asthmatic patients. The normal volunteers were challenged while breathing dry, 21% and 100% O2, and the maximal percent falls in forced expired volume in is (FEV1) following inhalation of the highest concentration of MCH (64 mg/ml) were 8 +/- 5% and 9 +/- 8%, respectively; P = NS. The asthmatic patients had their MCH challenge breathing the same gas composition and the provocative concentrations that caused a 20% fall in FEV1 (PC20) were 0.18 mg/ml (range 0.06-5.73) and 0.25 mg/ml (range 0.07-8.49), respectively, which were statistically not significantly different. We conclude that in humans, 100% O2 does not affect bronchial reactivity to MCH.
Wollner
A
A
Internal Medicine Department, Hadassah, University Hospital, Mt. Scopus Jerusalem, Israel.
Ben-Dov
I
I
Bar-Yishay
E
E
D000280:Administration, Inhalation; D000328:Adult; D001249:Asthma / Q000503:physiopathology*; D001250:Asthma, Exercise-Induced / Q000503:physiopathology; D001980:Bronchi / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D004311:Double-Blind Method; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D016210:Methacholine Chloride / Q000008:administration & dosage*; D010100:Oxygen / Q000008:administration & dosage / Q000494:pharmacology*; D011897:Random Allocation
D016210:Methacholine Chloride; D010100:Oxygen