Blood Flow, Blood Trauma & Fluid Path Analysis in Medical Devices

Exponent’s multidisciplinary expertise provides superior technical and scientific support to assist our clients in addressing issues related to blood management and blood trauma in medical devices as well as associated intellectual property design considerations. We provide rapid, focused, market-sensitive solutions to solve a variety of challenges associated with device design, device performance, and behavior of blood within the fluid path of medical devices, using our competency in requirements definition, concept evaluation and down-selection, design input/output review, verification/validation test method development and execution, risk management for blood fluid-path devices, and experimental feasibility device evaluation. We also provide engineering analysis of the flow path for blood damage through computational fluid dynamics (CFD) modeling and additional damage models.

We can supplement clients’ process development through detailed process reviews, root-cause analysis and resolution, product lifecycle management activities (evergreen risk management processes triggered by material, supplier, or design changes; complaint and CAPA technical investigation support; and support of regulatory submissions). This capability assists our clients as they characterize the safety and effectiveness of their infusion, transfusion, collection, dialysis, cardiovascular, filtration, separation, vascular access, and other blood management devices.

Our engineers and scientists have extensive expertise in the medical device product development process, including fluid path design, biomaterial selection and characterization, preclinical test-method development and strategy, experimental and analytical performance evaluations using either custom test methods or standard tests defined by the International Organization for Standardization (ISO) and the American Society for Testing and Materials (ASTM), as well as manufacturability, regulatory, quality assurance, and post-market surveillance.

Hemolysis Index Midplane

Evaluation of Blood Component Damage Risk in the Device Fluid Path

The design of the fluid paths of medical devices and extracorporeal circuits must be done with great care to avoid shear-induced hemolysis of red blood cells and minimize platelet activation. For multiple-pass device systems, the analysis needs to expand to the full extent of the therapy time and may include the patient in the scope.

Exponent engineers and scientists are experienced in computational and experimental methods to ensure that the medical device’s design fluid path treats blood gently, and to manage the risk of damaging blood components. Computational methods are available to compute the hemolysis index for both simple and complex shapes. 

Evaluation of Pressure-drop Budget in the Fluid Path

The fluid circuit in blood processing devices includes pumps or other prime movers. The flow rate through the circuit and pressure drops across subassemblies and components need to be selected such that the propulsion of the blood through the circuit is possible, predictable, and sustainable. Developing pressure-drop budgets for subassemblies and reconciling this budget with other needs (such as separation, mass transport, or caps on hemolysis induced in the subassembly) is the fundamental trade-off in the design process. Exponent engineers and scientists are knowledgeable and experienced in this unique craft.  

Evaluation of Localized Pressure in the Fluid Path

Exponent engineers and scientists utilize computational and experimental methods to assess pressure distribution to avoid the creation of bubbles by outgassing, cavitation, or exceeding the bubble point pressure in a variety of filters and membranes. 

Identification of Stagnant Regions and Regions of Secondary Flow

Exponent engineers and scientists use computational and flow visualization techniques to assess the localized flow patterns to identify regions in the fluid path that may potentially cause localized stagnant regions, shear-induced trauma, depletion of oxygen and nutrients, build-up of waste products, and localized clotting.

Heating and Cooling of Blood and Biological Fluids

Our experience with thermal requirements and computational methods that can guide medical-device designers to achieve efficient designs for blood and biological fluid heaters and heat exchangers, under both temperature and shear-rate constraints. 

Priming Issues with Blood and Biological Fluid Paths

The lack or incompleteness of priming in such fluid paths can lead to an inability to initiate flow, as well as degradation of flow rate, loss of flow accuracy, and flow stoppage during clinical use.