Treatment of airway inflammation improves exercise pulmonary gas exchange and performance in asthmatic subjects.
BACKGROUND
Asthma is an inflammatory disease of the airways that can lead to impaired arterial blood oxygenation during exercise.


OBJECTIVE
We asked whether treatment of airway inflammation in asthmatic subjects would improve arterial blood gases during whole-body exercise.


METHODS
By using a double-blind parallel-group design, 19 asthmatic subjects completed treadmill exercise to exhaustion on 2 occasions: (1) before and (2) after 6 weeks' treatment with an inhaled corticosteroid (ICS; n = 9) or placebo (n = 10).


RESULTS
The ICS group had improved resting pulmonary function, decreased exercise-induced bronchospasm, and decreased postexercise sputum histamine during the posttreatment study compared with that during the pretreatment study. In the ICS group exercise Pao(2) was significantly increased after treatment (84.8 to 93.8 mm Hg). Increased alveolar ventilation (arterial Pco(2) decreased from 36.9 to 34.1 mm Hg) accounted for 37% of the increased Pao(2) and improved gas exchange efficiency (alveolar-to-arterial Po(2) difference decreased from 22.5 to 16.3 mm Hg) accounted for the remaining 63% of the increased Pao(2) after treatment. In the ICS group exercise time to exhaustion was increased from 9.9 minutes during the pretreatment study to 14.8 minutes during the posttreatment study.


CONCLUSIONS
Treatment of airway inflammation in asthmatic subjects can improve arterial blood oxygenation during exercise by (1) improving airway function, thereby allowing increased alveolar ventilation during exercise, and (2) improving the efficiency of alveolar-to-arterial blood O(2) exchange.


CONCLUSIONS
In asthmatic patients ICSs not only attenuate exercise-induced bronchospasm but also improve arterial blood oxygenation during exercise.
Haverkamp
Hans C
HC
Department of Medicine, University of Vermont, Vermont Lung Center, Burlington, VT 05405, USA. hans.haverkamp@uvm.edu
Dempsey
Jerome A
JA
Pegelow
David F
DF
Miller
Jordan D
JD
Romer
Lee M
LM
Santana
Marcus
M
Eldridge
Marlowe W
MW
D000328:Adult; D000730:Androstadienes / Q000627:therapeutic use; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy*; D004311:Double-Blind Method; D005080:Exercise Test; D005260:Female; D000068298:Fluticasone; D006801:Humans; D008297:Male; D011014:Pneumonia / Q000188:drug therapy*; D011659:Pulmonary Gas Exchange / Q000187:drug effects*; D012123:Pulmonary Ventilation / Q000187:drug effects; D015656:Respiratory Mechanics
D000730:Androstadienes; D018927:Anti-Asthmatic Agents; D000068298:Fluticasone