21 | Differential lung ventilation and extracorporeal CO₂ removal as rescue strategy in severe post-traumatic acute respiratory distress syndrome – a case report

Background. Major trauma is a recognized risk factor for Acute Respiratory Distress Syndrome (ARDS), resulting from direct lung injury (e.g. pulmonary contusions) or indirect mechanisms mediated by inflammation and endothelial dysfunction. Trauma-related risk factors include pulmonary injury, head trauma, hemorrhagic shock, massive transfusion, and long bone or pelvic fractures. Initial management relies on lung-protective mechanical ventilation with a tidal volume <6 mL/kg PBW and moderate PEEP. In cases of severe ARDS with refractory hypoxemia or hypercapnia, extracorporeal CO₂ removal (ECCO₂R) may serve as a rescue strategy, enabling CO₂ clearance and allowing ultra-protective ventilation without substantially affecting oxygenation.

Methods. A 30-year-old patient with multiple traumatic injuries was admitted and showing thoracic asymmetry and absent breath sounds on the right side, consistent with an extensive right pneumothorax. Imaging revealed multiple pulmonary contusions in both lungs, with fractures of the ribs, and sternal manubrium. After 7 days under mechanical ventilation, the patient developed severe ARDS (P/F 83). A single prone positioning attempt failed to improve oxygenation. A double lumen tracheostomy cannula was positioned to allow separate ventilation of the two lungs. Ultra-protective ventilation was set on the most injured side and enabling extracorporeal CO₂ removal during concurrent renal replacement therapy (Figure 1, AI generated).

Results. Following surgical tracheostomy and insertion of a double-lumen cannula, differential lung ventilation was initiated, using ultra-protective settings (Vt≈3.5mL/kg PBW). This maintained expired minute volumes of 1.46L/min (right lung) and 5.28L/min (left lung). Simultaneously, ECCO₂R was started via a dialysis-oxygenator circuit (blood flow ∼300mL/min; sweep gas flow 10L/min). In the first 48h, PaCO₂ progressively decreased from 95 to 49mmHg, normalizing the pH (7.03→7.27) (Figure 2). PaO₂ and the P/F ratio remained stable (155→120) despite ultra-protective ventilation and CO₂ reduction, confirming preserved oxygenation efficiency. Following improved gas exchange, the patient began a ventilator weaning protocol and was transferred to the Physical and Rehabilitative Medicine Unit on day 45.

Conclusions. The combination of differential lung ventilation and ECCO₂R during RRT allowed safe ventilation and effective CO₂ clearance in severe trauma-related ARDS refractory to conventional management. The treatment maintained stable oxygenation while improving ventilation–perfusion efficiency, suggesting feasibility and potential as a rescue strategy in selected patients.