Therefore, we evaluated the sterility and maintenance of artificial lung performance in ECMO circuits containing artificial lungs with silicone membranes having porous polypropylene hollow fiber as support during 30 days of storage. The ECMO circuit used was the MERA Exceline circuitHP2 “#ST SOLAS23H-CSP3 Hepa”(SENKO MEDICAL INSTRUMENT Mfg. CO., LTD.). The ECMO circuits were categorized into a dry group(n=5), which were kept in an unfilled condition, and a wet group(n=5), which were filled and primed. Bacteriological tests included bacterial culture evaluation using a BHI medium and endotoxin evaluation. Furthermore, oxygen transfer, carbon dioxide transfer, and pressure drop were assessed as part of the artificial lung performance evaluation.