Central Venous Catheter 中央靜脈導管
◼ 1.1 About central venous catheter
A central venous catheter, also known as a central venous line, is a catheter placed into the major central vein in the body, such as the superior vena cava, primarily for the purpose of administering medications or measuring central venous pressure (CVP).
The catheter can be inserted into the central vein through the internal jugular vein, subclavian vein, axillary vein, femoral vein, or veins in the arm.
The main purpose of a central venous catheter is to administer drugs (such as chemotherapy drugs) or solutions (such as parenteral nutrition) directly into the central vein. These medications or solutions often have a certain concentration, and injecting them through peripheral veins can cause damage to smaller veins, leading to inflammation and pain. Due to the high blood flow in the central veins, the risk of complications such as inflammation is lower when using a central venous catheter, making it a safer and more appropriate method.
In addition, a central venous catheter can also be used for blood sampling, especially for measuring central venous oxygen saturation. It can also measure central venous pressure (CVP), which is used to assess the function of the heart, lungs, and circulatory system.
◼ 1.2 Purposes of central venous catheter
A central venous catheter has various clinical uses:
- The primary use of a central venous catheter is to provide access for long-term administration of chemotherapy drugs, antibiotics, pain medications, or parenteral nutrition.
- A central venous catheter can be used to measure the central venous pressure (CVP) in a patient’s body. In critically ill patients, the measured values can be used to assess the patient’s circulatory system parameters, estimate fluid balance, and evaluate changes in cardiopulmonary function.
- A central venous catheter can provide a route for rapid intravenous fluid administration. For example, in cases of significant bleeding or emergencies, a large volume of intravenous fluids can be quickly administered through a central venous catheter.
- Prior to major surgery, anaesthetists often recommend the placement of a central venous catheter.
- The catheter can be used for procedures such as plasma exchange, collection of peripheral blood stem cells, and hemodialysis.
◼ 1.3 Types of central venous catheter
Central venous catheters can be divided into two main types:
Non-implantable catheters: Hickman Catheter
This type of central venous catheter has its distal end located within the central vein, with the catheter passing through a tunnel in the skin. The other part of the catheter, including the connectors, remains outside the body, allowing healthcare providers to administer fluids and draw blood through the catheter’s connectors.
These catheters can be left in place for several months to over a year and are considered long-term options. When the patient no longer requires the central venous catheter, it can be removed. Non-implantable catheters can have a single lumen, double lumen, or triple lumen configuration.
Totally implantable catheters: Port-A Catheter
This type of catheter is often referred to as a subcutaneous implanted infusion port. It consists of an injection port (portal) and a catheter with a locking mechanism. Implantable catheters are fully placed inside the body, with the injection port positioned beneath the skin, typically below the right clavicle. When healthcare providers need to draw blood or administer fluids, they access the port by puncturing the skin over the injection port using a butterfly needle.
When the patient no longer needs this type of central venous catheter, a minor surgical procedure is required to remove both the catheter and the injection port.
◼ 1.4 Procedures for placement of the catheter
- The placement of a central venous catheter can be done under local anesthesia using either an open or percutaneous approach.
- Open approach: In this method, a surgeon makes an incision below the right clavicle or in the neck to access the subclavian vein or internal jugular vein, respectively. The catheter is then inserted into the vein, and under X-ray guidance, the distal end of the catheter is positioned within the superior vena cava (central vein). After ensuring hemostasis and suturing the incision, the surgery is completed.
- Percutaneous approach: In this approach, the catheter is inserted into the subclavian vein or internal jugular vein under ultrasound guidance. Then, using X-ray guidance, the catheter is advanced into the superior vena cava. The advantage of this method is that it involves smaller incisions, resulting in less postoperative pain for the patient.
- The surgical procedure takes approximately 30 minutes to complete. Since the surgery is performed under local anesthesia, patients can resume eating immediately after the procedure.
◼ 1.5 Points to note after surgery
Non-implantable catheter: Hickman catheter
- After surgery, medication can be administered through the catheter if there are no specific complications with the incision.
Fully implantable catheter: Port-A artificial blood vessel
- In general, after surgery, the doctor needs to observe the incision for 24 hours to ensure there is no bleeding, inflammation, or swelling. Afterward, the central venous catheter can be used.
- Healthcare providers will insert a special butterfly needle into the raised portion of the artificial blood vessel and connect it to the infusion tubing for treatment.
General nursing points
- During intravenous infusion, healthcare providers will secure the infusion catheter with a curved needle to the clothing to prevent the catheter from pulling on the central line and causing dislodgement.
- If the patient experiences pain, bleeding, or detects any leakage, it should be immediately reported to the doctor.
- Healthcare providers will disinfect the catheter site with 75% alcohol or iodine solution during catheter blood withdrawal or infusion set replacement.
- After the completion of fluid infusion or blood withdrawal, healthcare providers will flush the catheter with an anticoagulant to prevent blood clot obstruction in the artificial blood vessel.