FiftyYearsofResearchinARDS.Setting Positive End-Expiratory Pressure in Acute Respiratory Distress Syndrome

Abstract

Positive end-expiratory pressure (PEEP) has been used during mechanical ventilation since the first description of acute respiratory distress syndrome (ARDS). In the subsequent decades, many different strategies for optimally titrating PEEP have been proposed. Higher PEEP can improve arterial oxygenation, reduce tidal lung stress and strain, and promote more homogenous ventilation by preventing alveolar collapse at end expiration. However, PEEP may also cause circulatory depression and contribute to ventilator-induced lung injury through alveolar overdistention. The overall effect of PEEP is primarily related to the balance between the number of alveoli that are recruited to participate in ventilation and the amount of lung that is overdistended when PEEP is applied. Techniques to assess lung recruitment from PEEP may help to direct safer and more effective PEEP titration. Some PEEP titration strategies attempt to weigh beneficial effects on arterial oxygenation and on prevention of cyclic alveolar collapse with the harmful potential of overdistention. One method for PEEP titration is a PEEP/Fi table that prioritizes support for arterial oxygenation. Other methods set PEEP based on mechanical parameters, such as the plateau pressure, respiratory system compliance, or transpulmonary pressure. No single method of PEEP titration has been shown to improve clinical outcomes compared with other approaches of setting PEEP. Future trials should focus on identifying individuals who respond to higher PEEP with recruitment and on clinically important outcomes (e.g., mortality).

Ultra-high-resolution computed tomography can demonstrate alveolar collapse in novel coronavirus (COVID-19) pneumonia

“…Allbarello et al reported decreased normal lung volume in COVID-19 pneumonia patients with acute respiratory distress syndrome (ARDS) [9]. We believe this volume loss resulted due to alveolar collapse, which is commonly seen in ARDS [10].…”

Ventilatory support and mechanical properties of the fibrotic lung acting as a “squishy ball”

“…In ARDS, lung protection is provided using low tidal volumes, low plateau transpulmonary and driving pressures, but also a positive end-expiratory pressure (PEEP) level sufficient to maintain oxygenation while preventing the opening-closing of alveolar units causing shear stress throughout the respiratory cycle [20]. Clinical trials in ARDS investigated the effect of an open lung strategy, namely involving the use of PEEP levels higher than those strictly required to maintain acceptable oxygenation [21], often in conjunction with recruitment maneuvers to maximize lung aeration [22].…”

Pharmacological modulation of C‐X‐C motif chemokine receptor 4 influences development of acute respiratory distress syndrome after lung ischaemia–reperfusion injury

“…While several independent risk factors for development of ARDS have been identified, such as pneumonia, non‐pulmonary‐sepsis or severe injuries, the molecular events leading to ARDS remain poorly understood . Thus, therapeutic options are currently limited to lung‐protective ventilation strategies . Pharmacological interventions that may attenuate progression of mild ARDS to moderate or severe ARDS are currently not available, but urgently needed.…”