Venous access devices use a catheter, or a long, thin, flexible, spaghetti-sized tube, as a way to deliver repeated doses of medications directly into the bloodstream and allow blood draws (without new vein punctures) or rapid exchange of blood for treatments like dialysis or plasmapheresis.
Access devices can be implanted directly into a vein in a person's arm, neck, or chest and left in place for long periods of time.
Like oxygen and nutrients, medications are delivered to the body's cells through the bloodstream. By using a hypodermic needle to inject drugs through a vein in the arm and into the bloodstream, medications can be transported very quickly through the body to the drug's site of action or the place in the body at which the drug is needed.
In some cases, using a needle to inject medication may not be the best intravenous delivery method. When a person has weak arm vessels, or to prevent the pain and potential damage to small blood vessels caused by repeated needle punctures or caustic drugs, doctors may use venous access devices to deliver drugs directly into the bloodstream.
Venous access devices are small medical appliances that can be connected directly to veins. Access devices use a catheter, or a long, thin, hollow tube that serves as a kind of artificial vein, with one end of the catheter inside a vein in the body, and the other end very close to the surface of the skin or outside the skin. The catheters are made of silicone, a soft material that does not irritate body tissues. Access devices can be inserted directly into a vein in a person's arm, neck, or chest and left in place for long periods of time. Using the part of the device outside or near the surface of the skin as a kind of channel into the venous system, health care professionals can:
Administer intravenous drugs;
Supply hydrating and nutritional fluids;
Draw blood samples; and/or
Transfuse blood or blood products.
Even the basic intravenous venous (IV) catheter, or "tube," on the back of the hand or the inside of the elbow, is a kind of venous access device. These basic IVs are called short-term peripheral catheters or peripheral intravenous lines. These catheters are inserted directly through the skin and immediately into a vein.
Other kinds of catheters have their tips located in a central vein, close to a person's heart. Generally, these types of catheters are called central lines, central venous access devices, or central venous catheters. Types of central venous access devices include:
Peripherally inserted central catheters (PICC lines);
Tunneled catheters, also called subclavian inserted central catheters (SICC lines); and
Subcutaneous vascular access devices (SVADs).
Other types of venous access devices may be required for people with kidney problems who require hemodialysis, or the process of filtering blood through an external device to remove wastes and toxins.
WHEN IS VENOUS ACCESS INDICATED?
Venous access devices are indicated in a variety of situations, but the need for an access device is most common when a person has a condition that requires prolonged access to the venous system and the veins in the person's arms are inadequate. This commonly occurs in people with cancer, because the strong chemotherapy drugs used may damage the small veins of the arm, and in people who may require weeks of antibiotic treatment for a severe systemic infection.
Before placing an access device, physicians may order tests to evaluate potential placement sites and to make sure a person's veins are healthy and open. Those tests may include:
Duplex Ultrasound; and/or
WHAT TO EXPECT
Although the procedure for inserting a venous access device varies depending on the type of device and the location on a person's body where the device is inserted, there are some basic procedural similarities the various devices share. Generally, most venous access procedures consist of the following steps:
Accessing the vein;
Inserting the device into the vein;
Positioning the tip of the device within the vein or vena cava; and
Closing or dressing the catheter exit point or incision.
POST TREATMENT GUIDELINES
The incisions and catheter exit sites must be properly cared for to avoid the risk of infection or blood clots forming and clogging the catheter.
The following guidelines will help to keep the venous access device risk free.
Flush the catheter with saline solution or an anti-clotting drug called heparin after each use, or daily when not in use; certain types may be flushed weekly.
Flush subcutaneous access devices at least monthly during any time they are not accessed.
Keep the skin surrounding the catheter as clean as possible.
Keep any hair surrounding the site clipped.
Allow the exit site to dry fully after cleaning and disinfecting before applying a clean bandage.
Change dressings that cover the exit site at least one to three days or any time they become wet.
Complications that arise from a venous access device are grouped into two categories, early complications and late complications. Early complications may arise immediately following the insertion of the device; late complications arise after having the device in place for some time.
Early complications may include:
Bleeding from the vein puncture site.
More rarely, serious complications may arise during device insertion, including:
Air embolus, or the presence of an air bubble that can block a vein;;
Pneumothorax or hemothorax, or a collection of air or blood, respectively, in the membrane surrounding the lungs;
Abnormal heart rhythms;
Perforation of a vein or artery, or of lung or heart tissue; or
Venous thrombosis, which is the presence of a blood clot in the veins that can move with the flow of blood into the lungs.
Other early complications may include the catheter tip inside the vena cava migrating or the catheter becoming blocked or disconnected.
Late complications may include:
Infection in the bloodstream related to catheter use;
Infection in the veins (known as phlebitis);
Infection in the catheter tunnels or exit sites; and/or
Infection in the blood (known as sepsis).
Some catheters may be impregnated with antiseptics or antibiotics to help prevent infection.
Conditions that require immediate medical attention include:
Bleeding or oozing from any incision point or catheter exit site;
Skin that is red or tender;
Catheters or access devices that become loose or fall out; and/or