Which factors can influence the number of forced expiratory manoeuvres on spirometry in schoolchildren?

Spirometry is of great value for understanding respiratory function and management of lung diseases. Adaptations in the exam were made to meet paediatric population since the forced expiratory manoeuvres (FEM) present in the exam require effort and cooperation; therefore, its use should be reconsidered.

To analyse factors that may influence the number of FEM required for successful spirometry in schoolchildren.

Healthy children aged between 6 and 12 years were tested. FEM were conducted according to the American Thoracic Society/European Respiratory Society guideline. The children were divided into three groups according to the number of attempts: G3M if child completed the test in three FEM; G4M if child completed in four attempts FEM; and G5/8M if child completed the test in five to eight FEM. Factors that potentially influenced the number of FEM included: age; impulse oscillometry parameters; slow vital capacity; respiratory muscle strength; orofacial motor function, school performance, physical activity level and quality of life. The Kolmogorov-Smirnov test was performed, followed by the Chi-Square, repeated measures ANOVA and Kruskal-Wallis tests; thereafter, a multinomial logistic regression was applied.

One hundred and forty-nine schoolchildren (80 girls) with mean age of 9.13 years (±1.98) were included, age was related to the required number of FEM (F = 3.38(2), P = .03) and children with poor school performance had a 2.84-fold greater chance of completing the exam in more than five attempts.

Age and school performance influenced the number of FEM required for a successful spirometry in schoolchildren.