Skip to main content

Removal of drug delivered via a central venous catheter by a dual-lumen haemodiafiltration catheter inserted at the same site: a quantitative flow model


The objectives of this study were to model and visualise flow in a central vein during continuous venovenous haemodiafiltration (HDF), to measure drug removal when an HDF catheter is co-located with a central venous catheter (CVC) infusing medication. Dual lumen HDF catheters are commonly used to deliver continuous venovenous renal replacement therapy in critical care. These catheters are often co-located with a CVC used to infuse drugs, with the tips lying in close approximation in a great vein. The effect of this co-location on drug delivery to the patient due to aspiration by the HDF machine may be of serious import, with the elimination of important vasoactive drugs or minimally protein-bound antibiotics just two possibilities. This effect has never been studied.


A model of a human central vein was constructed using transparent polyvinyl chloride piping. A CVC and an HDF catheter were inserted into this and water flow in the central vein and extracorporeal circuit was generated by centrifugal pumps at physiological volume flow rates. Ink was used as a visual tracer and creatinine solution as a quantifiable tracer to determine the extent of removal of CVC infusate via the HDF catheter. The longitudinal distance of the CVC infusion point from the arterial port of the HDF catheter was altered to quantify its effect on tracer removal.


Volume flow rates of 1.45 l/minute and 200 ml/minute were achieved in the central vein model and the HDF circuit model, respectively, with laminar flow in the central vein confirmed by Duplex imaging and ink flow analysis. All visible ink and 100% of creatinine tracer infused via the CVC were aspirated by the HDF catheter unless the point of infusion was ≥1 cm downstream of the proximal aspect of the arterial port. No measurable tracer was aspirated when the infusion was ≥2 cm downstream. Orientation of side ports did not significantly affect tracer removal.


This initial study suggests that drugs infused via a CVC co-located with an in-use HDF catheter may be completely and immediately aspirated into the extracorporeal circuit. This phenomenon could lead to significant drug underdosing with potentially severely deleterious consequences for patients. When co-location cannot be avoided, drugs with important immediate effects or high membrane clearance should be infused sufficiently distal to the inlet of an adjacent HDF catheter.

Author information

Authors and Affiliations


Rights and permissions

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and Permissions

About this article

Cite this article

Kam, R., Mari, J. & Wigmore, T. Removal of drug delivered via a central venous catheter by a dual-lumen haemodiafiltration catheter inserted at the same site: a quantitative flow model. Crit Care 15 (Suppl 1), P109 (2011).

Download citation

  • Published:

  • DOI:


  • Renal Replacement Therapy
  • Central Venous Catheter
  • Polyvinyl Chloride
  • Central Vein
  • Volume Flow Rate