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A central venous catheter (CVC), also known as a central line(c-line), central venous line, or central venous access catheter, is a
catheter In medicine, a catheter (/ˈkæθətər/) is a thin tubing (material), 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 surgi ...
placed into a large
vein Veins are blood vessels in humans and most other animals 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 oxygenat ...
. It is a form of
venous access Venous access is any method used to access the bloodstream through the veins, either to administer intravenous therapy (e.g. medication, fluid), parenteral nutrition, to obtain blood for analysis, or to provide an access point for blood-based treat ...
. 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 (
internal jugular vein 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. It begins in the poste ...
),
chest The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...
( subclavian vein or
axillary vein In human anatomy, the axillary vein is a large blood vessel that conveys blood from the lateral aspect of the thorax, axilla (armpit) and upper limb toward the heart. There is one axillary vein on each side of the body. Structure Its origin ...
),
groin In human anatomy, the groin (the adjective is ''inguinal'', as in inguinal canal) is the junctional area (also known as the inguinal region) between the abdomen and the thigh on either side of the pubic bone. This is also known as the medial comp ...
(
femoral vein In the human body, the femoral vein is a blood vessel that accompanies the femoral artery in the femoral sheath. It begins at the adductor hiatus (an opening in the adductor magnus muscle) as the continuation of the popliteal vein. It ends a ...
), or through veins in the arms (also known as a
PICC line A peripherally inserted central catheter (PICC or PIC line), less commonly called a percutaneous indwelling central catheter, is a form of intravenous access that can be used for a prolonged period of time (e.g., for long chemotherapy regimens ...
, or peripherally inserted central catheters). Central lines are used to administer medication or fluids that are unable to be taken by mouth or would harm a smaller
peripheral vein The peripheral vascular system is the part of the circulatory system that consists of the veins and arteries not in the chest or abdomen (i.e. in the arms, hands, legs and feet). The peripheral arteries supply oxygenated blood to the body, a ...
, obtain blood tests (specifically the "central venous oxygen saturation"), administer fluid or blood products for large volume resuscitation, and measure
central venous pressure Central venous pressure (CVP) is the blood pressure in the venae cavae, near the right atrium of the heart. CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood back into the arterial system. CVP ...
. The catheters used are commonly 15–30 cm in length, made of silicone or
polyurethane Polyurethane (; often abbreviated PUR and PU) refers to a class of polymers composed of organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane is produced from ...
, and have single or multiple lumens for infusion.


Medical uses

The following are the major indications for the use of central venous catheters: # Difficult peripheral venous access – central venous catheters may be placed when it is difficult to gain or maintain venous access peripherally (e.g. obesity, scarred veins from prior
cannulation A cannula (; Latin meaning 'little reed'; plural or ) 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 ...
s, agitated patient). # Delivery of certain medications or fluids – medications such as
vasopressors An antihypotensive agent, also known as a vasopressor agent or simply vasopressor, or pressor, is any substance, whether endogenous or a medication, that tends to raise low blood pressure. Some antihypotensive drugs act as vasoconstrictors to in ...
(e.g.,
norepinephrine Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad' ...
,
vasopressin Human vasopressin, also called antidiuretic hormone (ADH), arginine vasopressin (AVP) or argipressin, is a hormone synthesized from the AVP gene as a peptide prohormone in neurons in the hypothalamus, and is converted to AVP. It then trave ...
,
phenylephrine Phenylephrine is a medication primarily used as a decongestant, to dilate the pupil, to increase blood pressure, and to relieve hemorrhoids. In the United States, it was previously used orally as an over-the-counter decongestant to relieve nas ...
etc.), chemotherapeutic agents, or
hypertonic In chemical biology, tonicity is a measure of the effective osmotic pressure gradient; the water potential of two solutions separated by a partially-permeable cell membrane. Tonicity depends on the relative concentration of selective membrane- ...
solutions are damaging to
peripheral vein The peripheral vascular system is the part of the circulatory system that consists of the veins and arteries not in the chest or abdomen (i.e. in the arms, hands, legs and feet). The peripheral arteries supply oxygenated blood to the body, a ...
s and often require placement of a central line. Additionally, catheters with multiple lumens can facilitate the delivery of several parenteral medications simultaneously. # Prolonged intravenous therapies – parenteral medications that must be delivered for extended periods of time (more than a few days) such as long-term
parenteral nutrition Parenteral nutrition (PN) is the feeding of nutritional products to a person intravenously, bypassing the usual process of eating and digestion. The products are made by pharmaceutical compounding companies. The person receives a nutritional mi ...
, or
intravenous antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...
are administered through a central line. # Specialized treatment – interventions such as
hemodialysis Hemodialysis, also spelled haemodialysis, or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as creatinin ...
,
plasmapheresis Plasmapheresis (from the Greek πλάσμα, ''plasma'', something molded, and ἀφαίρεσις ''aphairesis'', taking away) is the removal, treatment, and return or exchange of blood plasma or components thereof from and to the blood circulati ...
, transvenous
cardiac pacing An artificial cardiac pacemaker (or artificial pacemaker, so as not to be confused with the natural cardiac pacemaker) or pacemaker is a medical device that generates electrical impulses delivered by electrodes to the chambers of the heart eith ...
, and invasive
hemodynamic Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously mo ...
monitoring (e.g.
pulmonary artery catheterization A pulmonary artery catheter (PAC), also known as a Swan-Ganz catheter or right heart catheter, is a balloon-tipped catheter that is inserted into a pulmonary artery in a procedure known as pulmonary artery catheterization or right heart cathete ...
) require central venous access. There are no absolute contraindications to the use of central venous catheters. Relative contraindications include: coagulopathy, trauma or local infection at the placement site, or suspected proximal vascular injury. However, there are risks and complications associated with the placement of central lines, which are addressed below.


Complications

Central line insertion may cause several complications. The benefit expected from their use should outweigh the risk of those complications.


Pneumothorax

The incidence of
pneumothorax A pneumothorax is an abnormal collection of air in the pleural space between the lung and the chest wall. Symptoms typically include sudden onset of sharp, one-sided chest pain and shortness of breath. In a minority of cases, a one-way valve i ...
is highest with subclavian vein catheterization due to its anatomic proximity to the apex of the lung. In the case of catheterization of the internal jugular vein, the risk of pneumothorax is minimized by the use of
ultrasound Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...
guidance. For experienced clinicians, the incidence of pneumothorax is about 1.5–3.1%. The
National Institute for Health and Clinical Excellence The National Institute for Health and Care Excellence (NICE) is an executive non-departmental public body of the Department of Health and Social Care in England that publishes guidelines in four areas: * the use of health technologies withi ...
(UK) and other medical organizations recommend the routine use of ultrasonography to minimize complications. If a pneumothorax is suspected, an upright chest x-ray should be obtained. An upright chest x-ray is preferred because free air will migrate to the apex of the lung, where it is easily visualized. Of course, this is not always possible, particularly in critically ill patients in the
intensive care unit 220px, Intensive care unit An intensive care unit (ICU), also known as an intensive therapy unit or intensive treatment unit (ITU) or critical care unit (CCU), is a special department of a hospital or health care facility that provides intensi ...
.
Radiographs Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical radiography ("diagnostic" and "therapeut ...
obtained in the supine position fail to detect 25–50% of pneumothoraces. Instead, bedside
ultrasound Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...
is a superior method of detection in those too ill to obtain upright imaging.


Vascular perforation

Perforation of vasculature by a catheter is a feared and potentially life-threatening complication of central lines. Fortunately, the incidence of these events is exceedingly rare, especially when lines are placed with ultrasound guidance. Accidental cannulation of the carotid artery is a potential complication of placing a central line in the
internal jugular vein 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. It begins in the poste ...
. This occurs at a rate of approximately 1% when ultrasound guidance is used. However, it has a reported incidence of 0.5–11% when an anatomical approach is used. If the carotid is accidentally cannulated and a catheter is inserted into the artery, the catheter should be left in place and a vascular surgeon should be notified because removing it can be fatal.


Catheter-related bloodstream infections

All catheters can introduce bacteria into the bloodstream. This can result in serious infections that can be fatal in up to 25% of cases. The problem of central line-associated bloodstream infections (CLABSI) has gained increasing attention in recent years. They cause a great deal of
morbidity A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...
(harm) and deaths, and increase health care costs. Microbes can gain access to the bloodstream via a central catheter a number of ways. Rarely, they are introduced by contaminated infusions. They might also gain access to the lumen of the catheter through break points such as hubs. However, the method by which most organisms gain access is by migrating along the portion of the catheter tracking through subcutaneous tissue until they reach the portion of the catheter in the vein. Additionally, bacteria present in the blood may attach to the surface of the catheter, transforming it into a focus of infection. If a central line infection is suspected in a person,
blood culture A blood culture is a medical laboratory test used to detect bacteria or fungi in a person's blood. Under normal conditions, the blood does not contain microorganisms: their presence can indicate a bloodstream infection such as bacteremia or ...
s are taken from both the catheter and a vein elsewhere in the body. If the culture from the central line grows bacteria much earlier (>2 hours) than the other vein site, the line is likely infected. Quantitative blood culture is even more accurate, but this method is not widely available. Antibiotics are nearly always given as soon as a patient is suspected to have a catheter-related bloodstream infection. However, this must occur after blood cultures are drawn, otherwise the culprit organism may not be identified. The most common organisms causing these infections are
coagulase negative staphylococci ''Staphylococcus'' is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillales. Under the microscope, they appear spherical (cocci), and form in grape-like clusters. ''Staphylococcus'' species are facultative ...
such as '' staphylococcus epidermidis''. Infections resulting in bacteremia from '' Staphylococcus aureus'' require removal of the catheter and antibiotics. If the catheter is removed without giving antibiotics, 38% of people may still develop
endocarditis Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves. Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or the ...
. Evidence suggests that there may not be any benefit associated with giving antibiotics before a long-term central venous catherter is inserted in cancer patients and this practice may not prevent gram positive catheter-related infections. However, for people who require long-term central venous catheters who are at a higher risk of infection, for example, people with cancer who at are risk of neutropenia due to their chemotherapy treatment or due to the disease, flushing the catheter with a solution containing an antibiotic and heparin may reduce catheter-related infections. In a
clinical practice guideline Clinical may refer to: Healthcare * Of or about a clinic, a healthcare facility * Of or about the practice of medicine Other uses * ''Clinical'' (film), a 2017 American horror thriller See also * * * Clinical chemistry, the analysis of bodily flu ...
, the American
Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...
recommends against routine culturing of central venous lines upon their removal. The guideline makes several other recommendations to prevent line infections. To prevent infection, stringent cleaning of the catheter insertion site is advised.
Povidone-iodine Povidone-iodine (PVP-I), also known as iodopovidone, is an antiseptic used for skin disinfection before and after surgery. It may be used both to disinfect the hands of healthcare providers and the skin of the person they are caring for. It may ...
solution is often used for such cleaning, but
chlorhexidine Chlorhexidine (CHX) (commonly known by the salt forms chlorhexidine gluconate and chlorhexidine digluconate (CHG) or chlorhexidine acetate) is a disinfectant and antiseptic that is used for skin disinfection before surgery and to sterilize surgi ...
appears to be twice as effective as iodine. Routine replacement of lines makes no difference in preventing infection. The CDC makes a myriad of recommendations regarding risk reduction for infection of CVCs, including: * The preferred site of insertion (including for non-tunneled catheter placement), from an infection prevention point of view, is in the subclavian vein, and to generally avoid the femoral vein if possible. * There is no clear recommendation for a tunneled catheter site in the guidelines. * Selection of catheters should include those with minimal ports to accomplish the clinical goal. * Sterile gloves are required for CVC * Full body sterile drapes, cap, mask, gloves are required for placement of CVCs * The catheter site should be monitored visually and with palpation (through dressing) on a regular basis to assess for infection. * It is, however, acceptable to use clean, non-sterile, gloves for changing the dressing of intravascular catheters. * Both chlorhexidine and povidone-iodine are acceptable skin cleansers, though chlorhexidine is preferred. * For short-term CVC sites, dressings must be changed at least every 7 days for transparent dressings, and every 2 days for gauze dressings. * For long-term implanted or tunneled catheters, dressings are to be changed no more than once weekly unless soiled or loose. *Routine removal and replacement of a central venous catheter is not recommended. While central line catheters should be removed as soon as they are no longer necessary, scheduled removal and replacement, whether over a guidewire or with a new puncture site, has not been shown to be beneficial in preventing infections. *Medication impregnated dressing products can reduce the risk getting catheter-related blood stream infection. *There is inconclusive evidence whether longer interval of changing dressings for central venous access devices is associated with more or less infections. *It is unclear whether cleaning the skin antiseptics or without skin cleansing can reduce the rate of catheter-related bloodstream infections.


Occlusion

Venous catheters may occasionally become occluded by kinks in the catheter, backwash of blood into the catheter leading to thrombosis, or infusion of insoluble materials that form precipitates. However, thrombosis is the most common cause of central line occlusion, occurring in up to 25% of catheters . CVCs are a risk factor for forming blood clots (
venous thrombosis Venous thrombosis is blockage of a vein caused by a thrombus (blood clot). A common form of venous thrombosis is deep vein thrombosis (DVT), when a blood clot forms in the deep veins. If a thrombus breaks off (embolizes) and flows to the lungs to ...
) including upper extremity
deep vein thrombosis Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enla ...
. It is thought this risk stems from activation of clotting substances in the blood by trauma to the vein during placement. The risk of blood clots is higher in a person with cancer, as cancer is also a risk factor for blood clots. As many as two thirds of
cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
patients with central lines show evidence of catheter-associated thrombosis. However, most cases (more than 95%) of catheter-associated thrombosis go undetected. Most symptomatic cases are seen with placement of
femoral vein In the human body, the femoral vein is a blood vessel that accompanies the femoral artery in the femoral sheath. It begins at the adductor hiatus (an opening in the adductor magnus muscle) as the continuation of the popliteal vein. It ends a ...
catheters (3.4%) or
peripherally inserted central catheter A peripherally inserted central catheter (PICC or PIC line), less commonly called a percutaneous indwelling central catheter, is a form of intravenous access that can be used for a prolonged period of time (e.g., for long chemotherapy regimens ...
s (3%). Anti-clotting drugs such as heparin and
fondaparinux Fondaparinux (trade name Arixtra) is an anticoagulant medication chemically related to low molecular weight heparins. It is marketed by GlaxoSmithKline. A generic version developed by Alchemia is marketed within the US by Dr. Reddy's Laboratorie ...
have been shown to decrease the incidence of blood clots, specifically
deep vein thrombosis Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enla ...
, in a person with cancer with central lines. Additionally, studies suggest that short term use of CVCs in the subclavian vein is less likely to be associated with blood clots than CVCs placed in the femoral vein in non-cancer patients. In the case of non-thrombotic occlusion (e.g. formation of precipitates), dilute acid can be used to restore patency to the catheter. A solution of 0.1N
hydrochloric acid Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid Acid strength is the tendency of an acid, symbol ...
is commonly used. Infusates that contain a significant amount of lipids such as total parenteral nutrition (TPN) or propofol are also prone to occlusion over time. In this setting, patency can often be restored by infusing a small amount of 70% ethanol.


Misplacement

CVC misplacement is more common when the anatomy of the person is different or difficult due to injury or past surgery. CVCs can be mistakenly placed in an artery during insertion (for example, the carotid artery or
vertebral artery The vertebral arteries are major arteries of the neck. Typically, the vertebral arteries originate from the subclavian arteries. Each vessel courses superiorly along each side of the neck, merging within the skull to form the single, midline ba ...
when placed in the neck or
common femoral artery The femoral artery is a large artery in the thigh and the main arterial supply to the thigh and leg. The femoral artery gives off the deep femoral artery or profunda femoris artery and descends along the anteromedial part of the thigh in the fem ...
when placed in the groin). This error can be quickly identified by special tubing that can show the pressure of the catheter (
arteries An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...
have a higher pressure than
vein Veins are blood vessels in humans and most other animals 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 oxygenat ...
s). In addition, sending blood samples for acidity, oxygen, and carbon dioxide content ( pH, pO2, pCO2 respectively) can show the characteristics of an
artery An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...
(higher pH/pO2, lower pCO2) or
vein Veins are blood vessels in humans and most other animals 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 oxygenat ...
(lower pH/pO2, higher pCO2). During subclavian vein central line placement, the catheter can be accidentally pushed into the internal jugular vein on the same side instead of the superior vena cava. A chest x-ray is performed after insertion to rule out this possibility. The tip of the catheter can also be misdirected into the contralateral (opposite side) subclavian vein in the neck, rather than into the
superior vena cava The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm) short length vein th ...
.


Venous air embolism

Entry of air into venous circulation has the potential to cause a venous air embolism. This is a rare complication of CVC placement – however, it can be lethal. The volume and the rate of air entry determine the effect an air embolus will have on a patient. This process can become fatal when at least 200–300 milliliters of air is introduced within a few seconds. The consequences of this include: acute embolic stroke (from air that passes through a patent foramen ovale),
pulmonary edema Pulmonary edema, also known as pulmonary congestion, is excessive liquid accumulation in the tissue and air spaces (usually alveoli) of the lungs. It leads to impaired gas exchange and may cause hypoxemia and respiratory failure. It is due t ...
, and acute right heart failure (from trapped air in the
right ventricle A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the uppe ...
) which can lead to cardiogenic shock. The clinical presentation of a venous air embolism may be silent. In those who are symptomatic, the most common symptoms are sudden-onset shortness of breath and cough. If the presentation is severe, the patient may become rapidly
hypotensive Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dia ...
and have an
altered level of consciousness An altered level of consciousness is any measure of arousal other than normal. Level of consciousness (LOC) is a measurement of a person's arousability and responsiveness to stimuli from the environment. A mildly depressed level of consciousn ...
due to cardiogenic shock. Symptoms of an acute stroke may also be seen. Echocardiography can be used to visualize air that has become trapped in the chambers of the heart. If a large air embolism is suspected, a syringe can be attached to the catheter cap and pulled pack in an attempt to remove the air from circulation. The patient can also be placed in the
left lateral decubitus position Lyingalso called recumbency, prostration, or decubitus in medicine ()is a type of human position in which the body is more or less horizontal and supported along its length by the surface underneath. Lying is the most common position while bein ...
. It is thought that this position helps relieve air that has become trapped in the right ventricle.


Catheter-related thrombosis

Catheter-related
thrombosis Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (t ...
(CRT) is the development of a
blood clot A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of ...
related to long-term use of CVCs. It mostly occurs in the upper extremities and can lead to further complications, such as
pulmonary embolism Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream ( embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathin ...
, post-thrombotic syndrome, and vascular compromise. Symptoms include pain, tenderness to palpation, swelling, edema, warmth,
erythema Erythema (from the Greek , meaning red) is redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries. It occurs with any skin injury, infection, or inflammation. Examples of erythema not asso ...
, and development of collateral vessels in the surrounding area. However, most CRTs are asymptomatic, and prior catheter infections increase the risk for developing a CRT. Routine flushings may help to prevent catheter thrombosis. If there is catheter obstruction, thrombolytic drugs can be used if the obstruction is caused by clots or fibrin deposition. Anticoagulant treatment is indicated if the obstruction is caused by
thrombus A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of ...
formation. There is inadequate evidence whether heparin saline flush is better than
normal saline Saline (also known as saline solution) is a mixture of sodium chloride (salt) and water. It has a number of uses in medicine including cleaning wounds, removal and storage of contact lenses, and help with dry eyes. By injection into a vein i ...
flush to maintain central venous catheter patency and prevent occlusion.


Insertion

Before insertion, the patient is first assessed by reviewing relevant labs and indication for CVC placement, in order to minimize risks and complications of the procedure. Next, the area of skin over the planned insertion site is cleaned. A
local anesthetic A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general a ...
is applied if necessary. The location of the vein is identified by landmarks or with the use of a small ultrasound device. A hollow needle is advanced through the skin until blood is aspirated. The color of the blood and the rate of its flow help distinguish it from
arterial An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...
blood (suggesting that an artery has been accidentally punctured). Within North American and Europe, ultrasound use now represents the gold standard for central venous access and skills, with diminishing use of landmark techniques. Recent evidence shows that ultrasound-guidance for subclavian vein catheterization leads to a reduction in adverse events. The line is then inserted using the
Seldinger technique 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 th ...
: a blunt guidewire is passed through the needle, then the needle is removed. A dilating device may be passed over the guidewire to expand the tract. Finally, the central line itself is then passed over the guidewire, which is then removed. All the lumens of the line are aspirated (to ensure that they are all positioned inside the vein) and flushed with either saline or heparin. A chest X-ray may be performed afterwards to confirm that the line is positioned inside the
superior vena cava The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm) short length vein th ...
and no
pneumothorax A pneumothorax is an abnormal collection of air in the pleural space between the lung and the chest wall. Symptoms typically include sudden onset of sharp, one-sided chest pain and shortness of breath. In a minority of cases, a one-way valve i ...
was caused inadvertently. On anteroposterior X-rays, a catheter tip between 55 and 29 mm below the level of the
carina Carina may refer to: Places Australia * Carina, Queensland, a suburb in Brisbane * Carina Heights, Queensland, a suburb in Brisbane * Carina, Victoria, a locality in Mildura Serbia * Carina, Osečina, a village in the Kolubara District ...
is regarded as acceptable placement. Electromagnetic tracking can be used to verify tip placement and provide guidance during insertion, obviating the need for the X-ray afterwards. File:A technique for the fixation of central venous catheters.png, A central venous catheter secured to the skin with suture Image:Subclavian central veinous catheter xray.png, Chest x-ray with catheter in the right subclavian vein File:Mediastinal structures on chest X-ray, annotated.jpg, The outline of superior vena cava on a chest X-ray is labeled at left.


Catheter flow


Hagen–Poiseuille equation

The
Hagen–Poiseuille equation In nonideal fluid dynamics, the Hagen–Poiseuille equation, also known as the Hagen–Poiseuille law, Poiseuille law or Poiseuille equation, is a physical law that gives the pressure drop in an incompressible and Newtonian fluid in laminar fl ...
describes the properties of flow through a rigid tube. The equation is shown below: Q = \Delta P * (\pi r^4/8\mu L) The equation shows that flow rate (Q) through a rigid tube is a function of the inner radius (r), the length of the tube (L), and the viscosity of the fluid (μ). The flow is directly related the fourth power of the inner radius of the tube, and inversely related to the length of the tube and viscosity of the fluid. This equation can be used to understand the following vital observations regarding venous catheters: that the inner radius of a catheter has a much greater impact on flow rate than catheter length or fluid viscosity, and that for rapid infusion, a shorter, large bore catheter is optimal because it will provide the greatest flow rate.


Types

There are several types of central venous catheters; these can be further subdivided by site (where the catheter is inserted into the body) as well as the specific type of catheter used.


By site


Percutaneous central venous catheter (CVC)

A percutaneous central venous catheter, or CVC, is inserted directly through the skin. The internal or external
jugular The jugular veins are veins that take deoxygenated blood from the head back to the heart via the superior vena cava. The internal jugular vein descends next to the internal carotid artery and continues posteriorly to the sternocleidomastoid mus ...
, subclavian, or
femoral vein In the human body, the femoral vein is a blood vessel that accompanies the femoral artery in the femoral sheath. It begins at the adductor hiatus (an opening in the adductor magnus muscle) as the continuation of the popliteal vein. It ends a ...
is used. It is most commonly used in critically ill patients. The CVC can be used for days to weeks, and the patient must remain in the hospital. It is usually held in place with sutures or a manufactured securement device. Commonly used catheters include
Quinton catheter Quinton catheters are non-tunneled central line catheters, which are often used for acute (i.e. temporary) access for hemodialysis or infusion of medicine when peripheral IV access is not possible (e.g. small vessel caliber, extensive burn injuries) ...
s.


Peripherally inserted central catheters (PICC)

A peripherally inserted central catheter, or
PICC line A peripherally inserted central catheter (PICC or PIC line), less commonly called a percutaneous indwelling central catheter, is a form of intravenous access that can be used for a prolonged period of time (e.g., for long chemotherapy regimens ...
(pronounced "pick"), is a central venous catheter inserted into a vein in the arm (via the basilic or
cephalic A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple animals m ...
veins) rather than a vein in the neck or chest. The basilic vein is usually a better target for cannulation than the cephalic vein because it is larger and runs a straighter course through the arm. The tip of the catheter is positioned in the superior vena cava. PICC lines are smaller in diameter than central lines since they are inserted in smaller peripheral veins, and they are much longer than central venous catheters (50–70 cm vs. 15–30 cm). Therefore, the rate of fluid flow through PICC lines is considerably slower than other central lines, rendering them unsuitable for rapid, large volume fluid resuscitation. PICCs can easily occlude and may not be used with
phenytoin Phenytoin (PHT), sold under the brand name Dilantin among others, is an anti-seizure medication. It is useful for the prevention of tonic-clonic seizures (also known as grand mal seizures) and focal seizures, but not absence seizures. The in ...
. PICC lines may also result in venous thrombosis and stenosis, and should therefore be used cautiously in patients with chronic kidney disease in case an
arteriovenous fistula An arteriovenous fistula is an abnormal connection or passageway between an artery and a vein. It may be congenital, surgically created for hemodialysis treatments, or acquired due to pathologic process, such as trauma or erosion of an arterial ...
might one day need to be created for hemodialysis. However, PICC lines are desirable for several reasons. They can provide venous access for up to one year. The patient may go home with a PICC. They avoid the complications of central line placement (e.g. pneumothorax, accidental arterial cannulation), and they are relatively easy to place under ultrasound guidance and cause less discomfort than central lines. PICC lines may be inserted at the bedside, in a home or radiology setting. It is held in place with sutures or a manufactured securement device.


Subcutaneous or tunneled central venous catheter

Tunneled catheters are passed under the skin from the insertion site to a separate exit site. The catheter and its attachments emerge from underneath the skin. The exit site is typically located in the chest, making the access ports less visible than catheters that protrude directly from the neck. Passing the catheter under the skin helps to prevent infection and provides stability. Insertion is a surgical procedure, in which the catheter is tunnelled subcutaneously under the skin in the chest area before it enters the SVC. Commonly used tunneled catheters include
Hickman Hickman or Hickmann may refer to: People * Hickman (surname), notable people with the surname Hickman or Hickmann * Hickman Ewing, American attorney * Hickman Price (1911–1989), assistant secretary in the United States Department of Commerce * ...
, and Groshong, or Broviac catheters and may be referred to by these names as well. A tunnelled catheter may remain inserted for months to years. These CVCs have a low infection rate due to a Dacron cuff, an antimicrobial cuff surrounding the catheter near the entry site, which is coated in antimicrobial solution and holds the catheter in place after two to three weeks of insertion.


Implanted central venous catheter (ICVC, port a cath)

An implanted central venous catheter, also called a port a cath or port a catheter, is similar to a tunneled catheter, but is left entirely under the skin and is accessible via a
port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as H ...
. Medicines are injected through the skin into the catheter. Some implanted ports contain a small reservoir that can be refilled in the same way. After being filled, the reservoir slowly releases the medicine into the bloodstream. Surgically implanted infusion ports are placed below the clavicle (infraclavicular fossa), with the catheter threaded into the heart (
right atrium The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves. There are two at ...
) through a large vein. Once implanted, the port is accessed via a "gripper" non-coring Huber-tipped needle (PowerLoc is one brand, common sizes are length; 19 and 20 gauge. The needle assembly includes a short length of tubing and
cannula A cannula (; Latin meaning 'little reed'; plural or ) 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 ...
) inserted directly through the skin. The clinician and patient may elect to apply a topical anesthetic before accessing the port. Ports can be used for medications, chemotherapy, and blood sampling. As ports are located completely under the skin, they are easier to maintain and have a lower risk of infection than CVC or PICC catheters. An implanted port is less obtrusive than a tunneled catheter or PICC line, requires little daily care, and has less impact on the patient's day-to-day activities. Port access requires specialized equipment and training. Ports are typically used on patients requiring periodic venous access over an extended course of therapy, then flushed regularly until surgically removed. If venous access is required on a frequent basis over a short period, a catheter having external access is more commonly used.


Catheter types


Triple-lumen catheter

The most commonly used catheter for central venous access is the triple lumen catheter. They are preferred (particularly in the ICU) for their three infusion channels that allow for multiple therapies to be administered simultaneously. They are sized using the French scale, with the 7 French size commonly used in adults. These catheters typically have one 16 gauge channel and two 18 gauge channels. Contrary to the French scale, the larger the gauge number, the smaller the catheter diameter. Although these catheters possess one 16 gauge port, the flow is considerably slower than one would expect through a 16 gauge peripheral IV due to the longer length of the central venous catheter (see section on "catheter flow" above). It is important to note that the use of multiple infusion channels does not increase the risk of catheter-related blood stream infections.


Hemodialysis catheter

Hemodialysis catheters are large diameter catheters (up to 16 French or 5.3mm) capable of flow rates of 200–300 ml/min, which is necessary to maintain the high flow rates of
hemodialysis Hemodialysis, also spelled haemodialysis, or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as creatinin ...
. There are two channels: one is used to carry the patient's blood to the dialysis machine, while the other is used to return blood back to the patient. These catheters are typically placed in the internal jugular vein.


Introducer sheaths

Introducer sheaths are large catheters (8–9 French) that are typically placed to facilitate the passage of temporary vascular devices such as a
pulmonary artery catheter A pulmonary artery catheter (PAC), also known as a Swan-Ganz catheter or right heart catheter, is a balloon-tipped catheter that is inserted into a pulmonary artery in a procedure known as pulmonary artery catheterization or right heart cathet ...
or transvenous pacemaker. The introducer sheath is placed first, and the device is then threaded through the sheath and into the vessel. These catheters can also serve as stand-alone devices for rapid infusion given their large diameter and short length. When paired with a pressurized infusion system, flow rates of 850 ml/min have been achieved.


Routine catheter care

The catheter is held in place by an adhesive dressing, suture, or staple which is covered by an occlusive dressing. Regular flushing with saline or a heparin-containing solution keeps the line open and prevents blood clots. There is no evidence that heparin is better than saline at preventing blood clots. Certain lines are impregnated with antibiotics, silver-containing substances (specifically
silver sulfadiazine Silver sulfadiazine, sold under the brand Silvadene among others, is a topical antibiotic used in partial thickness and full thickness burns to prevent infection. Tentative evidence has found other antibiotics to be more effective, and therefore ...
) and/or
chlorhexidine Chlorhexidine (CHX) (commonly known by the salt forms chlorhexidine gluconate and chlorhexidine digluconate (CHG) or chlorhexidine acetate) is a disinfectant and antiseptic that is used for skin disinfection before surgery and to sterilize surgi ...
to reduce infection risk. Specific types of long-term central lines are the Hickman catheters, which require clamps to make sure that the valve is closed, and Groshong catheters, which have a valve that opens as fluid is withdrawn or infused and remains closed when not in use. Hickman lines also have a "cuff" under the skin, to prevent bacterial migration. The cuff also causes tissue ingrowth into the device for long term securement.


See also

*
Peter Pronovost Peter J. Pronovost (born February 22, 1965) is Chief Quality and Transformation Officer at University Hospitals Cleveland Medical Center, the main affiliate of the Case Western Reserve University School of Medicine. At UH, Pronovost is responsible ...
*
Quinton catheter Quinton catheters are non-tunneled central line catheters, which are often used for acute (i.e. temporary) access for hemodialysis or infusion of medicine when peripheral IV access is not possible (e.g. small vessel caliber, extensive burn injuries) ...


References


External links


Central Venous Catheter Placement & Pulmonary Artery Catheter – Vìdeo Dailymotion
(without ultrasound guidance)
Video tutorial on how to start central venous lines in various locationsCentral line care, comparison, indications, complications and uses
{{DEFAULTSORT:Central Venous Catheter Catheters Articles containing video clips