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In medicine, a port (or portacath) is a small medical appliance that is installed beneath the skin. A catheter connects the port to a vein. Under the skin, the port has a septum through which drugs can be injected and blood samples can be drawn many times, usually with less discomfort for the patient than a more typical "needle stick".
The port is usually inserted in the upper chest (known as a "chest port"), just below the clavicle or collar bone, leaving the patient's hands free.
The term portacath is a portmanteau of "portal" and "catheter". Port-a-Cath is a registered trade mark of Smiths Medical; others include Eco Port, Clip-a-Port, SmartPort, Microport, Bardport, PowerPort (power injectable), Passport, Infuse-a-Port, Medi-Port, BioFlo and Lifesite (for hemodialysis patients). The term totally implantable venous access system (TIVAS) is also used. Additionally, a portacath is the main form of a central venous access device, and is frequently referred to as such in the medical field.
A port consists of a reservoir compartment (the portal) that has a silicone bubble for needle insertion (the septum), with an attached plastic tube (the catheter). The device is surgically inserted under the skin in the upper chest or in the arm and appears as a bump under the skin. It requires no special maintenance and is completely internal so swimming and bathing are not a problem. The catheter runs from the portal and is surgically inserted into a vein (usually the jugular vein, subclavian vein, or superior vena cava). Ideally, the catheter terminates in the superior vena cava, just upstream of the right atrium. This position allows infused agents to be spread throughout the body quickly and efficiently.
The septum is made of a special self-sealing silicone rubber; it can be punctured hundreds of times before it weakens significantly. To administer treatment or to withdraw blood, a health professional will first locate the port and disinfect the area. Then he or she will access the port by puncturing the overlying skin with a 90° Huber point needle although a winged needle may also be used. (Due to its design, there is a very low infection risk, as the breach of skin integrity is never larger than the caliber of the needle. This gives it an advantage over indwelling lines such as the Hickman line.) Negative pressure is created to withdraw blood into the vacuumized needle, to check for blood return and see if the port is functioning normally. Next, the port will be flushed with a saline solution. Then, treatment will begin. After each use, a heparin lock is made by injecting a small amount of heparinized saline (an anticoagulant) into the device. This prevents development of clots within the port or catheter. In some catheter designs where there is a self-sealing valve at the far end, the system is locked with just saline. The port can be left accessed for as long as required. The port is covered in a dressing to protect the site from infection and to secure the needle in position.
If a port is used infrequently, it may be necessary to access the port, flush it with saline, and inject a new heparin lock every month to prevent clotting between uses.
The surgery itself is considered minor, and is typically performed under both local anaesthesia and conscious sedation. Patients sometimes have a little discomfort after the procedure, and can be managed with a narcotic, such as demerol for 24–48 hours.
A port is most commonly inserted as a day surgery procedure in a hospital or clinic by a surgeon or an interventional radiologist, under conscious sedation. When no longer needed, the port can be removed in the operating room.
Ports have many uses:
There are many different types of portacaths. The particular type selected is based on the patient's specific medical conditions.
Portacaths can be put in the upper chest or arm. The exact positioning itself is variable as it can be inserted to avoid visibility when wearing low cut shirts, and to avoid excess contact due to a backpack or bra strap. The most common placement is on the upper right portion of the chest, with the catheter itself looping through the right subclavian vein down towards the patient's heart. It can also be situated on the muscle that sits on the ribs with the tube coming up towards the heart.