Forced expiratory parameters in healthy preschool children (3–6 years of age)

Abstract

In a group of 173 healthy preschool children 3-6 years of age (body height, 90-130 cm; 102 boys and 71 girls) out of total 279 children examined, maximum expiratory flow-volume (MEFV) curves were recorded in cross-sectional measurements. The majority (62%) of preschool children were able to generate an MEFV curve as correctly as older children. From the curves, maximum expiratory flows at 25%, 50%, and 75 % of vital capacity (MEF(25), MEF(50), and MEF(75)), peak expiratory flow (PEF), forced expiratory volume in 1 sec (FEV(1)), forced vital capacity (FVC), and area delineated by MEFV curve (A(ex)) were obtained. The purpose of the study was to establish reference values of forced expiratory parameters in preschool children suitable for assessment of lung function abnormalities in respiratory preschool children. The values of the studied parameters increased nonlinearly and correlated significantly with body height (P < 0.0001); the correlation was much lower with age. A simple power regression equation was calculated for the relationship between each parameter and body height. A best-fit regression equation relating functional parameters and body height was a power function. Based on the obtained regression equations with upper and lower limits, we prepared tables listing reference values of forced expiratory parameters in healthy Caucasian preschool children, against which patients can be compared. No statistically significant gender differences were observed for MEF(25), MEF(50), MEF(75), PEF, FEV(1), FVC, and A(ex) by extrapolation. The reference values were close to those obtained in our older children. A decline of the ratios PEF/FVC, FEV(1)/FVC and MEF/FVC with increasing body height suggested more patent airways in younger and smaller preschool children.

Efeito da terminação precoce da expiração nos parâmetros espirométricos em crianças pré-escolares saudáveis

“…The proportion of acceptable curves in the nETE group (34%) was lower than that reported in a previous study (40%), (6) possibly because of the lower mean age of the children in our study (4.7 years vs. 5.1 years). A recent study, in which the 2007 ATS/ERS recommendations were used, found that 56% of preschool children (4-6 years of age) were able to produce acceptable and reproducible spirometry results.…”

“…(2)(3)(4) Acceptability was found to increase with age, a finding that is in accordance with data in the literature. (4,6) Although the number of small children who were able to perform maneuvers in accordance with the 2007 ATS/ERS acceptability criteria was small (7.4% of those aged 3 years and 29.5% of those aged 4 years), with the acceptance of the ETE>10 group curves, FEV 0.5 could have been assessed in 20% more of the children tested, raising the proportion of preschool children with available FEV 0.5 data to 73%, which would justify the use of spirometry in this age group.…”

“…(1)(2)(3)(4)(5)(6)(7)(8)(9) The publication of reference values and study reports, showing that 40-90% of preschool children can perform spirometry appropriately, has promoted its use in clinical practice. (1)(2)(3)(4)(5)(6)(7)(8) The acceptability criteria for spirometry in adults, standardized by the American Thoracic Society (ATS), (10) cannot be applied to children, especially because of the brevity of the expiratory maneuver, usually lasting less than 2-3 s. The major technical limitation is early termination of exhalation (ETE), characterized by the sudden interruption of exhalation. To allow for ETE, the following criteria for acceptable curves have been proposed (5,8,9) : minimum flows ≤ 25% of the highest PEF; minimum flows ≤ 10% of the highest PEF; and minimum flows ≤ 0.3 L/s.…”

“…Because there is no consensus regarding the criterion for curve termination in this age group, (5,6,8,9) the acceptable tests were divided into three groups, based on the criterion for curve termination, in order to determine the validity of partial maneuvers-no child was classified as belonging to more than one group. For the analysis, we selected only the tests with at least Considering the nETE and ETE≤10 groups collectively and by age (% of those in the sample as a whole), we obtained at least two acceptable curves in 9 children in the 3-year-old group (7.4%); in 36 children in the 4-year-old group (29.5%); and in 65 children in the 5-year-old group (53.3%), demonstrating that acceptability increases with age.…”

Measurement of Interrupter Respiratory Resistance and Spirometry in Preschool Children: Influence of Respiratory Symptoms

“…Young children have small absolute lung volumes and large airway size relative to lung volume compared with older children and adults. The descending limb of the flow-volume curve is convex in young children, on account of the rapid interruption of flow towards the end of the forced expiration, which is completed in a shorter time (18,19). For these reasons FEV!…”