The influence of dilution on the offline measurement of exhaled nitric oxide
| Autor: | Victoria MacBean, Anne Greenough, Dharmika Pooranampillai, Alan Lunt, Catherine Howard |
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| Rok vydání: | 2017 |
| Předmět: |
Adult
Male medicine.medical_specialty Physiology Dead space Biomedical Engineering Biophysics 030204 cardiovascular system & hematology Nitric Oxide 03 medical and health sciences Young Adult 0302 clinical medicine Physiology (medical) Internal medicine medicine Humans Asthma business.industry Airway inflammation Objective measurement Exhalation Gold standard (test) respiratory system medicine.disease respiratory tract diseases Dilution 030228 respiratory system Breath Tests Exhaled nitric oxide Cardiology Female business |
| Zdroj: | Physiological measurement. 39(2) |
| ISSN: | 1361-6579 |
| Popis: | OBJECTIVE Measurement of fractional exhaled nitric oxide (FeNO) is used to determine the presence and severity of eosinophilic airway inflammation in asthma and other wheezing illnesses. The gold standard of online measurement during a single prolonged exhalation is not suitable for use in young children. The international guidelines for offline measurements recommend collection of exhaled gas in an appropriate reservoir for later analysis in young children. The apparatus required for gas collection, however, creates dead space within the system, which may result in sample dilution and hence inaccuracy. Our objective was to investigate the effect such dilution might have on the accuracy of offline FeNO by comparing the results to online results. APPROACH Thirty-five adult subjects without respiratory disease underwent online measurement of FeNO and, thereafter, undertook offline FeNO measurements via exhalation into a collection reservoir using one, five or ten inhalation-exhalation cycles. Fifteen of the subjects also exhaled using the five-breath technique via apparatus with additional dead space. An equation incorporating dead space volume and the number of breaths was used to predict the degree of dilution; the predicted results were compared to the measured results. MAIN RESULTS The median (IQR) FeNO from a one-breath technique (22 (15-28) ppb was not significantly different to online values (19 (12-27) ppb, p = 1.00), but the results from the five-breath technique (11 (4-19) ppb, p |
| Databáze: | OpenAIRE |
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