High Flow Oxygen Therapy in Patients Suffering From Chronic Obstructive Pulmonary Disease Exacerbation: Effects and Mechanisms of Action
High Flow Oxygen Therapy in Patients Suffering From Chronic Obstructive Pulmonary Disease Exacerbation: Effects and Mechanisms of Action
Acute exacerbation of chronic obstructive pulmonary disease (COPD) is associated with poor
 outcome, especially when intubation is required, thus underlining the importance of
 optimizing non-invasive ventilatory support to avoid intubation. Practically, because of
 treatment intolerance, non-invasive ventilation (NIV) cannot be administered 24-hour a day
 for a long period of time and alternative solutions must be found to deliver oxygen as
 efficiently as possible to allow NIV interruptions. High flow humidified oxygen therapy
 (HFHO) consists of delivering a high-flow (15-60 L/minute) heated air-oxygen mixture (FIO2
 21-100%) through a dedicated nasal cannula and can be interesting in this context. This well
 tolerated technique improves oxygenation and decreases respiratory rate and dyspnea in
 patients suffering from acute hypoxemic respiratory failure. In chronic COPD patients, using
 HFHO can decrease respiratory rate and PaCO2. In COPD exacerbation, using HFHO can
 conceptually be interesting. First, the high air-oxygen flow delivered well matches the
 patient's inspiratory demand and should decrease the work of breathing. Second, as during
 HFHO a high flow is continuously delivered in the airways, a wash-out of the anatomical dead
 space should occur and CO2 clearance should be enhanced. Despite this strong physiological
 rational for the use of HFHO in patients suffering from COPD exacerbation, the effects of
 using HFHO instead of conventional oxygenotherapy in combination with non-invasive
 ventilation (NIV) in this context has never been explored.

 The main objective of the study is to explore the effects of using HFHO in combination with
 NIV in acute COPD exacerbation and to assess the underlying mechanisms of action.
Inclusion Criteria:

 -  COPD patients suffering from acute hypercapnic respiratory failure (PaCO2 > 50 mmHg)
 due to COPD exacerbation and requiring intermittent NIV treatment can be included in
 the study provided they do not require immediate intubation.

 Exclusion Criteria:

 -  Patients younger than 18 years old

 -  Inability to give informed consent or denied informed consent

 -  Severe acute respiratory failure requiring immediate intubation defined as respiratory
 rate > 40/minute, severe hypoxemia with PaO2/FIO2 ratio < 150 mmHg despite high FIO2,
 severe respiratory acidosis with pH< 7.2, altered mental status)

 -  Very intensive NIV treatment required defined as an impossibility to stop NIV
 treatment during more than one hour.

 -  Severe hypoxemia requiring more than 4l/minute of conventional oxygenotherapy between
 NIV treatments

 -  Poor short term prognosis (defined by the clinician in charge as a high risk of death
 during the next 7 days) or ongoing palliative treatment.

 -  Patients with "Do not resuscitate" order already established