Benefits of a reservoir nasal cannula (Oxymizer®) vs. a conventional nasal cannula during exercise in hypoxemic patients with pulmonary fibrosis

Abstract

Background: The Oxymizer ® device is a special oxygen nasal cannula that provides a higher luminal diameter in combination with an incorporated oxygen reservoir. In the past we found that Oxymizer® was beneficial in hypoxemic COPD patients by increasing oxygenation during exercise. Objective: Aim of this prospective cross-over study was to investigate the effects of an Oxymizer® in comparison to a conventional nasal cannula (CNC) during exercise in hypoxemic patients with pulmonary fibrosis. Methods: 24 patients with pulmonary fibrosis (m:f=:15:9; VC=54±22%pred.; DLCO=20±12mmol/kg/min; PaO 2 =54,90±7,3mmHg; PaCO 2 =40,5±5,5mmHg, peak work rate [PWR]=74±21Watt) were recruited during pulmonary rehabilitation. After an initial incremental cycle test, patients performed 4 constant cycling work rate tests (CWRT) at 70% of their PWR (twice with Oxymizer ® and twice with CNC in random order). Results: Endurance time (581sec.[351-1142] vs. 498sec.[303-796], p=0.009) and oxygen saturation during exercise (90%[87-93] vs. 88%[85-91], p=0.002) were significantly higher by using Oxymizer® compared to CNC. No significant differences were found between Oxymizer® and CNC regarding PaCO2 (37.8mmHg [33.5-41.0] vs. 37.6mmHg [33.3-41.5], p=n.s.) and perceived dyspnea rated on the modified Borg scale (7.5pts. [7-8] vs. 7.5pts. [6-8], p=n.s.). Discussion: This study showed that oxygen delivery via Oxymizer ® is superior to CNC in patients with pulmonary fibrosis with regard to a longer endurance time and although a better oxygenation during exercise. Oxymizer ® seems to be a simple and useful device in hypoxemic patients with pulmonary fibrosis.