Port (medical)

The port catheter (in short: Port ) is a subcutaneous, sustained access to the venous or arterial circulation or in rare cases in the abdominal cavity. Ports are provided with particularly thin catheter and a filter used in the long-term epidural anesthesia.

A port consists of a chamber with a thick silicone membrane and a connected or connectable tube ( catheter ) and is a version of a central venous access ( CVC ), the end of which is placed just before the right atrium of the heart. The small chamber can either be made ​​of titanium, stainless steel, ceramic, plastic or a composite of the aforementioned materials. The port catheter is implanted as part of a surgical procedure.

Transcutaneous by piercing with a cannula through the silicone membrane of the access is made to the blood circulation in the main application. About the in- port chamber cannula opening a drug or preparation by infusion can now be added to the blood stream, or, under the special circumstances of a port - catheter can also be taken from the blood.

Areas of application

A port catheter is used primarily in the treatment of oncological diseases and in the treatment of diseases for which a common and safe venous or arterial access is required; Further, if not seem possible because of the anatomical and physiological conditions, or a known or expected pharmacological effect of the use of peripheral vascular access for the administration of liquid drugs, drug formulations or therapeutic agents or. A port catheter may be used for blood withdrawal and administration of blood and blood products.

The implanted under the skin port is protected from external influences, and it allows the patient to maintain the previously transmitted usual movement. To enable port - catheter a high quality of life. Patients can carry out their usual daily activities previously on, so take a shower, bathe and swim in treatment- free periods. Is immerse themselves in terms of the port - catheter, without any restrictions.

Useful life

The dwell time and thus use can be up to five years or more. It has already been reported in patients who had their port "forget" about the time and after 10 years was still consistent and functional. Nevertheless, a Weiter-/Wiederverwendung is longer than five years for periods clarified taking into account the medical indication and in the past about the port administered and in the future to be administered drugs with the responsible physician.

It also speaks not mind a port to remove again when the therapy is completed. The engagement is similar to the port at implantation. The time to do this but should also be discussed in consultation with the responsible physician.

Implantation / plant

As for the access path (port ) catheter can be basically any larger veins questioned about a central venous catheter may be placed.

Examples:

A) The most commonly used surgical technique via the dissection ( phlebotomy ) of the cephalic vein. Here, under local anesthesia, a small incision in the so-called deltopectoral groove, ie the region of the transition from the deltoid muscle is applied to the pectoralis major muscle at the front of the chest wall. From this section of the running there cephalic vein is opened with a small incision and inserted the catheter. Just off of this, the port chamber is placed in a small pocket in the subcutaneous fatty tissue on the chest muscle and thus the first or second rib.

B ) It can also be punctured without first section, for example, the subclavian vein by the Seldinger technique and the catheter inserted into the vein. A small incision is placed in the subcutaneous adipose tissue and of the puncture site, starting by pulling the catheter through the subcutaneous tissue to the skin bag ( tunneled ) away from the puncture site as described above, the port chamber. This tunneling also serves as a subsequent natural infection barrier.

In all three methods, a radiological control position of the catheter, and to record. The catheter is then cut to the length required in the skin bag outside the vein until the final position of the port chamber and connected to the port chamber. In the next step, the port is sutured to the skin chamber bag to the underlying fascia. Thereafter, the skin incision surgically closed ( sutured ). With the rib as " abutment " the port can be from now ( " tapped " ) in dotted lines.

As mentioned above, there are for specific applications even further access port catheter types such as on the arteria hepatica, peritoneally or epidural, but are not to be explained further here. However, the basic function of the port is always the same: Primary repeated administration of drugs or preparations for an extended period of time.

Aspiration

The puncture of the port ( port puncture) is a nursing or medical procedure to repeatedly deliver drugs or infusion solutions by a doctor and according to a schedule. In fact, it may be a port catheter puncture or even to a port needle exchange. Special port needles are always used for the puncture ( Huber needle ), in contrast to normal hypodermic needles - due to the special form of the cannula tip - can punch out any particles from the silicone membrane of the port.

Important principles of operation are

• Port not puncture the patient lying down, but in " Beach Chair Position" ( about 60 ° to almost sitting upright), which masses of tissue in the upper body will follow as well the gravity and are before the puncture " correct position "
• Produce pressure- stable support for the patient in the back to minimize retreat at the puncture
• Sterile as possible work
• Note of exposure to the disinfectant used in each case
• Circular perform, from the inside to the outside circular wiping disinfection of the skin area above the port
• Not build up pressure on the port pin
• Therefore no smaller syringes 10ml syringes use (the smaller the syringe plunger is higher for the same force of the pressure generated in the process )
• The materials used must be kept sterile
• Compliance with the five- times - R control ( drug safety )
• The fixation of the port needle should be transparent so that the puncture of the needle is visible. If redness or even pustules at the injection site, the needle should be drawn.
• The port catheter must be flushed prior to needle removal with sufficient saline solution. After blood collection via the port is immediately flush with at least 2x20ml saline. A rinsing and blocking with the addition of heparin, which is to prevent possible thrombosis of the catheter contents during therapy breaks, does not have any benefits is medically rather disadvantageous and legally problematic ( not approved in the German market Heparin is approved for that purpose ). Also, heparin can not prevent because of its pharmacokinetics a possible thrombosis, but only delayed.

Complications

Potential complications can be infections, hemorrhage, pneumothorax, hemothorax, or thrombosis. The manifold described in the literature pinch-off is the fraction of the catheter at the level of the clavicle with the crossing point to the first rib when the venous access catheter was deducted directly there or medially. If the catheter is removed it does so, the remainder of the vascular system catheter fragment further hike in blood flow direction. Cause is fatigue of the catheter through constantly repeated contusion due to ( unavoidable ) physical activity with involvement of the shoulder girdle. To prevent pinch-off, one by more laterally remote puncture is recommended, or apply a deviating technology (eg venous access after dissection of the cephalic vein or access via the jugular vein ).

There are also reports of poorly running or completely occluded catheters. Deposits in the chamber or port at the inner wall of catheter, particularly after many infusions of nutritional solutions may be a cause. Ports with modern, current optimized flute geometry seem to have advantages. Also when pulling the needle from the port through the resulting change in volume of a small quantity of blood is drawn at the end of the catheter. This can clot and cause partial or complete catheter occlusion. With a suitable technique in which the same bit rinse solution is subsequently forced into the syringe during the withdrawal of the needle, it can be prevented. Port catheter is no longer continuous, as medical actions are indicated to establish the continuity again. Dishwasher tests by ( over) pressure, however, are displayed here in any case.