title: Detection of ventilation unevenness by nitrogen washout and forced vital capacity manoeuvres: its limits and reliability.
abstract: We investigated the behaviour of several indices of ventilation unevenness in a sample of 234 normal subjects aged between 20 and 80 years, divided into 12 classes of 5 years each. The aim of the present study was to find out whether it is possible to predict a reliable value for each of these indices as a function of age, height and TLC. For each index a large dispersion of experimental points and a high unexplained variance was found, so that it does not seem worthwhile predicting its value as a function of age, height and TLC. We concluded that there is no reason to employ these indices to detect the beginning of a lung function impairment.
mesh_terms: D000328:Adult; D000368:Aged; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009584:Nitrogen; D012044:Regression Analysis; D012129:Respiratory Function Tests / Q000379:methods*; D014109:Total Lung Capacity; D014797:Vital Capacity
chemical_list: D009584:Nitrogen