ABSTRACTS from 16th International COnference on ... - CRRT Online

A09
Vascular Access /Membrane and Circuit
Luis Juncos MD
8:15-9:45
Wednesday, February 15
Educational Objectives:
1. To describe the fundamentals of hemodialysis catheters and their importance in maintaining adequate blood
flow and circuit patency during CRRT.
2. To describe the basic characteristics of hemofiltration membranes and the different mechanisms by which
they clear solutes <strong>from</strong> the blood.
3. To describe a typical CRRT circuit and discuss the practical issues related to the circuits during the different
CRRT modalities.
Content Description:
To obtain maximum benefit of CRRT, one must achieve the therapeutic goals including the delivery of an appropriate
dose. However, delivery of the prescribed dose of CRRT is frequently not accomplished for a variety of
reasons. These include the frequent existence of a large amount of down time because of premature clotting or
failure of the extracorporeal circuit, as well as the presence of suboptimal blood flows (which not only can
decrease clearance, but also contributes to premature clotting). Moreover, frequent clotting/failure of the CRRT
circuit not only leads to decreased dose delivery, but has many other important implications such as blood loss,
irregular clearance that can cause suboptimal dosing of medications (e.g. antibiotics), and increase costs.
Consequently, it is important to identify the cause of premature circuit failure and suboptimal dosing so that the
cause can be specifically addressed. In this respect it is important to note that while insufficient anticoagulation
is commonly assumed to be the most frequent cause of premature clotting, suboptimal blood flow mechanics
within the circuit due to a poorly functioning/placed hemodialysis access is often (if not most often) the culprit.
Thus, in order to better identify and address the cause of premature/frequent circuit clotting, it is essential that
one understands the fundamentals of the CRRT circuit and membrane, and how they interact. This presentation
will describe the fundamental concepts of the structure and function of dialysis catheters, CRRT circuits and
membranes, as well as their interactions in determining the function of CRRT.
Suggested Reading:
1. Vascular Access Work Group: Clinical practice guidelines for vascular access. Am J Kidney Dis 48(Suppl.
1):S248–S273, 2006.
2. Schwab SJ, Beathard G. The hemodialysis catheter conundrum: Hate living with them, but can’t live without.
Kidney <strong>International</strong> Vol 56 (1999); 1-17.
3. Vijayan A. Vascular access for continuous renal replacement therapy. Semin Dial. 2009 Mar-Apr;22(2):133-6.
Review.
4. Wentling AG. Hemodialysis catheters: materials, design and manufacturing. Contrib Nephrol. 2004;142:112-
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5. Uchino S, Fealy N, Baldwin I, Morimatsu H, Bellomo R. Continuous is not continuous: the incidence and
impact of circuit "down-time" on uraemic control during continuous veno-venous haemofiltration. Intensive Care
Med. 2003 Apr;29(4):575-8.
6. Parienti JJ, Mégarbane B, Fischer MO, Lautrette A, Gazui N, Marin N, Hanouz JL, Ramakers M, Daubin C,
Mira JP, Charbonneau P, du Cheyron D; Cathedia Study Group. Catheter dysfunction and dialysis performance
according to vascular access among 736 critically ill adults requiring renal replacement therapy: a randomized
controlled study. Crit Care Med. 2010 Apr;38(4):1118-25.
7. Parienti JJ, Thirion M, Mégarbane B, Souweine B, Ouchikhe A, Polito A, Forel JM, Marqué S, Misset B,
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