In vitro clotting technique for hemodialysis circuits

Area of Science:

• Biomedical Engineering
• Nephrology
• Materials Science

Background:

• Hemodialysis extracorporeal circuits are prone to blood clotting, impacting circuit performance and patient safety.
• Accurate simulation of in vivo clotting is crucial for developing and testing new dialysis technologies.
• Existing in vitro methods may not fully replicate the complex clotting processes observed in clinical settings.

Purpose of the Study:

• To develop and validate a novel in vitro method for inducing and controlling physiologic blood clotting in a hemodialysis circuit.
• To assess the distribution and impact of induced clotting on dialyzer performance and solute clearances.
• To establish a reliable model for qualitative assessment of hemodialysis extracorporeal circuits.

Main Methods:

• A closed-loop in vitro system using defibrinated bovine blood was employed.
• Controlled, slow infusion of ACD bovine plasma (5-15 ml/hr) was used to induce gradual clotting.
• Clotting extent (10-40% dialyzer volume reduction) was achieved and monitored over approximately 100 minutes.

Main Results:

• The in vitro clotting method successfully mimicked the appearance and distribution of clots seen in clinical dialysis circuits.
• Clots were observed in the venous drip chamber filter, non-streamlined bloodline areas, and dialyzer fibers/header space.
• Dialyzer performance correlated with fiber bundle volume (FBV); solute clearances (urea, creatinine, vitamin B12) and ultrafiltration coefficient (kUF) showed predictable relationships with FBV.

Conclusions:

• The developed in vitro clotting method provides a realistic simulation of hemodialysis circuit clotting.
• This technique allows for controlled induction of clotting, enabling qualitative assessment of extracorporeal circuit performance.
• The findings support the utility of this method for research and development in hemodialysis technology.