Respiratory Failure
Conditions
Brief summary
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.
Detailed description
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.
Interventions
Comparison of different flow levels
Low flow of air delivered through conventional nasal prongs
Sponsors
Study design
Eligibility
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).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Work of breathing | 10 minutes | Work of breathing at the end of each period is calculated from the measurement of esophageal pressure and tidal volume (composite outcome). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Esophageal pressure-time product | 10 minutes | Measured at the end of each period |
| Tidal Volume | 10 minutes | Measured at the end of each period |
| Comfort of breathing | 10 minutes | Subjective evaluation at the end of each period |
| Blood gases | 10 minutes | Arterial or capillary blood gases at the end of each period |
| Oxygen saturation | 10 minutes | Measured at the end of each period |
| Respiratory Rate | 10 minutes | Measured at the end of each period |
| End-tidal carbon dioxide | 10 minutes | Measured at the end of each period |
| Heart rate | 10 minutes | Measured at the end of each period |
| Dyspnea | 10 minutes | Evaluation on a borg scale at the end of each period |
Countries
Canada