Shear Stress, Energy Losses, and Costs: A Resolved Dilemma of Pulsatile Cardiac Assist Devices
Figure 5
Pulsatile flow pulse pressure (a) and systolic pressure (b). Energy losses with different tube positions: I is 6 cm from aortic cannula; II is 150 cm from aortic cannula; III is pre-oxygenator. P1–P5 are perfusion pressure records (mmHg) at main circuit energy losses spots. At P5 the pulse pressure (a) as well as the systolic pressure (b) were significantly higher in position I (red color) compared to other position II (blue color) and III (violet color). Circuit I: P1, P2 are pre/post-oxygenator pressure; P3, P4 are pre/post-tube. Circuit II: P1 is pre-oxygenator; P2, P3 are pre/post-tube; P4 is pre-aortic cannula. Circuit III: P1, P2 are pre/post-tube; P3 is post-oxygenator; P4 is pre-aortic cannula. P5 is post simulated resistance in all circuits. Pm is mean pulsatile pressure; Ps: systolic pulsatile pressure, Pd: pulsatile diastolic pressure; PP: pulse pressure. Pulse pressure was higher at P5 in circuit I, compared with II and III. Pm was higher at P5 compared to NP with position I ().
