title: Evaluation of a test of density-dependence of the expiratory flows in the screening of peripheral airways obstruction.
abstract: A test of density-dependence of flow at 50% of vital capacity has been investigated in two groups of subjects (86 in total) in order to evaluate respectively: a) influences that on it may be exerted by altered mechanical properties of the lung in chronic airflow obstruction; b) accuracy and precision of the test in latent and clinical asthma. Lung elastic recoil pressure does not seem to be related to the intensity of density-dependence. Relationships between MEF50 on air and on He-O2, expressed as means of groups allow distinguish between each other, whereas a definite overlap between groups is patent; absolute flows, either on air or on He-O2 are quite satisfactorily reproducible, both in health and disease. Delta% MEF50 shows a good specificity but a poor sensitivity; reproducibility is unacceptable, unless when using on a qualitative scale of figure of 20% as borderline to distinguish subjects responders from non responders.
mesh_terms: D000402:Airway Obstruction / Q000175:diagnosis*; D001249:Asthma / Q000175:diagnosis; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008168:Lung / Q000502:physiology; D008170:Lung Compliance; D008297:Male; D008433:Mathematics; D012119:Respiration; D012129:Respiratory Function Tests / Q000379:methods*; D014797:Vital Capacity