Wean Early With HFNCO vs NPPV in Patients With AHRF

Study Overview
=================
Brief Summary
-----------------
The main purpose of the present study is to verify whether, as compared with conventional weaning, early weaning with high-flow nasal cannula oxygenation or noninvasive positive pressure ventilation may more effective in shortening the duration of invasive ventilation, hence reducing the rates of complications and mortality in patients with acute hypoxemic respiratory failure.

Official Title
-----------------
Wean Early With High-Flow Nasal Cannula Oxygenation Versus Noninvasive Positive Pressure Ventilation in Patients With Acute Hypoxemic Respiratory Failure: a Multicenter, Randomized, Controlled Trial (the WHEN Study)

Conditions
-----------------
Patients With Acute Hypoxemic Respiratory Failure

Intervention / Treatment
-----------------
* Device: High-Flow Nasal Cannula Oxygenation
* Device: Noninvasive Positive Pressure Ventilation
* Device: Conventional weaning


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Orotracheal intubation； PaO2 <60mmHg（venturi mask，FiO2=0.5），and PaCO2 ≤45mmHg； Meeting criteria for weaning readiness； Spontaneous breathing trial failure. Exclusion Criteria: Age<18； Duration of invasive ventilation <48h； Tracheotomy； Percentage of cuff leak volume in tidal volume<15.5%； Unable to spontaneously clear secretions from their airway； Recent oral，nasal，facial or cranial trauma or surgery； Recent gastric or esophageal surgery； Active upper gastro-intestinal bleeding； Severe abdominal distension； Lack of co-operation； Chronic respiratory disease such as chronic obstructive pulmonary disease, asthma, interstitial lung disease and neuromuscular disease.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High-Flow Nasal Cannula Oxygenation<br> | Device: High-Flow Nasal Cannula Oxygenation<br>* High-flow nasal cannula oxygenation will be applied immediately after early extubation, with a gas flow rate of 50 liters per minute and a fraction of inspired oxygen of 1.0 at initiation. The fraction of inspired oxygen will be subsequently adjusted to maintain a peripheral oxygen saturation of 92% or more.<br>|
| Experimental: Noninvasive Positive Pressure Ventilation<br> | Device: Noninvasive Positive Pressure Ventilation<br>* Noninvasive positive pressure ventilation will be applied immediately after early extubation, with a noninvasive ventilator (Respironics V60, Philips) using the NIPSV mode at initiation. The fraction of inspired oxygen will be adjusted to achieve SpO2 >92% with an initial expiratory positive airway pressure (EPAP) of 4 cmH2O. EPAP will be increased gradually in increments of 1-2 cmH2O, up to a maximum of 12 cmH2O, to achieve SpO2 >96%. Inspiratory positive airway pressure (IPAP) will be initially set at 8 cmH2O and be increased gradually in increments of 1-2 cmH2O according to patients' tolerance to obtain a tidal volume (VT) of 6-8 mL/kg.<br>|
| Active Comparator: Conventional Weaning<br> | Device: Conventional weaning<br>* The patients will undergo conventional weaning protocol. Extubation and subsequent oxygen therapy with venturi mask will be performed after successful spontaneous trial.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Duration of invasive mechanical ventilation |  | 2.5 years |