Acceptability and repeatability of spirometry in children using updated ATS/ERS criteria

Domestic airborne black carbon and exhaled nitric oxide in children in NYC

Differential exposure to combustion by-products and allergens may partially explain the marked disparity in asthma prevalence (3-18%) among New York City neighborhoods. Subclinical changes in airway inflammation can be measured by fractional exhaled nitric oxide (FeNO). FeNO could be used to test independent effects of these environmental exposures on airway inflammation. Seven- and eight-year-old children from neighborhoods with lower (range 3-9%, n=119) and higher (range 11-18%, n=121) asthma prevalence participated in an asthma case-control study. During home visits, FeNO was measured, and samples of bed dust (allergens) and air (black carbon; BC) were collected. Neighborhood built-environment characteristics were assessed for the 500 m surrounding participants' homes. Airborne BC concentrations in homes correlated with neighborhood asthma prevalence (P<0.001) and neighborhood densities of truck routes (P<0.001) and buildings burning residual oil (P<0.001). FeNO concentrations were higher among asthmatics with than in those without frequent wheeze (≥4 times/year) (P=0.002). FeNO concentrations correlated with domestic BC among children without seroatopy (P=0.012) and with dust mite allergen among children with seroatopy (P=0.020). The association between airborne BC in homes and both neighborhood asthma prevalence and FeNO suggest that further public health interventions on truck emissions standards and residual oil use are warranted.

Asthma outcomes: pulmonary physiology

BACKGROUND

Outcomes of pulmonary physiology have a central place in asthma clinical research.

OBJECTIVE

At the request of National Institutes of Health (NIH) institutes and other federal agencies, an expert group was convened to provide recommendations on the use of pulmonary function measures as asthma outcomes that should be assessed in a standardized fashion in future asthma clinical trials and studies to allow for cross-study comparisons.

METHODS

Our subcommittee conducted a comprehensive search of PubMed to identify studies that focused on the validation of various airway response tests used in asthma clinical research. The subcommittee classified the instruments as core (to be required in future studies), supplemental (to be used according to study aims and in a standardized fashion), or emerging (requiring validation and standardization). This work was discussed at an NIH-organized workshop in March 2010 and finalized in September 2011.

RESULTS

A list of pulmonary physiology outcomes that applies to both adults and children older than 6 years was created. These outcomes were then categorized into core, supplemental, and emerging. Spirometric outcomes (FEV(1), forced vital capacity, and FEV(1)/forced vital capacity ratio) are proposed as core outcomes for study population characterization, for observational studies, and for prospective clinical trials. Bronchodilator reversibility and prebronchodilator and postbronchodilator FEV(1) also are core outcomes for study population characterization and observational studies.

CONCLUSIONS

The subcommittee considers pulmonary physiology outcomes of central importance in asthma and proposes spirometric outcomes as core outcomes for all future NIH-initiated asthma clinical research.

Respiratory outcomes and atopy in school-age children who were preterm at birth, with and without bronchopulmonary dysplasia

OBJECTIVE

To assess pulmonary function and the prevalence of atopy in school-age children who were very low birth weight as infants and to compare those who had bronchopulmonary dysplasia to those who did not.

METHOD

We studied 85 (39 male and 46 female) at a mean age of 84 (range, 62 to 107) months who were very low birth weight infants. Bronchopulmonary dysplasia was defined as oxygen dependency at 36 weeks gestational age. We excluded 8 patients (4 for cerebral palsy and 4 for no collaboration). Detailed perinatal and clinical data were collected. Lung function was evaluated using conventional spirometry. Atopy (assessed by the allergy skin-prick test) was considered when at least one positive skin test occurred in a panel of the most common environmental allergens in the local region. Comparisons between the bronchopulmonary dysplasia and no bronchopulmonary dysplasia groups were performed using the Mann-Whitney, x2 and Fisher's exact tests.

RESULTS

We compared the bronchopulmonary dysplasia (n = 13) and no bronchopulmonary dysplasia (n = 64) groups. Atopy was observed in 4 (30.8%) of the bronchopulmonary dysplasia patients and in 17 (26.6%) of the no bronchopulmonary dysplasia patients (p = 0.742). Two (15.4%) patients with bronchopulmonary dysplasia had a family history of atopy vs. 17 (26.6%) in the no bronchopulmonary dysplasia group (p = 0.5). Lung function tests showed airway obstruction in 2 (15.4%) of the bronchopulmonary dysplasia patients and in 10 (15.6%) of the no bronchopulmonary dysplasia patients (p = 1.0). Four (33.3%) of the bronchopulmonary dysplasia patients had small airway obstruction vs. 14 (22.2%) of the no bronchopulmonary dysplasia patients (p = 0.466).

CONCLUSION

Our data showed no significant differences in lung function between bronchopulmonary dysplasia and no bronchopulmonary dysplasia patients at school age and no evidence of an association between atopy and bronchopulmonary dysplasia.

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.