Investigating the Hydrodynamics of Intravenous Drug Infusions.

One of the most common reported adverse events for intravenous (IV) infusions are infusion site reactions, ranging from redness and pain at the site of infusion to thrombophlebitis.  The connection between drug infusion and what drives these adverse events is not well understood. To aid in understanding these phenomena, it is crucial to accurately characterize the evolving hemodynamic environment of the infusion site when developing new intravenous formulations, as too rapid dilution may cause precipitation in the vein, while too little dilution might contribute to phlebitis. In this study, a Large-Eddy Simulation (LES) turbulence modeling inside a Computational Fluid Dynamics (CFD) framework has been used to simulate the flow and mixing characteristics of an infusion entering the bloodstream. This work represents the first such study reporting transient flow fields for intravenous infusions using LES CFD simulations with a realistic non-Newtonian blood model. The output of the CFD model closely resembled the flow and mixing patterns generated in benchtop tests for infusions into a blood analogue and water as the venous fluid across a wide range of flow rates.  These models were then investigated further to compare how changes to the fluid rheology model, needle orientation and needle position within the vein resulted in altered mixing regimes at different flow rates.