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Updated: May 9, 2025

Normothermic Negative Pressure Ventilation Ex Situ Lung Perfusion: Evaluation of Lung Function and Metabolism
Published on: February 14, 2022
Low versus high positive end expiratory pressure in noninvasive ventilation for hypoxemic respiratory failure: a
Jun Duan1, Xiaoyi Liu2, Weiwei Shu3
1Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Chongqing Medical University, Yuzhong District, Chongqing, China. duanjun412589@163.com.
Purpose:
To assess whether high positive end expiratory pressure (PEEP) reduces the rate of noninvasive ventilation (NIV) failure in hypoxemic patients.
Methods:
This multicenter, open-label, randomized controlled trial was conducted across seven ICUs in China. Hypoxemic patients who received NIV via oronasal or nasal mask were randomized 1:1 to either low PEEP (5 cmH2O) or high PEEP (10-15 cmH2O) groups, with inspiratory positive airway pressure (IPAP) set at 10-20 cmH2O and 15-20 cmH2O, respectively. The primary outcome was NIV failure, defined as intubation, death, or therapy withdrawal (refusal of intubation despite need).
Results:
Between January 11, 2022, and August 31, 2024, 380 patients (190 per group) were enrolled in an intention-to-treat analysis. NIV failure occurred in 43% (82/190) of the low PEEP group and 32% (61/190) of the high PEEP group (absolute difference: 11.1%, 95% CI 1.3-20.5%, p = 0.034). Within 72 h post-randomization, the low PEEP group exhibited lower PaO2/FiO2 ratios (mean difference: - 31 mmHg, 95% CI - 38 to - 24) and higher tidal volume (0.8 mL/kg predicted body weight, 95% CI 0.5-1.1) than the high PEEP group. However, the low PEEP group required higher support pressure (mean difference: 2.9 cmH2O, 95% CI 2.7-3.1). Adverse events did not differ between the groups.
Conclusions:
High PEEP during NIV may reduce treatment failure in patients with acute hypoxemic respiratory failure, although this benefit may be partially confounded by higher tidal volume observed in the low PEEP group. However, the interpretation of this effect should be carried out with caution as the study has insufficient statistical power to detect a significant difference.
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