چكيده به لاتين
Extracorporeal Membrane Oxygenation (ECMO) is a cardiopulmonary device which supports blood circulation and/or respiratory system of the patients with severe cardiac and/or respiratory problems during and after surgeries. Cannula is part of this machine which is the interface between patient’s body and ECMO. This component is designed in different shapes with different application. The main role of cannula is to provide the maximum flow without causing any damage to the blood cells and it is chosen by the specialists based on the required flow and patient’s anatomy. Two of the most common damage is hemolysis and clot formation which are the results of high shear stress and stagnation areas.
This project investigates the geometrical parameters of one of the newest geometries of cannula with application of veno-venous ECMO. This cannula has two lumen which extracts deoxygenated blood from one of them, and infuse oxygenated blood from another one. With this aim, first, the investigated geometry is modeled in SOLIDWORKS Software. Then, Computational Fluid Dynamics (CFD) simulation of the model is implemented considering blood as Newtonian fluid. In the next step, the modeled geometry was build and the complete circuit of the simulation was assembled.
The simulation was validated using experimental data including pressure and flow rate. In the end, by changing different geometrical parameters of the cannula, such as the number of side holes, their diameter etc. hemodynamics parameters of the flow are monitored and analyzed due to critical values of blood.
Results show that increasing the number of side holes and their diameter improves the flow characteristic in the cannula. On the other hand, increasing the longitudinal distance between the holes’ row decreases the overall flow rate of drainage lumen and increases the maximum wall shear stress and average shear rate. Moreover, increasing the number of down side holes enhances the shear stress field, maximum wall shear stress and shear rate. However, increasing the number of upper side holes results in reducing the flow rate from tip of the cannula. In the end, considering the interaction of down and upper side holes, it is recommended to do a multi-optimization study on achieved effective parameters to find the best values.