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Central Venous Access Devices

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1Central Venous Access Devices www.asrt.org

PATRICIA A. MILLER, M.S., RN, CCRN

After completing this article, the reader should be able to:■ Identify and define the various types of central venous access devices (CVADs).■ Define the advantages and disadvantages of CVADs.■ Know how to safely administer contrast media or radioisotopes using a CVAD.■ Discuss the use of power injectors for administering contrast media through a CVAD.

Central Venous Access Devices

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Over the years, central lines have evolved from short-term, triple-lumen catheters used to administer medications and fluids to acutely ill patients into central venous access devices (CVADs) designed for long-term use in both hospitalized patients and outpatients. However, com-plications related to CVADs, especially catheter-related infections, can be costly in terms of patient mortal-ity and health care dollars. Radiologic technologists who have a working knowledge of CVADs can contribute to patient management, reduce complications and provide safe, comfortable care.

This ASRT Directed Reading Classic was originally published in Radiologic Technology, March/April 2006, Vol. 77/No. 4.

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Central venous catheters (CVCs) or central lines were, at one time, only used for critically ill patients who needed acute

central venous access, hemodynamic monitoring or both. These central lines were usually triple lumen and were used short term. Over the years, different kinds of central venous access devices (CVADs) have been developed to admin-ister IV fluids and medications to patients in hospital settings, long-term care facilities, home care and in outpa-tient treatment. These devices allow patients to leave the hospital earlier, while continuing treatment.

Imaging professionals may find some chronically ill patients have limited or very difficult peripheral access, so the only venous access may be a CVAD or central line. Although using a central line may not be the most desirable means of injecting contrast media or radioisotopes, the practitioner has little choice. To provide safe patient care, it is essential that radiologic science profes-sionals be familiar with the different types of CVADs, the risks and benefits of these devices and the standard of care for injecting contrast media or radioiso-topes into a CVAD.

What Is a Central Venous Access Device?

A CVAD is a venous catheter designed to deliver medications and fluids to the lower third of the superior vena cava (SVC) or right atrium. CVADs usually are inserted via the internal jugular, subcla-vian or femoral veins. Peripheral access also can be gained through the large veins of the upper arm. Indications for CVADs are:

■ Large-volume fluid resuscitation.■ Hemodynamic monitoring.■ Administration of hyperosmolar

IV fluids.■ Administration of long-term antibi-

otic or chemotherapeutic agents.■ Poor peripheral venous access.■ Administration of multiple complex

IV medications and solutions simul-taneously.

■ Short-term central venous access for hemodialysis.

Although it may seem that use of an existing central line may be the simplest route, it is important to realize that CVADs are not convenience devices and injecting into one is not without risk. It has been estimated that the cost of patient complications related to CVADs in the United States might be as high as $1 billion annually.1 Potential problems with

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Central Venous Access Devices www.asrt.org

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and usually are inserted in emergency situations. They are the typical triple-lumen catheters used for hospital inpatients. Veins used for insertion are the internal jugu-lar, subclavian and femoral. Nontunneled catheters gen-erally are left in place for a few days and not more than 2 weeks. It is quite unusual for patients to be discharged to home or an outpatient facility with a triple-lumen catheter.

Tunneled CVCs usually are inserted into the subclavi-an vein by way of a tunnel created under the skin. Other major veins can be used if the subclavian vein is not accessible. The exit site is usually on the anterior chest wall; however, exit sites also may be on the abdomen or the back. All tunneled catheters have a small cuff that sits in a subcutaneous tunnel. The cuff is designed to secure the catheter in place with scarring and to inhibit bacterial migration into the subcutaneous tunnel. The catheter tunnel may be palpable or visible, especially on thin patients. These catheters are relatively secure once

CVADs include:■ Catheter infection and sepsis.■ Complications related to the insertion process

(pneumothorax and hemorrhage).■ Catheter migration that causes vascular damage,

scarring or cardiac arrhythmia. ■ Catheter-induced thrombus or embolus.■ Catheter rupture resulting from excessive force

during injection. There are several kinds of CVADs. The choice of

device is related to patient needs and intended length of treatment. CVC devices are manufactured with 1, 2 or 3 lumens. Each lumen is an independent catheter port so there is no mixing of injected medications. Ports open distally at different lengths and the external ports may be labeled proximal, medial or distal. Hospital policy may dictate which port is reserved for injecting medica-tion, radioisotopes or contrast media. Most catheters are latex free.

CVADs may be open ended or valved. (See Fig. 1.) Valves can be at the proximal or distal end and are designed to prevent reflux of blood into the catheter. The valve is designed to stay closed unless actively opened by pressure from infusion or aspiration. Valved catheters generally need to be flushed less frequently than open-ended catheters.

Open-ended catheters must be clamped when not in use to prevent air entrance or blood backup into the catheter. Serious hemorrhage can result from an open-ended catheter left unclamped. Open-ended catheters require regular flushing to prevent occlusion from clots. Air embolus also can occur if an open-ended catheter is left unclamped. Air embolus and hemorrhage from unclamped CVCs can be fatal. Positive pressure valves that screw into the luer-lock end of the catheter can be used as a safety measure to minimize complications of open-ended CVADs.

Documentation concerning a patient’s CVAD should include the type and gauge of catheter, length and insertion date, and any other information required by hospital protocol. With peripherally inserted central catheters (PICCs), the external length also should be documented. Outpatients should carry information con-cerning their catheters with them.2

Types of Central Venous Access DevicesNontunneled CVCs are inserted directly into a large

vein and are intended for short-term use. Nontunneled catheters are 15 to 20 cm long, usually have 3 ports and are open ended. These catheters can be placed quickly

Fig. 1. A. Cross section of a triple-lumen catheter showing 3 dis-tinct separate lumens. B. Open-ended catheter. Most short-term central venous access devices are open ended. Blood can back up, resulting in clot or hemorrhage. Air can enter the catheter if it is not clamped. C. Valved catheter (distal end). Valve opens only with negative or positive pressure. Reflux of blood cannot occur.