Forced expiratory maneuvers in children aged 3 to 5 years

Maternal exposure to pyrethroid insecticides during pregnancy and respiratory allergy symptoms among children participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE)

BACKGROUND

Pyrethroid insecticides use for indoor residual spraying (IRS) in malaria-endemic areas results in high levels of exposure to local populations. Pyrethroids may cause asthma and respiratory allergies but no prior study has investigated this question in an IRS area.

METHODS

We measured maternal urinary concentrations of pyrethroid metabolites (cis-DBCA, cis-DCCA, trans-DCCA, 3-PBA) in samples collected at delivery from 751 mothers participating in the Venda Health Examination of Mothers, Babies, and their Environment (VHEMBE), a birth cohort study based in Limpopo, South Africa. At 3.5-year and 5-year follow-up visits, caregivers of 647 and 620 children, respectively, were queried about children's respiratory allergy symptoms based on validated instruments. We applied marginal structural models for repeated outcomes to estimate associations between biomarker concentrations and asthma diagnosis as well as respiratory allergy symptoms at ages 3.5 and 5 years.

RESULTS

We found that a10-fold increase in maternal urinary cis-DCCA, trans-DCCA and 3-PBA concentrations were associated with more than a doubling in the risk of doctor-diagnosed asthma (cis-DCCA: RR = 2.1, 95% CI = 1.3, 3.3; trans-DCCA: RR = 2.1, 95% CI = 1.1, 3.9; 3-PBA: RR = 2.4, 95% CI = 1.0, 5.8) and an about 80% increase in the risk of wheezing or whistling in the chest (cis-DCCA: RR = 1.8, 95% CI = 1.1, 3.0; trans-DCCA: RR = 1.7, 95% CI = 1.1, 2.6; 3-PBA: RR = 1.8, 95% CI = 1.0, 3.3) and suspected asthma (cis-DCCA: RR = 1.8, 95% CI = 1.1, 3.1; trans-DCCA: RR = 1.8, 95% CI = 1.1, 2.8). We also observed that higher concentrations of cis-DBCA and 3-PBA were related to increases in the risks of dry cough at night (RR = 3.5, 95% CI = 1.3, 9.5) and seasonal rhinoconjunctivitis (RR = 2.0, 95% CI = 1.1, 3.9), respectively.

CONCLUSION

Maternal exposure to pyrethroids may increase the risk of asthma and other respiratory allergy symptoms among preschool children from an IRS area.

Question 3: Can we diagnose asthma in children under the age of 5 years?

The diagnosis of asthma in children under five years has been controversial due to changing concepts of what true asthma is in this age group. Previous diagnostic algorithms that used clinical indices to predict the persistence of asthma symptoms or phenotypes based on asthma triggers do not predict which children will benefit from asthma medication. A pragmatic approach to asthma diagnosis in this age group is based on identifying signs and symptoms of reversible airflow obstruction and documenting their response to asthma medication. Hopefully, this approach will provide clearer guidance to clinicians and improve asthma morbidity in these young children.

Spirometry and Impulse Oscillometry in Preschool Children: Acceptability and Relationship to Maternal Smoking in Pregnancy

BACKGROUND

Comparisons of the technical acceptability of spirometry and impulse oscillometry (IOS) and clinical correlations of the measurements have not been well studied in young children. There are no large studies focused on African American and Hispanic children.

OBJECTIVES

We sought to (1) compare the acceptability of spirometry and IOS in 3- to 5-year-old children and (2) examine the relationship of maternal smoking during pregnancy to later lung function.

METHODS

Spirometry and IOS were attempted at 4 sites from the Urban Environmental and Childhood Asthma Study birth cohort at ages 3, 4, and 5 years (472, 471, and 479 children, respectively). We measured forced expiratory flow in 0.5 s (forced expiratory volume in 0.5 seconds [FEV0.5]) with spirometry and area of reactance (AX), resistance and reactance at 5 Hz (R5 and X5, respectively) using IOS.

RESULTS

Children were more likely to achieve acceptable maneuvers with spirometry than with IOS at age 3 (60% vs 46%, P < .001) and 5 years (89% vs 84%, P = .02). Performance was consistent among the 4 study sites. In children without recurrent wheeze, there were strong trends for higher FEV0.5 and lower R5 and AX over time. Maternal smoking during pregnancy was associated with higher AX at ages 4 and 5 years (P < .01 for both years). There was no significant difference in FEV0.5 between children with and without in utero exposure to smoking.

CONCLUSION

There is a higher rate of acceptable maneuvers with spirometry compared with IOS, but IOS may be a better indicator of peripheral airway function in preschool children.

Respiratory function in healthy Emirati children using forced oscillations

BACKGROUND

The forced oscillation technique (FOT) allows the quantification of respiratory function, does not require active cooperation and as such is ideally suited for use in young children. The application of the FOT in non-Caucasian populations is limited and it remains unclear if current reference ranges for the FOT in Caucasian children are appropriate for children in the Arabian Peninsula. This study explored the use of the FOT in healthy school-aged children in the United Arab Emirates (UAE).

METHODS

Lung function using FOT was assessed in healthy Emirati children aged 4-12 years. Using a validated questionnaires general medical and respiratory histories were obtained. Prediction equations for resistance (Rrs), reactance (Xrs), and area under reactance curve (AX) were calculated and compared to previous studies.

RESULTS

FOT was successfully obtained in 291 healthy Emirati children. Linear regression modelling including weight, height, age, and gender in transformed FOT outcomes demonstrated that height was the strongest predictor of FOT outcomes (P < 0.001). Using the equated prediction equation Z-scores were calculated. FOT outcomes in Emirati children did not match previously published reference equations in Caucasians children (P < 0.001).

CONCLUSION

FOT measurements were feasible in Emirati school-children. New FOT reference equation in Emirati children were derived. FOT reference equation in Emirati children was different from published equations in Caucasians.

Long-acting inhaled bronchodilators for cystic fibrosis

BACKGROUND

Cystic fibrosis is a life-limiting inherited condition which affects one in 2500 newborns in the UK and 70,000 children and adults worldwide. The condition is multifaceted and affects many systems in the body. The respiratory system is particularly affected due to a build up of thickened secretions and a predisposition to infection. Inhaled bronchodilators are prescribed for 80% of people with cystic fibrosis in order to widen the airways and alleviate symptoms. Both short- and long-acting inhaled bronchodilators are used to improve respiratory symptoms. Short-acting inhaled bronchodilators take effect in minutes and typically last for four to eight hours (muscarinic antagonists). Long-acting inhaled bronchodilators also take effect within minutes but typically last for around 12 hours and sometimes longer. This review is one of two which are replacing a previously published review of both long- and short-acting inhaled bronchodilators.

OBJECTIVES

This review aims to evaluate long-acting inhaled bronchodilators in children and adults with cystic fibrosis in terms of clinical outcomes and safety. If possible, we aimed to assess the optimal drug and dosage regimen.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books.Date of last search: 10 October 2017.We also carried out a separate search of Embase and the reference lists of included trials. We searched clinical trials registries for any ongoing trials and made contact with pharmaceutical companies for any further trials.Date of Embase search: 11 October 2017.

SELECTION CRITERIA

Randomised or quasi-randomised parallel trials comparing long-acting inhaled bronchodilators (beta-2 agonists and muscarinic antagonists) with placebo, no treatment or a different long-acting inhaled bronchodilator in adults and children with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed trials for inclusion (based on title, abstract and full text). The authors independently assessed the included trials for quality and risk of bias and extracted data. Discrepancies were resolved by a third party.

MAIN RESULTS

The searches identified 195 unique references, of which 155 were excluded on title and abstract. We assessed the full texts of the remaining references, excluded 16 trials (28 references) and included four trials (12 references) in the review with 1082 participants.One trial (n = 16) measuring the effect of beta-2 agonists reported an improvement in forced expiratory volume at one second (FEV₁) after treatment (at one month), but the trial was small with an unclear risk of bias so we judged the evidence to be very low quality. The trial did not report on participant-reported outcomes, quality of life or adverse events.Three trials (n = 1066) looked at the effects of the muscarinic antagonist tiotropium at doses of 2.5 µg and 5.0 µg in both the short term (up to 28 days) and the longer term (up to three months). Only one of the trials reported the change in FEV₁ (L) after 28 days treatment and showed no significant difference between groups; with 2.5 µg tiotropium, mean difference (MD) -0.02 (95% confidence interval (CI) -0.13 to 0.09), or 5.0 µg tiotropium, MD 0.00 (95% CI -0.10 to 0.10) (moderate-quality evidence). All three trials of muscarinic antagonists provided data on adverse events which were found to differ little from placebo at doses of 2.5 µg, risk ratio (RR) 1.01 (95% CI 0.92 to 1.11) or 5.0 µg, RR 0.98 (95% CI 0.90 to 1.06). Very little participant-reported outcome data or quality of life data were available for analysis. Two of the trials were at low risk of bias overall whilst the remaining trial was at an unclear risk overall.

AUTHORS' CONCLUSIONS

Neither long-acting beta-2 agonists nor long-acting muscarinic antagonist bronchodilators demonstrate improvement in our primary outcome of FEV₁. No difference was observed between intervention and placebo in terms of quality of life or adverse events. The quality of evidence for the use of beta-2 agonists was very low. The use of a long-acting inhaled bronchodilator may help to reduce the burden of treatment for people with cystic fibrosis as it is taken less often than a short-acting inhaled bronchodilator, but future trials would benefit from looking at the effects on our primary outcomes (spirometric changes from baseline, quality of life and adverse effects) in the longer term.

[Quality scale for preschool spirometry interpretation]

Since 2007, there are international guidelines for implementation and interpretation of spirometry in preschool children. A percentage of these patients cannot obtain maneuvers that meet all eligibility criteria. The objective of this study was to develop a quality scale for interpreting these partially acceptable spirometry.

MATERIAL AND METHOD

Delphi methodology was used, which allows to reach consensus among experts analyzing a defined problem. We invited to participate pediatric pneumologists dedicated to lung function and who participated actively in scientific specialty societies in Chile. Successive rounds were conducted with questionnaires about criteria used to assess spirometry in preschool children. These criteria define the acceptability of spirometric maneuvers according to international guidelines. Proposed quality grades were “very good”, “good”, “fair” and “bad”.

RESULTS

Thirteen of the 15 invited experts accepted our invitation. In the first round 9 disagreed with the degree of “regular” quality. In the second round this was removed and 11 experts answered, 9 of them agreed with the use of this new version. The most contentious criterion was the end of expiration.

CONCLUSION

Most experts agreed with the final scale, using “very good”, “good” and “bad” judgments. This would help to improve the performance of spirometry in children between 2 and 5 years.

Prediction equations for spirometry in four- to six-year-old children

OBJECTIVE

To generate prediction equations for spirometry in 4- to 6-year-old children.

METHODS

Forced vital capacity, forced expiratory volume in 0.5s, forced expiratory volume in one second, peak expiratory flow, and forced expiratory flow at 25-75% of the forced vital capacity were assessed in 195 healthy children residing in the town of Sete Lagoas, state of Minas Gerais, Southeastern Brazil. The least mean squares method was used to derive the prediction equations. The level of significance was established as p<0.05.

RESULTS

Overall, 85% of the children succeeded in performing the spirometric maneuvers. In the prediction equation, height was the single predictor of the spirometric variables as follows: forced vital capacity=exponential [(-2.255)+(0.022×height)], forced expiratory volume in 0.5s=exponential [(-2.288)+(0.019×height)], forced expiratory volume in one second=exponential [(-2.767)+(0.026×height)], peak expiratory flow=exponential [(-2.908)+(0.019×height)], and forced expiratory flow at 25-75% of the forced vital capacity=exponential [(-1.404)+(0.016×height)]. Neither age nor weight influenced the regression equations. No significant differences in the predicted values for boys and girls were observed.

CONCLUSION

The predicted values obtained in the present study are comparable to those reported for preschoolers from both Brazil and other countries.

Spirometry interpretation feasibility among pre-school children according to the European Respiratory Society and American Thoracic Society Guidelines

INTRODUCTION

Spirometry is the most used test to evaluate pulmonary function. Guidelines that defined acceptability and repeatability criteria for its implementation and interpretation among preschoolers were published in 2007. Our objective was to quantify the actual compliance with these criteria among pre-school patients.

METHODS

A review was performed on the baseline spirometry measured in patients aged 2 to 5 years in the Pediatric Respiratory Laboratory of the Pontificia Universidad Católica de Chile, who were admitted due to recurrent or persistent coughing or wheezing. Only those results obtained in patients who took the test for the first time were considered. They were analyzed by international standards.

RESULTS

A total of 93 spirometry results (mean age 57.4 ± 8.6 months, 48 males) were obtained, of which 44 (47%) met all acceptable criteria, 87 (93%) obtained expiratory time of ≥ 0.5seconds, and 67 (72%) of the patients had an end-expiratory flow of ≤10% from peak flow. The variation in the measurement of forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) was very low (intraclass correlation coefficient > 0.9).

CONCLUSION

It was possible to meet the acceptability and repeatability criteria for spirometry among pre-school children in our Center, which was similar to previous reports. As in older children, this test is fully recommended for pre-school children who require lung function studies.

Chest radiography in supporting the diagnosis of asthma in children with persistent cough

OBJECTIVE

To establish whether chest radiographic findings suggestive of lower airway obstruction (LAO) disease support the diagnosis of asthma in pediatric patients with persistent cough in an outpatient setting.

METHODS

180 patient charts were reviewed. The patients were children aged 1 to 18 years referred over a 3-year period to a pediatric pulmonary subspecialty clinic for evaluation of cough lasting ≥ 4 weeks. Chest radiographic images obtained after the initial evaluation of 90 patients diagnosed with cough-variant asthma and 90 patients diagnosed with persistent cough from nonasthma origins were compared with radiologic findings of a control group consisting of patients with a positive tuberculin skin test and no respiratory symptoms. Increased peribronchial markings/peribronchial cuffing and hyperinflation were considered radiographically suggestive findings of LAO disease.

RESULTS

Children diagnosed with cough-variant asthma at the initial evaluation had higher rates of chest radiographic findings suggestive of LAO disease (30.00%) than children with persistent cough from other causes (17.80%) or those with a positive tuberculin skin test and no respiratory symptoms (8.16%) (overall P value = 0.0063). They also had higher rates of spirometry abnormalities suggestive of an LAO defect. Children with chest radiographic findings suggestive of LAO disease were found to be younger than those with normal chest radiographic findings (5.0 ± 2.7 years vs 8.6 ± 4.7 years; P < 0.0001).

CONCLUSION

This study suggests that chest radiographic findings indicative of an LAO in correlation with the clinical presentation can support the diagnostic suspicion of asthma, especially in younger children unable to perform spirometry.

Profiling of volatile organic compounds in exhaled breath as a strategy to find early predictive signatures of asthma in children

Wheezing is one of the most common respiratory symptoms in preschool children under six years old. Currently, no tests are available that predict at early stage who will develop asthma and who will be a transient wheezer. Diagnostic tests of asthma are reliable in adults but the same tests are difficult to use in children, because they are invasive and require active cooperation of the patient. A non-invasive alternative is needed for children. Volatile Organic Compounds (VOCs) excreted in breath could yield such non-invasive and patient-friendly diagnostic. The aim of this study was to identify VOCs in the breath of preschool children (inclusion at age 2-4 years) that indicate preclinical asthma. For that purpose we analyzed the total array of exhaled VOCs with Gas Chromatography time of flight Mass Spectrometry of 252 children between 2 and 6 years of age. Breath samples were collected at multiple time points of each child. Each breath-o-gram contained between 300 and 500 VOCs; in total 3256 different compounds were identified across all samples. Using two multivariate methods, Random Forests and dissimilarity Partial Least Squares Discriminant Analysis, we were able to select a set of 17 VOCs which discriminated preschool asthmatic children from transient wheezing children. The correct prediction rate was equal to 80% in an independent test set. These VOCs are related to oxidative stress caused by inflammation in the lungs and consequently lipid peroxidation. In conclusion, we showed that VOCs in the exhaled breath predict the subsequent development of asthma which might guide early treatment.

Pulmonary function testing in children and infants

Pulmonary function testing is performed in children and infants with the aim of documenting lung development with age and making diagnoses of lung diseases. In children and infants with an established lung disease, pulmonary function is tested to assess the disease progression and the efficacy of therapy. It is difficult to carry out the measurements in this age group without disturbances, so obtaining results of good quality and reproducibility is challenging. Young children are often uncooperative during the examinations. This is partly related to their young age but also due to the long testing duration and the unpopular equipment. We address a variety of examination techniques for lung function assessment in children and infants in this review. We describe the measuring principles, examination procedures, clinical findings and their interpretation, as well as advantages and limitations of these methods. The comparability between devices and centres as well as the availability of reference values are still considered a challenge in many of these techniques. In recent years, new technologies have emerged allowing the assessment of lung function not only on the global level but also on the regional level. This opens new possibilities for detecting regional lung function heterogeneity that might lead to a better understanding of respiratory pathophysiology in children.

Reference values for spirometry in preschool children

OBJECTIVES

Reference values for lung function tests differ in samples from different countries, including values for preschoolers. The main objective of this study was to derive reference values in this population.

METHODS

A prospective study was conducted through a questionnaire applied to 425 preschool children aged 3 to 6 years, from schools and day-care centers in a metropolitan city in Brazil. Children were selected by simple random sampling from the aforementioned schools. Peak expiratory flow (PEF), forced vital capacity (FVC), forced expiratory volumes (FEV1, FEV0.50), forced expiratory flow (FEF25-75) and FEV1/FVC, FEV0.5/FVC and FEF25-75/FVC ratios were evaluated.

RESULTS

Of the 425 children enrolled, 321 (75.6%) underwent the tests. Of these, 135 (42.0%) showed acceptable results with full expiratory curves and thus were included in the regression analysis to define the reference values. Height and gender significantly influenced FVC values through linear and logarithmic regression analysis. In males, R(2) increased with the logarithmic model for FVC and FEV1, but the linear model was retained for its simplicity. The lower limits were calculated by measuring the fifth percentile residues.

CONCLUSION

Full expiratory curves are more difficult to obtain in preschoolers. In addition to height, gender also influences the measures of FVC and FEV1. Reference values were defined for spirometry in preschool children in this population, which are applicable to similar populations.

Spirometry. Spanish Society of Pulmonology and Thoracic Surgery (SEPAR)

Spirometry is the main pulmonary function test and is essential for the evaluation and monitoring of respiratory diseases. Its utility transcends the field of Respiratory Medicine, is becoming increasingly important in primary care and applications have even been described outside the field of respiratory diseases. This document is therefore intended to serve as support for all health professionals who use spirometry, providing recommendations based on the best scientific evidence available. An update of the indications and contraindications of the test is proposed. The document sets out recommendations on the requirements necessary for conventional spirometers and portable office equipment, as well as on spirometer hygiene and quality control measures. Spirometric parameters that must be considered, performance of manoeuvres, criteria for acceptability and repeatability of measurements and their quality control are defined. A proposal is also established for presentation of the results and an evaluation and interpretation is proposed according to information generated in recent years. Finally, lines of adaptation and integration of spirometry in the field of new technologies are considered.

Forced oscillation technique and childhood asthma

Most infants and preschool children are not able to voluntarily perform the physiological maneuvers required to complete the pulmonary function tests that are used in adults and older children. Recently, commercial devices using forced oscillation technique (FOT) suitable for young children have become available. In devices with FOT, an oscillation pressure wave is generated by a loud speaker, is applied to the respiratory system, usually at the mouth, and the resulting pressure-flow relationship is analyzed in terms of impedance (Zrs). Zrs encompasses both resistance (Rrs) and reactance (Xrs). Rrs is calculated from pressure and flow signals, and is a measure of central and peripheral airway caliber. Xrs is derived from the pressure in the phase with volume and is related to compliance (Crs) and inertance (Irs). These parameters individually indicate the condition of the small and large airways in each patient and indirectly suggest the presence of airway inflammation. It is agreed that the clinical diagnostic capacity of FOT is comparable to that of spirometry. One of the advantages of FOT is that minimal cooperation of the patient is needed and no respiratory maneuvers are required. The use of FOT should be considered in patients in whom spirometry or other pulmonary function tests cannot be performed or in cases where the results of other tests appear to be unreliable. In addition, this approach is effective in assessing bronchial hyperresponsiveness. Considering these qualities, FOT is a useful method to study pulmonary function in preschool children with asthma.

Early termination of exhalation: effect on spirometric parameters in healthy preschool children

OBJECTIVE

To evaluate the acceptability and reproducibility of spirometry in preschool children; to estimate the effect size of early termination of exhalation (ETE) on FVC, FEV(1) and FEV(0.5); and to evaluate the validity of FEV(0.5) in curves with ETE.

METHODS

Spirometric data were obtained from 240 healthy preschool children, who were selected by simple sampling. On the basis of the best curve from each child according to the end of exhalation, three groups were formed: no ETE (nETE); ETE and flow ≤ 10% of the highest PEF (ETE≤10); and ETE and flow > 10% of the highest PEF value (ETE>10). The reproducibility of FVC, FEV(1) and FEV(0.5) was compared among the three groups. The effect of ETE on FVC, FEV(1), and FEV(0.5) was assessed.

RESULTS

Of the 240 children tested, 112 (46.5%)-82 (34.0%) of those in the nETE group and 30 (12.5%) of those in the ETE≤10 group--had acceptable curves for all the parameters. In 64 (27.0%) of those in the ETE>10 group, the curves were acceptable only for FEV(0.5), increasing the proportion of children with valid FEV(0.5) to 73.0%. There were no significant differences between the nETE and ETE≤10 groups in terms of the mean values of the parameters assessed.

CONCLUSIONS

Maneuvers with ETE and flow ≤ 10% of the highest PEF are valid. In individuals with a flow > 10% of the highest PEF value, these maneuvers are only valid for FEV(0.5).

Impulse oscillometry in the evaluation of diseases of the airways in children

OBJECTIVE

To provide an overview of impulse oscillometry and its application to the evaluation of children with diseases of the airways.

DATA SOURCES

Medline and PubMed search, limited to English language and human disease, with keywords forced oscillation, impulse oscillometry, and asthma.

STUDY SELECTIONS

The opinions of the authors were used to select studies for inclusion in this review.

RESULTS

Impulse oscillometry is a noninvasive and rapid technique requiring only passive cooperation by the patient. Pressure oscillations are applied at the mouth to measure pulmonary resistance and reactance. It is employed by health care professionals to help diagnose pediatric pulmonary diseases such asthma and cystic fibrosis; assess therapeutic responses; and measure airway resistance during provocation testing.

CONCLUSIONS

Impulse oscillometry provides a rapid, noninvasive measure of airway impedance. It may be easily employed in the diagnosis and management of diseases of the airways in children.

Viabilidade da realização de espirometria em pré-escolares

OBJETIVO: Determinar a taxa de sucesso na obtenção de resultados adequados de espirometria em pacientes pré-escolares. MÉTODOS: Foram analisados os resultados de espirometrias de crianças menores que 6 anos. Todos os testes foram realizados no Laboratório de Função Pulmonar do Hospital Infantil Jeser Amarante Faria, em Joinville (SC) entre junho de 2009 e fevereiro de 2010. O programa utilizado continha um incentivo de animação (bolhas de sabão).Os procedimentos foram realizados por um pneumologista infantil e obedeceram aos critérios de reprodutibilidade e aceitabilidade preconizados pela American Thoracic Society. Buscou-se atingir um tempo expiratório de pelo menos 1 s. Os seguintes parâmetros foram registrados: CVF, VEF0,5, VEF1 e relação VEF1/CVF. RESULTADOS: Nossa amostra consistiu de 74 crianças. A taxa de sucesso foi de 82%, com melhora no desempenho do teste em idades mais avançadas, mas sem significado estatístico (p > 0,05). Em média, foram necessárias 6,6 tentativas durante o exame para a obtenção de curvas aceitáveis e reprodutíveis. Todos os 61 testes bem sucedidos tiveram resultados de VEF0,5 e VEF1 satisfatórios. Através de escore Z, constatou-se que 21,6 % das crianças apresentavam com padrão obstrutivo. CONCLUSÕES: A taxa de sucesso da espirometria foi alta em nossa amostra, mostrando que esse é um método válido de avaliação da função pulmonar em pré-escolares. O uso de métodos de incentivo e a realização do teste por profissionais treinados no trabalho com crianças podem estar associados à elevada taxa de sucesso em nossa amostra

Reference values for respiratory system impedance using impulse oscillometry in healthy preschool children

PURPOSE

The normal values for lung resistance and lung capacity of children, as determined by impulse oscillometry (IOS), are different for children of different ethnicities. However, reference values there is no available reference value for Korean preschool children have yet to be determined. The aim of the present study was to determine the normal ranges of IOS parameters in Korean preschool children.

METHODS

A total of 133 healthy Korean preschool children were selected from 639 children (aged 3 to 6 years) who attended kindergarten in Seongnam, Gyeonggi province, Korea. Healthy children were defined according to the European Respiratory Society (ERS) criteria. All subjects underwent lung function tests using IOS. The relationships between IOS value (respiratory resistance (Rrs) and reactance (Xrs) at 5 and 10 Hz and resonance frequency (RF)) and age, height, and weight were analyzed by simple linear and multiple linear regression analyses.

RESULTS

The IOS success rate was 89.5%, yielding data on 119 children. Linear regression identified height as the best predictor of Rrs and Xrs. Using stepwise multiple linear regressions based on age, height, and weight, we determined regression equations and coefficients of determination (R(2)) for boys (Rrs(5)=1.934-0.009×Height, R(2)=12.1%; Xrs(5)=0.774+0.006×Height-0.002×Age, R(2)=20.2% and for girls (Rrs(5)=2.201-0.012×Height, R(2)=18.2%; Xrs(5)=-0.674+0.004×Height, R(2)=10.5%).

CONCLUSION

This study provides reference values for IOS measurements of normal Korean preschool children. These provide a basis for the diagnosis and monitoring of preschool children with a variety of respiratory diseases.

Clinically useful spirometry in preschool-aged children: evaluation of the 2007 American Thoracic Society Guidelines

RATIONALE

In 2007 the American Thoracic Society (ATS) recommended guidelines for acceptability and repeatability for assessing spirometry in preschool children. The authors aim to determine the feasibility of spirometry among children in this age group performing spirometry for the first time in a busy clinical practice.

METHODS

First-time spirometry for children age 4 to 5 years old was selected from the Children's Hospital Boston Pulmonary Function Test (PFT) database. Maneuvers were deemed acceptable if ( 1 ) the flow-volume loop showed rapid rise and smooth descent; ( 2 ) the back extrapolated volume (V(be)), the volume leaked by a subject prior to the forced maneuver, was ≤ 80 ml and 12.5% of forced vital capacity (FVC); and ( 3 ) cessation of expiratory flow was at a point ≤ 10% of peak expiratory flow rate (PEFR). Repeatability was determined by another acceptable maneuver with forced expiratory volume in t seconds (FEV(t)) and FVC within 10% or 0.1 L of the best acceptable maneuver. Post hoc analysis compared spirometry values for those with asthma and cystic fibrosis to normative values.

RESULTS

Two hundred and forty-eight preschool children performed spirometry for the first time between August 26, 2006, and August 25, 2008. At least one technically acceptable maneuver was found in 82.3% (n = 204) of the tests performed. Overall, 54% of children were able to perform acceptable and repeatable spirometry based on the ATS criteria. Children with asthma or cystic fibrosis did not have spirometry values that differed significantly from healthy controls. However, up to 29% of the overall cohort displayed at least one abnormal spirometry value.

CONCLUSIONS

Many preschool-aged children are able to perform technically acceptable and repeatable spirometry under normal conditions in a busy clinical setting. Spirometry may be a useful screen for abnormal lung function in this age group.

Lung function testing in preschool-aged children with cystic fibrosis in the clinical setting

In cystic fibrosis (CF) lung function testing is a means of monitoring progression of lung disease. The preschool years have often been referred to as the "silent years" due to the previous lack suitable measures of lung function testing in this age group. This review outlines the various techniques of lung function testing in preschool children with CF in the clinical setting. This includes measures requiring tidal breathing including the forced oscillation technique, the interrupter technique, plethysmography, and multiple breath washout, as well as spirometry that requires respiratory maneuvers. We describe the feasibility and variability of different lung function methods used in preschoolers and report measurements made during tidal breathing have greater feasibility, although greater variability compared to spirometry. We also report associations with lung function and markers of CF lung disease. In the preschool age group measurements made during tidal breathing may be more appropriate in the clinic setting than those that require a higher degree of cooperation and specific respiratory maneuvers.maneuvers.

Spirometric pulmonary function parameters of healthy Chinese children aged 3-6 years in Taiwan

Spirometry is a well-known technique for evaluating pulmonary function, but few studies have focused on preschool children. The aim of this study was to determine reference values of forced spirometric parameters in young Chinese children, aged 3-6 years, in Taiwan. Spirometric measurements were performed at day care centers by experienced pediatricians. Of 248 children without a history of chronic respiratory illness, at least two valid spirometric attempts were obtained from 214 children (109 boys and 105 girls; age: 36-83 [mean = 61] months; height: 90-131 [mean = 111] cm). Values of forced expiratory volume in 1 sec (FEV1) and 0.5 sec (FEV(0.5)), forced vital capacity (FVC), peak expiratory flow rate (PEF), forced expiratory between 25% and 75% FVC (FEF(25-75)), and forced expiratory flow rate at 25%, 50%, and 75% of FVC (FEF(25), FEF(50), and FEF(75)) were derived and analyzed. There were significant positive correlations between study parameters and body height, body weight, and age. Height was the most consistently correlated measurement in both boys and girls. Although boys tended to have higher spirometric values than girls, we found significant differences only in FVC and FEV1 between boys and girls aged 6 years. The regression equations of each parameter were obtained. In conclusion, spirometric pulmonary function tests are feasible in 3- to 6-year-old children. The obtained values and regression equations provide a reference for Chinese preschool children and may be of value in evaluating pulmonary function of children with respiratory problems in this age group.

Spirometry in 5-year-olds--validation of current guidelines and the relation with asthma

INTRODUCTION

Spirometry is more frequently measured in younger children. Our primary aim was to validate 2005 ATS-ERS Task Force standards for spirometry in adults and older children among a population of 5-year-old children. Our secondary aim was to relate spirometry to asthma symptoms.

METHODS

Children were participants in a longitudinal cohort study where asthma symptoms and spirometry were assessed.

RESULTS

Of the 827 children assessed, spirometry was obtained in 638 (85 with wheeze). A back-extrapolated volume/FVC ratio of <5% was achieved in 99% of children, the best two FVC were < or =150 ml of each other in 89% and three efforts were obtained within six attempts in 88%. The best two FVC were within 10% of each other in 82% of children. Only 13% achieved a forced expiratory time (FET) of > or =3 sec, whereas 80% had an FET of > or =1 sec. All criteria (including FET > or =1 s and FVC < or =10%) were met in 400 (65%) of the 638 children. Most spirometric indices were reduced in association with current wheeze and a history of asthma; children with current wheeze had a mean reduction of 0.65 FEV(1) z score compared to healthy children, P < 0.001. An FEV(1) z score of -1.0 had 82% sensitivity but only 50% specificity for current wheeze, the corresponding numbers for an FEF(50) z score of -1.0 being 79% and 71%.

CONCLUSIONS

The standards for spirometry are mostly achieved in this age group but are not necessarily valid and require revision. Reliable spirometry is feasible in 5-year-old children where reduced measurements are associated with asthma symptoms and in whom FEF(50) appears to be the most discriminatory variable.

Endpoints for clinical trials in young children with cystic fibrosis

The availability of sensitive, reproducible, and feasible outcome measures for quantifying lung disease in children with cystic fibrosis (CF) younger than 6 years is critical to the conduct of clinical trials in this important population. Historically, identifying and quantifying the presence of lung disease in very young children with CF was hampered by a lack of reproducible measures of lung function or lung pathology. Over the past 10 years, significant progress has led to physiologic, anatomic, and bronchoscopic measures that may serve as endpoints for future intervention trials. These endpoints include infant and preschool lung function testing, computed tomography of the chest, and bronchoalveolar lavage markers of inflammation and infection. Much progress has occurred in standardizing lung function testing, which is essential for multicenter collaboration. Pulmonary exacerbation has the potential to serve as a clinical endpoint; however, there is currently no standardized definition in children with CF younger than 6 years. Further development of these outcomes measures will enable clinical trials in the youngest CF population with the objective of improving long-term prognosis.

Spirometric pulmonary function in 3- to 5-year-old children

Forced expiratory maneuvers are routinely used in children, 6 years of age and older for the diagnosis and follow-up of respiratory diseases. Our objective was to establish normative data for an extensive number of parameters measured during forced spirometry in healthy 3- to 5-year-old children. Children aged between 3 and 5 years were tested in 11 daycare centers. Usual parameters, including FEV1, FVC, PEF, FEF(25-75), FEF25, FEF50, FEF75, and Aex were measured and analyzed in relation to sex, age, height, and weight. In addition, the same analysis was performed for FEV0.5 and FEV0.75. One hundred sixty-four children were recruited for testing including 87 girls and 77 boys. Thirty-five were 3 years old, 63 were 4 years old, and 66 were 5 years old. Overall, 143 children (87%) accepted to perform the test and 128 children (78%) were able to perform at least two technically acceptable expiratory maneuvers. Analyses using different regression models showed that height was the best predictor for every parameter. In conclusion, the present study confirms that most healthy 3-5 years old children can perform valid forced expiratory maneuvers. In agreement with other studies, we found that height is the most important single predictor of various parameters measured on forced spirometry. The present study is the first to establish normative values for FEV0.75, as well as to demonstrate that Aex can be easily performed in the majority of children aged 3-5 years. These are likely important parameters of lung function in this age range.

Reference values of Forced Expiratory Volumes and pulmonary flows in 3-6 year children: a cross-sectional study

BACKGROUND

The aims of this study were to verify the feasibility of respiratory function tests and to assess their validity in the diagnosis of respiratory disorders in young children.

METHODS

We performed spirometry and collected information on health and parents' lifestyle on a sample of 960 children aged 3-6.

RESULTS

The cooperation rate was 95.3%. Among the valid tests, 3 or more acceptable curves were present in 93% of cases. The variability was 5% within subjects in 90.8% of cases in all the parameters. We propose regression equations for FVC (Forced Vital Capacity), FEV1, FEV0.5, FEV0.75 (Forced Expiratory Volume in one second, in half a second and in 3/4 of a second), and for Maximum Expiratory Flows at different lung volume levels (MEF75, 50, 25). All parameters are consistent with the main reference values reported in literature. The discriminating ability of respiratory parameters versus symptoms always shows a high specificity (>95%) and a low sensitivity (<20%) with the highest OR (10.55; CI 95% 4.42-25.19) for MEF75. The ability of FEV0.75 to predict FEV1 was higher than that of FEV0.50: FEV0.75 predicts FEV1 with a determination coefficient of 0.95.

CONCLUSION

Our study confirms the feasibility of spirometry in young children; however some of the current standards are not well suited to this age group. Moreover, in this restricted age group the various reference values have similar behaviour.

Spirometry

Recent data indicate that clinicians and researchers should dismiss the myth that preschoolers are unable to perform spirometry. Reproducible, acceptable flow-volume curves are possible in this age group; however, modifications to the ATS/ERS adult criteria are critical due to physiologic differences. Reference data is available and the clinical applicability of this technique is being evaluated.

Spirometry in 3-5-year-old children with asthma

Spirometry with incentive games was applied to 207 2-5-year-old preschool children (PSC) with asthma in order to refine the quality-control criteria proposed by Aurora et al. (Am J Respir Crit Care Med 2004;169:1152-159). The data set in our study was much larger compared to that in Aurora et al. (Am J Respir Crit Care Med 2004;169:1152-159), where 42 children with cystic fibrosis and 37 healthy control were studied. At least two acceptable maneuvers were obtained in 178 (86%) children. Data were focused on 3-5-year-old children (n = 171). The proportion of children achieving a larger number of thresholds for each quality-control criterion (backward-extrapolated volume (Vbe), Vbe in percent of forced vital capacity (FVC, Vbe/FVC), time-to-peak expiratory flow (time-to-PEF), and difference (Delta) between the two FVCs (DeltaFVC), forced expiratory volume in 1 sec (DeltaFEV(1)), and forced expiratory volume in 0.5 sec (DeltaFEV(0.5)) from the two "best" curves) was calculated, and cumulative plots were obtained. The optimal threshold was determined for all ages by derivative function of rate of success-threshold curves, close to the inflexion point. The following thresholds were defined for acceptability: Vbe <or=75 ml and <or=10% of FVC, time-to-PEF <120 msec, and repeatability: DeltaFEV(1) and DeltaFEV(0.5) <or=110 ml and <or=10% of best effort, and DeltaFVC <or=100 ml and <or=12.5%. These were obtained in 85%, 93%, 94%, 90%, and 89% of children, respectively. For practical reasons, we suggest choosing the same threshold for all repeatability criteria, i.e., DeltaFVC, DeltaFEV(1), and DeltaFEV(0.5) <or=110 ml and <or=10%. In conclusion, a majority of PSC with asthma can perform at least two acceptable maneuvers. Acceptability and repeatability criteria defined in a larger data set can be applied to preschool children. Spirometry could therefore be used to assess respiratory function in preschool children with asthma.

Asthma therapy for children under 5 years of age

PURPOSE OF REVIEW

The evidence for effectiveness of currently used asthma medication for wheeze in young children is reviewed.

RECENT FINDINGS

The management of the infant and preschool child with wheezing is complicated by the uncertainty with respect to the aetiology. Difficulties in defining phenotypes and objective outcome parameters combined with the transient nature of symptoms which often resolve spontaneously have confounded many therapeutic studies. Recent studies on the effect of pharmacotherapy in wheezing infants have tried to define a more homogeneous phenotype as well as make a selection of patients that are likely to respond to the studied drug. In addition, these studies have used lung function parameters and nitric oxide as one of the outcome measurements. Studies on the nature of inflammation and the development of airway remodelling in infants and young children are done to further define phenotypes.

SUMMARY

Currently, there are no evidence-based guidelines and not even consensus statements on the right approach in pharmacological treatment of wheezing in infants and preschool children. The main issue still is the difficulty in coming to a correct diagnosis. Further studies are needed on the nature and the diagnostics of phenotypes and on the effect of early intervention.

Spirometry in the diagnosis of asthma in children

PURPOSE OF REVIEW

To review the diagnostic accuracy of lung function measurements made using spirometry for childhood asthma, recent guidelines for the measurement and interpretation of spirometric lung function tests and recent developments for diagnosing asthma.

RECENT FINDINGS

Measurements of lung function and bronchial lability made using spirometry may not perform any better than other tests such as skin prick testing, or measurements of exhaled nitric oxide for diagnosing asthma. New guidelines are available.

SUMMARY

Spirometry is a simple, robust and widely available tool for investigating lung function. There are published guidelines for making measurements and their interpretation. The place of spirometry in the diagnosis of asthma, however, needs clarification. The diagnostic profiles of measurements of bronchodilator responsiveness and bronchial hyperreactivity made using spirometry, although reasonable, are not perfect. In schoolchildren, they are no better than knowledge of aeroallergen sensitization when considering a diagnosis of asthma.

Assessing respiratory function in young children: Developmental considerations

The purpose of this review is to provide practitioners and clinical investigators with an update on methods of assessing respiratory function in young children. The importance of this topic is presented in light of the natural history of asthma, as well as maturational changes that occur early in life in terms of airway development. Models of disease are cited to support the concept that injury of the mammalian airway early in postnatal life might have far-reaching consequences in terms of control of airway caliber and responsiveness. The methods currently available to measure respiratory function in our younger patients are outlined. The ability of children to perform the maneuvers necessary for this testing is considered as a function of age. Areas in which research and development are needed are highlighted.

The effect of montelukast on exhaled nitric oxide and lung function in asthmatic children 2 to 5 years old

OBJECTIVE

The study was undertaken to investigate the influence of once-daily treatment with montelukast (Singulair; MSD; Glattbrugg, Switzerland) on levels of exhaled nitric oxide (eNO) and lung function in preschool children with asthma.

METHODS

A total of 30 children (19 girls), 2 to 5 years of age, in whom asthma had been newly diagnosed, who had a positive first-degree family history of asthma and a positive allergy test result, were allocated to undergo a 1-week run-in period of montelukast treatment. eNO and airway resistance were measured in all patients before (visit 1) and after the run-in period (visit 2), and after treatment with montelukast (4 mg once daily) for 4 weeks (visit 3).

RESULTS

There were no significant differences in all parameters before and after the run-in period. However, the mean (SD) levels of eNO and the mean (SD) levels of airway resistance after treatment at visit 3 were 11.6 parts per billion (ppb) [9.5 ppb] and 1.15 kPa/L/s (0.26 kPa/L/s), respectively, and were significantly lower compared to values of 33.1 ppb (12.0 ppb) and 1.28 kPa/L/s (0.23 kPa/L/s), respectively, before treatment (p < 0.001) and at visit 2 (p = 0.01). There was no significant change in mean bronchodilator responsiveness between visit 3 (13.2%; SD, 6.8%) and visit 1/visit 2 (13.3%; SD, 7.0%; p = 0.47).

CONCLUSION

We have shown that montelukast has a positive effect on lung function and airway inflammation as measured by nitric oxide level in preschool children with allergic asthma.

Quality control for spirometry in preschool children with and without lung disease

The reliability of spirometry is dependent on strict quality control. We examined whether quality control criteria recommended for adults could be applied to children aged 2-5 years. Forty-two children with cystic fibrosis and 37 healthy children attempted spirometry during their first visit to our laboratory. Whereas 59 children (75%) were able to produce a technically satisfactory forced expiration lasting 0.5 second, only 46 (58%) could produce an expiration lasting 1 second, with the youngest children having the most difficulty. Start of test criteria for adults were inappropriate for this age group, with only 16 of 59 children producing a volume of back extrapolation as a proportion of forced vital capacity of less than 5%, whereas all but 4 could produce a volume of back extrapolation of 80 ml or less. More than 90% of children were able to produce a second forced vital capacity and a second forced expired volume in 0.75 second within 10% of their highest. Errors in the spirometry software resulted in inaccurate reporting of expiratory duration and inappropriate timed expired volumes in some children. We describe recommendations for modified start of test and repeatability criteria for this age group, and for improvements in software to facilitate better quality control.

Measurements of airway mechanics in spontaneously breathing young children

This paper gives an overview of the general principles of airway mechanics and methods to measure lung function in non-sedated, spontaneously breathing young children. Although lower airway obstruction is probably best evaluated using FEV(1), other techniques can be applied when such measurement is impossible, as in young children. These techniques include measurement of resistance using the interrupter or impulse oscillation techniques.

Interrupter resistance and wheezing phenotypes at 4 years of age

It is difficult to distinguish young children with respiratory symptoms who will develop asthma from those with transient symptoms only. Measurement of interrupter resistance may help to identify children at high risk of asthma. The aim of this study is to compare interrupter resistance in 4-year-old children with different wheezing phenotypes. All children participated in the Prevention and Incidence of Asthma and Mite Allergy cohort, a prospective birth cohort of more than 4,000 children. At 4 years of age, data on interrupter resistance plus wheezing phenotype were available for 838 children. Mean interrupter resistance values (95% confidence interval) were 0.95 (0.93, 0.97), 0.95 (0.92, 0.98), 0.96 (0.87, 1.05), and 1.08 (1.02, 1.14) kPa.L(-1).second for never (n = 482), early transient (n = 236), late-onset (n = 22), and persistent (n = 98) wheezing phenotypes, respectively. Additional analyses were performed for children with atopic and nonatopic mothers separately. Both in children with atopic and nonatopic mothers, children with persistent wheeze had significantly higher interrupter resistance values than children with never and early wheeze. In conclusion, mean interrupter resistance values were higher in children with persistent wheeze as compared with children with never and early transient wheezing phenotypes.

Respiratory Inductance Plethysmography in Healthy 3- to 5-Year-Old Children *

STUDY OBJECTIVES

Because of the challenges of using standard measurements such as spirometry to measure respiratory function in 3- to 5-year-old children, there may be a role for respiratory inductive plethysmography (RIP), which is noninvasive and requires minimal subject cooperation. In this study, we described normative values of thoracoabdominal motion and timing mechanics in 3- to 5-year-old children, and hypothesized positional dependence of these measurements in this age group.

DESIGN

We measured relative thoracoabdominal motion during tidal breathing using the phase angle (Phi), the labored breathing index, and the phase relation during the total breath and timing mechanics with the ratio of time to peak tidal expiratory flow to expiratory time (TPTEF/TE).

SETTING

Preschools within the greater Philadelphia area and the Pulmonary Office of The Children's Hospital of Philadelphia.

PATIENTS OR PARTICIPANTS

Fifty healthy children between 3 years and 5 years of age.

INTERVENTIONS

RIP.

MEASUREMENTS AND RESULTS

All measures varied with position. Thoracoabdominal motion was nearly synchronous in the sitting position and most asynchronous in the supine position (Phi, 15.7 +/- 4.0 degrees vs 56.1 +/- 4.3 degrees, respectively; p < 0.001). This also led to an increase in the TPTEF/TE from the sitting to the supine positions (30.3 +/- 1.4% vs 37.0 +/- 1.6%, respectively; p < 0.001). Measurements of thoracoabdominal motion and timing mechanics did not change with age, weight, height, or gender.

CONCLUSIONS

We conclude that the positional dependence of these measurements is due to the alteration in respiratory mechanics between the sitting, standing, and supine positions. We further conclude that if RIP is to be a useful longitudinal measure of respiratory function in this age range, comparison measurements should be made in the same position.

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

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.

Feasibility of measuring lung function in preschool children

BACKGROUND

There have been difficulties in applying spirometric tests to children of preschool age.

METHODS

The feasibility of measuring lung function was examined in 652 children aged 3-6 years using dynamic spirometry with an animation programme and the guidelines approved by the European Respiratory Society.

RESULTS

Data from 603 (92%) children with at least two acceptable forced expiratory manoeuvres were analysed; 408 (68%) achieved at least three acceptable manoeuvres. Children with only two acceptable manoeuvres were younger, shorter, and weighed less (p<0.001). The lower levels of lung function in this group were partly explained by body size. 63% of those with three acceptable manoeuvres had a difference of </=5% between the highest and second highest forced expiratory volume in 1 second (FEV(1)); when a difference of </=10% was applied, 91% of the children were included. A similar trend was seen for forced vital capacity (FVC). The acceptability and reproducibility increased with increasing age, and levels of lung function increased linearly with age. The linear regression model showed that standing height was a satisfactory predictor of lung function; the explained fraction of variance (R(2)) was 59% for FEV(1). Most FVC manoeuvres in children older than 3 years were acceptable and reproducible.

CONCLUSIONS

Spirometric testing is feasible in preschool children and may be useful for both clinical practice and research. This study may fill the deficiency in reference values for European preschool children.

[Evaluation of systematic pulmonary function testing for asthma in children aged three to five years]

Pulmonary function testing is not usually done in the preschool child, despite the recent data showing early deterioration in airway function in asthma.

METHODS

We evaluated feasibility and clinical interest of flow-volume loop by forced expiratory maneuver and measure of airway resistance by interrupter technique (interrupter resistance), before and after inhalation of salbutamol, in 75 children aged three to five years seen in the ambulatory setting for asthma.

RESULTS

Feasibility rate (92%) and reproducibility rate (91%) of those techniques were good, so that 84% of the cases could be exploited (63 children of 75). We found few significant associations between clinical parameters and flow-volume loop. We found a significant association between elevated interrupter resistance at basis and night-symptoms (P = 0.03), between diminished interrupter resistance after salbutamol and exercise-symptoms (P = 0.03), symptoms in the ambulatory setting (P = 0.02) and absence of inhaled corticosteroid treatment (P = 0.046). Pulmonary function testing resulted in treatment modification in 14% of cases.

CONCLUSION

Our study shows that flow-volume loop and measure of airway resistance by interrupter technique can be done with a good reproducibility in the preschool child. Interrupter resistance appears to be better correlated than flow-volume loop with usually evaluated clinical parameters.

An interactive computer-animated system (SpiroGame) facilitates spirometry in preschool children

Although airway disease in preschool children is common, standard spirometry is limited by the level of cooperation. We evaluated a computer-animated system (SpiroGame) aimed at improving children's performance in spirometry. SpiroGame includes a commercial pneumotachograph (ZAN100; ZAN Messgeraete GmbH, Oberthulba, Germany) and games teaching tidal breathing and all steps of an FVC maneuver. SpiroGame was compared with commercial flow-targeted candle-blowing software (MasterLab, Jaeger, Germany), and with extrapolated predicted values. Of 112 children aged 3 to 6 yr, 10 refused spirometry and 102 proceeded to FVC games and were randomized to initially perform either SpiroGame or candle-blowing. Training lasted 5 to 10 min for SpiroGame and 3 to 7 min for candle-blowing. Acceptable spirometry was performed by 69 of 102 children with SpiroGame and 48 of 102 with candle-blowing (p = 0.005). Order did not affect success. Acceptable FEV(1) maneuvers were achieved by 55 children with SpiroGame and two children with candle-blowing. The intrasubject coefficient of variation was 4.0% for FVC and 3.3% for FEV(1) with SpiroGame. A premature expiratory break occurred in 41 subjects with candle-blowing and in six with SpiroGame. FEV(0.5) could be measured with both systems. FVC and maximal midexpiratory flow at 50% of FVC (MMEF(50)) values were similar, whereas peak expiratory flow was higher with candle-blowing. In 39 healthy children, most parameters with SpiroGame were similar to extrapolated normal values. We conclude that an interactive computer-animated system facilitates successful spirometry in preschool children.