[Therapy of ARDS. 1. Current therapeutic strategy including extracorporeal gas exchange]

Recent studies and reviews continue to report a high mortality associated with the acute respiratory distress syndrome (ARDS), which involves a severe inflammatory reaction within the whole lung that is frequently associated with multiple-organ failure. Important factors contributing to the poor results in severe ARDS are the aggressive procedures required to maintain sufficient arterial oxygenation, such as mechanical ventilation with high inspiratory pressures and high inspired oxygen concentrations (FiO2) which themselves contribute to the progression of the disease. As no specific therapy that reduces or prevents the general inflammatory reaction is known, current therapy is limited to procedures that minimize peak inspiratory pressures and FiO2. Therefore, pressure- and volume-limited ventilation modes with positive end-expiratory pressure, controlled hypercapnia, differential lung ventilation when appropriate, positioning (particularly prone), and aggressive dehydration are used. Should these procedures fail to improve arterial gas exchange, the patients may be additionally treated by veno-venous extracorporeal gas exchange. To reduce the risk of severe haemorrhagic complications due to high levels of systemic heparinization, systems internally coated with covalently bound heparin, which allow a lower level of systemic anticoagulation, should be used. From April 1989 to August 1993, 89 patients were transferred to our intensive care unit for treatment of severe ARDS; 52 were treated by combining the described conventional methods without artificial gas exchange (survival rate 88%) and 37 additionally underwent artificial gas exchange (survival rate 57%). The overall survival rate was 75%. On the basis of these experiences, we conclude that this step-by-step approach may improve survival in patients with severe ARDS.