Power port contrast medium flushing and trapping: impact of temperature, an in vitro experimental study

Gérard Guiffant,¹ Jean Jacques Durussel,¹ Patrice Flaud,¹ Laurent Royon,¹ Pierre Yves Marcy,² Jacques Merckx<sup>1,3

1</sup>University Paris Diderot, Paris, France; ²Radiodiagnosis and Interventional Radiology Department, Caen, France; ³University Teaching Hospital Necker-Enfants Malades, Paris, France

Purpose: The use of totally implantable venous access devices (TIVADs) certified as "high pressure resistant" or "power port" has begun to spread worldwide as a safe procedure for power contrast injection. Owing to the thermo-rheological properties of the contrast media, the primary aim of this work is to present an in vitro experimental impact study concerning the impact of the temperature level on flushing efficiency after contrast medium injection. Moreover, we report experimental data that confirms the role of needle bevel orientation. The secondary aim is to answer the following questions: Is there significant device contrast medium trapping after contrast medium injection? Is saline flushing efficient? And, finally, is it safe to inject contrast medium through an indwelled port catheter?
Results: The experimental results show that in addition to hydrodynamics, temperature is a key parameter for the efficiency of device flushing after contrast medium injection. It appears that this is the case when the cavity is incompletely rinsed after three calibrated flushing volumes of 10 mL saline solution, even by using the Huber needle bevel opposite to the port exit. This leads to a potentially important trapped volume of contrast medium in the port, and consequently to the possibility of subsequent salt precipitates and long term trisubstituted benzene nuclei delivery that might impair the solute properties, which may be further injected via the power port later on.
Conclusion: We thus suggest, in TIVADS patients, the use of a temporary supplementary intravenous line rather than the port to perform contrast medium injections in daily radiology routine practice.

Keywords: contrast medium, implantable ports, totally implantable venous access devices (TIVADs), flushing, obstruction, prevention, central lines