In medicine, a port or chemoport is a small appliance that is installed beneath the skin. A catheter (plastic tube) connects the port to a vein. Under the skin, the port has a septum (a silicone membrane) through which drugs can be injected and blood samples can be drawn many times, usually with less discomfort for the patient (and clinician) than a more typical "needle stick".
A port is more correctly known as a "totally implantable venous access device". They are also commonly referred to as a Portacath or Chemo port. Brand names include Eco Port, Clip-a-Port, SmartPort, Microport, Bardport, PowerPort, Passport, Port-a-Cath, Infuse-a-Port, Medi-Port, and Bioflo.
Ports are used mostly to treat hematology and oncology patients. Ports were previously adapted for use in hemodialysis patients, but were found to be associated with increased rate of infections and are no longer available in the US. [1]
The port is usually inserted in the upper chest (known as a "chest port"), just below the clavicle or collar bone, with the catheter inserted into the jugular vein.
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 other than occasional flushing to keep clear. It 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 or less optimally the subclavian vein). Ideally, the catheter terminates in the superior vena cava or 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; it can be punctured hundreds of times before it weakens significantly. To administer treatment or to withdraw blood, a health care professional will first locate the port and disinfect the area, then access the port by puncturing the overlying skin with a Huber point (non-coring) needle. [a] 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 is flushed with a saline solution. Then, treatment will begin.
Ports have many uses:
Installation of a port is absolutely contraindicated when a patient has bacteremia or sepsis. In those with contrast allergy, or allergy to food or medications, the procedure can still be carried out with prednisolone coverage.
Other relative contraindications include coagulopathy (abnormal coagulation) or platelet count less than 50x109/L. However, if the port is needed urgently, platelet transfusion may be given while the procedure is ongoing on table. [3]
A port is most commonly inserted as an outpatient surgery procedure in a hospital or clinic by an interventional radiologist or surgeon, under moderate sedation. Implantation is increasingly performed by interventional radiologists due to advancements in techniques and their facile use of imaging technologies. When no longer needed, the port can be removed in the interventional radiology suite or an operating room. Fluoroscopy is useful in guiding the insertion of ports. [4]
Right internal jugular vein (IJV) is frequently chosen as the site of access. A 19G puncture needle is used to obtain access to the vein under ultrasound guidance. The needle should be pointed away from the common carotid artery (CCA) as the CCA just lie medially to the IJV. If there is difficult puncture, micropuncture set can be used to puncuture the vein and later switch to a bigger access system. If bilateral IJVs are thrombosed, then right external jugular vein is chosen as the puncture site. The puncture site should not be the same side as the pathological site such as breast cancer site or an area that is chosen as the potential site for radiation therapy. [3]
After the entry site is punctured with ultrasound, a guidewire is inserted with the tip of the guidewire reaching the inferior vena cava. The proximal end of the guidewire is secured to prevent dislodgement. Then a chemoport pocket is created on the deltopectoral region at 2.5 cm below the level of clavicle by using a scalpel. Bupivacaine with adrenaline (0.25%) is used as local anesthetic to reduce the formation of haematoma and prolong the anesthetic effect. After the pocket is created, a trocar is used insert a silicone catheter from the pocket towards the internal jugular vein puncture site. A peel-away sheath is then inserted to facilitate the insertion of the silicone catheter into the cavoatrial junction. Silicone catether insertion should be done during breath hold at inspiration. The peel-away sheath should be pinched to prevent air embolism. The proximal end of the catheter is connected to the port within the skin pocket later after irrigation of the pocket with normal saline. [3]
The port is then sutured on two sites to the underlying muscles. The tip of the catheter is checked for kinks and position using a fluoroscope. Besides that, aspiration of blood and contrast injection through the chemoport can also be used to confirm the position. The port is the closed in two layers (subcutaneous tissue is sutured first, followed by the skin). Sterile dressing is then placed on the port. [3] The optimum site to park the tip of the catheter is at the cavo-atrial junction or with margin of error of not more than 4 cm above the junction. [3]
The insertion site of the IJV is fixed between the two heads (sternal and clavicular heads) of the sternocleidomastoid. 2% lignocaine is to infiltrate the puncture site. Using a 24G needle attached to 5 cc syringe, the needle is advanced through the puncture site with its tip pointing towards the nipple of the same side. Once the backflow of venous blood is seen in the syringe, the puncture of the IJV is considered successful. Then a port needle is advanced through the pre-existing 24G needle and backflow of blood is confirmed by aspirating another syringe attached to the port needle. Then a guidewire is inserted through the port needle. The guidewire should not extend past the SA node of the right atrium as it can stimulate the heart arrhythmia. The port needle is then removed and the guidewire is fixed in place. The puncture is then widened by using 11-number knife and mosquito haemostat. [5]
The port access site is fixed at 5 cm below the midline of the clavicle and 9 to 10 cm lateral to the midline of the chest. Then, a 5 to 6 cm incision is made to create a subcutaneous tissue pouch for the placement of port access site. A tunnel is made from the port access site until adjacent to the internal jugular neck wound. A port catheter is passed through the tunnel where one end is attached to the chemport and another end is left hanging out near the IJV insertion site. The length of the hanging port catheter should be about 16 to 17 cm (or can be measured from the IJV insertion site until 2 cm below the sternal angle where the right atrium should begin). This portion of the port catheter should later be inserted through the IJV insertion site until it reaches the aortocaval junction. The IJV insertion is dilated using a plastic dilator. Peel-off sheath was then inserted over the guidewire. Blood is aspirated from the catheter to confirm the position. Then, the free-end of the port catheter is inserted through the peel-off sheath. After the tip of the port catheter is confirmed at the aortocaval junction, the peel-off sheath is taken-off by peeling away with two hands. While peeling off, the port catheter should remain in-situ. Stitches are only removed after 14 days post operation. [5]
A follow-up on a chest radiograph can immediately detect complications associated with the procedure such as pneumothorax, hemothorax and malpositions of the catheter. However, routine chest radiography is not needed due to the low complication rates associated with the procedure. The chest radiograph is only done if there is clinical suspicion of a complication. [4]
The side of the patients' chest the port is implanted in will usually be chosen to avoid damage to the port and the veins by the seat belt in case of accident when seated as the driver. Thus, there is a potential conflict by left- and right-hand traffic as the rule of the road.[ clarification needed ] [6] [7]
Ports 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 jugular vein, and down towards the patient's heart.[ citation needed ]
There are many different models of ports. The particular model selected is based on the patient's specific medical conditions.
Portals:
Catheters:
For applications such as CT scan, high pressure infusion allowing ports are needed. [8] [9]
The major manufacturers of ports are AngioDynamics, B. Braun Medical, [10] Bard Access Systems, [9] Cook Medical, MedComp, Navilyst Medical, Norfolk Medical Products, and Smiths Medical.
The most common complications are: catheter blockage (7.4%), and catheter-related infection (5.6%). Other complications are: malpositioning of the catheter, venous thrombosis, catheter leak or dislodgement. [3]
The common carotid artery may be injured during the puncture of the internal jugular vein as the artery lies close to the vein. This mostly due to the needle overshooting into the artery rather than the inability to recognise vein and artery under ultrasound guidance. The risk of puncture increases when the artery lies superficial to the vein and for those with short neck and obese people. However, these cases can be easily controlled using compression and it does not leave a hematoma at the site of puncture. [3] The overall risk of arterial puncture is 0.5%. [3] The subclavian artery can be inadvertently punctured while attempting a subclavian vein access, leading to a subcutaneous hematoma and occasionally a pseudoaneurysm. An alternative site may need to be used for port placement. Puncture of the carotid artery is significantly more rare, since attempts to access the nearby jugular vein are increasingly done with ultrasound guidance.[ citation needed ]
The incidence of catheter fracture is 2.3%. The fracture can be due to "pinch-off syndrome" when the vein and the catheter is compressed when passes between the clavicle and first rib before turning 90 degrees into the superior vena cava. Fractured catheter component can dislodge most commonly into pulmonary arteries (35%), right atrium (27%), right ventricle (22%), and superior vena cava and peripheral veins (15.4%). [5]
Malpositioning of the catheter happens in 0.1 to 5.6% of the time. This can be due to malposition within or outside the superior vena cava. Causes includes: unexpected branches of the veins, vessel angulations, vein stenosis or venous tortousity. [5]
Thrombosis or the formation of a blood clot in the catheter may block the device irrevocably. It happens in 0.3 to 28.3% of the cases. Administering cancer drugs through the port, frequent injury to the vessel during usage, or simply prolonged usage of the port can contribute to clot formation within the catheter. To prevent risk of thrombosis, right internal jugular vein is usually selected, as it has the lowest risk of thrombus formation than subclavian vein. Once thrombosis happens, either anticoagulant therapy is given or the port is totally removed. [5]
Attempts to gain access to the subclavian vein can injure the lung coverings, potentially causing a pneumothorax. The risk of pneumothorax is 1.5 to 6% depending upon the surgeon's experience. [11]
To reduce damage or coring of the septum (cutting out small pieces of membrane with the needle, plugging it up), low or non coring needles are to be used. [12]
After every cycle of chemotherapy, the port should be flushed with 1:10 diluted heparin (5000 IU/ml) to prevent clot formation within the port. If the port is not used for a long time, it should be flushed with diluted heparin every two months. [5]
Sometimes, the physical condition of the patient, especially the structure of their veins, does not allow for the insertion of a port. An alternative is the PICC line, despite drawbacks such as external entry point and limited lifespan of the device. [13]
In the 1984 cyberpunk novel Neuromancer , a minor character, Peter Riviera, has a kind of medical port placed in his arm to facilitate his recreational drug use. [14]
Niederhuber et al. first reported the use of totally implantable central venous port system (TICVPS) in 1982. [5]
A central venous catheter (CVC), also known as a central line (c-line), central venous line, or central venous access catheter, is a catheter placed into a large vein. It is a form of venous access. Placement of larger catheters in more centrally located veins is often needed in critically ill patients, or in those requiring prolonged intravenous therapies, for more reliable vascular access. These catheters are commonly placed in veins in the neck, chest, groin, or through veins in the arms.
Intravenous therapy is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrients for those who cannot, or will not—due to reduced mental states or otherwise—consume food or water by mouth. It may also be used to administer medications or other medical therapy such as blood products or electrolytes to correct electrolyte imbalances. Attempts at providing intravenous therapy have been recorded as early as the 1400s, but the practice did not become widespread until the 1900s after the development of techniques for safe, effective use.
In medicine, a catheter is a thin tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. Catheters are manufactured for specific applications, such as cardiovascular, urological, gastrointestinal, neurovascular and ophthalmic procedures. The process of inserting a catheter is called catheterization.
A cannula is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of samples. In simple terms, a cannula can surround the inner or outer surfaces of a trocar needle thus extending the effective needle length by at least half the length of the original needle. Its size mainly ranges from 14 to 26 gauge. Different-sized cannula have different colours as coded.
Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.
In surgery, a percutaneous procedure is any medical procedure or method where access to inner organs or other tissue is done via needle-puncture of the skin, rather than by using an "open" approach where inner organs or tissue are exposed.
Cerebral angiography is a form of angiography which provides images of blood vessels in and around the brain, thereby allowing detection of abnormalities such as arteriovenous malformations and aneurysms. It was pioneered in 1927 by the Portuguese neurologist Egas Moniz at the University of Lisbon, who also helped develop thorotrast for use in the procedure.
A dialysis catheter is a catheter used for exchanging blood to and from a hemodialysis machine and a patient.
Cardiac catheterization is the insertion of a catheter into a chamber or vessel of the heart. This is done both for diagnostic and interventional purposes.
The internal jugular vein is a paired jugular vein that collects blood from the brain and the superficial parts of the face and neck. This vein runs in the carotid sheath with the common carotid artery and vagus nerve.
A peripherally inserted central catheter, also called a percutaneous indwelling central catheter or longline, is a form of intravenous access that can be used for a prolonged period of time or for administration of substances that should not be done peripherally. It is a catheter that enters the body through the skin (percutaneously) at a peripheral site, extends to the superior vena cava, and stays in place for days, weeks or even months.
A Hickman line is a central venous catheter most often used for the administration of chemotherapy or other medications, as well as for the withdrawal of blood for analysis. Some types are used mainly for the purpose of apheresis or dialysis. They have also been used in total parenteral nutrition (TPN). Hickman lines may remain in place for extended periods and are used when long-term intravenous access is required.
The subclavian vein is a paired large vein, one on either side of the body, that is responsible for draining blood from the upper extremities, allowing this blood to return to the heart. The left subclavian vein plays a key role in the absorption of lipids, by allowing products that have been carried by lymph in the thoracic duct to enter the bloodstream. The diameter of the subclavian veins is approximately 1–2 cm, depending on the individual.
The Seldinger technique, also known as Seldinger wire technique, is a medical procedure to obtain safe access to blood vessels and other hollow organs. It is named after Sven Ivar Seldinger (1921–1998), a Swedish radiologist who introduced the procedure in 1953.
Vascular access refers to a rapid, direct method of introducing or removing devices or chemicals from the bloodstream. In hemodialysis, vascular access is used to remove the patient's blood so that it can be filtered through the dialyzer. Three primary methods are used to gain access to the blood: an intravenous catheter, an arteriovenous fistula (AV) or a synthetic graft. In the latter two, needles are used to puncture the graft or fistula each time dialysis is performed.
In medicine, a peripheral venous catheter, peripheral venous line, peripheral venous access catheter, or peripheral intravenous catheter, is a catheter placed into a peripheral vein for venous access to administer intravenous therapy such as medication fluids.
A cardiac electrophysiology study is a minimally invasive procedure using catheters introduced through a vein or artery to record electrical activity from within the heart. This electrical activity is recorded when the heart is in a normal rhythm to assess the conduction system of the heart and to look for additional electrical connections, and during any abnormal heart rhythms that can be induced. EP studies are used to investigate the cause, location of origin, and best treatment for various abnormal heart rhythms, and are often followed by a catheter ablation during the same procedure.
Ambesh maneuver is a technique that involves the simple external compression of internal jugular vein in supraclavicular fossa to prevent and diagnose misplacement of the subclavian vein catheter into the internal jugular vein (IJV). The subclavian vein is a big vessel that drains the blood from the hand, forearm and the upper arm into the right side of the heart through superior vena cava. The subclavian veins lie just behind the clavicle on each side and therefore known as subclavian vein.
Venous access is any method used to access the bloodstream through the veins, either to administer intravenous therapy, parenteral nutrition, to obtain blood for analysis, or to provide an access point for blood-based treatments such as dialysis or apheresis. Access is most commonly achieved via the Seldinger technique, and guidance tools such as ultrasound and fluoroscopy can also be used to assist with visualizing access placement.
In medicine, vascular access is a means of accessing the bloodstream through the peripheral or central blood vessels in order to obtain blood or deliver medications including chemotherapy. A vascular access procedure involves insertion of a sterile plastic tube called a catheter into a blood vessel. Types of catheters can be either peripherally or centrally located. Peripheral catheters are approximately one inch (25 mm) long and are inserted into the small veins of the forearm. Central catheters are bigger and longer and are inserted into the large veins of the extremities, neck, or chest. Central venous catheters are the primary modality used for delivery of chemotherapeutic agents. The duration of central venous catheterization is dependent on the type of treatment given.
Verlauf des Autosicherheitsgurts in die Überlegungen mit einzubeziehen (to include the place of the safety belt into the planning)
Auf welcher Seite wird der Sicherheitsgurt angebracht? (which side is the safety belt)
Liegedauer von 4 Monaten
Riviera loosened and removed the elastic length of surgical tubing from his arm. 'Yes. It's more fun.' He smiled, his eyes distant now, cheeks flushed. 'I've a membrane set in, just over the vein, so I never have to worry about the condition of the needle.' 'Doesn't hurt?' [said Case] The bright eyes met his. 'Of course it does. That's part of it, isn't it?'
