Effects of Long-term Dry and Humidified Low-flow Oxygen Via Nasal Cannula

After agreeing to the terms of informed consent, the individual will be admitted to the study. The objective of this study was to evaluate the effects of humidified oxygen and not humidified nasal catheter (12-24 hours/day) on the nasal epithelium of patients with chronic respiratory failure by non-invasive tests in 36 volunteers, of both sexes aged ≥ 18 years with a medical indication for the use of home oxygen via nasal cannula on: (1) nasal mucociliary transport through the saccharin test, (2) the physical properties of nasal mucus by simulated cough machine and contact angle, (3) cellularity via nasal and total count differential white blood cell nasal lavage, (4) ph nasal lavage and exhaled breath condensate (5) quantification of cytokines in nasal lavage and (6) quality of life questionnaire with rhinosinusitis (SNOT20). Assessments will be performed at baseline, 12 hours, 7 days, 30 days, 12 months and 24 months of use. Volunteers will be recruited from three Basic Health Supervision of Cathedral Health, City Health Department, City of São Paulo.