High Flow During Weaning From Mechanical Ventilation
Condition: Acute Respiratory Failure
MeSH terms: Respiratory Insufficiency
Study type: Interventional

Summary: 
      Detection and relief of dyspnea in mechanically ventilated patients is a priority.
      Optimization of mechanical ventilation settings is unfortunately often insufficient to
      relieve dyspnea in patients entering the weaning process. Pharmacological treatments are
      effective but their use is likely to delay separation with the ventilator. Promoting the
      development of non-pharmacological interventions is therefore an interesting avenue. The
      hypothesis is that the application of high-flow humidified nasal air in orotracheally
      intubated patients can decrease the work of breathing and relieve dyspnea at the time of
      weaning from mechanical ventilation. Patients will be exposed to stepwise increase in high
      flow nasal air (0 L/min, 30 L/min, 50 L/min and 70 L/min) before to undergo a 60 minutes
      spontaneous breathing trial. During the protocol, dyspnea, inspiratory effort, respiratory
      drive, respiratory muscles electromyogram (EMG) and patient's comfort will be assessed.
    

Detailed description: 
      Patients equipped with an esophageal probe and deemed ready to undergo a spontaneous
      breathing trial will be included.

      During, the inclusion visit, main characteristics of the patients and ICU stay will be
      collected in the patient's chart: age, sex, comorbidities, date of admission to intensive
      care, date of intubation, severity score (SOFA), reason for admission to intensive care ,
      weight, height, ventilation settings, P0.1, respiratory rate, SpO2, dyspnea and comfort
      score.

      Secondarily, the quality of the esophageal pressure signal will be checked. Esophageal
      pressure will be collected using a nasogastric tube (NutriventTM, SIDAM, Italy). Esophageal
      pressure will be measured continuously by the Labchart system installed on the department's
      dedicated computer.

      Third, the EMG collection device will be implemented. EMG signals will be collected by
      surface electrodes on the scalene and intercostal muscles and on the sides of the nose. The
      electrodes are connected to collection modules operating with the LabChart system.

      Finally, the high-flow humidified air device will be installed (AIRVO 2; Fisher and Paykel
      Healthcare, Auckland, New Zealand) and nasal cannulas adapted to the patient's anatomy will
      be positioned. The FiO2 will be fixed at 21% for the duration of the study. The flow will be
      set at 0 L/min at the inclusion visit. The humidified air temperature will be set to 37°C.

      The protocol will consist of installing the high-flow humidified nasal oxygen therapy device
      and varying the nasal flow (4 different conditions: 0 L/min, 30 L/min, 50 L/min and 70 L/min)
      then performing the spontaneous breathing trial (duration 60 minutes). During each of the
      steps of the protocol, a collection of the intensity of the dyspnea, a measurement of the
      esophageal pressure, a measurement of the respiratory drive, an EMG measurement of the
      respiratory muscles and a comfort assessment will be carried out.
    

Intervention name(s): High Flow Nasal Air
Intervention type(s): Device
Intervention description(s): Administration of air at high flow by using a high flow nasal oxygenation (FiO2 21%) device
Other intervention name(s): High Flow Nasal Cannula
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: Dyspnea; Weaning; Mechanical ventilation; High flow nasal air