Minimal-flow ECCOR in patients needing CRRT does not facilitate lung-protective ventilation.

Extracorporeal CO removal (ECCOR) is intended to facilitate lung protective ventilation in patients with hypercarbia. The combination of continuous renal replacement therapy (CRRT) and minimal-flow ECCOR offers a promising concept for patients in need of both. We hypothecated that this system is able to remove enough CO to facilitate lung protective ventilation in mechanically ventilated patients. In 11 ventilated patients with acute renal failure who received either pre- or postdilution CRRT, minimal-flow ECCOR was added to the circuit. During 6 h of combined therapy, CO removal and its effect on facilitation of lung-protective mechanical ventilation were assessed. Ventilatory settings were kept in assisted or pressure-controlled mode allowing spontaneous breathing. With minimal-flow ECCOR significant decreases in minute ventilation, tidal volume and paCO were found after one and three but not after 6 h of therapy. Nevertheless, no significant reduction in applied force was found at any time during combined therapy. CO removal was 20.73 ml CO/min and comparable between pre- and postdilution CRRT. Minimal-flow ECCOR in combination with CRRT is sufficient to reduce surrogates for lung-protective mechanical ventilation but was not sufficient to significantly reduce force applied to the lung. Causative might be the absolute amount of CO removal of only about 10% of resting CO production in an adult as we found. The benefit of applying minimal flow ECCOR in an uncontrolled setting of mechanical ventilation might be limited.