Variability and reproducibility in the measurement of tracheobronchial clearance in healthy subjects and patients with different obstructive lung diseases.
The purpose of this study was to establish the inter- and intra-subject/patient variability of tracheobronchial clearance, measured for 6 h, using a radioaerosol technique. Inter-subject variability was evaluated in five groups: 33 healthy non-smokers (NS); 19 asymptomatic smokers (S); 40 asthmatics (A); 27 chronic bronchitics (CB) and 12 bronchiectatics (B). Intra-subject variability was evaluated in 16 A and 27 CB who were studied twice. The inter-subject/patient coefficient of variation (CoV) of tracheobronchial clearance was 13% for NS and 28-39% for the remaining four groups. The intra-patient CoV was about half of the inter-patient CoV. Inter-subject CoV (for A and CB) appeared to be independent of initial tracheobronchial deposition of radioaerosol and frequency of cough. We were also able to estimate the approximate number of patients required for a crossover study in order to avoid statistical, type II errors when investigating the effect of a drug or of a therapeutic intervention on tracheobronchial clearance.
Del Donno
M
M
Department of Thoracic Medicine, Royal Free Hospital, School of Medicine, Hampstead, London, England.
Pavia
D
D
Agnew
J E
JE
Lopez-Vidriero
M T
MT
Clarke
S W
SW
D000328:Adult; D000336:Aerosols; D001249:Asthma / Q000503:physiopathology*; D001987:Bronchiectasis / Q000503:physiopathology*; D001991:Bronchitis / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D009079:Mucociliary Clearance; D012907:Smoking / Q000503:physiopathology*; D013667:Technetium
D000336:Aerosols; D013667:Technetium