Long-Term Venovenous Connection for Extracorporeal Carbon Dioxide Removal (ECCO2R)–Numerical Investigation of the Connection to the Common Iliac Veins

Abstract

Purpose-Currently used cannulae for extracorporeal carbon dioxide removal (ECCO 2 R) are associated with complications such as thrombosis and distal limb ischemia, especially for long-term use. We hypothesize that the risk of these complications is reducible by attaching hemodynamically optimized grafts to the patient's vessels. In this study, as a first step towards a long-term stable ECCO 2 R connection, we investigated the feasibility of a venovenous connection to the common iliac veins. To ensure its applicability, the drainage of reinfused blood (recirculation) and high wall shear stress (WSS) must be avoided. Methods-A reference model was selected for computational fluid dynamics, on the basis of the analysis of imaging data. Initially, a sensitivity analysis regarding recirculation was conducted using as variables: blood flow, the distance of drainage and return to the iliocaval junction, as well as the diameter and position of the grafts. Subsequently, the connection was optimized regarding recirculation and the WSS was evaluated. We validated the simulations in a silicone model traversed by dyed fluid. Results-The simulations were in good agreement with the validation measurements (mean deviation 1.64%). The recirculation ranged from 32.1 to 0%. The maximum WSS did not exceed 5.57 Pa. The position and diameter of the return graft show the highest influence on recirculation. A correlation was ascertained between recirculation and WSS. Overall, an inflow jet directed at a vessel wall entails not only high WSS, but also a flow separation and thereby an increased recirculation. Therefore, return grafts aligned to the vena cava are crucial. Conclusion-In conclusion, a connection without recirculation could be feasible and therefore provides a promising option for a long-term ECCO 2 R connection.

In Vitro and In Vivo Feasibility Study for a Portable VV-ECMO and ECCO2R System

“…Our study showed the need for the investigation of the safe deployment of existing cannulas in different inlet and outlet positions in the relevant vessels, especially with respect to the altered hemodynamics of a sitting or mobilized patient. Due to the limitations of the currently available single-and dual-lumen cannulas, new concepts for the patient-ECMO interfaces seem necessary to provide efficient gas-transfer rates and simultaneously safe mobilization of the patient [45].…”

Oxygenation performance assessment of an artificial lung in different central anatomic configurations

“…Different anatomical positions of a possible connection of an AL may influence gas exchange properties. Steuer et al 5 aimed to create a venovenous connection to the common iliac veins. A peripheral cannulation was used also by Reng et al 6 for their pumpless extracorporeal lung assist.…”

Inflow from a Cardiopulmonary Assist System to the Pulmonary Artery and Its Implications for Local Hemodynamics—a Computational Fluid Dynamics Study

“…Computational fluid dynamics (CFD) has proved to be a valuable tool to investigate the flow in blood vessels, providing data of high spatial and temporal resolution, for example, of the aorta [ 10 – 12 ] or the PA [ 13 – 15 ]. The changes induced by the inflow jet from a graft [ 16 – 18 ] or cannula [ 11 , 19 , 20 ] have been investigated, showing, among others, nonphysiologic flow patterns and high wall shear stress (WSS) in the inflow region. The reinfusion of graft flow to the PA has, however, not yet been investigated.…”