Exploring the association of two oxygenators in parallel or in series during respiratory support using extracorporeal membrane oxygenation.

Objective: To characterize the pressures, resistances, oxygenation, and decarboxylation efficacy of two oxygenators associated in series or in parallel during venous-venous extracorporeal membrane oxygenation support.

Methods: Using the results of a swine severe respiratory failure associated with multiple organ dysfunction venous-venous extracorporeal membrane oxygenation support model and mathematical modeling, we explored the effects on oxygenation, decarboxylation and circuit pressures of in-parallel and in-series associations of oxygenators.

Results: Five animals with a median weight of 80kg were tested. Both configurations increased the oxygen partial pressure after the oxygenators. The return cannula oxygen content was also slightly higher, but the impact on systemic oxygenation was minimal using oxygenators with a high rated flow (~ 7L/minute). Both configurations significantly reduced the systemic carbon dioxide partial pressure. As the extracorporeal membrane oxygenation blood flow increased, the oxygenator resistance decreased initially with a further increase with higher blood flows but with a small clinical impact.

Conclusion: Association of oxygenators in parallel or in series during venous-venous extracorporeal membrane oxygenation support provides a modest increase in carbon dioxide partial pressure removal with a slight improvement in oxygenation. The effect of oxygenator associations on extracorporeal circuit pressures is minimal.