Reduction of F_ENO by tap water and carbonated water mouthwashes: magnitude and time course

Abstract

Fractional exhaled nitric oxide (F_ENO) assesses eosinophilic inflammation of the airways, but F_ENO values are also influenced by oral nitric oxide (NO). The aim of this pilot study was to measure F_ENO and compare the effect of two different mouthwashes on F_ENO and analyse the duration of the effect. F_ENO was measured in 12 randomized volunteers (healthy or asthmatic subjects) with a NIOX VERO® analyser at an expiratory flow rate of 50 mL/s. After a baseline measurement, a mouthwash was performed either with tap water or carbonated water and was measured during 20 min in 2 min intervals. The procedure was repeated with the other mouthwash. We found that both mouthwashes reduced F_ENO immediately at the beginning compared to the baseline (p < .001). The carbonated water mouthwash effect lasted 12 min (p ranging from <0.001 to <0.05). The tap water mouthwash reduced F_ENO statistically significantly only for 2 min compared with the baseline. We conclude that a single carbonated water mouthwash can significantly reduce the oropharyngeal NO contribution during a 12 min time interval.

Keywords:

• Fractional exhaled nitric oxide (F_ENO)
• carbonated water
• mouthwash
• tap water
• asthma
• inflammation
• laboratory standardization

Acknowledgements

Kirsi-Marja Hiillos and Riitta Saleva-Sjöblom for kindly providing information regarding tap water and carbonated water.

Disclosure statement

No conflicts of interest are declared by the authors.

Additional information

Funding

This work was supported by the Nummela Sanatorium Foundation (PP 2015), (AS 2016), the Finnish State Funding for University-level Health Research (TYH: 2013354), The Research Foundation of the Pulmonary Diseases (PLK 2017), Tampere Tuberculosis Foundation: Eero Hämäläinen (PLK 2017), Ida Montin Foundation (PLK 2017), and Väinö and Laina Kivi Foundation (PLK 2017).