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Modifications improve an offline exhaled nitric oxide collection device for use with young children

2008; Elsevier BV; Volume: 122; Issue: 1 Linguagem: Inglês

10.1016/j.jaci.2008.03.030

1097-6825

Matthew S. Perzanowski, Maria José Rosa, Adnan Divjan, Alina Johnson, Judith S. Jacobson, Rachel L. Miller,

Chronic Obstructive Pulmonary Disease (COPD) Research

To the Editor:We recently read with great interest the article by Moeller et al1Moeller A. Diefenbacher C. Lehmann A. Rochat M. Brooks-Wildhaber J. Hall G. et al.Exhaled nitric oxide distinguishes between subgroups of preschool children with respiratory symptoms.J Allergy Clin Immunol. 2008; 121: 705-709Abstract Full Text Full Text PDF PubMed Scopus (89) Google Scholar and the editorial by Bacharier2Bacharier L.B. Does exhaled nitric oxide measurement help distinguish between wheezing phenotypes in preschool children?.J Allergy Clin Immunol. 2008; 121: 710-711Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar describing the usefulness of offline measurement of exhaled nitric oxide (NO) for distinguishing subgroups of children with respiratory symptoms. (Offline measurement denotes collection and storage of a breath sample in a reservoir in which NO is measured subsequently.) As the study showed, offline measurement of fractional concentrations of exhaled NO provides an objective measure of airway inflammation that can be collected in both clinical and nonclinical settings and is especially useful in epidemiologic studies.The American Thoracic Society/European Respiratory Society guidelines for offline measurement have been published.3ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005.Am J Respir Crit Care Med. 2005; 171: 912-930Crossref PubMed Scopus (2774) Google Scholar However, available pediatric offline collection devices lack 2 important features: (1) visual feedback/incentives appropriate for young children and (2) an indicator of proper inhalation of NO-free air. To address these problems, we developed 2 modifications for commercially available (no. CBSK 01400-01; GE Instruments, Boulder, Colo) and previously described3ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005.Am J Respir Crit Care Med. 2005; 171: 912-930Crossref PubMed Scopus (2774) Google Scholar offline collection devices.Fractional concentrations of exhaled NO are influenced by exhalation flow rate, and therefore standardized collection rates are recommended and important for reliable measurements.3ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005.Am J Respir Crit Care Med. 2005; 171: 912-930Crossref PubMed Scopus (2774) Google Scholar Offline devices commonly use a pressure gauge for determining flow. Subjects are asked to exhale at a constant pressure that corresponds to the recommended flow, but many young children find it difficult to follow those instructions. Our solution was to attach the picture of a small, well-known cartoon character to the pressure gauge dial. We partially covered the gauge faceplate with opaque tape so that the child could only see the character when exhaling at the correct speed (Figure 1). We instructed the children to blow out fast enough to keep the character in sight.A second major concern with offline sampling discussed in the American Thoracic Society/European Respiratory Society guidelines is sample contamination with ambient NO.3ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005.Am J Respir Crit Care Med. 2005; 171: 912-930Crossref PubMed Scopus (2774) Google Scholar Offline collection devices are fitted with NO scrubbers to provide NO-free inspired air. We found it difficult to train young children to inhale through the device and for technicians to verify proper oral (nonnasal) inhalation. To solve this problem, we inserted a toy noisemaker (Siren Whistle; Amscan, Elmsford, NY) between the 1-way valve and the NO scrubber (Figure 1). The noisemaker sounds only when the child inhales through the scrubber, and its pitch and volume rise with increasing flow, encouraging the child to inhale rapidly through the mouth. The noisemaker also informs the technician that proper inhalation has occurred, which is useful in offline collection from children or adults.By using a device with these modifications, the vast majority of 5-year-olds in our study comprehended the inhalation maneuver, achieved a test in the correct flow range, and perceived the test as fun. The modifications might still not make the device usable with children in the youngest age group studied by Moeller et al,1Moeller A. Diefenbacher C. Lehmann A. Rochat M. Brooks-Wildhaber J. Hall G. et al.Exhaled nitric oxide distinguishes between subgroups of preschool children with respiratory symptoms.J Allergy Clin Immunol. 2008; 121: 705-709Abstract Full Text Full Text PDF PubMed Scopus (89) Google Scholar but they have made NO measurement in our 4- to 5-year-old subjects much easier and more accurate. To the Editor: We recently read with great interest the article by Moeller et al1Moeller A. Diefenbacher C. Lehmann A. Rochat M. Brooks-Wildhaber J. Hall G. et al.Exhaled nitric oxide distinguishes between subgroups of preschool children with respiratory symptoms.J Allergy Clin Immunol. 2008; 121: 705-709Abstract Full Text Full Text PDF PubMed Scopus (89) Google Scholar and the editorial by Bacharier2Bacharier L.B. Does exhaled nitric oxide measurement help distinguish between wheezing phenotypes in preschool children?.J Allergy Clin Immunol. 2008; 121: 710-711Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar describing the usefulness of offline measurement of exhaled nitric oxide (NO) for distinguishing subgroups of children with respiratory symptoms. (Offline measurement denotes collection and storage of a breath sample in a reservoir in which NO is measured subsequently.) As the study showed, offline measurement of fractional concentrations of exhaled NO provides an objective measure of airway inflammation that can be collected in both clinical and nonclinical settings and is especially useful in epidemiologic studies. The American Thoracic Society/European Respiratory Society guidelines for offline measurement have been published.3ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005.Am J Respir Crit Care Med. 2005; 171: 912-930Crossref PubMed Scopus (2774) Google Scholar However, available pediatric offline collection devices lack 2 important features: (1) visual feedback/incentives appropriate for young children and (2) an indicator of proper inhalation of NO-free air. To address these problems, we developed 2 modifications for commercially available (no. CBSK 01400-01; GE Instruments, Boulder, Colo) and previously described3ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005.Am J Respir Crit Care Med. 2005; 171: 912-930Crossref PubMed Scopus (2774) Google Scholar offline collection devices. Fractional concentrations of exhaled NO are influenced by exhalation flow rate, and therefore standardized collection rates are recommended and important for reliable measurements.3ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005.Am J Respir Crit Care Med. 2005; 171: 912-930Crossref PubMed Scopus (2774) Google Scholar Offline devices commonly use a pressure gauge for determining flow. Subjects are asked to exhale at a constant pressure that corresponds to the recommended flow, but many young children find it difficult to follow those instructions. Our solution was to attach the picture of a small, well-known cartoon character to the pressure gauge dial. We partially covered the gauge faceplate with opaque tape so that the child could only see the character when exhaling at the correct speed (Figure 1). We instructed the children to blow out fast enough to keep the character in sight. A second major concern with offline sampling discussed in the American Thoracic Society/European Respiratory Society guidelines is sample contamination with ambient NO.3ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005.Am J Respir Crit Care Med. 2005; 171: 912-930Crossref PubMed Scopus (2774) Google Scholar Offline collection devices are fitted with NO scrubbers to provide NO-free inspired air. We found it difficult to train young children to inhale through the device and for technicians to verify proper oral (nonnasal) inhalation. To solve this problem, we inserted a toy noisemaker (Siren Whistle; Amscan, Elmsford, NY) between the 1-way valve and the NO scrubber (Figure 1). The noisemaker sounds only when the child inhales through the scrubber, and its pitch and volume rise with increasing flow, encouraging the child to inhale rapidly through the mouth. The noisemaker also informs the technician that proper inhalation has occurred, which is useful in offline collection from children or adults. By using a device with these modifications, the vast majority of 5-year-olds in our study comprehended the inhalation maneuver, achieved a test in the correct flow range, and perceived the test as fun. The modifications might still not make the device usable with children in the youngest age group studied by Moeller et al,1Moeller A. Diefenbacher C. Lehmann A. Rochat M. Brooks-Wildhaber J. Hall G. et al.Exhaled nitric oxide distinguishes between subgroups of preschool children with respiratory symptoms.J Allergy Clin Immunol. 2008; 121: 705-709Abstract Full Text Full Text PDF PubMed Scopus (89) Google Scholar but they have made NO measurement in our 4- to 5-year-old subjects much easier and more accurate.