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Central Venous Catheters for Dialysis (CVCDs)
Catheter Related Bloodstream Infection (CRBSI) |
The
use of central venous catheters (CVCs) either in chronic or acute
care settings are not without their challenges. The most frequently
reported complications associated with CVCs are the high incidence
of catheter-related bloodstream infections (CRBSI), development of
biofilm on the catheter wall surfaces and poor blood flow rates as
a result of clotting, blockages and sheaths. The failure rates
of central venous catheters as a result of these complications are
significant and quite often require the removal of the catheter prematurely.
Failure
Rates of Catheters & Ports Due to CRBSI* |
Non-tunneled catheters
(acute) |
16.5% / month |
66.1% / 6 months |
Tunneled catheters (long
term) |
10.0% / month |
46.9% / 6 months |
PICC lines |
6.5% / month |
33.2% / 6 months |
Implantable ports |
3.3% / month |
18.2% / 6 months |
*Source:
Calculated from data by Alan D. Tice, MD,
FACP, Infections Limited, University of Washington
The most common causes of CRBSI are:
- Intraluminal bacterial migration from contaminated catheter hubs
- Intraluminal bacterial growth in biofilm on the surface of the
catheter walls
- Migration of bacteria throughout the bloodstream exposing all
cells
- Both gram positive (65%) and gram negative (35%) bacteria are
present in CRBSI infections in dialysis patients
A major contributor to the rising incidence and reoccurrence of
CRBSI is the development of biofilm on catheter surfaces. Microbial
biofilm develops when microorganisms irreversibly adhere to catheter
surfaces and produce extra-cellular polymers that facilitate adhesion
and provide a structural matrix for growth. Biofilm-associated
microorganisms behave differently from planktonic (freely suspended)
organisms with respect to their growth rates as well as their ability
to resist antimicrobial treatments such as antibiotics. The
eradication of biofilm with today’s therapeutic options is
nearly impossible. As a result, the development of biofilm
in a CVC is a near certainty. Not only does it promote the
growth of bacteria, it plays a significant role in the escalating
antibiotic resistance rates and high morbidity and mortality of patients
who develop CRBSI.
In addition to the development of biofilm and
the high incidence of CRBSI, another common complication of CVCs
is poor blood flow (patency) rates. According to the National
Kidney Foundations KDOQI Guidelines sufficient blood rates for a
CBCD are defined as 300 mL/min., however, most healthcare professionals
would view this as a minimum and are more realistically targeting
400 mL/min. Attaining these flow rates for long periods is nearly
impossible with current catheter designs.
The
most common causes of poor catheter blood flow (patency):
- Blockages form within the lumen
- Clotting at the tip of the catheter
- Development of fibrous sheaths (“bio sheath”) outside
the flow passages (small holes in the catheter lumen) and in the
tip of the catheter
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