- What is venous access?
- Why is venous access used?
- What is venous access used for?
- What are venous access devices?
- How is a central venous line inserted?
- How to prepare for a central venous line insertion?
Venous access is any method used to access the bloodstream directly through the veins. It allows substances, such as intravenous (IV) medicine, to enter the blood directly, and also facilitates the drawing of blood. It is a common procedure used in hospitals and clinics.
Venous access is used to prevent repeatedly piercing a patient’s skin with a needle and provides an effective and efficient way to take blood or deliver medication painlessly.
Venous access is a very useful method of delivering medicine directly to the patients' bloodstream. Such medicine includes:
In addition to pharmaceuticals, the following can also be administrated:
- IV feeding (when unable to give food or supplements in other forms)
- large quantities of fluids
- blood transfusions
Other uses of venous access are:
- taking blood repeatedly
- monitoring blood pressure in the central vein
There are a few different venous access devices. The type used depends on the duration the patient will need it and the frequency of access. The most common device is a simple peripheral IV (PIV) line. This is a basic, plastic tube usually allowing access to a small vein in the arm. This is used during short hospital stays to provide medicine or fluid to the patient. Although common, these are not suitable as long-term solutions and the access point (the point where the device enters through the skin to the vein) needs to be changed every 72 to 96 hours to prevent complications, like vein inflammation or infection.
For this reason, central venous access is used in cases that require IV access over a longer period. This involves a long, hollow, plastic catheter, or line, being inserted through the skin into a vein, located in the neck, arm, or leg. These catheters are designed to extend to the largest central vein in the heart, the superior or inferior vena cava, which can tolerate the tube much better than a smaller vein, reducing the risk of complications. Furthermore, compared to a standard IV-line, vascular access catheters are more durable and less likely to block or become infected.
- A peripherally inserted central catheter (PICC) is inserted into a vein in the hand, forearm, or feet, travelling through a minor vein to the vena cava.
- If access is required over a longer period, for several weeks or even months, a centrally inserted central catheter (CICC) is preferred. These catheters access larger veins in the body, as they are more robust and may damage smaller veins due to their size or purpose, i.e., if they are delivering medicine that could cause damage to smaller veins.
There are three main types of CICC used:
- Non-tunnelled: These are larger than PICCs that are placed running via a larger and more central vein, like the jugular vein in the neck or the femoral vein in the groin. The point of exit on the skin is close in proximity to the entry point of the vein.
- Tunnelled: Tunnelled catheters have a small cuff at one end that stimulates tissue growth to hold the catheter in place and keep it secure. This decreases the risk of infection, meaning the catheter can remain in place for a long time.
- Implantable ports: also called port catheters, port-a-cath or subcutaneous implantable ports are a catheter with a port, or revisor, attached to the tube. Both the port and tube are inserted under the skin. The port is the designated access point for the administration of medicine or for the drawing of blood. To do so, the skin above the port will be treated with an anaesthetic cream, cleaned and a needle will be placed through the skin to access the port. Like the tunnelled catheter, as the implanted one is located entirely under the skin, this reduces the likelihood of infection by a lot and means it can remain in place for a longer period.
When a suitable candidate receives a central venous line, they are given a local anaesthetic so to numb the surface area of the skin. The insertion is carried out by a specialist, an interventional radiologist, or a specially trained surgeon who will make us of ultrasounds and x-rays to guide the catheter to the vena cava. If a part of the catheter remains outside of the skin, it will be secured to the skin through stitches and a dressing. Heart beat and blood pressure will be monitored constantly throughout the process.
Before the procedure, the patient should inform their doctor if:
- They are pregnant. The doctor will carry out an x-ray only if necessary to avoid exposing the baby to radiation.
- They have had a recent illness or a current condition.
- They have allergies, especially to anaesthesia or materials in the catheter.
- They are taking any medication, including herbal supplements and aspirin.
The patient may be advised to avoid aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs) i.e. ibuprofen, or blood thinners before the procedure.