Hydrodynamics of the new Medos aortic cannula.
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.
Gerdes
Anja
A
Department of Cardiac Surgery, Medical University of Lübeck, Germany.
Hanke
Thorsten
T
Sievers
Hans-H
HH
D001011:Aorta; D002404:Catheterization / Q000009:adverse effects; D004867:Equipment Design; D006801:Humans; D011312:Pressure; D012039:Regional Blood Flow