Current study aimed to explore the effect of high PEEP during noninvasive ventilation among hypoxemic patients with acute respiratory failure.

This was a 1:1 randomized control trial to explore the effect of high versus low PEEP in noninvasive ventilation hypoxemic patients with acute respiratory failure. Several ICUs in China performed this study. In the high PEEP group, the PEEP maintained at 10-15 cmH2O, the inspiratory pressure maintained at 15-20 cmH2O. In the low PEEP group, the PEEP maintained at 5 cmH2O, the inspiratory pressure maintained at 10-20 cmH2O. The primary outcome was incidence of noninvasive ventilation failrue.

Inclusion Criteria

• age between 16 and 85 years
• use of dedicated noninvasive ventilator
• PaCO2 ≤50 mmHg
• PaO2/FiO2 ≤300mmHg
• expectation of noninvasive ventilation >12 hours
• consciousness (Kelly score ≤3 or GCS≥13)

Exclusion Criteria

• use of noninvasive ventilation before randomization > 24 hours
• use of noninvasive ventilation due to heart failure, asthma, acute excerbation of COPD
• presence of contraindication of noninvasive ventilation such as malformation, rencent pulmonary or esophageal surgery et al.
• end stage disease (expectation of life < 6 months)
• pneumothorax
• noninvasive ventilation intolerance
• refusal of paticipation
• pregant woman
• requirement of emergency intubation