Feasibility and reproducibility of spirometry and inductance plethysmography in healthy Brazilian preschoolers

Abstract

RATIONALE: Preschoolers show peculiarities that reinforce the importance of assessing their pulmonary function. However, there are few data on the success rate and between-occasions reproducibility of pulmonary function tests in preschoolers, particularly in the Brazilian population. OBJECTIVE: To assess the success rate and between-occasions reproducibility of the variables obtained by spirometry and respiratory inductive plethysmography in healthy children aged 4-6 years. METHODS: Breathing pattern was assessed by plethysmography (tidal volume-V(T), respiratory rate-f, inspiratory duty cycle-Ti/Ttot, mean respiratory flow-V(T)/Ti, displacement of the rib cage-RC and phase relation during the total breath-PhRTB) and spirometry (forced vital capacity-FVC, forced expiratory volume in 0.5 sec-FEV0.5 and forced expiratory volume in first second-FEV1) in 47 healthy children, aged 4-6 years. To evaluate between-occasions reproducibility, 10 children (according to the sample size calculation) were reassessed after 3 weeks. Between-occasions reproducibility was evaluated by paired t-test, considering significant P < 0.05, Intraclass Correlation Coefficient (ICC) and coefficient of variation of method error (CV(ME)). RESULTS: The results showed an 83% success rate for spirometry and a 98% success rate for plethysmography. Regarding reproducibility, there were no significant differences between the variables of any test. Spirometry ICC was above 0.80 and the CV(ME) was lower than 10%. The plethysmography ICC was between 0.61 and 0.95, and the CV(ME) was between 2% and 31%. CONCLUSIONS: These results suggest a high success rate in performing the pulmonary function tests and good between-occasions reproducibility for spirometry and plethysmography in healthy preschoolers.