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Long Term Central Venous Catheters: Issues for CareRita Wickham, MS, RN; Sandra Purl, MS, RN; and Diane Welker MS, RN From the College of Nursing and Section of Medical Oncology, Rush Presbyterian St. Luke's Medical Center, Chicago, IL; and Harley Medical Center, Flint, MI. Seminars in Oncology Nursing l996;8,2(May):133-147. Long-term central venous catheters (hereafter referred to as catheters) have become a fact of life for a significant number of persons with cancer and for their caregivers. The placement of a catheter in most instances allows the safe administration of chemotherapy, blood and blood products, total parenteral nutrition (TPN), fluids, and other medications. The use of central venous catheters has led to increased patient comfort as well as enhanced therapeutic options such as continuous intravenous (IV) infusions of vesicant agents and ambulatory continuous IV therapy. Despite their benefits, at least 10% of patients will experience problems secondary to catheter placement and/or use.1 Although the risk of certain complications, may be greater with one type of device over another, some risk exists for every person who has a catheter. Thus, the health care team must practice preventative measures, recognize early signs and symptoms of complications and provide adequate care should complications occur. This article will focus on the major catheter complications including fibrin sleeve and mural thrombus formation, infection, catheter occlusion, extravasation, and catheter malposition, and will examine current recommendations for their management, particularly as it relates to the nurse's role. Overview of Long-Term Central Venous CatheterThree general types of long-term catheters are available: nontunneled, tunneled, and implanted ports. Table 1 depicts different types of catheters and specific features.2-5 All catheters have a radiopaque strip so they can be visualized on chest radiograph or fluoroscope after placement to document the position of the catheter tip. The optimal catheter tip location is in the superior vena cava (SVC) at or above the junction of the right atriums.6 Extraluminal Catheter OcclusionExtraluminal occlusion involves either fibrin sleeve or thrombus formation, which may present similar clinical findings but are entirely different processes. Fibrin Sleeve Fibrin sleeves, which do not adhere to the venous intima beyond their point of origin or to the catheter surface, develop in the majority of silicone catheters in as little as 48 hours or up to several months after placement.7 8 The sleeve originates at the point of venous entry and forms as a consequence of exposure of the catheter surface to blood. Platelets and fibrin are deposited along the catheter in a tubelike fashion and over time extend to the distal catheter tip and even beyond it. Once the sleeve extends beyond the catheter tip, withdrawal occlusion may occur, in which the catheter can be easily flushed but blood cannot be aspirated. Instructing the patient to change positions or to perform the Valsalva maneuver may allow blood to be withdrawn. Administering 5,000 to 10,000 units of urokinase through the catheter and allowing it to dwell within the device for more than 1 hour more reliably lyses the sleeve to restore blood sampling capability.9 l0 Lack of blood return in and of itself does not mean a catheter cannot be used for infusions unless withdrawal occlusion results from other complications (i.e., catheter occlusion or displacement). Thrombus Formation Catheter-induced thrombosis is most likely multifactorial. Catheterization itself causes endothelial injury of the vessel wall from the catheter tip, catheter, or introducer during cannulation.ll 12 This injury induces the release of thromboplastic substances and causes platelets to aggregate at the site of injury. The initial damage may progress to small thrombi that arise from and adhere firmly to the vessel wall (mural thrombi), and ultimately to large veno-occlusive thrombi, which may propagate retrograde and/or antegrade into the superior and/or inferior vena cava and/or right atrium.l3 Although stiff catheters (i.e., polyvinyl chloride) are most likely to damage the venous intima, polyurethane and silicone catheters are also implicated in thrombosis.l4 Larger bore catheters are associated with a greater risk for thrombosis as is catheterization from the left side.l6 The catheter within the vein alters laminar blood flow and maximizes contact of blood cells with the venous intima, inducing a cycle of the release of thromboplastic substances and platelet aggregation at the basement membrane of the damaged areas.l5 l7 l8 Normally, the body's fibrinolytic system becomes activated to lyse the clot, but this requires an intact intima. Other factors, such as sclerosing chemotherapy agents, venous compression by mediastinal tumor, or bacterial colonization may initiate or aggravate this process.l8-22 Hypercoagulability, associated with malignancies including mucin-secreting adenocarcinomas of the lung, gastrointestinal tract, pancreas and ovary, promyelocytic leukemia, and myeloproliferative disorders could also exacerbate thrombosis.l7 23 Patients with adenocarcinomas experience a higher rate of catheter related thrombi than do those with squamous cell tumors.l9 Signs and symptoms of thrombosis. Rates of thrombosis of 3.7% to 10% have been documented.24 25 Signs and symptoms of thrombosis may be subtle and delayed until complete occlusion of the vein occurs.13 l6 24 Physical findings relate to impeded venous return and may include edema of the neck, chest, or affected extremity as well as prominent superficial collateral veins on the ipsilateral chest (Fig. 1).26 Mild to moderate neck pain that may radiate down the arm or to the back, numbness and tingling of the ipsilateral extremity, skin temperature changes, or skin discoloration are later symptoms. Diagnosis is usually made when the patient has symptoms of complete occlusion, that is facial swelling, neck vein distention, and infusional difficulties.27 Nurses should document and communicate progressive symptoms, as lytic therapy is more likely to be successful if initiated early before calcification of the clot occurs.15 Thrombus location is usually confirmed by venogram through the catheter as well as through an ipsilateral peripheral vein.23 28 Duplex venous scans, doppler ultrasonography, and computed tomography (CT) have been used to visualize thrombi.29 30 Management of extraluminal thrombus. Management depends on the severity of the symptoms, the need for the catheter, and other associated complications (i.e., infected thrombus). Studies have confirmed that low-dose warfarin (1 mg/day) can significantly reduce the rate of thrombus development without causing bleeding states.3l 32 However, therapy is more commonly initiated when symptoms of occlusive thrombus occur. Symptomatic catheter-related thrombi are treated with anticoagulants, thrombolytic agents, and rarely surgical removal of the thrombus.30 Although some clinicians recommend removing the catheter before anticoagulant therapy, this decision depends on the severity of symptoms, the availability of peripheral access, risk for pulmonary emboli, and previous history of thrombosis.33 Heparin prevents further propagation of the thrombus and allows the formation of venous collaterals.15 Continuous IV thrombolytic therapy, either streptokinase or urokinase, has successfully lysed extraluminal thrombi in some cases.34 35 There are no standard doses or methods of administering fibrinolytic therapy. Fraschini et al35 recommend treating catheter tip thrombi directly with an infusion through the device and mural thrombi by peripheral infusion, using a vein as close to the thrombus as possible. Streptokinase and urokinase activate the fibrinolytic system, so they can potentially induce hemorrhage.25 Nursing management thus includes identification of high-risk patients who would probably not receive this therapy, including those who have active internal bleeding, a recent history of cerebral vascular accident, intracranial or intraspinal surgery, or blood dyscrasias.36 Urokinase is derived from human kidney cells and streptokinase from bacteria. Streptokinase is much less expensive than urokinase but is more antigenic, and in rare instances causes fever, urticaria, nausea and vomiting, headache, and flushing.37 38 Patients receiving streptokinase are pretreated with acetaminophen, diphenhydramine, and hydrocortisone to minimize side effects. The only laboratory value that relates to bleeding complications in patients receiving fibrinolytic therapy is serum fibrinogen, which is maintained at 80 to 100 mg/dL by titration of the fibrinolytic agent.35
Table 1. Overview of Catheter Features
Abbreviations: OD, outer diameter; ID, inner diameter; IVC, inferior vena cava; PICC percutaneously inserted central catheter. AcknowledgementThe authors acknowledge the generous educational grant from Pharmacia Deltec that made the printing of the color prints possible. [NOTE: The balance of this article will be reprinted in a future issue of Meditheses.] Reprinted by permission of Seminars in Oncology Nursing. References
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