Transpulmonary Driving Pressure, End-Expiratory Transpulmonary Pressure, and Mortality in Pediatric ARDS

Background: Respiratory system driving pressure (ΔP) reflects the combined mechanics of the lung and chest wall and may not represent the distending pressure transmitted specifically to the lung. Transpulmonary driving pressure (ΔP L ) offers a lung-specific estimate of cyclic mechanical stress, while end-expiratory transpulmonary pressure (P L, EE ) may indicate end-expiratory lung stability. We evaluated the associations of ΔP L and P L, EE with 28-day mortality in pediatric ARDS. Methods: This retrospective, multi-center cohort study included invasively ventilated children with ARDS treated in 5 tertiary pediatric ICUs between January 2019 and February 2025. Respiratory mechanics, esophageal pressure, ventilator variables, and arterial blood gases were collected during the first valid assessment within 24 h of ARDS diagnosis. The primary outcome was 28-day mortality. Logistic regression models were used to evaluate the associations between ΔP L and P L, EE and mortality. Youden-derived thresholds were applied to explore transpulmonary pressure phenotypes. Results: Among 154 subjects, 29 (18.8%) died within 28 days. Nonsurvivors had higher ΔP L , lower P L, EE , lower lung compliance, higher lung elastance, and higher predicted body weight–normalized mechanical power than survivors. ΔP L was independently associated with 28-day mortality after adjustment for age, sex, ARDS severity, and Pediatric Logistic Organ Dysfunction-2 score (adjusted odds ratio [OR] = 1.47 per 1 cm H 2 O increase, 95% CI: 1.19–1.81, P < .001; area under the curve [AUC] = 0.759). Lower P L, EE was also independently associated with mortality (adjusted OR = 0.48 per 1 cm H 2 O increase, 95% CI: 0.32–0.72, P < .001; AUC = 0.744). Exploratory thresholds were ΔP L ≥11.9 cm H 2 O and P L, EE ≤0.8 cm H 2 O. Mortality increased across phenotypes, from 8.4% in subjects with low ΔP L /preserved P L, EE to 54.2% in those with high ΔP L /low P L, EE . Conclusions: In children with ARDS, higher ΔP L was independently associated with 28-day mortality. Lower P L, EE provided complementary prognostic information, and the combination of elevated ΔP L and reduced P L, EE suggested a high-risk mechanical profile. Prospective validation of these exploratory thresholds is required before clinical implementation.