Effect of Structural Changes in Extracorporeal Membrane Oxygenation Return Cannulas on Hemodynamic Performance and Blood Damage Associated with Cannulation

Purpose: This study aimed to investigate the effects of different arterial cannula models on hemodynamic performance and blood damage associated with femoral artery cannulation in venoarterial extracorporeal membrane oxygenation (VA-ECMO). Methods: Eleven cannula models were constructed and processed to study their hydrodynamic performance and hemolysis in a circulated loop. All circulation environments were analyzed using computational fluid dynamics to investigate hemodynamic changes under different ECMO flow conditions. Results: The multiple side-hole cannula structure effectively reduces the cannula pressure drop and ECMO blood pumping rate compared to cannula without side holes, thereby reducing overall blood damage in the ECMO circulation. The cannula pressure drop decreased with increasing number of side holes and became the lowest in the four and six-side-hole cannula models. A gradual increase in the number of cannula side holes improved the lower limb blood diversion ratio of ECMO, and this increase was less pronounced with a higher number of side holes. Adding a lower-extremity diversion hole can further increase the level of lower-extremity perfusion. The overall hemolytic damage in the ECMO circuit decreased gradually with an increasing number of cannula-side holes, reaching to the lowest levels in the 4 and 6-side hole cannulation models. The lower extremity blood flow rate reduced after the cannula was implanted into the vessel, forming an area of high blood retention and platelet activation in the cannula vicinity, with a greater risk of thrombosis. Conclusion: Cannula structure plays an important role in determining ECMO limb perfusion distribution, hemolysis, and thrombosis risk. A modest increase in the number of cannula side holes and cannula size could improve lower-limb perfusion and reduce the risk of hemolysis and thrombosis. Adding a lower limb diversion structure to a multiple side-hole cannula can further improve lower extremity diversion and reduce the risk of hemolysis and thrombosis.