Three-Dimensional Fluid-Structure Interaction Reveals Trade-offs Among Oxygen Delivery, Shear, and Washout in Pediatric Roller-Pump Cardiopulmonary Bypass

In pediatric roller-pump cardiopulmonary bypass simulations, 10 settings delivering ~9–12 mL/min oxygen showed peak shear stress spanning ~25–70 pascals due to different flow environments.

• Why it matters: Oxygen delivery targets can mask harmful trade-offs between shear exposure and washout, so joint assessment is needed to choose roller speed, occlusion, and hematocrit.
• What they did: A 3D closed-loop fluid-structure interaction model ran 40 simulations across roller speeds 38–95 rpm, occlusion 77% vs 83%, and hematocrit 15%–50%, quantifying oxygen delivery, peak shear stress, and viscosity-normalized relative residence time.
• The result: Flow rose nearly linearly with speed and increased with occlusion with little hematocrit dependence, while higher speed/occlusion increased peak shear and reduced residence time; within an illustrative oxygen threshold, lower hematocrit enabled lower shear and residence time.