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

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.

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.

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 H₂O 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 H₂O increase, 95% CI: 0.32-0.72, P < .001; AUC = 0.744). Exploratory thresholds were ΔP_L ≥11.9 cm H₂O and P_L,EE ≤0.8 cm H₂O. 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.

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.