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

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

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

This study evaluates the work of breathing among healthy subjects under various conditions of treatment with high flow nasal cannulas. Ten subjects will be included. The design of this study is a cross over of five treatment periods with different flow settings.

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.

Subjects will be breathing with nasal prongs delivering 5 L/min of air (inspired fraction of oxygen: 0.21)

Subjects will be breathing with high flow nasal cannulas delivering 20 L/min with an inspired fraction of oxygen of 0.21.

Subjects will be breathing with high flow nasal cannulas delivering 40 L/min with an inspired fraction of oxygen of 0.21.

Subjects will be breathing with high flow nasal cannulas delivering 60 L/min with an inspired fraction of oxygen of 0.21.

Work of breathing at the end of each period is calculated from the measurement of esophageal pressure and tidal volume (composite outcome).

Inclusion Criteria: Healthy subjects Written and informed consent Exclusion Criteria: Pregnant or breastfeeding women; Subject enrolled in another study excluding co-enrolment; Cardio-vascular or respiratory disease; History of ear nose and throat disease (i.e. surgery, epistaxis, trauma), eso-gastric disease (i.e. esophageal varices, digestive haemorrhage), rheumatologic or neurologic disease possibly interfering with the design of the study; Subject feeling nauseous or under recent fed condition (<1h).

Delorme M, Bouchard PA, Simon M, Simard S, Lellouche F. Physiologic Effects of High-Flow Nasal Cannula in Healthy Subjects. Respir Care. 2020 Sep;65(9):1346-1354. doi: 10.4187/respcare.07306. Epub 2020 Apr 14.