The potential risk of ventilator-induced lung injury from five different PEEP titration techniques in ARDS

The optimal positive end-expiratory pressure (PEEP) in acute respiratory distress syndrome (ARDS) remains uncertain. This study compared the PEEP levels using five distinct titration methods to assess potential ventilator-induced lung injury (VILI).

This study included 21 patients with moderate to severe ARDS who were monitored using esophageal balloon manometry and electrical impedance tomography (EIT). A recruitment maneuver followed by decremental PEEP titration was performed. Optimal PEEP (OP) was assessed using five criteria: highest respiratory system compliance (C_RS), highest lung compliance (C_L), end-expiratory transpulmonary pressure (P_{tp_ee_direct}) ≥ 0 cm H₂O, elastance-derived end-inspiratory transpulmonary pressure (P_{tp_ei_derived}) ≤ 25 cm H₂O, and EIT-based analysis balancing the degree of overdistention and lung collapse.

Significant differences in OP were observed across the methods (p = 0.001): C_RS 8.0 cmH₂O (8.0,13.9); C_L 9.8 cmH₂O (8.0,14.0); P_{tp_ee_direct} ≥ 0 cmH₂O 14.0 cm H₂O (11.9,17.9); P_{tp_ei_derived} ≤ 25 cmH₂O 12.0 cmH₂O (10.0,13.9); EIT balancing the degree of overdistention and lung collapse 13.01 cmH₂O (9.88,14.78). The OP guided by P_{tp_ee_direct} of ≥ 0 cm H₂O is significantly higher than OP by the highest C_RS (p = 0.001) and the highest C_L (p = 0.002), and met the overdistension criteria, namely plateau pressure > 30 cm H₂O and the highest percentage of overdistension by EIT. The PEEP guided by C_RS had a higher potential risk of lung collapse, reflected by the negative value of P_{tp_ee_direct} and a higher percentage of lung collapse by EIT.

Transpulmonary pressure-guided PEEP titration yielded higher PEEP levels, while C_RS-guided PEEP was lower and associated with a higher risk of collapse. Overdistension and collapse varied with the chosen PEEP method. In patients with moderate to severe ARDS, OP can vary depending on the method of assessment.