"When it comes to infection of the port cavity, the design of the chamber plays a key role: the more sharp edges there are in the port cavity, the greater the risk of deposition of blood components, which in turn provide a good breeding ground for germs of all kinds."
Source: Haind H., Müller H., Schmoll E. (eds) 1993,
Port Catheter Systems, p. 176 "Port Infection"
The measurable difference
In the FDA guidelines for the approval of ports, a defined measurement setup* is described, the so-called "Clearing Index". This indicates how much flushing volume is required to flush out (clean) a port chamber without leaving any residue. This test has also been adopted in the ISO standard for port catheter systems 10555-6**.
This can be used to illustrate the measurable differences between different port designs.
In a study by Norfolk Medical Inc., USA ***, the respective flushing characteristics were compared in a measurement of four different port systems. The difference between the system with a conventional cylindrical port chamber and central catheter outlet and our NuPort® chamber geometry with tangentially positioned catheter outlet is clear.
Almost 40% more flushing volume is required with a conventional port for residue-free flushing.
The chamber geometry therefore makes the decisive difference in the flushing (cleaning) of port systems. Under certain circumstances, this is precisely the difference that prevents occlusion of the port system.
Average values chamber flushing volume*
|Port||Port Chamber||Flushing volume difference in percent|
central baseline outlet
|Conventional Port A
High Pressure Injection
|Conventional Port B
* FDA "Guidance on 510(k) Submissions for Implanted Infusion Ports".
** DIN EN ISO 10555-6, Annex B "Determination of the flushing volume (clearing index)".
*** Measured values determined by Norfolk Medical, Inc. USA with reference to FDA "Guidance on 510(k) Submissions for Implanted Infusion Ports" and DIN EN ISO 10555-6