Abstract
Introduction: Increasing numbers of end-stage renal disease patients are becoming dependent on hemodialysis catheters (HCs) for chronic hemodialysis access. Recirculation measurement is considered as useful to check for inadequate catheter blood flow and blood clots at the catheter tip. HCs normally have the outflow tip extending approximately 2 to 3 cm beyond the inflow tip to prevent blood recirculation (R) during dialysis. The purpose of this study is to assess the accuracy of recirculation measurements based on the thermal dilution technique.
Methods: R was measured in-vitro with a blood temperature monitor (BTM, Fresenius Medical Care, Germany) using temperature sensors placed on the arterial and venous segment of the extracorporeal blood line. Hereby R was physically prevented by placing a flexible hose over the venous outflow tip of the catheter.
Results: Recirculation with standard lumens of well-functioning catheters is normally negligible. However, thermal dilution techniques applied to dual lumen catheters always result in positive R values which increase with decreasing blood flow. As arterial and venous catheter lumens are in direct contact, temperature boli which are injected in the venous lumen are partly transferred through the catheter wall to the arterial lumen.
Conclusion: BTM thermodilution measurements with non-recirculating dual lumen catheters always yield positive recirculation results. Furthermore the displayed R value is dependent on extracorporeal blood flow and decreases with increasing flow.
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© 2009 Springer-Verlag Berlin Heidelberg
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Mohr, C., Kleinekofort, W. (2009). In-vitro Validation of Catheter Recirculation Measured by Thermal Dilution. In: Dössel, O., Schlegel, W.C. (eds) World Congress on Medical Physics and Biomedical Engineering, September 7 - 12, 2009, Munich, Germany. IFMBE Proceedings, vol 25/7. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-03885-3_142
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DOI: https://doi.org/10.1007/978-3-642-03885-3_142
Publisher Name: Springer, Berlin, Heidelberg
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