Central Venous Access Devices

Central Venous Access Devices ATI The Basics    Central venous catheters, also known as central venous access devices (CVADs) or central lines, have become a mainstay for patients requiring intravenous (IV) administration of medications and other therapies. Unlike peripheral intravenous catheters typically inserted into the veins of the hand or forearm, central access devices are inserted into large veins in the central circulation. The tip of a central venous catheter is generally threaded into the internal or external jugular veins or into the lower third of the vena cava (superior or inferior) that leads to an area just above the right atrium. At the time of insertion, a chest x-ray is done to confirm proper tip location and catheter position and to make sure that there is no pneumothorax. Unlike peripheral catheters, a central line, depending on the type, can remain in place for several weeks to years. Central lines are especially beneficial for patients who have chronic diseases and require long-term intravenous therapy. General Indications  A central line is indicated for patients who need: o ◾parenteral nutrition o ◾chemotherapy or other vesicant or irritating solutions o ◾blood products o ◾antibiotics o ◾IV medications or solutions (when peripheral access is limited) o ◾central venous pressure monitoring o ◾hemodialysis Lumens    A lumen is a hollow channel within a tube. Some central catheters have just one lumen while others have multiple lumens. A single-lumen catheter consists of a tube or lumen ending in a hub that can either be connected to tubing for a continuous infusion of fluid or medication or capped and used for intermittent infusions. A single-lumen central venous catheter is used for patients who need an infusion into a large, central vein. When a single-lumen catheter is in place for infusing parenteral nutrition, it cannot be used to sample blood or to transfuse blood. This is because blood cells tend to adhere to the lumen and impede the flow of the nutrition solution. A multi-lumen catheter (MLC) increases the advantages of a single-lumen catheter. An MLC has separate color-coded ports to identify the different lumens. Each lumen opens separately from the other lumens at the distal end of the catheter or along various areas of the catheter. This means that solutions do not mix as they travel through the catheter. With a multi-lumen catheter in place, several treatments can be performed via a single central line insertion site. The number of lumens within an MLC varies from two to four. The multiple ports allow for administration of medications, blood infusions, blood sampling, fluid replacement, and pressure monitoring. Any one, any two, or all three may be capped and filled with heparinized saline or saline solution for intermittent use. Distinguishing the ports     A fairly common MLC configuration is three ports, commonly labeled and used as follows: ◾distal lumen: Used for the administration of blood or other viscous fluids o ◾middle lumen: Used for parenteral nutrition o ◾proximal lumen: Used for the administration of medications or blood Blood samples can be taken from any port not being used for fluid administration. The configurations vary, though. For example, a central catheter with two proximal lumens and one distal lumen is available. Always become familiar with particular MLC catheter you are accessing. Check the manufacturer’s instructions and how the lumens are labeled (color-coded, labeled by size, labeled by their proximal-medial-distal relationship). And, follow your facility’s procedures for labeling each lumen according to how it is used (for drawing blood samples, infusing fluids, infusing parenteral nutrition). Also, keep in mind that the designation of proximal, medial, or distal relates to the holes or eyelets at different places along the part of the catheter that sits in the superior vena cava. The first hole that sits inside the patient’s vein is the proximal port (closest to the entry and farthest from the right atrium). The next hole is the medial opening, and the next is the distal (the hole farthest from the site of entry and closest to the right atrium). In other words, you cannot tell by glancing at the external portion of the catheter which is the proximal, medial, or distal lumen. You have to depend on how the manufacturer labels the lumens. General Principles for all Central Lines     Syringe size. Excessive pressure from the syringe you use to deliver therapy through a central line can rupture the catheter. Therefore, use only 10-mL or larger syringes and avoid excessive force when flushing the lines or administering medications. Flushing with larger syringes creates less pressure; smaller syringes create more pressure. Flushing. Flushing with preservative-free, sterile 0.9% sodium chloride solution helps ensure and maintain patency of all types of central venous access devices. Your facility’s policies will specify flushing procedures to perform after catheter placement, before fluid infusion, and before and after blood sampling and drug, blood-product, and parenteral nutrition infusions. When flushing a central venous access device catheter, use a pulsing (push – stop – push – stop) flush to create turbulence that helps clear blood and medications from the line. If you meet resistance or cannot aspirate blood, take further steps to assess the catheter’s patency before you administer medications and solutions. Do not flush the catheter forcefully. (See the accepted practice section on troubleshooting.) Heparin flushing. Central venous access devices may require heparin flushing. The concentration and volume will depend on the type of central line and agency protocols. Valve-tip or closed-end valve catheters such as a Groshong incorporate a valve that opens from positive or negative pressure, as is generated by flushing or aspirating. Otherwise, the valve remains closed to keep blood from entering the catheter. These types of valves require only saline flushes. Flushing with heparin helps ensure and maintain patency of the central venous access device. Heparin is available in several concentrations. Check your facility’s policies to determine the concentration and volume of heparin required for the specific device as well as the frequency of the flush. The goal is not systemic anticoagulation; it is catheter patency. Valve-tip or closed-end valve catheters, such as a Groshong, incorporate a valve that opens from positive or negative pressure, as is generated by flushing or aspirating. Otherwise, the valve remains closed to keep blood from entering the catheter. These types of valves require only saline flushes.  Clamping. If central lines are not clamped, air might enter the patient’s central circulation, causing an air embolus. Keep central catheters clamped when not in use. This includes the time in between syringe changes. Use the small plastic clamp attached to the central line for clamping. A catheter with a valved or closed tip such as a Groshong does not require clamping. Fluid Displacement Needleless Connectors  Negative displacement devices let blood flow back into the catheter’s lumen when you disconnect the syringe or administration set. Blood reflux can lead to occlusions. When using a negative displacement device, it is important to use a positive-pressure flushing technique: Withdraw the syringe from the injection cap as you flush the last 0.5 mL of flush solution into the catheter. Or, flush all fluid into the catheter, maintain pressure on the syringe plunger, clamp the tubing between the catheter hub and the patient, then disconnect the syringe. Use a pressure flushing technique unless the device has a positive fluid displacement needleless cap. This device withholds a small amount of fluid to overcome blood reflux. When using a device with a needlefree positive fluid-displacement injection cap, do not use positive pressure flushing techniques. Disconnecting the administration set or syringe forces the reserved fluid into the catheter’s lumen. In this case, using a positive pressure flushing technique will cause blood reflux. Flush these devices only with saline and do not clamp the line. Drawing Blood from a Central Line     Central venous access devices can be used to avoid repeated venipunctures for patients who need frequent drawing of blood samples. Some sources express the view that drawing blood from central lines is not ideal, as the additional manipulation of the hub and the possibility of blood adhering to the inner surface of the catheter can increase the risk of bacterial growth, which is one factor that contributes to catheter-related bloodstream infection. However, for patients who require frequent venipuncture, the benefits of drawing blood from a central line do often outweigh the risks. Check your facility’s policy prior to collecting a blood sample from a central venous access device and familiarize yourself with the specifics of the device the patient has in place. Depending on its size, you might not be able to obtain a blood sample from a peripherally inserted central catheter (PICC). A lumen size of 4F or larger is recommended for drawing blood. Although sources vary, the Infusion Nurses Society recommends using the distal port of a multilumen catheter for blood sampling. The distal port is largest (16-gauge) and has a greater flow rate. You might have to use a different port for blood sampling if the distal port is already accessed for an infusion or if it is nonfunctional. Follow your facility’s policy for labeling each lumen to reserve it for a specific purpose or therapy. For example, label the distal port for blood sampling, the medial for parenteral nutrition, and the proximal for medication administration. For additional assurance that the laboratory results won’t be altered by the solutions infusing through the central access device, it is recommended to temporarily stop all other infusions until blood drawing has been completed. The amount of time in which infusions should be stopped prior to blood sampling may vary according to facility policy. For example, some policies may be very specific by stating a blood culture should not be drawn until after an hour of completion of an antibiotic infusion; whereas other polices may be more general, stating infusions should be stopped prior to sampling but not specify a specific time frame. Remember to resume infusions after blood sampling is completed. The nurse should consider the lab tests that are being prescribed and the types of fluids that have been infusing through the line(s). For example, a heparin infusion could interfere with coagulation studies or an antibiotic infusion, such as vancomycin, could interfere with serum medication levels. The nurse should be aware of the need for patient fasting, appropriate blood collection tubes, and the need to change the needleless connector cap prior to the procedure if the agency policy requires this. An example of would be prior to drawing a blood culture. Blood Collection Methods    Use either the syringe method or the evacuated collection tube system (trade name, Vacutainer) method to collect blood samples. Follow the recommendations of the manufacturer of the central access device and your facility’s policy to determine the method to use. When you use the syringe method, vigorously clean the needleless connector and attach a small syringe to the appropriate port. Unclamp the line and then slowly aspirate the appropriate amount of blood from the central line. Only the amount of blood needed for testing should be obtained. When you use the evacuated collection tube system, vigorously clean the needleless connector and attach the Vacutainer holder. When you unclamp the line and push the evacuated blood tube inside the tube holder, blood will begin to flow into the tube. Fill the number of tubes of the correct color stopper as required by the laboratory for the prescribed tests. Cleaning the needleless connector  It is important to adhere to appropriate infection preventive practices when working with needleless connectors, as they are recognized sites for microbial contamination and a source for developing catheter-related bloodstream infections. Facility policies may vary in what is used to clean needleless connectors. Policies may include the use of 70% alcohol,chlorhexidine or a single-use access valve disinfection cap (SwabCap). The disinfection cap contains isopropyl alcohol. With each use, a new cap gets twisted onto the needleless connector. It replaces the need to clean the connector with an alcohol or chlorhexidine prep pad. Once the disinfection cap is in place, the line is ready to use. The disinfection cap remains in place until the next use. When it is time to access the needleless connector again, the existing disinfection cap is removed and replaced with a new sterile disinfection cap. Discarding blood  The amount of blood to aspirate or pull from the central catheter and discard before filling the tubes is sometimes called “blood discard” or “waste.” The purpose of withdrawing fluid/blood before obtaining a blood sample is to clear the catheter of any intravenous fluid or medications that could alter the laboratory test results. Refer to your facility’s policy for the recommended volume of blood to discard. Implanted Vascular Access Devices   An implanted central venous access device, often referred to as an implanted port or by the popular brand name Port-A-Cath, is a device placed under the skin without any portion of it exiting the skin. It consists of a single or double injection port with a self-sealing silicone septum covering a metal or plastic reservoir called the body. The catheter connects the port and reservoir to a central vein, typically the superior vena cava. An implanted port can be used to administer medication including chemotherapy, to deliver fluids, and to draw blood samples. To access the port, use a noncoring, non-barbed (Huber) needle. Noncoring needles have a deflected point that helps avoid septal injury by slicing through the septum without coring out a tiny piece of it each time the port is accessed. Additionally, the septum is made of self-sealing  silicone, which allows it to be accessed many times without damaging the septum. Most facilities’ policies allow access to the implanted port with the same needle for 7 days. The implanted central access device insertion is performed in the surgical suite or in the radiology department. The most common site for implanted port placement is the anterior chest, just below the clavicle. Other less common sites for implanted port placement include the upper arm, the abdomen, and the back. Implanted Port      Implanted ports are available with single or double lumens. A double-lumen port has two noncommunicating reservoirs. Advantages of implanted ports are that they are cosmetically appealing, they have the lowest risk of infection of all chest-accessed central lines, they allow patients to carry on virtually all activities including bathing and swimming when it is not in use, and they do not require exit-site care. Some implanted ports are considered power-injectable and can handle 5 mL/second infusions at high pressure, which is needed during contrast enhanced computed tomography. The patient with this type of implanted port may carry an identification card that includes information regarding power-injection capability of the implanted port. Others may wear a wrist band identifying the presence of the power injection port. Special power-injection rated needles should be used to access the port. Implanted ports may be open-ended or valved. Open-ended ports require heparin flushing while valved ports do not require heparin. You’ll find more details in the accepted practice section on valve tips and open-ended tips. And be sure to review your facility’s policies addressing the frequency of flushing. When an implanted port is not accessed, monthly flushing is usually sufficient. Flushing practices: Prior to each use, aspirate for a blood return to confirm device patency. The port must be flushed with 10 mL 0.9% sodium chloride after each use, and when not accessed monthly flushing is usually sufficient. Prior to removing the Huber needle (called deaccessing), the port should be “locked” with a heparin solution per facility protocol. Nontunneled catheters     Nontunneled percutaneous central catheters are sometimes called subclavian, percutaneous, acute-care, or short-term catheters. This type of catheter is usually inserted into the internal jugular or subclavian vein, with the catheter tip resting in the superior vena cava just above the right atrium. Nontunneled catheters most often have multiple lumens. Indications for placement of this type of catheter include intravenous therapy, blood sampling, and central venous pressure monitoring. The femoral vein may be used if necessary. This site is not preferred, and the catheter should be removed as soon as possible due to high risk of infection. These catheters are not commonly used for long-term care. Dwell time (how long the catheter stays in place) is typically less than 6 weeks, though maximum dwell time is not well researched. The patient should be assessed daily for need and removal when no longer needed to reduce the risk of catheter-associated bloodstream infection. The insertion method is percutaneous venipuncture and does not require sedation. The provider may insert the catheter at the patient’s bedside or, if necessary, in an emergency setting. Because a nontunneled catheter protrudes externally and because there is no subcutaneous tunneling, the risk for infection is greater than with other central venous access devices. Also, venipuncture directly above the lungs increases the risk of pneumothorax. Peripherally Inserted Central Catheters           A peripherally inserted central catheter (PICC) is a long central catheter that is inserted into the basilic (preferred) or cephalic vein in the arm (thus the term peripheral). The end of the catheter rests in the superior vena cava just above the right atrium. A PICC can have single or multiple lumens. PICC lines are intended for patients who require therapy for several days to months. Clear lines of communication must be established so that the healthcare team is aware that the PICC is not a peripheral IV line. Document this information in patient’s medical record and follow any procedures your facility has established for alerting the team to the type of central line the patient has in place. PICCs are indicated for administering fluids, blood, and medications, as well as for blood sampling, although blood sampling through a PICC can be difficult, especially with smaller lumen PICCs. After blood sampling, the line is flushed with 20 mL sterile saline. A 10-mL syringe is always used for flushing to avoid the dangers posed by increased pressures from smaller syringes. PICC placement can be done at the bedside by a physician or, in some facilities, by a specially certified RN. If the PICC is not placed under fluoroscopy, an x-ray must verify the position of the distal tip. PICCs can be sutured in place, but this practice is no longer recommended because suture sites create additional breaks in the skin that can become inflamed, thus increasing the risk of bacterial colonization at the exit site. Most PICCs are secured with wound closure strips (such as Steri-strips) or a securing device (such as StatLock) to prevent catheter migration and damage. Your assessment includes measuring the patient’s upper arm circumference to establish baseline data. For standardization, it is best to measure at the level of the top of the axilla. This serves as a reference point to determine with later measurements the presence of swelling or edema. Also, be sure to measure and document the length of the external portion of the catheter from the insertion site to the hub of the access cap. Later, you’ll compare the length of the external catheter to the previously documented length to detect catheter dislodgement from the insertion site. If the new measurement differs, contact the provider. Ongoing care includes a dressing change (usually with a transparent semi-permeable dressing) 24 hours post insertion and then on a weekly basis. Assess the site for redness, drainage, swelling, and pain. Follow your facility’s policies for flushing. A typical schedule for flushing is every 12 hours when medications or fluids are not being administered. The Infusion Nursing Society’s recommendations include 5 mL of heparin (10 units/mL) flush once daily for a PICC not in use. Avoid measuring blood pressure and performing venipuncture in the arm with the PICC. Also, keep scissors, razors, and other sharp objects away from the PICC to prevent damage. Patient education should include activity limitations, such as avoiding heavy lifting, which could dislodge the catheter. The catheter and insertion site will also need to be kept dry during bathing and showering. Proper care, such as flushing, precautions for preventing infection, and signs and symptoms of complications, should also be taught. Care of insertion site  A dressing at the insertion site of a central line acts as a protective covering to prevent infection and also helps stabilize the catheter to prevent migration. How often you change the dressing varies with the type of dressing (gauze versus transparent) and the appearance of the dressing (soiled or damp versus clean and dry). Always use surgical asepsis (sterile technique) when changing the dressing and be sure to follow your facility’s policy for specific guidelines.          The Centers for Disease Control and Prevention recommends changing a dressing when it is damp, loosened, or soiled. The Infusion Nurses Society recommends changing gauze dressings every 48 hours and transparent dressings 3 to 7 days or whenever they are no longer intact. A transparent semipermeable membrane dressing is often preferred as it allows easy visualization of the insertion site. Typically, gauze dressings are not recommended unless there is drainage from the site. Gauze placed under a transparent dressing is not advised as it obscures visualization of the site. A chlorhexidine patch may be considered at the insertion site to reduce the possibility of infection. Recommended antiseptics to use for site care vary with the facility. Chlorhexidine gluconate is the preferred agent to clean the insertion site, but some use alcohol and povidone-iodine. The age of the patient is also a consideration when choosing an antiseptic. For example, the INS does not recommend using isopropyl alcohol or chlorhexidine for neonates. Povidone-iodine can be used but must be removed completely with sterile water or saline to prevent product absorption. Povidone-iodine ointment and topical antibiotics are no longer recommended as they can promote the colonization of fungi. When using chlorhexidine, use a back-and-forth motion. Cleanse the site for 30 seconds. With this or povidone-iodine and alcohol, be sure to cleanse the skin well beyond the dressing area. Povidone-iodine requires contact with the skin for a minimum of two minutes in order for it to be effective. Central venous catheters have a special cap on the end where IV tubing or syringes connect into the line. This cap is called the injection or access cap/needleless connector. The needleless connectors should be changed as indicated by agency policy. They should also be changed if blood or debris is visible, upon contamination, or prior to drawing a blood culture. Before attaching the new needleless connector, it should be primed with 0.9% sodium chloride and applied using aseptic technique. A single-use Luer-Lok access cap/connector is also available. The use of this eliminates the need to change the cap and it also eliminates the need to swab or clean the end of the cap with alcohol or chlorhexidine. The single use cap (Swab Cap) contains isopropyl alcohol and is twisted over and onto the needleless connector prior to each use and left in place until the next use. At the time of the next use, the single use cap is removed and replaced with a new one. In addition to site care and cap changes, your ongoing care includes assessing the insertion site for redness, drainage, inflammation, swelling, tenderness, and warmth. As part of the evidencedbased interventions to reduce catheter-related bloodstream infections, documentation should also include criteria supporting the continued need for the central venous access device. Tunneled Catheters    Tunneled central venous access devices (CVADs) are designed for long-term use (months to years) as they are designed to reduce infection without compromising mobility. A Dacron cuff lies within a subcutaneous tunnel created between the insertion site of the dermis and the site where the catheter enters the bloodstream. Tissue granulates around the cuff, anchoring the catheter and acting as a barrier to the spread of organisms from the skin to the bloodstream. Some cuffs contain antibiotics to further prevent infection. This type of CVAD can be used for administering fluids, chemotherapy, antibiotics, blood, and parenteral nutrition, as well as for central venous pressure monitoring and blood sampling. The distal catheter tip is advanced into the vessel and is placed in the superior vena cava, while the proximal end is tunneled subcutaneously to an incisional exit site on the patient’s trunk. The usual exit sites allow the patient to care for them conveniently, while also making it possible to conceal them under clothing. Tunneled catheters are often referred to by the trade names Hickman, Broviac, Leonard, and Groshong. Opened- ended catheters    Examples include Hickman and Broviac catheters. They differ slightly in lumen construction and size. A Hickman catheter may have single or multiple lumens. It is surgically inserted into the patient’s chest and into a central vein. It is tunneled under the chest tissue after it exits from the vein so that the exit site at the skin is a distance from its exit from the vein. Near the exit site, the catheter is surrounded by a Dacron cuff, which allows tissue to grow into the material, forming a seal against microbes and anchoring the catheter to minimize the risk of dislodgment. It takes approximately 3 weeks for the catheter to heal thoroughly into place. The internal diameter of a 9.6-French Hickman catheter is 1.6 mm. This is large enough to allow withdrawal of blood and infusion of fluid into the vein. This type of catheter can be kept open with a continuous infusion or capped and filled with heparin to be used for intermittent access to the vein. A Broviac catheter is a similar single-lumen catheter that is inserted in the same way as a Hickman catheter. The major difference between the two is that a 2.7-French Broviac catheter has a smaller internal diameter of 0.5 mm, so problems with clotting can arise when a catheter this small is used for drawing blood. This type of catheter is usually used for pediatric patients or for adults with small central vessels and generally only for infusing fluids and medications. Valved (closed) catheter tips   A valved catheter, such as a Groshong, has a specially designed end. When fluid is introduced, positive pressure pushes the valve open to allow fluid to flow into the bloodstream. The tip also can be opened with the negative pressure created by a syringe. When negative pressure is applied, the valve opens inward, thus allowing the catheter to be used for drawing blood. When no pressure is applied, the valve remains closed. This keeps blood from entering the catheter and forming a clot. In addition, the patient is protected from air emboli because the tip does not transfer the negative pressure in the chest to the catheter’s lumen. Unlike open-ended catheters, valved catheters do not require heparin flushes. The catheter is filled with normal saline when not in use. Because no heparin is administered to keep it open, it is safer for patients who should not receive heparin. Also, valved catheters do not require clamping when not in use.