[Normograms of spirometric values for the city of Buenos Aires]

There is a large variability between the different normograms of spirometric values, so that we designed our normogram for Buenos Aires and Gran Buenos Aires. We performed forced spirometry, under American Thoracic Society standardization, in 237 normal subjects (105 females) between 18 to 86 years old, and 144 to 194 cm. We measured Forced Vital Capacity (FVC), forced Expiratory Volume in one second (FEV1), and forced expiratory flow during the middle half of the Forced vital capacity (FEF25-75), in previously calibrated by the explosive decompressor spirometers. Linear regression using height and age was used for each measured value for each sex. The values obtained were in normal distribution, so that we determined the Low Limit of Normality calculating the 95% confidence interval to one tail, and this should replace the common method of the fixed percent of each value to determine the lower limit of normality for a predicted value.