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 (ΔPL) offers a lung-specific estimate of cyclic mechanical stress, while end-expiratory transpulmonary pressure (PL,EE) may indicate end-expiratory lung stability. We evaluated the associations of ΔPL and PL,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 ΔPL and PL,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 ΔPL, lower PL,EE, lower lung compliance, higher lung elastance, and higher predicted body weight-normalized mechanical power than survivors. ΔPL 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 H2O increase, 95% CI: 1.19-1.81, P < .001; area under the curve [AUC] = 0.759). Lower PL,EE was also independently associated with mortality (adjusted OR = 0.48 per 1 cm H2O increase, 95% CI: 0.32-0.72, P < .001; AUC = 0.744). Exploratory thresholds were ΔPL ≥11.9 cm H2O and PL,EE ≤0.8 cm H2O. Mortality increased across phenotypes, from 8.4% in subjects with low ΔPL/preserved PL,EE to 54.2% in those with high ΔPL/low PL,EE. CONCLUSIONS: In children with ARDS, higher ΔPL was independently associated with 28-day mortality. Lower PL,EE provided complementary prognostic information, and the combination of elevated ΔPL and reduced PL,EE suggested a high-risk mechanical profile. Prospective validation of these exploratory thresholds is required before clinical implementation.