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Pediatr Pulmonol. 2015 Oct;50(10):1017-24. doi: 10.1002/ppul.23112. Epub 2014 Nov 3.

Reference ranges for shape indices of the flow-volume loop of healthy children.

Author information

1
Pulmonary Function Testing Unit, CHU de Lille, Lille, France.
2
Univ Lille Nord de France, UDSL, Lille, France.

Abstract

BACKGROUND:

The concavity of the descending limb of the maximum expiratory flow-volume loop (MEFVL) is the earliest change associated with airflow obstruction in small airways (ATS/ERS Task Force). The shape of the MEFVL changes with age but there are no reference values for shape indices for preschool and school children.

OBJECTIVES:

To define pediatric reference values for spirometric data and 3 shape indices of MEFVL: 2 geometric indices: the β angle i.e., the angle between the first ½ part and the 2nd part of the MEFVL and the forced expiratory flow after 50% of the forced vital capacity (FVC) has been exhaled/peak expiratory flow (FEF50 /PEF) ratio; and a ratio that describes relative growth between airway and lung parenchyma, the forced expiratory flow between 25 and 75% of FVC/FVC ratio (FEF25-75 /FVC ratio).

METHODS:

Data were obtained from 446 Caucasian children (2.5 to 15-year-old). The lambda, mu, sigma method was applied.

RESULTS:

References for spirometric parameters and 3 shape indices. The geometric indices decreased with age from 3 years of age (mean β angle was 215° and FEF50 /PEF ratio was 0.82) until 8 years of age (mean β angle was 191° and FEF50 /PEF ratio was 0.60) and then remained constant. The FEF25-75 /FVC ratio also decreased with age. Sex was a significant determinant for FEF25-75 /FVC ratio predicted values.

CONCLUSIONS:

This study provides standard reference equations for indices of mid-expiratory flows in children and we suggest using the FEF50 /PEF index.

KEYWORDS:

Pediatric lung function testing; Spirometry refference values; preschool and school lung function

PMID:
25367592
DOI:
10.1002/ppul.23112
[Indexed for MEDLINE]

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