Evaluation of Oxygen Therapy Delivery Systems in Hypoxemic Acute Respiratory Failure (OPTI O2)

The main objective of this study is to evaluate the efficiency of the oxygen therapy delivery system Optiflow® compared to 2 others standard oxygen therapy delivery systems (Ospal®, non invasive ventilation).12 immunocompetent patients will compare the successive use of oxygen therapy delivery systems Optiflow®/Ospal® and 12 immunodeficient patients will compare the successive use of systems Optiflow®/Non invasive ventilation.

Acute respiratory failure, Oxygen therapy delivery systems, Non invasive ventilation, High concentration mask, Hypoxemic pneumonia

T-60 (minutes) : clinical examination, blood gas, electrocardiogram; T0 / First oxygen therapy delivery system: clinical examination, blood gas, electrocardiogram, measurement of positive and expiratory pressure and FiO2; T10 : blood gas; Between T0 and T60 (every 10 minutes): clinical examination, measurement of positive and expiratory pressure and FiO2; T60 / Second oxygen therapy delivery system: clinical examination, blood gas, electrocardiogram, measurement of positive and expiratory pressure and FiO2; T70 : blood gas; Between T60 and T120 (every 10 minutes): clinical examination, measurement of positive and expiratory pressure and FiO2; T120: clinical examination, blood gas, electrocardiogram, measurement of positive and expiratory pressure and FiO2

The main objective of this study is to evaluate the efficiency of the oxygen therapy delivery system Optiflow® compared to 2 others standard oxygen therapy delivery systems (Ospal®, non invasive ventilation) by calculating the ratio PaO2/FiO2

The secondary outcomes are to understand the mechanisms of action of Optiflow system and to evaluate the tolerance of this system: number of adverse events: respiratory events, trophic troubles, subjective events (comfort, dryness of mucous membranes, gastric distension, preferred system), serious hemodynamic and cardiovascular events impact on work of breathing: measure of respiratory frequency and blood gas measure of positive and expiratory pressure

The secondary outcomes are to understand the mechanisms of action of Optiflow system and to evaluate the tolerance of this system: number of adverse events: respiratory events, trophic troubles, subjective events (comfort, dryness of mucous membranes, gastric distension, preferred system), serious hemodynamic and cardiovascular events impact on work of breathing: measure of respiratory frequency and blood gas measure of positive and expiratory pressure

The secondary outcomes are to understand the mechanisms of action of Optiflow system and to evaluate the tolerance of this system: number of adverse events: respiratory events, trophic troubles, subjective events (comfort, dryness of mucous membranes, gastric distension, preferred system), serious hemodynamic and cardiovascular events impact on work of breathing: measure of respiratory frequency and blood gas measure of positive and expiratory pressure

Inclusion Criteria: Patient hospitalized in the intensive care unit of Nantes University Hospital Signed informed consent Patient with not hypercapnic acute hypoxemic respiratory failure Immunocompetent and immunodeficient patient Exclusion Criteria: Age < 18 years Pregnancy Contra-indication to non invasive ventilation Allergy to xylocaine Coagulation troubles Tracheotomized patient Urgent indication to intubation Hypercapnic acute respiratory failure Acute pulmonary edema Face or nose malformation