Why a Central Line Is Necessary and Associated Risks

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A central line is a type of catheter that is placed in a large vein that allows multiple IV fluids to be given and blood to be drawn. When compared to a typical IV line, a central line is larger, can stay in place longer, can deliver a greater volume of fluids, and allows blood to be drawn easily.

Administering drugs through a central line.
Science Photo Library / Getty Images 

A central line can also be used to measure fluid volume status, and to help determine if a patient is dehydrated or has received an adequate amount of fluid to support bodily functions.

A PICC line, a type of IV access that can be maintained for weeks and months, is not a central line but shares many characteristics with this type of IV access.

Purpose of a Central Line

A central line may be placed for multiple reasons. A central line may have up to five lumens, which are ports in which fluid can be infused, blood can be drawn or measurements may be taken.

If a patient needs fluid resuscitation, meaning large amounts of intravenous fluids need to be given, a central line may be placed to allow fluid to flow faster.

Central lines can be used to draw blood as well. In some cases, two of the lumens on the central line can be used to perform dialysis, with one lumen used to take blood out of the vascular system and another lumen used to return the dialyzed blood to the body.

For patients who require frequent blood draws to be sent to the laboratory, the central line allows for blood to be drawn without repeatedly "sticking" the patient.

One function that is unique to some central lines is the ability to measure central venous pressure. This measurement gives the healthcare team insight into how much fluid is in the vascular system, and if the patient has received too much or too little fluid.

If the central line is a Swan-Ganz type catheter, a pulmonary wedge pressure can also be obtained, which can indirectly indicate how the left atrium of the heart is functioning. For patients who are having serious heart issues or recent heart surgery, this information can be extremely valuable.

A central line is also appropriate when long-term therapy is expected, such as weeks of IV antibiotic treatment, or if caustic medications are needed that cannot be given through a standard IV, such as chemotherapy.

Insertion of a Central Line

In order to insert a central line, the patient must be lying flat, and the area of the body where the central line will be inserted is exposed.

The most common veins used for placement of a central line are the internal jugular in the neck, the subclavian vein near the clavicle, and the femoral vein in the groin.

The patient is covered, typically from head to toe, with a sterile drape. The drape is a sterile paper sheet with a hole in it to allow the individual placing the central line access to the vein.

The sterile drape is intended to help reduce the risk of infection, and studies have shown that covering the entire body, rather than just the area where the central line will be placed, is the best practice for the prevention of infection.

Once the patient is draped, the area of skin is cleaned. If the patient is awake, the area of skin may also be numbed with a local anesthetic.

Using sterile technique, a hollow catheter is inserted into the vein, typically using ultrasound to locate the appropriate blood vessel. The catheter is then stitched in place, or an adhesive device is used to hold the catheter still at the insertion site.

The area is then cleaned again with antiseptic and a sterile dressing is placed over the insertion site, with the lumens accessible. Placement of the catheter must be confirmed using an X-ray before the central line can be used, to avoid accidentally infusing medications into a tissue or the wrong blood vessel.

In some cases, the catheter may be in the correct vessel, but need slight adjustment because the catheter is either too far in the vessel or not quite far enough.

Risks of a Central Line

There are risks associated with the insertion of a central line, which must be weighed against the patient's need for the line. Infection is the greatest risk.

Central Line-Associated Bloodstream Infection

One of the risks of central line placement and usage is a central line-associated bloodstream infection (CLABSI). To help prevent infections, standardized best practices have been implemented.

These practices include scheduled sterile dressing changes, the use of a full-body sterile drape during placement of the line, removing the line as soon as it is no longer necessary, and only inserting central lines that are absolutely necessary.

Central lines are typically placed above the waist when possible to minimize the risk of infection. Femoral vein sites are associated with higher rates of infection.

The dressing placed over the insertion site is typically clear, which allows the healthcare team to check for signs of infection without exposing the insertion site to air more than absolutely necessary.

Other Risks

Other risks include pneumothorax (collapsed lung), particularly if the central line is placed in the subclavian vein. This is treated with a chest tube when necessary.

During the insertion of some types of central lines, the heart may be irritated by the process while the line travels through the blood vessels near the heart, causing an alteration in the heart's rhythm. This typically resolves with appropriate placement of the line but may require medication for some rare individuals.

One final complication of central lines is an air embolism, a condition where air enters the vascular system and begins to travel through the body. This condition, which is very serious, is also very rare and largely preventable.

Frequently Asked Questions

How is a PICC line different from a central line?

PICC lines are one type of central line but they are placed in the arm rather than the chest, neck, or groin. PICC lines are also a very long type of catheter that is threaded up the arm to the vein in need of access.

How long can a central line remain in place?

A central line can remain in place for days, weeks, or months as long as there are no complications, such as an infection or blockage.

How is a central line removed?

After a central line is no longer needed, the patient is placed on their back in a position so that the head rests slightly below the heart and feet. As the catheter is being removed, the patient may be asked to breathe out strongly while holding their nose with the hand opposite the catheter. The person performing the removal procedure puts pressure on the site during this time.

A Word From Verywell

A central line is extremely useful when a patient is ill, but it is not risk-free. For many patients, the benefit of not having multiple "sticks" for blood draws and having dependable IV access in place is greater than the risks presented by this type of access. 

For some patients, the central line makes a hospitalization more bearable, while others are not bothered by blood draws and prefer to avoid the potential complications that a central line can bring. 

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9 Sources
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