RELAx RCT – Low vs High PEEP Without ARDS

Written by Clay Smith

Spoon Feed
Low PEEP in mechanically ventilated patients without ARDS was noninferior to high PEEP for number of ventilator-free days.


Why does this matter?
We know that low tidal volume is good for ARDS, and the ARDSnet protocol calls for high levels of PEEP. But do we need high PEEP in patients without ARDS?

Should we RELAx our PEEP strategy?
This was an unblinded, multicenter RCT based in the Netherlands that enrolled 980 patients anticipated to be on mechanical ventilation for >24 hours but who did not have ARDS. They were randomized to a low PEEP strategy (0-5 cm H2O) or high PEEP (8 cm H2O). For the primary outcome of ventilator-free days at day 28, the low PEEP cohort was noninferior to high PEEP (median 18 days vs 17 days; mean ratio 1.04, 95%CI 0.95-infinity). The a priori lower bound of noninferiority was -10% difference in ventilator-free days, which this easily met. There was also no statistical difference in severe hypoxemia, need for a rescue ventilator strategy, or mortality. It looks like low PEEP in patients without ARDS is a viable ventilation strategy.

Source
Effect of a Lower vs Higher Positive End-Expiratory Pressure Strategy on Ventilator-Free Days in ICU Patients Without ARDS: A Randomized Clinical Trial. JAMA. 2020 Dec 22;324(24):2509-2520. doi: 10.1001/jama.2020.23517.

What are your thoughts?

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