PMID: 9176538May 1, 1997Paper

Effect of acute alterations in inspired oxygen tension on methacholine induced bronchoconstriction in patients with asthma

Thorax
K D DaggN C Thomson

Abstract

Recent in vitro and in vivo studies in animals have suggested that ambient oxygen tension may influence airway responsiveness to bronchoconstrictor stimuli. These observations may have relevance to the management of acute exacerbations of asthma. The present studies were designed to examine the influence of inspired oxygen tension (Fio2 1.0, 0.21, 0.15) on methacholine-induced broncho-constriction in patients with asthma. In a dual study two groups of asthmatic patients performed methacholine inhalation challenges breathing either air (Fio2 0.21) or a hypoxic gas mixture (Fio2 0.15) in study 1 and air (Fio2 0.21) or hyperoxia (Fio2 1.0) in study 2. The gases were administered through a closed breathing circuit in a randomised double blind fashion. The PC20 values (dose of methacholine causing a 20% fall in forced expiratory volume in one second (FEV1) were calculated after each methacholine challenge by linear interpolation from the logarithmic dose response curve. Plasma catecholamine levels were measured before and after methacholine challenges as well as heart rate, oxygen saturation, and percentage end tidal carbon dioxide levels. The geometric mean PC20 value for methacholine was significantly lower on the hypoxic study da...Continue Reading

References

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Citations

May 17, 2000·Current Opinion in Pulmonary Medicine·T P Miller, R G Barbers
Jan 27, 2005·High Altitude Medicine & Biology·Annalisa CogoRobert Schoene
Jun 13, 2009·High Altitude Medicine & Biology·Annalisa Cogo, Giuseppe Fiorenzano
May 19, 2010·Expert Review of Respiratory Medicine·Joshua O StreamColin K Grissom
Jan 16, 2010·Journal of Travel Medicine·Kelly MieskeTimothy O'Brien
Mar 13, 2010·The Anatomical Record : Advances in Integrative Anatomy and Evolutionary Biology·Alma RusMaría Luisa Del Moral
Apr 5, 2017·High Altitude Medicine & Biology·Colin K Grissom, Barbara E Jones
Jul 17, 2010·The Journal of Asthma : Official Journal of the Association for the Care of Asthma·Henrike K HuismansTineke E J Renkema

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