Development of a compact extracorporeal membrane oxygenation (ECMO) system.

In recent years, extracorporeal membrane oxygenation (ECMO) has been used for treatment of neonates with respiratory failure. A prototype of a compact ECMO system for neonates was developed. A single-lumen catheter, inserted into the right atrium via a jugular vein, was used for withdrawal and infusion of blood through the catheter. An extracapillary flow hollow-fiber membrane lung made of microporous polypropylene has a total surface area of 0.6 m2. To prevent the increase of plasma free hemoglobin, the ratio of withdrawal/infusion is controlled by a microcomputer. The system is compact in size with a low priming volume (less than 90 ml), which allows for ECMO with no additional blood transfusions. Its potential application as a respiratory support system is evaluated in animal experiments. The total intermittent veno-veno bypass flow was 15-30 ml/min/kg. The O2 transfer rate was 20 ml/min and the CO2 transfer rate was 33 ml/min at a blood flow rate of 300 ml/min. The O2 and CO2 exchange with the ECMO system was efficient enough to eliminate the respiratory failure induced by mechanical ventilation. The increase in plasma free hemoglobin was only 4 mg/dl after 6 h of ECMO. The system was considered applicable to respiratory aid for neonates.