Throwing a Lifeline: The Central Line Experience

There is somewhat of a mystique with medical procedures. In the pediatric intensive care unit (ICU), many procedures are performed. Sometimes, these procedures are performed under the direst of circumstances. Placing a central line is one such procedure and can actually be a lifeline for many a child in the pediatric ICU. However, what is a central line?

A central line is a catheter that is placed into the larger veins in the body, usually in the internal jugular veins in the neck, the subclavian veins under the clavicles, or the femoral veins in the groin. It is used to give medications and fluids that may be more caustic to small veins that are usually the spot where peripheral intravenous (IV) catheters are placed. The larger veins are much more durable and are secure for administering medications such as epinephrine or dopamine and high-sugar fluids used for total parenteral nutrition (nutritional fluids given to patients via the venous blood system, if they are not able to tolerate nutritional support given into their stomach and intestines). The central line is also a useful piece of equipment because blood can easily be drawn from the catheter for routine or repeated testing of the blood which may be required in more critically ill patients. Overall, it is reliable access to the venous blood system to supply the body with potentially life-saving medications and enables easy access for testing of the blood to make medical decisions.

The procedure itself is surreal in that one accesses the targeted blood vessel in a very elegant method. But, before the procedure is performed, the access area of the skin needs to be cleansed with antibacterial agents and, then, all other areas are draped with special sterile towels to cover areas around the cleansed area to keep the procedural site sterile or devoid of infectious microorganisms. The individual participating in the procedure also washes their hands and dons sterile equipment to prevent transmission of microorganisms into the sterile environment as well. The patient is in a vulnerable position from an infectious standpoint, so efforts are made to reduce the risk of infection from the procedure which is always a concern.

Once infection protective measures have been performed, the procedure can resume. In the instance of placing a central line in the groin, one must locate the blood vessel first. In most cases, the procedure is performed blindly. This means that one does not actually see the blood vessel with the naked eye, but finds the location of the blood vessel by anatomical landmarks. In some instances, the procedure is not performed in a blind fashion and the blood vessel is located by visualizing it through an ultrasound technique. Nevertheless, the blood vessel can be located by landmarks by feeling the femoral artery pulse and knowing that the vein is always medial to the pulse’s locations.

Once the vessel has been located in the groin, a needle with a syringe attached is inserted below the fold in the groin at a 30-45 degree angle to the skin and parallel to the pulse of the femoral artery making sure to stay just medial to the pulse itself. Usually, one hand has fingers on the pulse and the other hand holds the needle with the syringe. As the needle punctures the skin, the plunger on the attached syringe is drawn back to create a negative pressure in the syringe. As the needle finds the blood vessel, blood rushes into the barrel of the syringe to alert one that the needle is in the proper position in the blood vessel. The next step is the novel part of the procedure.

The Seldinger technique is the innovative method that is used to place the catheter into the vessel. Once the needle has found the vessel and there is verified blood flow back into the syringe, the syringe is disconnected while the needle is carefully held in place in the skin. Of note, the blood coming out of the hub of the needle is viewed to make sure that it is dark red and flowing out of the needle hub slowly. If the blood is pulsating strongly out of the hub of the needle and is bright red, this means that the needle is in the femoral artery and not in the femoral vein. Because they are side by side, it is not uncommon for the needle to perforate the artery instead of the intended vein. So, after confirming that the needle is indeed in the femoral vein, a blunt-tipped wire (smaller than the diameter of the needle) is placed into the hub of the needle and threaded into the vein. As the wire is felt to smoothly pass into the vessel, the needle is withdrawn while holding the end of the wire and maintaining the wire placement in the vessel. With the needle removed, the central line catheter is carefully slid over the wire, through the entrance in the skin, and into the vessel while holding the wire so it does not get pushed further into the vessel as well. Once the catheter is inserted through the skin and into the vessel up to the hub of the catheter, the wire is removed. Blood is aspirated from the catheter and the catheter is flushed with saline to make sure that the catheter is in the correct spot and still in the vein. With proof of correct position, the Seldinger technique has been successfully executed.

The central line is then tied to the skin with sutures to make sure that it doesn’t slide out or become displaced. A dressing is applied over the area of the central line’s entrance through the skin to protect the individual from infection because of the foreign body entering the skin (the catheter itself). Part of the body’s defense against invading organisms is the skin. Once that has been breached, even by a sterilely placed central line, infection of the skin and entry of organisms into the bloodstream is still possible. So, special care is required to prevent infection by keeping the insertion site clean and covered, as well as reducing the number of times that the central line is opened to draw blood out of it or medications have been administered through it.

The placement of a central line is not without risks. As mentioned previously, infection is a concern. However, placing a foreign body in a blood vessel can also precipitate clot formation within the chosen blood vessel which may necessitate anti-coagulation treatment. Furthermore, when one accesses a blood vessel with a needle, there is always a risk of bleeding. The risks of complications also vary depending on the area where the central line is being placed and how critically ill the patient is. When one is placing a central line in a subclavian vein under the clavicle, the insertion area is close to the lung where a needle may puncture it inadvertently and cause air to leak into the chest outside of the lung tissue itself to cause a pneumothorax. Blood can also leak outside the blood vessel into the chest to cause a hemothorax. Both pneumothorax and hemothorax may require interventions to evacuate displaced air or blood, respectively.

Given that placing a central line is not without risks, it is important to weigh the risks and benefits of the procedure. This means that the reasons for placing the central line need to be substantial and contribute to the health of the patient in a way that normal vascular access, such as a peripheral intravenous (IV) catheter, cannot provide. The central line may be critical to sustaining a patient’s life depending upon how it is being utilized. Under those circumstances, a central line is not just simple vascular access. A central line is a lifeline.

After reading this article, did it help you understand this procedure better?  Was it something that you have been curious about?  Please feel free to put your answers in the comments!