The impact of changing patient interfaces on delivering aerosol with titrated oxygen in the high flow system

Introduction: Despite the widespread oxygen-culture as more is better in prehospital and hospital settings, the use of titrated oxygen-flow within a high-flow system can be beneficial especially when combined with aerosol-delivery and also save the patient from unnecessary-hyperoxia.

Methods: Forty-five COPD patients were included in this study where they allocated in three-groups (nasal-delivery, oral-delivery, and oronasal-delivery groups). All patients were received their inhaled-salbutamol dose using Aerogen Solo nebuliser by one of the three interfaces, eg, nasal-cannula, mouthpiece, and facemask in two conditions; with oxygen-flow and without any oxygen-flow. Pulmonary and systemic salbutamol deposition was estimated by collecting two urine-samples from the patient; 30 min post-inhalation and cumulatively 24 hr post-inhalation. The quantity of salbutamol in these collected samples was measured by high-performance liquid chromatography. Lung function measurement was performed pre-bronchodilator inhalation and 30 min post-bronchodilator to estimate the change in pulmonary functions post-inhalation regarding all tested interfaces.

Results: COPD patients showed the highest salbutamol percentage excreted 30 min post-inhalation of 5.7% (1.4) with mouthpiece interface when combined with oxygen at P < .002. While with the same condition using oxygen, valved-facemask showed the highest salbutamol percentage excreted in 24 hr post inhalation samples but the difference is only significantly compared with nasal cannula (P < .006). Moreover, without oxygen delivery, mouthpiece and valved facemask showed approximately the same salbutamol percentage excreted in 30 min post-inhalation samples, higher than that delivered by nasal cannula (P < .001). Of note, salbutamol delivery is significantly increased with oxygen flow for all interfaces (P < .05) except with nasal cannula.

Conclusions: The nasal cannula is a more comfortable and tolerable interface despite the lower fraction of the delivered drug compared with other tested interfaces. The use of oxygen-flow with aerosol delivery within a high flow system positively affects the delivered drug fraction and the pulmonary deposition of the drug.