We compared four commercially available 10F pediatric aortic cannulae with different geometric designs (DLP-Long tip, DLP-Short tip, RMI-Long tip, and Surgimedics-Short tip) during pulsatile versus nonpulsatile perfusion in terms of pressure drops and surplus hemodynamic energy (SHE) levels in an in vitro neonatal model of cardiopulmonary bypass. The pseudo patient was subjected to seven pump flow rates at 100 ml/min increments in the 400-1,000 ml/min range. A total of 44 experiments (n = 22, nonpulsatile; n = 22, pulsatile) were performed at each of the seven flow rates. Surgimedics had significantly higher pressure drops than the other three cannulae at various flow rates during nonpulsatile and pulsatile perfusion, respectively. When the perfusion mode was changed from nonpulsatile to pulsatile flow, SHE levels at both precannula and postcannula sites increased seven to nine times at all flow rates in all four cannulae. Surgimedics generated a significant lower SHE level when compared with the other three cannulae at all flow rates at both precannula and postcannula sites. The results suggest that different geometries of aortic cannulae have a significant impact on pressure drops of the cannulae as well as hemodynamic energy generation and delivery. Pulsatile perfusion generates more "extra" hemodynamic energy when compared with the nonpulsatile perfusion mode with all four cannulae used in this study.
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