Extracorporeal Membrane Oxygenation (ECMO) is a life support device for patients with severe heart and/or lung failure. Emergency situations require immediate ECMO response. Primed circuits have become a routine practice, as it may take 30-60 min to assemble and prime. There remains a lack of data to support the sterility of primed and stored ECMO circuits. This bench study assessed the impact of storage environment and priming solution on specific microbial growth of primed ECMO circuits.

Twelve adult ECMO circuits were tested for sterility for 56 days between September-December 2020. Circuits were assembled and primed in a perfusion lab in Chicago, IL. Six were stored in a sterile environment and six in a non-sterile environment, with three circuits primed using normal saline (NaCl) and three with Plasmalyte-A for each environment. Samples were collected on days 0, 3, 7, 14, 28, 42, and 56 in anaerobic bottle cultures testing for potential pathogen growth, such as Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli.

Samples obtained from the 12 primed ECMO circuits demonstrated no microbial growth of S. aureus, P. aeruginosa, and E. coli in the bottle cultures. Similarly, there was no difference in the circuit sterility based on the storage environment (sterile vs nonsterile) or priming solution (NaCl vs Plasmalyte-A).

Our findings showed that ECMO circuits can be primed for 56 days without evidence of the specified bacterial growth. Furthermore, the storage conditions and the prime utilized did not affect the sterility of the primed ECMO circuits.