REBEL EM - February 01, 2021 - By Frank Lodeserto
Paper: Writing Committee and Steering Committee for the RELAx Collaborative Group. Effect of a Lower vs Higher Postive End-Expiratory Pressure Strategy on Ventilator-Free Days in ICU Patients Without ARDS: A Randomized Clinical Trial. JAMA 2020. PMID: 33295981
"Clinical Question: For patients in the ICU who received invasive ventilation for reasons other than ARDS, is a ventilation strategy with lower PEEP noninferior to a strategy using higher PEEP with respect to the number of ventilator-free days at day 28?
Author conclusion: “Among patients in the ICU without ARDS who were expected not to be extubated within 24 hours, a lower PEEP strategy was noninferior to a higher PEEP strategy with regard to the number of ventilator-free days at day 28. These findings support the use of lower PEEP in patients without ARDS.”
Take-home point: In this trial a lower PEEP strategy was shown to be noninferior to higher PEEP in non-ARDS patients (i.e. as good as). However, there are some concerning findings of increased rates of severe hypoxemia, need for rescue strategies, decreased P/F ratios, and increased driving pressures in the lower PEEP group compared to the higher PEEP group. Finding the optimal PEEP can be challenging, and likely tied to the degree of recruitable alveoli. In some patient populations, particularly obese patients (which were excluded from this trial), for example, this will require applying clinical judgement and understanding the benefit vs the harm of PEEP which depends on the balance of alveolar recruitment vs overdistention (i.e. the sweet spot)"