Small airway function before and after cold dry air challenge in pediatric asthma patients during remission

• Published in: Pediatric pulmonology Vol. 52; no. 7; pp. 873 - 879
• Main Authors: Steinbacher, Michael, Pfleger, Andreas, Schwantzer, Gerold, Jauk, Stefanie, Weinhandl, Elisabeth, Eber, Ernst
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.07.2017
• Subjects: Adolescent; Air; Albuterol - therapeutic use; Asthma; Asthma - drug therapy; Asthma - metabolism; Asthma - physiopathology; Breath Tests; Bronchodilator Agents - therapeutic use; Child; children; cold dry air challenge; Cold Temperature - adverse effects; Exhalation; Female; Humans; lung function test; Male; multiple breath washout; Nitric Oxide - metabolism; Pediatrics; remission; Spirometry; lung function test; spirometry; children; multiple breath washout; cold dry air challenge; remission; asthma
• ISSN: 8755-6863; 1099-0496; 1099-0496
• DOI: 10.1002/ppul.23724

Background We wanted to compare cold dry air challenge (CACh) induced changes in spirometric parameters with changes in nitrogen multiple breath washout (N2MBW) parameters in pediatric asthma patients during clinical remission over the past year (ie, with “inactive asthma”). As N2MBW assesses ventilation heterogeneity we expected to gain detailed information about peripheral airways contribution. Methods In subjects with normal spirometry N2MBW, spirometry and body plethysmography were performed at baseline, after CACh, and after salbutamol inhalation. An initial measurement of the fraction of exhaled nitric oxide (FeNO) was conducted. Results Forty‐three (20 female) subjects, mean age 13.7 years (range 6.5‐18.6) performed reproducible N2MBW measurements. Ten were tested hyperresponsive (23.3%) and 33 normoresponsive (76.7%). Baseline spirometry and body plethysmography as well as FRC (N2MBW) were similar in both groups. Scond (0.031 vs 0.022), Sacin (0.057 vs 0.067), and FeNO (92.0 vs 28.5 ppb) were not statistically different between hyperresponsive and nomoresponsive subjects at baseline. Subjects with airway hyperresponsiveness (AHR) showed significant increases in lung clearance index (LCI, P = 0.011) and Scond (P = 0.008) after CACh, and significant decreases after salbutamol (LCI: P = 0.005; Scond: P = 0.005). In contrast, normoresponsive subjects showed no relevant changes after CACh, and only a decrease of Scond after salbutamol (P = 0.007). There were significant correlations between the CACh induced changes in FEV1 and changes in LCI (r = −0.45, P = 0.003), Scond (r = −0.30, P = 0.047), and Sacin (r = −0.47, P = 0.008), respectively. Conclusion Our study provides evidence of small airway involvement in children and adolescents with inactive asthma and airway hyperresponsiveness.