Paeds · respiratory-sleep-and-airway
Spirometry and paediatric pulmonary-function testing
Also known as Spirometry and paediatric pulmonary-function testing · Paediatric lung function testing · Spirometry in children · Pulmonary function tests in children · Flow-volume loop interpretation · Bronchodilator reversibility testing
Fellowship guide to spirometry and pulmonary-function testing in children: how a forced blow into a spirometer generates the FEV1, FVC and their ratio and the flow-volume loop, how the ratio below the lower limit of normal defines obstruction and a low FVC with a preserved ratio raises restriction that lung volumes confirm, how bronchodilator responsiveness is measured and read, why the Global Lung Function Initiative reference equations and z-scores have replaced fixed cut-offs and percent-predicted, how quality is judged against ATS/ERS acceptability and repeatability standards, and how the whole result is interpreted in the child sitting in front of you rather than in isolation.
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- A spirometry result must never be interpreted without first checking that the effort was acceptable and repeatable — a submaximal or coughing blow produces a falsely low FEV1 and FVC that mimics disease and can commit a well child to unnecessary treatment
- Do not diagnose airflow obstruction in a child from a fixed FEV1/FVC below 0.70 — that adult threshold over-diagnoses restriction and under-diagnoses obstruction in growing lungs; use the age-, height-, sex- and ethnicity-adjusted lower limit of normal from the Global Lung Function Initiative equations
- A reduced FVC on spirometry alone does not prove restriction — it is far more often caused by incomplete exhalation or early airway closure in obstruction; true restriction requires a reduced total lung capacity measured by lung-volume testing, not by spirometry
- Normal spirometry does not exclude asthma or exercise symptoms, because lung function is frequently normal between episodes; a normal test in a symptomatic child should prompt reversibility or challenge testing rather than reassurance
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- Spirometry and pulmonary function testing in children
- Interpretation of paediatric spirometry: obstructive and restrictive patterns, bronchodilator response and reference values
- Spirometry in children: quality, pattern recognition and Global Lung Function Initiative interpretation
- Short case: interpret this child's flow-volume loop and spirometry report
- Long case: the child with chronic respiratory symptoms and longitudinal lung function
- Pulmonary function testing in children
- Spirometry and lung function interpretation in children
- Respiratory: interpreting paediatric lung function
- Pulmonology: pulmonary function testing and spirometry interpretation
- Medical Knowledge: interpretation of paediatric pulmonary function tests
- Medical Expert: paediatric pulmonary function testing and interpretation
Overview & Definition
A child takes the deepest breath they can, seals their lips around a mouthpiece, and blasts the air out as hard and as long as they can manage. That single forced manoeuvre is spirometry, and from it come the three numbers that anchor almost every lung-function report: the total volume blown out, called the forced vital capacity or FVC; the volume blown out in the first second, the FEV1; and the ratio of the two, FEV1/FVC, which describes how quickly the lungs can empty. The machine also plots the effort as a flow-volume loop, whose shape tells the practised eye as much as the numbers. [1] [7]
Spirometry is only the most familiar member of a wider family of pulmonary-function tests. When spirometry cannot answer the question, the laboratory can measure absolute lung volumes to look for true restriction, the diffusing capacity to probe gas transfer, airway resistance by oscillometry, and airway responsiveness to a bronchodilator or a challenge agent. The purpose of all of them is the same — to turn a child's breathing into reproducible numbers that can be compared with healthy children of the same size and read over time. [2] [6]
References12ShowHide
- [1]Graham BL; Steenbruggen I; Miller MR; Barjaktarevic IZ; Cooper BG; Hall GL; et al Standardization of Spirometry 2019 Update. An Official American Thoracic Society and European Respiratory Society Technical Statement. Am J Respir Crit Care Med, 2019.PMID 31613151
- [2]Stanojevic S; Kaminsky DA; Miller MR; Thompson B; Aliverti A; Barjaktarevic I; et al ERS/ATS technical standard on interpretive strategies for routine lung function tests. Eur Respir J, 2022.PMID 34949706
- [3]Quanjer PH; Stanojevic S; Cole TJ; Baur X; Hall GL; Culver BH; et al Multi-ethnic reference values for spirometry for the 3-95-yr age range: the global lung function 2012 equations. Eur Respir J, 2012.PMID 22743675
- [4]Stanojevic S; Stocks J; Bountziouka V; Aurora P; Kirkby J; Bourke S; et al The impact of switching to the new global lung function initiative equations on spirometry results in the UK CF registry. J Cyst Fibros, 2014.PMID 24332996
- [5]Beydon N; Davis SD; Lombardi E; Allen JL; Arets HG; Aurora P; et al An official American Thoracic Society/European Respiratory Society statement: pulmonary function testing in preschool children. Am J Respir Crit Care Med, 2007.PMID 17545458
- [6]Pellegrino R; Viegi G; Brusasco V; Crapo RO; Burgos F; Casaburi R; et al Interpretative strategies for lung function tests. Eur Respir J, 2005.PMID 16264058
- [7]Miller MR; Hankinson J; Brusasco V; Burgos F; Casaburi R; Coates A; et al Standardisation of spirometry. Eur Respir J, 2005.PMID 16055882
- [8]Culver BH; Graham BL; Coates AL; Wanger J; Berry CE; Clarke PK; et al Recommendations for a Standardized Pulmonary Function Report. An Official American Thoracic Society Technical Statement. Am J Respir Crit Care Med, 2017.PMID 29192835
- [9]Hall GL; Filipow N; Ruppel G; Okitika T; Thompson B; Kirkby J; et al Official ERS technical standard: Global Lung Function Initiative reference values for static lung volumes in individuals of European ancestry. Eur Respir J, 2021.PMID 33707167
- [10]Gaillard EA; Kuehni CE; Turner S; Goutaki M; Holden KA; de Jong CCM; et al European Respiratory Society clinical practice guidelines for the diagnosis of asthma in children aged 5-16 years. Eur Respir J, 2021.PMID 33863747
- [11]Gunawardana S; Tuazon M; Wheatley L; Vyas B; Douglas C; Alahmadi F; et al Airwave oscillometry and spirometry in children with asthma or wheeze. J Asthma, 2023.PMID 36218195
- [12]Levy ML; Bacharier LB; Bateman E; Boulet LP; Brightling C; Buhl R; et al Key recommendations for primary care from the 2022 Global Initiative for Asthma (GINA) update. NPJ Prim Care Respir Med, 2023.PMID 36754956