Low flow veno-venous extracorporeal CO2 removal for acute hypercapnic respiratory failure.

BACKGROUND Ventilation with low tidal volume and airway pressure results in a survival benefit in ARDS patients. Previous research suggests that avoiding mechanical ventilation altogether may be beneficial in some cases of respiratory failure. Our hypothesis was that low flow veno-venous extracorporeal CO2 removal (ECCO2R) enables maintenance of a lung protective ventilation strategy or awake spontaneous ventilation despite severe hypercapnic respiratory failure (HRF). METHODS Twenty patients with HRF were investigated while mechanically ventilated (N.=14) or breathing spontaneously close to respiratory exhaustion (N.=6). Low flow ECCO2R was performed using a hemoperfusion device with a polypropylene gas-exchanger. RESULTS Causes of HRF were severe ARDS (N.=11), COPD (N.=4), chronic lung transplant rejection (N.=3) and cystic fibrosis (N.=2). During the first 8h of ECCO2R, PaCO2 decreased from 10.6 (9.3-12.9) to 7.9 (7.3-9.3) kPa (P<0.001) and pH increased from 7.23 (7.09-7.40) to 7.36 (7.27-7.41) (P<0.05). Thereafter, steady state was achieved while maintaining lung protective tidal volume (4.7 (3.8-6.5) mL/kg) and peak ventilator pressure (28 (27-30) mbar at 24 h). During the first 48 h, thrombocyte count decreased by 52% (P<0.01), Fibrinogen by 38% (P