Hemodynamic evaluation of cannulas for ECMO

Despite significant advances in extracorporeal life support (ECLS) technology, there is still a substantial risk of ECLS-related complications. Over the years, cannula problems have consistently been reported as one of the most frequent mechanical issues for both respiratory and cardiac ECLS cases. Therefore it is critical to not only improve but also optimize arterial, venous, and dual-lumen cannulas for a given ECLS circuit. Most cannula manufacturers derive their hemodynamic parameters based on evaluations performed with water, and prior evaluations of Food and Drug Administration–approved femoral arterial cannulas have revealed drastic differences between pressure-flow curves derived from water versus human blood. Additionally, other cannula characteristics like the cannula size, inner diameter, tip type, length, end-hole, and side-hole may have an impact on the hemodynamic parameters too. Furthermore, studies have also shown that cannulas of the same size from different manufacturers can perform variably. Therefore translational research is a crucial to reevaluate all cannulas in terms of flow rates, circuit pressures, pressure drops, M-numbers, and hemodynamic energy transmission prior to use in clinical application. The evaluations presented in this chapter have been performed at Penn State Children’s Hospital Pediatric Cardiovascular Research Center using identical clinical conditions for the simulated models.