Impact of Forced Exhalation Maneuvers During Spirometry on Airway Resistance Measured by Oscillometry in Healthy Children

Objective To analyze the impact of repeated forced spirometry maneuvers on oscillometry parameters of healthy children. Methods This is a cross-sectional study with healthy children (6–12 y old) from schools in Florianopolis-SC/Brazil. Good health condition was confirmed through questionnaires, health history, and normal spirometry. Spirometry maneuvers and impulse oscillometry were conducted according to the American Thoracic Society guidelines. The school children were grouped according to the number of spirometry maneuvers performed: 1) 3 maneuvers; 2) 4 maneuvers and 3) 5 to 8 maneuvers. The following oscillometry values were considered: at rest (T 0 ); after the first spirometry maneuver (T 1 ); and after the last maneuver (T 2 ), according to the groups’ allocation. The mixed model ANOVA was applied to verify the interaction of oscillometry parameters in all 3 moments and groups. The Friedman test was used for analysis of Fres ( p < 0.05). Results In 149 school children (mean age: 9.13 y old ± 1.98), there was a significant increase in Z5, R5, R20, and X5 values at rest and after the first spirometry maneuver, and values at rest and after the last maneuver in all groups. The effects on analyzed variables were significant in Z5 (F: 12.35; gl: 2; p < 0.001), R5 (F: 11.14; df : 2, p < 0.001), R20 (F: 7.53; df : 2, p < 0.001), and X5 (F: 4.30; df : 2, p = 0.014). Conclusion There were changes in respiratory mechanics after spirometry, like the increase in baseline Z5, R5, R20, and X5 after the first forced spirometry maneuver, and in comparison to the last maneuver obtained.