Table 1.

Implications of prone positioning for PEEP management in patients with severe ARDS

Physiological effects of prone positioning	Implications for PEEP management
Reduced pleural pressure gradient	Improved ventilation homogeneity: PP can enhance ventilation distribution across different lung regions, potentially allowing for a wider range of effective PEEP levels. This can result in better compliance for both non-dependent and dependent lung regions at the same PEEP setting
Increased chest wall elastance	Possible reduction in alveolar overdistension: PP, combined with higher PEEP levels, may help mitigate alveolar overdistension by promoting a more uniform distribution of ventilation
Improved ventilation homogeneity	Reduced dependence on higher PEEP: With improved ventilation homogeneity from PP, there may be less need for excessively high PEEP levels to achieve homogeneous ventilation across the lung
Lung recruitment*	Synergistic effects: The combination of PP and moderate PEEP may produce synergistic effects, potentially allowing for a reduction in PEEP levels while preserving EELV and optimizing gas exchange
Improved ventilation/perfusion matching	Reduced dependence on PEEP for oxygenation: PP can enhance gas exchange efficiency, potentially decreasing the reliance on higher PEEP to improve oxygenation
Right ventricular unloading*	Potential for moderate PEEP: PP may facilitate the use of moderate PEEP levels, optimizing both ventilation and hemodynamics while minimizing potential adverse effects associated with high PEEP

PEEP, positive end-expiratory pressure; ARDS, acute respiratory distress syndrome; PP, prone positioning; EELV, end-expiratory lung volume

^*Individual responses to prone positioning can vary, and effects such as lung recruitment and right ventricular unloading may be influenced by patient-specific factors