Application of finite element analysis for assessing biocompatibility of intra-arterial catheters and probes.

A commercial finite element modeling program (FIDAP) was adapted to compute the fluid dynamics of laminar blood flow around an intra-arterial catheter and/or sensor probe. The model provided an accurate transient solution to the Navier-Stokes equations under pulsatile blood flow conditions. To simulate the compliance in the catheter tubing set, a second order convolution integral was incorporated into the boundary conditions. The saline drip rate and catheter compliance could be specified, and the bulk blood flow, blood pressure, and heart rate were varied to simulate specific patient conditions. Analysis of the transient solution was used to assess probable sites for thrombus activation and deposition. The transient velocity and pressure fields identified regions of separated flow and recirculation. The computed shear rates and stresses were used to predict hemolysis, platelet activation, and thrombus formation. Analysis of particle paths provided an estimate of residence times and thrombus deposition sites.