Comparison of symmetrical hemodialysis catheters using computational fluid dynamics

Purpose: Symmetric-tip dialysis catheters have become alternative devices because of low access recirculation and ease of tip positioning. Flow characteristics of three symmetric catheters were compared based on computational fluid dynamics (CFD) as they relate to catheter function. Materials And Methods: In Palindrome, GlidePath, and VectorFloW catheters, a computational fluid dynamics based approach was used to assess W regions of flow separation, which are prone to thrombus development; (ii) shear-induced platelet activation potency; (iii) recirculation; and (iv) venous outflow deflection. A steady-state, laminar flow model simulated: catheter tip position within the superior vena cava. Catheter performance was investigated at high hemodialysis flow rate (400 mL/min). Blood was assumed as a Newtonian fluid. Results: Wide regions of flow separation downstream of the Palindrome side slot and close to the distal tip were observed in forward and reversed line configurations. Geometric asymmetry of the distal guide wire aperture of the GlidePath catheter produced the highest levels of inverted velocity flow when run in reversed configuration. The lowest mean shear-induced platelet activation was exhibited by GlidePath and VectorFloW catheters; the Palindrome catheter exhibited 152% higher overall platelet activation potency. All catheters were associated with a recirculation close to zero; the helically contoured lumens of the VectorFlow catheter produced the greatest amount of deflection of venous flow away from the arterial lumen. Conclusions: The VectorFlow catheter produced less shear-induced platelet activation than the Palindrome catheter and less flow separation than the Palindrome and GlidePath catheters irrespective of line configuration These findings have,potential implications for differences in thrombogenic risk during clinical performance of these catheters

Experimental study of the flow field in patient specific lower airways

In this study Particle Image Velocimetry (PIV) is used to visualize and measure airflow in the lower airways. Using Rapid Prototyping Manufacturing (RPM) technology, a hydraulic in vitro model was developed and constructed. Preliminary 2D PIV measurements compared successfully to Computational Fluid Dynamics (CFD) results

Swirlgraft versus conventional straight graft as vascular access: a full CFD-analysis

Two 3D models of an arterio-venous graft, a connection between an artery and a vein as vascular access for hemodialysis, were studied. One model of a conventional straight loop graft, the other of a graft with helical configuration (e.g. SwirlGraft (Veryan Medical, London, UK)). The statement that the helical design reduces Intimal Hyperplasia (IH) formation was studied by evaluating low wall shear stress and high oscillatory shear stress zones next to the helicity flow index. The IH-inducing zones were reduced but were not eliminated and the helicity of the flow was increased. The statement that the SwirlGraft avoids stenosis should however be considered with care in clinical practice

Multiplane Scanning Stereo PIV for Biofluid Applications

The aim of this project is to map the 3D intracardiac spatiotemporal structure flow by mean phase-locked Stereo-PIV. The developed setup permits the flow field measurment in the whole left ventricle model without repeating the complex stereo calibration. It consisted of coupling Stereo-PIV apparatus and cardiovascular simulator system

Is healthcare ready for a digital future?

While digital transformation is widespread in industry, health-care has only started to follow a similar path in the last few years, with COVID-19 leading to rapid acceleration. With the rise of the Internet of Medical Things, integrated care networks and connected healthcare, new opportunities emerge