Electrical impedance tomography–guided individualized ventilation strategy in patients with trauma-related and postoperative acute respiratory distress syndrome

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OBJECTIVE: Optimal positive end-expiratory pressure (PEEP) selection in acute respiratory distress syndrome (ARDS) is challenging because of marked regional lung heterogeneity. Electrical impedance tomography (EIT) provides bedside assessment of regional ventilation and may support individualized ventilation by informing PEEP titration, but evidence in trauma- and postoperative-associated ARDS remains limited. METHODS: In this single-center randomized controlled trial, 86 adults with moderate-to-severe trauma- or postoperative-associated ARDS were randomized to an EIT-guided individualized ventilation strategy (n = 43) or a lower-PEEP/FiO2 strategy (n = 43). Four patients were transferred early before analyzable follow-up data were collected; therefore, the modified intention-to-treat population included 42 patients in the EIT group and 40 in the control group. In the EIT group, the multicomponent strategy included EIT monitoring, recruitment maneuvers, decremental PEEP titration, repeated reassessment, and individualized PEEP selection based on the intersection of regional collapse and overdistension curves. The co-primary physiologic outcomes were PaO₂/FiO₂ and static respiratory system compliance (Cstat), assessed longitudinally over 3 days. Secondary outcomes included mechanical power (MP), Sequential Organ Failure Assessment (SOFA) scores, ventilator-free days, ICU length of stay, barotrauma, and 28-day mortality. Prespecified exploratory analyses evaluated physiologic responses according to pulmonary contusion status. This study was powered for physiologic endpoints rather than clinical outcomes. RESULTS: PaO₂/FiO₂ improved in both groups, with greater increases in the EIT group during Days 1-3 (Sidak-adjusted p < 0.05). Overall Cstat trajectories were similar between groups. The EIT-guided individualized ventilation strategy was associated with improved oxygenation without increases in plateau pressure or driving pressure. No differential temporal pattern in MP normalized to predicted body weight (MP/PBW) was observed, although overall values were modestly higher in the EIT group. Secondary clinical outcomes were broadly similar between groups. Exploratory analyses suggested greater SOFA score reduction and shorter ICU length of stay in the EIT group. Duration of mechanical ventilation, ventilator-free days, and 28-day mortality were similar between groups. Exploratory subgroup analyses suggested selected later improvements in Cstat among patients without pulmonary contusion, whereas MP/PBW was modestly higher in the EIT group across subgroups. CONCLUSIONS: In trauma- and postoperative-associated ARDS, an EIT-guided individualized ventilation strategy was associated with improved oxygenation compared with a lower-PEEP/FiO₂ strategy, while maintaining plateau and driving pressures within lung-protective ranges. These findings suggest the physiological feasibility of this strategy, but do not establish the independent effect of EIT monitoring or the underlying mechanistic pathway. Larger multicenter studies are needed to determine mechanisms and effects on patient-centered outcomes.