RT Journal Article
SR Electronic
T1 Effects of high altitude and cold air exposure on airway inflammation in patients with asthma
JF Thorax
JO Thorax
FD BMJ Publishing Group Ltd and British Thoracic Society
SP 906
OP 913
DO 10.1136/thoraxjnl-2013-203280
VO 68
IS 10
A1 Seys, Sven F
A1 Daenen, Marc
A1 Dilissen, Ellen
A1 Van Thienen, Ruud
A1 Bullens, Dominique M A
A1 Hespel, Peter
A1 Dupont, Lieven J
YR 2013
UL http://thorax.bmj.com/content/68/10/906.abstract
AB Aims Eighteen patients with asthma were evaluated during preparation to climb to extreme altitude in order to study the effects of low fractional inspired oxygen (FiO2), prolonged exposure to cold air and high altitude on lung function, asthma control and airway inflammation. Methods Spirometry and airway inflammation (fractional exhaled nitric oxide (FeNO) and induced sputum) were studied under different test conditions: hypoxic (FiO2=11%) exercise test, 24-hour cold exposure (−5°C) and before, during and after an expedition that involved climbing the Aconcagua mountain (6965 m). Results Forced expiratory volume in 1 s (FEV1) and FeNO values were slightly lower (p<0.04) after 1 h of normobaric hypoxia. FEV1 decreased (p=0.009) after 24-hour cold exposure, accompanied by increased sputum neutrophilia (p<0.01). During the expedition FEV1 and forced vital capacity decreased (maximum FEV1 decrease of 12.3% at 4300 m) and asthma symptoms slightly increased. After the expedition the Asthma Control Test score and prebronchodilator FEV1 were reduced (p<0.02), sputum neutrophil count was increased (p=0.04) and sputum myeloperoxidase levels, sputum interleukin 17 mRNA, serum and sputum vascular endothelial growth factor A levels were significantly higher compared with baseline. Patients with asthma with the lowest oxygen saturation during the hypoxic exercise test were more prone to develop acute mountain sickness. Conclusions Exposure to environmental conditions at high altitude (hypoxia, exercise, cold) was associated with a moderate loss of asthma control, increased airway obstruction and neutrophilic airway inflammation. The cold temperature is probably the most important contributing factor as 24-hour cold exposure by itself induced similar effects.