Stress-induced respiratory pattern changes in asthma
Psychosomatic Medicine, 07/08/2011
Ritz T et al. – Expiratory lengthening and variable tidal volumes are characteristic for individuals with asthma during psychosocial stress. The function and possible association of these changes with symptom exacerbations require further study.
Studied respiration during resting conditions and an acute psychosocial stressor (a free speech and mental arithmetic task) in participants with asthma (n = 20) and healthy controls (n = 19)
Respiratory pattern was recorded with respiratory inductance plethysmography
Partial pressure of end–tidal carbon dioxide (PCO2) measured with capnometry before and after stress
Overall minute ventilation was higher in asthma (mean [standard deviation] = 9.0 [4.0] L versus 6.8 [4.1] L, p < .05), but levels of the PCO2 were comparable (34.6 [3.5] mm Hg versus 35.0 [3.7] mm Hg, p = .667) to healthy controls during prestress and poststress phases
Participants with asthma also showed a significant lengthening of inspiration, expiration, and the total respiratory cycle during stress compared with healthy controls (p < .05)
During stress tasks, all participants showed marked increases in tidal volume, inspiratory flow, minute ventilation, tidal volume instability, ribcage contribution to tidal volume, and ribcage–abdominal asynchrony
Significant increase in tidal volume instability and tendency toward lengthening of expiration and total respiratory cycle were observed in quiet–sitting periods at prestress to poststress in asthma
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