Setting PEEP in patients with COVID-19-related ARDS: a physiological comparison between methods.

Area of Science:

• Critical Care Medicine
• Respiratory Physiology
• Medical Imaging

Background:

• Setting positive end-expiratory pressure (PEEP) for COVID-19-related acute respiratory distress syndrome (ARDS) lacks a definitive best approach.
• Existing methods for PEEP titration do not clearly correlate with resulting transpulmonary pressure, overdistension, or lung collapse.

Purpose of the Study:

• To compare PEEP setting strategies using electrical impedance tomography (EIT) with traditional methods.
• Specifically, to evaluate EIT targeting the crossing point of overdistension/collapse curves (EIT_CP) against targeting positive end-expiratory transpulmonary pressure (P_L,EE) and highest respiratory system compliance (C_RS).

Main Methods:

• A post-hoc analysis of 29 COVID-19 ARDS patients from two Dutch hospitals.
• Patients underwent a decremental PEEP trial with simultaneous recording of EIT and esophageal pressure data.
• Comparison of recommended PEEP, P_L,EE, overdistension, and collapse across different PEEP setting strategies.

Main Results:

• EIT_CP targeting resulted in higher PEEP (14 cmH₂O) and P_L,EE (1.4 cmH₂O) compared to P_L,EE targeting (12 cmH₂O).
• EIT_CP significantly reduced lung collapse (3.0%) compared to P_L,EE targeting (5.4%).
• No significant difference in overdistension was observed, but P_L,EE targeting showed higher rates of combined overdistension or collapse (51%).

Conclusions:

• EIT_CP offers a superior approach for PEEP setting in COVID-19 ARDS, yielding higher PEEP and P_L,EE.
• This method effectively minimizes lung collapse without increasing overdistension.
• EIT-based strategies provide better protection against detrimental lung mechanics compared to P_L,EE or C_RS targeting.