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

Abstract

Introduction: 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). Methods: 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<inf>RS</inf>), highest lung compliance (C<inf>L</inf>), end-expiratory transpulmonary pressure (P<inf>tp_ee_direct</inf>) ≥ 0 cm H<inf>2</inf>O, elastance-derived end-inspiratory transpulmonary pressure (P<inf>tp_ei_derived</inf>) ≤ 25 cm H<inf>2</inf>O, and EIT-based analysis balancing the degree of overdistention and lung collapse. Results: Significant differences in OP were observed across the methods (p = 0.001): C<inf>RS</inf> 8.0 cmH₂O (8.0,13.9); C<inf>L</inf> 9.8 cmH₂O (8.0,14.0); P<inf>tp_ee_direct</inf> ≥ 0 cmH₂O 14.0 cm H₂O (11.9,17.9); P<inf>tp_ei_derived</inf> ≤ 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<inf>tp_ee_direct</inf> of ≥ 0 cm H<inf>2</inf>O is significantly higher than OP by the highest C<inf>RS</inf> (p = 0.001) and the highest C<inf>L</inf> (p = 0.002), and met the overdistension criteria, namely plateau pressure > 30 cm H<inf>2</inf>O and the highest percentage of overdistension by EIT. The PEEP guided by C<inf>RS</inf> had a higher potential risk of lung collapse, reflected by the negative value of P<inf>tp_ee_direct</inf> and a higher percentage of lung collapse by EIT. Conclusion: Transpulmonary pressure-guided PEEP titration yielded higher PEEP levels, while C<inf>RS</inf>-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.