Maximal inspiratory flow rates in patients with COPD.
OBJECTIVE
To assess the relevance of maximal inspiratory flow rates (MIFR) in the assessment of airway obstruction in COPD.


METHODS
University teaching hospital.


METHODS
Ten consecutive COPD patients (O group; mean [+/- SD] age, 58.5+/-8.3 years) and 10 matched healthy subjects (H group; mean age, 58.7+/-7.4 years).


METHODS
Lung volumes, FEV(1), specific airway conductance, single-breath lung diffusing capacity, MIFR, and maximal expiratory flow rates (MEFR).


RESULTS
Mean FEV(1)/vital capacity (VC) was 74.7% in the H group and 37.8% in the O group (p<0.001). Total lung capacity was higher (p<0.001) in the O group compared with the H group. Lung diffusing capacity was less than half in the O group compared with the H group (p<0.001). MEFR at all lung volumes were lower in the O group (p<0.001). MIFR were comparable in the two groups, except at 25% inspired VC, where MIFR were lower in the O group (p< 0.05).


CONCLUSIONS
MIFR are less sensitive than MEFR to detect airway obstruction in COPD patients. Yet, the interest of MIFR lay in the possibility to separate intrinsic from extrinsic involvement of airways. A normal MIFR associated with low MEFR, as in the present study, suggests either a lack of parenchymal support, an increased collapsibility of the airways, or a reversible peripheral airway narrowing. A fixed, generalized airway narrowing would be associated with a decrease of both MIFR and MEFR.
Stănescu
D
D
Pulmonary Laboratory and Division, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium. stanescu@pneu.ucl.ac.be
Veriter
C
C
Van de Woestijne
K P
KP
D005540:Forced Expiratory Flow Rates / Q000502:physiology; D006801:Humans; D007320:Inspiratory Capacity / Q000502:physiology; D008168:Lung / Q000503:physiopathology*; D008173:Lung Diseases, Obstructive / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010991:Plethysmography; D011379:Prognosis; D012720:Severity of Illness Index