This study evaluates the work of breathing among patients under various conditions of treatment with high flow nasal cannulas. Sixteen spontaneously breathing patients with respiratory failure (hypercapnic or hypoxemic) will be included. The design of this study is a cross over of four 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 PaCO2. 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. The investigators will evaluate the baseline status with conventional oxygen therapy methods (low flows), and then compare it with three different levels of high flow oxygen therapy in a randomised order. The primary endpoint will be the work of breathing.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
16
High flow nasal cannulas
Low flow of oxygen delivered through conventional nasal prongs
IUCPQ
Québec, Quebec, Canada
RECRUITINGWork of breathing
Work of breathing at the end of each period is calculated from the measurement of esophageal pressure and tidal volume (composite outcome)
Time frame: 15 minutes
Esophageal pressure-time product
Measured at the end of each period
Time frame: 15 minutes
Tidal volume
Measured at the end of each period
Time frame: 15 minutes
Comfort of breathing
Subjective evaluation at the end of each period
Time frame: 15 minutes
Blood gases
Arterial or capillary blood gases at the end of each period
Time frame: 15 minutes
Dyspnea
Evaluation on a borg scale at the end of each period
Time frame: 15 minutes
Respiratory rate
Measured at the end of each period
Time frame: 15 minutes
Heart rate
Measured at the end of each period
Time frame: 15 minutes
End-tidal carbon dioxide
Measured at the end of each period
Time frame: 15 minutes
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Oxygen saturation
Measured at the end of each period
Time frame: 15 minutes