Τίτλος:
Exercise-induced flow limitation, dynamic hyperinflation and exercise
capacity in patients with bronchial asthma
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
It is known that, in stable asthmatics at rest, tidal expiratory flow
limitation (EFL) and dynamic hyperinflation (DH) are seldom present.
This study investigated whether stable asthmatics develop tidal EFL and
DH during exercise with concurrent limitation of maximal exercise work
rate (WRmax).
A total of 20 asthmatics in a stable condition and aged 32+/-13 yrs
(mean+/-SD) with a forced expiratory volume in one second (FEV1) of
101+/-21% of the predicted value were studied. Only three patients
exhibited an FEV1 below the normal limits. On a first visit, patients
performed a symptom-limited incremental (20 W(.)min(-1)) bicycle
exercise test. On the second visit, the occurrence of EFL (using the
negative expiratory pressure technique) and DH (via reduction in
inspiratory capacity) were assessed at rest and when cycling at 33, 66
and 90% of their predetermined WRmax. FEV1 was measured to detect
exercise-induced asthma, 5 and 15 min after stopping exercise at 90%
WRmax.
Only one patient showed EFL at rest, whereas 13 showed EFL. and DH
during exercise. In these 13 asthmatics, exercise capacity was
significantly reduced (WRmax 75+/-9% pred) compared to the seven
non-EFL patients (WRmax 95+/-13% pred). Moreover, a significant
correlation of WRmax (% pred) to the change in inspiratory capacity
(percentage of resting value) from rest to 90%, WRmax was found. Tidal
EFL during exercise was not associated with exercise-induced asthma,
which was detected in only three patients.
In conclusion, tidal expiratory flow limitation and dynamic
hyperinflation during exercise are common in stable asthmatics with
normal spirometric results and without exercise-induced asthma, and may
contribute to reduction in exercise capacity.
Συγγραφείς:
Kosmas, EN
Milic-Emili, J
Polychronaki, A
Dimitroulis, I and
Retsou, S
Gaga, M
Koutsoukou, A
Roussos, C
Koulouris, NG
Περιοδικό:
European Respiratory Journal
Εκδότης:
EUROPEAN RESPIRATORY SOC JOURNALS LTD
Λέξεις-κλειδιά:
asthma; dynamic hyperinflation; exercise; flow limitation
DOI:
10.1183/09031936.04.00113003
