[Spirometry reference values after inhalation of 200 microg of salbutamol].
OBJECTIVE
The criteria for disease severity established by the Global Initiative for Chronic Obstructive Lung Disease are based on forced expiratory volume in 1 second (FEV1) expressed as a percentage of the predicted value after application of a bronchodilator. This study aims to determine postbronchodilator spirometry reference values.


METHODS
A cluster sample of subjects aged 40 years or over was chosen to be representative of the metropolitan areas of 5 Latin American cities (São Paulo, Mexico City, Montevideo, Santiago, and Caracas). Spirometry was performed on 5183 subjects following the recommendations of the American Thoracic Society before and after inhalation of 200 microg of salbutamol. Multiple linear regression equations were fitted for the postbronchodilator spirometric values-FEV1, forced expiratory volume in 6 seconds (FEV6), peak expiratory flow rate, forced vital capacity (FVC), FEV1/FEV6, FEV1/FVC and forced expiratory flow between 25% and 75% of vital capacity (FEF25-75). These were adjusted for sex, age, and height in 887 asymptomatic subjects with no history of lung disease.


RESULTS
The postbronchodilator reference values for FEV1, FEV1/FVC, and FEV1/FEV6 were on average 3% higher than those obtained before bronchodilation. This apparently small difference caused an upward shift in the 5th percentile (lower limit of normal) of the predicted values. When prebronchodilation instead of postbronchodilation reference values were used, 3.2% of the results for airflow obstruction in our population of over-40-year-olds were false negatives.


CONCLUSIONS
The reported reference values are more appropriate for postbronchodilator spirometry and make it possible to reduce the number of misclassifications.
Pérez-Padilla
Rogelio
R
Instituto Nacional de Enfermedades Respiratorias, México DF, México. perezpad@servidor.unam.mx
Torre Bouscoulet
Luis
L
Vázquez-García
Juan Carlos
JC
Muiño
Adriana
A
Márquez
María
M
López
María Victorina
MV
Montes de Oca
María
M
Tálamo
Carlos
C
Valdivia
Gonzalo
G
Pertuze
Julio
J
Jardim
José
J
Menezes
Ana María B
AM
D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000420:Albuterol / Q000008:administration & dosage*; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013147:Spirometry
D001993:Bronchodilator Agents; D000420:Albuterol