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Hydrodynamics of the new Medos aortic cannula
Anja Gerdes1, Thorsten Hanke, Hans-H Sievers
1Department of Cardiac Surgery, Medical University of Lübeck, Germany.
Background:
Postoperative neurologic complications in cardiac surgery patients are considered to be associated with the design of an aortic cannula and its hydrodynamic profile. To gain knowledge about the hydrodynamics of a new cannula type, based on the integration of a helical stator in its tip, was the aim of the present study.
Methods:
Pressure gradients and back pressures of the new Medos aortic cannula were measured and compared with a commonly used single-stream cannula at varying flow rates in a mock circulation. Additionally, flow visualization was performed by ink injection.
Results:
Pressure gradients across the Medos cannula were 25.5-31.8% lower at all flow rates measured when compared to the reference cannula. Back pressures of the Medos cannula were 64.1-67.9% lower than reference back pressures.
Conclusions:
The Medos cannula provides improved hydrodynamic characteristics, probably reducing the risk of atherosclerotic embolism and cerebral malperfusion by avoidance of high back pressures and sandblasting effect.