Veno-venous Extracorporeal CO2 Removal in ARDS-patients to Treat Respiratory Acidosis

Hypothesis:

Extracorporeal removal of CO2 can treat hypercapnia and respiratory acidosis, which allows application of lung protective ventilation. This downgrading of mechanical ventilation promotes better and more quickly lung recovery.

Aim:

The aim of the study is to treat respiratory acidosis and to reduce plateau pressures by using an extracorporeal removal of CO2 (ECCO2-R).

This prospective study will include 10 patients with an Acute Respiratory Distress Syndrome (ARDS). ARDS is an inflammatory response in the lungs, the onset is acute with pulmonary oedema and shows bilateral densities on chest radiography. The take up of oxygen and the loss of CO2 in the lungs are difficult. Moreover the patient's blood can become acidic due to too much CO2.

To promote a better gas-exchange, the patient with ARDS will be mechanically ventilated. This can be aggressive and harmful for the lungs. With the use of an extra-corporeal CO2-remover, CO2 can be removed so that the mechanical ventilation setting will be less aggressive and will decrease lesions in the lung. The veno-venous extracorporeal CO2-remover pumps blood from a vein via a catheter through an oxygenator (gas exchanger that adds oxygen to the blood and extracts carbon dioxide from the blood) and back into a vein.

The investigators will use a standard dialysis catheter that will be put in a large vein. To prevent clotting of the system, the patient will receive heparin.

In the study the investigators will work in periods of two hours, the situation before and after carbon dioxide removal will be compared. With this study the investigators want to prove that the CO2 in the blood decreases with at least 20 % with the use of the extracorporeal CO2 remover. More over the investigators want to prove that lower mechanical ventilation settings (thanks to CO2-removal by the ECCO2-R) will produce fewer lesions to the lungs.