SPIROMETRY IN SCHOOLCHILDREN FOR FIELD STUDIES: DOES TESTING ON DIFFERENT DAYS CHANGE THE RESULT OF THE EXAM?

To analyze if there is variation in the results of spirometry performed by healthy schoolchildren on different days.

Cross-sectional study with healthy schoolchildren aged 7 to 12 years old, in Florianópolis, Santa Catarina, Southern Brazil. Prepubescent children, non-athletes, born at full term, without cardiorespiratory, rheumatic, musculoskeletal, neurological and visual or hearing deficit were included. The child's health was assessed by a health questionnaire and by the survey International Study of Asthma and Allergies in Childhood. The spirometric test was performed on 3 different days, not exceeding the interval of 15 days between the first and last exams, following the guidelines of the American Thoracic Society. The absolute values and percentages of predicted values of forced vital capacity, forced volume in the first second and peak expiratory flow were analyzed. Statistical analysis was performed using the Shapiro-Wilk normality test followed by one-way analysis of variance or Friedman test and by Bonferroni's post-hoc test for multiple parametric comparisons. Also, the intraclass correlation coefficient was applied to compare results on the same patients on the different tested days.

Twenty-two children were analyzed, with a mean age of 9.3±1.1 years. All the spirometric parameters showed a reduction in absolute value after the first exam, but without significant difference. Regarding reproducibility of spirometry results, the tests presented intraclass correlation coefficient >0.70.

There was no change in the results of spirometry performed by healthy schoolchildren on three different days.