Effects of Treatment With High Flow Nasal Cannulas on Respiratory Pattern and Work of Breathing Among Healthy Subjects

High flow oxygen therapy (HFOT) is a promising technique increasingly used in the management of acute respiratory failure. In hospitalised hypoxemic patients, recent clinical evidence showed that HFOT can reduce endotracheal intubation and reduce mortality. Physiologically, the HFOT causes a decrease in respiratory rate and minute-ventilation and may be associated with a decrease in carbone dioxyde arterial pressure. It is possible that these effects are associated with decreased work of breathing, which could explain some of the benefits in terms of comfort and efficiency.

The objective of this research is to evaluate the impact of a wash-out of anatomical dead space by high flow nasal cannulas on respiratory parameters and on the work of breathing among healthy subjects. The investigators will evaluate the baseline status in room air, and then compare it with four different levels of flow. The primary endpoint will be the work of breathing.