In the hollow fiber oxygenator design, blood flow is ________ the fiber bundle while gas flow is _________ the hollow fibers.

In the context of hollow fiber oxygenators, the blood flow is designed to move around the fiber bundle, while the gas (usually oxygen) flows through the hollow fibers. This design maximizes the interface between the blood and the gas exchange surface, facilitating efficient oxygen transfer to the blood while carbon dioxide is removed.

The arrangement allows for a large surface area for gas exchange due to the many fibers packed together, and the blood flowing around these fibers ensures that it comes into close contact with the gas that is flowing through them. This configuration aids in maintaining optimal flow dynamics and enhances the efficiency of oxygenation and decarboxylation processes.

Understanding the flow dynamics in this design is crucial as it impacts the performance of the oxygenator in clinical settings. The correct description of blood moving around the fiber bundle and gas moving through the fibers is essential for proper functioning of the device, ensuring adequate nutrition and oxygen delivery to tissues during procedures requiring cardiopulmonary bypass or intensive care scenarios.