Temperature characteristics of extracorporeal membrane oxygenation system for children in vitro model

Heart transplantation in children is not permitted and ventricular assist device of children has not developed in Japan. An operation or an adjunct treatment by extracorporeal membrane oxygenation (ECMO) is an exclusive treatment of the children with severe cardiac failure. However, the ECMO system for children is behind developing in comparison with one for adults. In particular, the ECMO system can cause the problems which deteriorate the patients' conditions. Major problems of the ECMO system are as follows: priming volume and blood-contacting surface area in the ECMO system are large for children. Therefore, it is necessary that ECMO device will be developed to improve the treatment outcome. Our future goal is to downsize the ECMO device. In this fundamental research, we focused on evaluating the temperature characteristics of the ECMO system. Our experimental devices consisted of two parts: a simulated patient's side and the ECMO system's side. We measured temperature differences between inlet and outlet of the ECMO system under the seven experimental conditions. We compared temperature differences between ECMO control conditions: fluid flow rate, V/Q (oxygen flow rates/fluid flow rates), temperature around ECMO system and temperature of inlet oxygen gas. The results showed that the temperature differences were significantly influenced by V/Q and temperature around ECMO system. There were no significant differences with temperature of inlet oxygen gas. In conclusion, we found that the ECMO system can have the thermal heating effect when the temperature around ECMO system was at 43 degrees Celsius, and oxygen flow rate was 5.0 L/min. These results suggested that we would develop the small applicable heating system instead of the conventional large heat exchanger, and it would realize that the ECMO system could be downsized.