A central venous catheter (CVC), often called a central line, is a medical device that delivers various treatments. It involves inserting a thin, flexible tube into a large vein, where it can remain for an extended period. This device provides a reliable way to administer medications, fluids, and blood products directly into the bloodstream.
What is a Central Venous Catheter?
A central venous catheter is a long, flexible tube inserted into a large vein, such as those in the neck, chest, arm, or groin. The tube is carefully guided until its tip rests in a large vein near the heart, specifically the vena cava, which empties into the heart. This placement in a central vein differentiates it from a peripheral intravenous (IV) line, which accesses smaller veins, typically in the hand or arm. CVCs are generally longer and have a larger diameter than peripheral IVs, allowing for more substantial fluid flow and specialized uses.
Why Are CVCs Necessary?
Central venous catheters are necessary when patients require prolonged or specialized intravenous therapies that peripheral IVs cannot accommodate. They administer medications that might irritate smaller veins, such as chemotherapy drugs or certain antibiotics. CVCs also provide a stable access point for long-term nutritional support, known as parenteral nutrition, when a patient’s digestive system cannot absorb nutrients properly.
CVCs are valuable for frequent blood draws, reducing the need for repeated needle sticks and preserving peripheral veins. In critical situations, CVCs allow for rapid infusion of large volumes of fluids or blood products and enable precise monitoring of central venous pressure, which provides important information about a patient’s fluid status and heart function. Specialized treatments like hemodialysis or plasmapheresis rely on the high flow rates and reliable access that CVCs provide.
Different Kinds of CVCs
There are several types of central venous catheters, each designed for different durations and medical needs. Non-tunneled CVCs are often used for short-term access, typically less than two weeks, and are inserted directly through the skin into a vein in the neck, groin, or upper chest. Peripherally Inserted Central Catheters (PICCs) are inserted into a vein in the upper arm and threaded to the vena cava, offering venous access for weeks to months, sometimes up to a year. PICC lines are often used for long-term antibiotic administration or other extended therapies and can be managed in outpatient settings.
Tunneled catheters, such as Hickman, Broviac, or Groshong catheters, are surgically placed under the skin, tunneling for several inches before entering a large vein. This design helps reduce the risk of infection and provides stability, making them suitable for access lasting more than two weeks. Implanted ports, also known as Port-a-Caths, are similar to tunneled catheters but are entirely beneath the skin, with a small reservoir accessible through the skin by a needle. These are designed for long-term use, typically three months or longer, and offer a discreet access point for intermittent treatments.
How a CVC is Inserted and Maintained
The insertion of a central venous catheter is a procedure performed by trained medical professionals in a sterile environment, often utilizing local anesthetic. Imaging guidance, such as ultrasound or X-ray, is frequently used to ensure accurate and safe placement. Once inserted, the CVC requires diligent care and maintenance to prevent complications.
Daily care involves regular dressing changes to keep the insertion site clean and dry, typically every seven days for transparent dressings or every two days for gauze dressings. Hand hygiene is essential for anyone handling the CVC, and sterile supplies are used to prevent contamination. The catheter lumens must be flushed regularly with saline or sometimes heparin solution to prevent blood clots and maintain patency, especially after medication administration or blood draws. Patients and caregivers receive specific instructions on how to keep the site clean and functional, including avoiding submerging the site in water.
Risks Associated with CVCs
While central venous catheters are valuable, they carry potential risks and complications. Infection is a significant concern, ranging from localized site infections to more serious bloodstream infections. The risk of infection can be higher with non-tunneled CVCs or PICC lines, particularly if the hub is outside the body. Medical teams mitigate this risk through strict aseptic techniques during insertion and maintenance, including skin antisepsis with chlorhexidine.
Other complications can occur during insertion, such as bleeding or injury to blood vessels. A collapsed lung, known as a pneumothorax, is another potential risk, especially for catheters inserted in the chest area. Air embolism, where air bubbles enter the bloodstream, is a serious complication during insertion or if the catheter is not properly clamped. After placement, catheters can sometimes become blocked by blood clots or fibrin, requiring flushing or medication to clear them. Catheter dislodgement, where the device moves out of its intended position, is also a possibility.