Noise Exposure From High-Flow Nasal Cannula Oxygen Therapy: A Bench Study on Noise Reduction

BACKGROUND: High-flow nasal cannula (HFNC) oxygen therapy produces noise at a level such that patients often complain. However, the noise level has not been measured digitally. METHODS: We evaluated 3 types of HFNCs without filters and 2 types with filters attached for noise reduction. Optiflow (with and without a filter), MaxVenturi (with and without a filter) and AIRVO2 (without a filter only) were positioned at the center of a hospital room. We measured the noise levels at the distance of 1 m from the equipment at various total flows (30, 40, 50, 60 L/min) and F IO 2 (0.40, 0.60, and 0.90). RESULTS: Noise levels were increased with the AIRVO2 and MaxVenturi when total flow and F IO 2 were increased. Noise levels decreased with the MaxVenturi when a filter was used. The noise level did not change with the Optiflow when total flow and F IO 2 were increased. The noise level decreased in the groups with AIRVO2 and Optiflow compared with MaxVenturi without a filter. CONCLUSIONS: The findings in this study show that the noise level of HFNC/Venturi could be reduced by attaching an intake filter. However, the noise level of HFNC/blender and HFNC/turbine decreased in comparison with HFNC/Venturi without an intake filter