CME articlePulmonary function testing in young children
Section snippets
General considerations
Young children are known to be emotionally vulnerable and have a short attention span. Therefore, in order to perform accurate PFT on such young children, it is essential for laboratory staff to be aware of the age-related challenges. Time and patience are a necessity, as well as enthusiastic rewards for the child's efforts. To make the child feel comfortable, adapted seats and games to play between measurements are essential. The parents’ presence can be warranted depending on the laboratory
Resistance measurement
Respiratory resistance (Rrs) reflects the relationship between changes in airway pressure and the corresponding airflow. In non-invasive airway-resistance measurements, the change in airflow is recorded at the airway opening, and alveolar pressure has to equilibrate mouth pressure at the time of measurement. For all resistance techniques, freedom of the upper airways is required. In young children, enlarged tonsils are frequently present, which makes inspection of the child's throat prior to
The forced oscillation technique (FOT)
An extensive methodological article has been published on this technique2 and a specific chapter on the FOT is included in the ATS/ERS statement.1 Briefly, an external pressure wave is applied to the respiratory system, usually at the mouth, and the resulting pressure–flow relationship is analysed in terms of respiratory impedance (Zrs). Zrs encompasses the Rrs and its reactance (Xrs). The measured Rrs is calculated from the pressure change in phase with flow, while the Xrs is derived from the
The interrupter resistance technique (Rint)
In the Rint technique, the change in mouth pressure during a brief airflow interruption is divided by the airflow measured immediately before the interruption to calculate the airway resistance. To reliably measure the pressure change that corresponds to the measured airflow, instantaneous interruption and assessment of pressure are required. Further details on the background of the Rint technique can be found in the ATS/ERS statement.1
Specific airway resistance
In the classical plethysmographic technique, airway resistance (Raw) is calculated from ‘Δ volume (V)’/’Δ gas flow (V′)’ and ‘Δ alveolar pressure (Palv)’/ΔV relationships, which are recorded during normal breathing or panting (ΔV/ΔV′), and ventilation against a closed shutter (ΔPalv/ΔV). It has been suggested that direct measurement of sRaw (Raw × thoracic gas volume (TGV)) is possible from the slope of the ΔV′/V relationship, omitting the TGV (ΔPalv/ΔV) measurement, which is difficult to
Spirometry
Spirometry is probably the most widely performed PFT in school children, adolescents and adults. The possibility of obtaining a reproducible flow–volume curve in young children has recently been reported, and despite relatively few data in this age group, knowledge is sufficient to give advice on the way to perform spirometry in young children.1 Young children may be unable to blow for 1 s, but this does not preclude reliable and reproducible measurement. In that case, forced expiratory volume
Conclusion
A number of PFTs are easy to perform in young children and are now commercially available. Some of these techniques are convenient for field studies or outpatient measurement, whereas others are better suited to the physiology department. It is essential to know the practical aspects and limitations of the techniques. Further studies will increase our knowledge to make better use of these techniques in clinical practice.
Conflict of interest statement
The author declares no conflict of interest.
Educational aims
- •
To perform an overview of easily available techniques for pulmonary function testing (PFT) in young, awake children.
- •
To explain the basic physiological principles that PFT in young children rely upon.
- •
To describe the data collection procedures for the different techniques used.
- •
To give references for normative values for resistance measurements and spirometry in young children.
- •
To discuss the clinical applications of the different techniques according to the current knowledge.
Practice points
- •
Resistance and spirometry are feasible in young children with a success that increases with age, from 3 to 6 years of age.
- •
Most of the technical issues have been clarified and recommendations are available for most of the described techniques.
- •
Baseline value might not be the sensitive enough to discriminate between healthy and sick young children, and bronchial responsiveness might be a better way to detect lung function impairment.
Research directions
- •
Some technical aspects as well as data collection issues have to be addressed. These include: the best algorithm for Rint technique, which FEVt is the more relevant parameter, how to express bronchial changes, absolute value and percentage predicted ranges for different populations.
- •
An international reference database could allow for the establishment of reference values from a large number of young children.
- •
More studies on bronchial responsiveness in healthy individuals are needed to validate
CME Section
This article has been accredited for CME learning by the European Board for Accreditation in Pneumology (EBAP). You can receive 1 CME credit by successfully answering these questions online.
- (A)
Visit the journal CME site at http://www.prrjournal.com.
- (B)
Complete the answers online, and receive your final score upon completion of the test.
- (C)
Should you successfully complete the test, you may download your accreditation certificate (subject to an administrative charge).
Acknowledgements
This review was first published in the ERS Buyer's Guide 2008/2009 and is reproduced with the permission of the ERS.
References (25)
- et al.
Interrupter resistance short-term repeatability and bronchodilator response in preschool children
Respir Med
(2007) - et al.
Plethysmographic measurements of specific airway resistance in young children
Chest
(2005) - et al.
The role of computer games in measuring spirometry in healthy and “asthmatic” preschool children
Chest
(2005) - et al.
Spirometry in early childhood in cystic fibrosis patients
Chest
(2007) - et al.
An official American Thoracic Society/European Respiratory Society statement: pulmonary function testing in preschool children
Am J Respir Crit Care Med
(2007) - et al.
The forced oscillation technique in clinical practice: methodology, recommendations and future developments
Eur Respir J
(2003) - et al.
Respiratory function in healthy young children using forced oscillations
Thorax
(2007) - et al.
Forced oscillations in the clinical setting in young children with neonatal lung disease
Eur Respir J
(2008) - et al.
Respiratory impedance in children with cystic fibrosis using forced oscillations in clinic
Eur Respir J
(2007) - et al.
Assessment of bronchodilator responsiveness in preschool children using forced oscillations
Thorax
(2007)
A simplified approach to the measurement of specific airway resistance
Pediatr Res
Lung function measured with a whole body plethysmograph: standard values for children and young adults
Acta Paediatr Belg
Cited by (26)
The role of parental psychological flexibility in childhood asthma management: An analysis of cross-lagged panel models
2020, Journal of Psychosomatic ResearchCitation Excerpt :This study relied on parental reports of childhood asthma, which may have been subject to recall bias and social desirability response bias. It should be noted that over one-third of the children (61/168 = 36.3%) in this study were aged five years or below, they might have had a short attention span and have been unable to follow instructions to perform an accurate measurement of lung function in the test to verify that their asthma symptoms had improved [57]. Meanwhile, the parental reports may even more closely reflect the actual status of the disease of the child at the time that the data were collected [58,59].
Respiratory pathology at the patients with cerebral palsy (CP) and severe disabilities
2016, Motricite CerebralePrediction equations for spirometry in four- to six-year-old children
2016, Jornal de PediatriaCitation Excerpt :Before the test, each child received age-appropriate instructions and then performed the maneuvers. The measurements were collected with the subject seated using a disposable well-adjusted mouthpiece (to prevent leaks), a nose clip, and computer-animation programs that provided instructions and stimuli to the participants.2 The subjects were asked to breathe in the tidal volume and then instructed to fill their lungs as much as possible and blow as strongly, rapidly and long as possible.
Office-based exhaled nitric oxide measurement in children 4 years of age and older
2013, Annals of Allergy, Asthma and ImmunologyCitation Excerpt :In young children, objective evaluation of asthma can be challenging. Difficulty with reliable performance of spirometry and mismatch between symptoms and lung function have been reported.16–18 The 2007 National Heart, Lung, and Blood Institute (NHLBI) guidelines state that spirometry is generally valuable in children older than 5 years, although some children may not adequately conduct the maneuver until 7 years of age.19
Exhaled nitric oxide in asthma management
2012, Annals of Allergy, Asthma and ImmunologyCitation Excerpt :The level of accuracy is higher than for traditional measurements, such as peak flows and spirometry, and similar to that associated with bronchial challenge tests.3,4 It can be challenging to perform spirometry reliably in younger children,5 and there can be a mismatch between symptoms and lung functions.6 In contrast, FeNO testing using currently available devices can be performed in school-aged children relatively easily.