The Effect of Spirometry on Bronchial and Alveolar Nitric Oxide in Subjects with Asthma

Abstract

Objective. The effect of spirometric maneuvers on exhaled nitric oxide (NO) at the constant flow rate of 50 ml/s (FE_NO) has been studied with equivocal results. Furthermore, the effects of spirometry on bronchial NO flux (J’aw_NO) and alveolar NO (CA_NO), two measurements increasingly being used in clinical and research protocols, are unknown. The aim of this study was to evaluate the effect of spirometry on FE_NO, J’aw_NO, and CA_NO in adults with asthma. Methods. Forty-four adults with asthma were studied. To assess the impact of exhaled NO measurement itself on exhaled NO values, FE_NO, J’aw_NO, and CA_NO were obtained twice, at baseline and after a resting period of 10 min. Then spirometry (with or without bronchodilator) was performed followed by exhaled NO measurements at 10 min. Results. In the group with pre-bronchodilator study only (n = 26), mean (95% CI) values before spirometry were 37.3 ppb (22.2–52.4) for FE_NO, 2375 pl/s (1613–3137) for J’aw_NO, and 1.65 ppb (0.95–2.35) for CA_NO, compared with 35.5 ppb (21.1–49.0, p = .10), 2402 pl/s (1663–3141, p = .85), and 1.60 ppb (0.64–2.56, p = .87) after spirometry, respectively. Spirometry-induced changes in exhaled NO values were also not significant in the group with both pre- and post-bronchodilators (n = 18). Furthermore, changes in FE_NO, J’aw_NO, and CA_NO values were similar in the two groups. Conclusions. Our findings demonstrate that spirometry (with or without bronchodilator) does not induce significant changes in bronchial NO flux or alveolar NO values. Therefore, exhaled NO values may be obtained after spirometric maneuvers.

• alveolar nitric oxide
• asthma
• bronchial nitric oxide
• exhaled nitric oxide
• spirometry

Acknowledgments

The authors thank Diater Laboratorios (Madrid, Spain) for help and collaboration. The excellent technical assistance of Rocio Rojas is gratefully acknowledged.

Declaration of Interest

The authors declare that they have no conflict of interest, financial or otherwise, related to this study.