Port (medical)
Encyclopedia
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".
Ports are used mostly to treat hematology
and oncology
patients, but recently ports have been adapted also for hemodialysis
patients.
The port is usually inserted in the upper chest, just below the clavicle
or collar bone, leaving the patient's hands free.
". Port-a-Cath is a brand name of Smiths Medical; others include SmartPort, Microport, Bardport, PowerPort (power injectable), Passport, Infuse-a-Port, Medi-Port, 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.
Portals:
Catheters:
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.
, Smiths Medical, MedComp, Rita Medical Systems and AngioDynamics.
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, a port (or portacath) is a small medical appliance that is installed beneath the skin. A catheter
Catheter
In medicine, a catheter is a tube that can be inserted into a body cavity, duct, or vessel. Catheters thereby allow drainage, administration of fluids or gases, or access by surgical instruments. The process of inserting a catheter is catheterization...
connects the port to a vein
Vein
In the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...
. Under the skin, the port has a septum
Septum
In anatomy, a septum is a wall, dividing a cavity or structure into smaller ones.-In human anatomy:...
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".
Ports are used mostly to treat hematology
Hematology
Hematology, also spelled haematology , is the branch of biology physiology, internal medicine, pathology, clinical laboratory work, and pediatrics that is concerned with the study of blood, the blood-forming organs, and blood diseases...
and oncology
Oncology
Oncology is a branch of medicine that deals with cancer...
patients, but recently ports have been adapted also for hemodialysis
Hemodialysis
In medicine, hemodialysis is a method for removing waste products such as creatinine and urea, as well as free water from the blood when the kidneys are in renal failure. Hemodialysis is one of three renal replacement therapies .Hemodialysis can be an outpatient or inpatient therapy...
patients.
The port is usually inserted in the upper chest, just below the clavicle
Clavicle
In human anatomy, the clavicle or collar bone is a long bone of short length that serves as a strut between the scapula and the sternum. It is the only long bone in body that lies horizontally...
or collar bone, leaving the patient's hands free.
Terminology
The term portacath is a portmanteau of "portal" and "catheterCatheter
In medicine, a catheter is a tube that can be inserted into a body cavity, duct, or vessel. Catheters thereby allow drainage, administration of fluids or gases, or access by surgical instruments. The process of inserting a catheter is catheterization...
". Port-a-Cath is a brand name of Smiths Medical; others include SmartPort, Microport, Bardport, PowerPort (power injectable), Passport, Infuse-a-Port, Medi-Port, 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.
How it works
Catheter
In medicine, a catheter is a tube that can be inserted into a body cavity, duct, or vessel. Catheters thereby allow drainage, administration of fluids or gases, or access by surgical instruments. The process of inserting a catheter is catheterization...
runs from the portal and is surgically inserted into a vein
Vein
In the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...
(usually the jugular vein
Jugular vein
The jugular veins are veins that bring deoxygenated blood from the head back to the heart via the superior vena cava.-Internal and external:There are two sets of jugular veins: external and internal....
, subclavian vein
Subclavian vein
The subclavian veins are two large veins, one on either side of the body. Their diameter is approximately that of the smallest finger.-Path:Each subclavian vein is a continuation of the axillary vein and runs from the outer border of the first rib to the medial border of anterior scalene muscle...
, or superior vena cava
Superior vena cava
The superior vena cava is truly superior, a large diameter, yet short, vein that carries deoxygenated blood from the upper half of the body to the heart's right atrium...
). 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
Silicone
Silicones are inert, synthetic compounds with a variety of forms and uses. Typically heat-resistant and rubber-like, they are used in sealants, adhesives, lubricants, medical applications , cookware, and insulation....
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
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
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
Hickman line
A Hickman line is an intravenous catheter most often used for the administration of chemotherapy or other medications, as well as for the withdrawal of blood for analysis. Some types of Hickman lines are used mainly for the purpose of apheresis or dialysis...
.) 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
Heparin
Heparin , also known as unfractionated heparin, a highly sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule...
lock is made by injecting a small amount of heparinized saline (an anticoagulant
Anticoagulant
An anticoagulant is a substance that prevents coagulation of blood. A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders. Some anticoagulants are used in medical equipment, such as test tubes, blood transfusion bags, and renal dialysis...
) into the device. This prevents development of clots
Thrombus
A thrombus , or blood clot, is the final product of the blood coagulation step in hemostasis. It is achieved via the aggregation of platelets that form a platelet plug, and the activation of the humoral coagulation system...
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.
Uses
Ports have many uses:- To deliver total parenteral nutritionTotal parenteral nutritionParenteral nutrition is feeding a person intravenously, bypassing the usual process of eating and digestion. The person receives nutritional formulae that contain nutrients such as glucose, amino acids, lipids and added vitamins and dietary minerals...
in those unable to take (adequate) food orally for a long period of time. - To deliver chemotherapyChemotherapyChemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
to cancerCancerCancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
patients who must undergo treatment frequently. Chemotherapy is often toxic, and can damage skin and muscle tissue, and therefore should not be delivered through these tissues. Portacaths provide a solution, delivering drugs quickly and efficiently through the entire body via the circulatory systemCirculatory systemThe circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...
. - To deliver coagulation factorCoagulationCoagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...
s in patients with severe hemophilia. - To withdraw (and/or return) blood to the body in patients who require frequent blood tests, and in hemodialysis patients.
- To deliver antibioticAntibioticAn antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s to patients requiring them for a long time or frequently, such as those with cystic fibrosisCystic fibrosisCystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...
and bronchiectasisBronchiectasisBronchiectasis is a disease state defined by localized, irreversible dilation of part of the bronchial tree caused by destruction of the muscle and elastic tissue. It is classified as an obstructive lung disease, along with emphysema, bronchitis, asthma, and cystic fibrosis...
. - Delivering medications to patients with immune disorders.
- For treating alpha 1-antitrypsin deficiencyAlpha 1-antitrypsin deficiencyAlpha 1-antitrypsin deficiency is an autosomal recessive genetic disorder caused by defective production of alpha 1-antitrypsin , leading to decreased A1AT activity in the blood and lungs, and deposition of excessive abnormal A1AT protein in liver cells...
with replacement therapy - For delivering radiopaque contrast agents, which enhance contrast in CT imaging.
- To fill or withdraw fluid from the Lap-Band or Realize gastric bands used in Bariatric surgeries.
Variations
There are many different types of portacaths. The particular type selected is based on the patient's specific medical conditions.Portals:
- can be made of plasticPlasticA plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
, stainless steelStainless steelIn metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
, or titaniumTitaniumTitanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color.... - can be single chamber or dual chamber
- vary in height (although the base is about the size of a quarter)
Catheters:
- can be made of biocompatible, medical-grade polyurethanePolyurethaneA polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...
or siliconeSiliconeSilicones are inert, synthetic compounds with a variety of forms and uses. Typically heat-resistant and rubber-like, they are used in sealants, adhesives, lubricants, medical applications , cookware, and insulation.... - can vary in length (cm)
- can vary in diameter (mm)
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
Subclavian vein
The subclavian veins are two large veins, one on either side of the body. Their diameter is approximately that of the smallest finger.-Path:Each subclavian vein is a continuation of the axillary vein and runs from the outer border of the first rib to the medial border of anterior scalene muscle...
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.
Risks
- InfectionInfectionAn infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
- a severe bacterial infection can compromise the device, require its surgical removal, and seriously jeopardize the health of the already weak patient. - ThrombosisThrombosisThrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent blood loss...
- formation of a blood clot in the catheter may block the device irrevocably. To prevent clotting the portacath is flushed with salineSaline (medicine)In medicine, saline is a general term referring to a sterile solution of sodium chloride in water but is only sterile when it is to be placed intravenously, otherwise, a saline solution is a salt water solution...
and heparinHeparinHeparin , also known as unfractionated heparin, a highly sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule...
, usually by a nurse or other medical professional, or someone properly trained that is a family member or the patient, at least once every four weeks, or more often in conjunction with administering medication. - Mechanical failure - is extremely unlikely. It is possible in a rare event that part of the system could break, usually the attached catheter, and become lodged in the circulatory system. In such a case it is unlikely to cause serious harm; many patients are asymptomatic but the mechanical failure is discovered because of an inability to flush or withdraw fluids from the port. In those rare instances intervention surgery is required to withdraw the failed vascular access device.
- Age - If the device is put into a child, the child's growth means that the catheter becomes relatively shorter and will move away from the inferior part of the superior vena cavaSuperior vena cavaThe superior vena cava is truly superior, a large diameter, yet short, vein that carries deoxygenated blood from the upper half of the body to the heart's right atrium...
- it might be necessary to remove or replace it. - PneumothoraxPneumothoraxPneumothorax is a collection of air or gas in the pleural cavity of the chest between the lung and the chest wall. It may occur spontaneously in people without chronic lung conditions as well as in those with lung disease , and many pneumothoraces occur after physical trauma to the chest, blast...
- Attempts to gain access to the subclavian veinSubclavian veinThe subclavian veins are two large veins, one on either side of the body. Their diameter is approximately that of the smallest finger.-Path:Each subclavian vein is a continuation of the axillary vein and runs from the outer border of the first rib to the medial border of anterior scalene muscle...
or jugular veinJugular veinThe jugular veins are veins that bring deoxygenated blood from the head back to the heart via the superior vena cava.-Internal and external:There are two sets of jugular veins: external and internal....
can injure the lung, possibly leading to this complication. If the pneumothorax is large enough, a chest tubeChest tubeA chest tube is a flexible plastic tube that is inserted through the side of the chest into the pleural space. It is used to remove air or fluid , or pus from the intrathoracic space...
might need to be placed. In experienced hands, the incidence of this complication is about 1%. - Arterial injury - The subclavian artery can be inadvertently punctured. This usually leads to a subcutaneous hematoma and occasionally a pseudoaneurysmPseudoaneurysmA pseudoaneurysm, also known as a false aneurysm, is a hematoma that forms as the result of a leaking hole in an artery. Note that the hematoma forms outside the arterial wall, so it is contained by the surrounding tissues. Also it must continue to communicate with the artery to be considered a...
. An alternative site may need to be used for port placement. Puncture of the carotid arteryCarotid arteryCarotid artery can refer to:* Common carotid artery* External carotid artery* Internal carotid artery...
is more rare, since attempts to access the nearby jugular veinJugular veinThe jugular veins are veins that bring deoxygenated blood from the head back to the heart via the superior vena cava.-Internal and external:There are two sets of jugular veins: external and internal....
are increasingly done with ultrasoundUltrasoundUltrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
guidance.
Manufacturers
The major manufacturers of ports are Bard Access Systems, Navilyst MedicalNavilyst Medical
Navilyst Medical headquartered in Marlborough, MA, was formed in February 2008 from Boston Scientific's Fluid Management and Vascular Access business units. Its devices including PASV Valve Technology, expanded line of Xcela PICCs, NAMIC Fluid Management products and Exodus Drainage Catheters help...
, Smiths Medical, MedComp, Rita Medical Systems and AngioDynamics.
See also
- Peripherally inserted central catheterPeripherally inserted central catheterA peripherally inserted central catheter is a form of intravenous access that can be used for a prolonged period of time...
or "PICC" - Central venous catheterCentral venous catheterIn medicine, a central venous catheter is a catheter placed into a large vein in the neck , chest or groin...
or "central line"
External links
- Bard Access Systems' Implantable Ports
- Smiths Medical Implantable Ports
- Portacath Catheter Information