Long-Term Central Venous Access
Long-Term Central Venous Access
Long-term central venous access (LTCVA) plays a critical role in the management of cancer patients. Such LTCVA devices are particularly important in providing a reliable venous route for successful administration of multidrug anticancer chemotherapy regimens and for various aspects of therapeutic and supportive care during bone marrow transplantation. Placement of LTCVA devices not only enables delivery of these complex therapeutic regimens, but it can also dramatically improve cancer patients' quality of life.
No definitive guidelines exist in the cancer literature regarding selection of the most appropriate type of LTCVA device for management of individual cancer patients. Nevertheless, there are several important factors to consider when selecting an LTCVA device:
• Frequency and duration of therapy
• Frequency of blood draws
• Nature of the therapy (eg, delivering vesicating agents into a central vein decreases the risk of extravasation)
• Need for supportive therapies (eg, total parenteral nutrition or systemic antibiotics)
• Need for stem cell collection, plasmapheresis, and bone marrow reinfusion
• Patient preference
LTCVA device placement should always be considered an elective procedure. Therefore, before an LTCVA device is placed, the patient should have recovered from any acute infections and the treatment of complications. If there is an absolute need for immediate central venous access (CVA), a temporary percutaneous CVA catheter can be placed. A history of vascular access catheter insertion, deep venous thrombosis of an upper extremity vein or central vein, thoracic surgery, neck surgery, irradiation, mediastinal and thoracic disease, or a history of congenital cardiac abnormalities should alert the surgeon to possible alterations or changes in the normal venous anatomy and venous drainage patterns. Always assess and correct the volume status of the patient (if possible) before attempting elective placement of an LTCVA device.
Physical examination, documenting the integrity of the skin, changes in the skin secondary to previous surgical treatment and reconstruction, sites of previous central venous access catheter insertions, evidence of venous obstruction (presence of venous collaterals in the skin of the chest, unilateral arm swelling, or superior vena cava syndrome), and pulmonary reserve, should be performed in every patient. If, on clinical examination or by history, there is any suspicion or documented evidence of congenital, treatment-induced, or disease-induced alterations in venous anatomy, consideration should be given to obtaining formal venous imaging prior to attempted LTCVA device placement. Such venous imaging studies include those described below.
Duplex Doppler Ultrasonography
Duplex Doppler ultrasonography can visualize the patency and flow of the neck and arm veins. Intrathoracic veins and the right atrium are not well visualized by standard transcutaneous duplex Doppler ultrasonography, but they can be better visualized with transesophageal echocardiography.
CT and MRI Venography
CT (computed tomography) and MRI (magnetic resonance imaging) venography are gaining more recognition as useful venous imaging modalities for documenting the presence of thrombosis and the patency of major intrathoracic veins.
Standard Contrast Venography
Standard contrast venography has been a long-time gold standard for studying venous anatomy. Standard contrast venography is useful not only for evaluation of the venous anatomy prior to attempted LTCVA device placement, but it can also be extremely useful at the time of attempted LTCVA device placement, if there is difficulty with passing/advancing the guidewire or the CVA catheter and when aberrant catheter position is suspected. Standard contrast venography performed at the time of attempted LTCVA device placement can allow for easy recognition of treatment-induced and disease-induced alterations of the thoracic central venous anatomy, as well as for easy recognition of congenital aberrancies of the thoracic central venous system, that could impact negatively upon the outcome of LTCVA device placement if otherwise unrecognized at the time of attempted placement.
Although it does not represent formal venous imaging, radiography of the chest (eg, chest x-ray) can reveal important information (eg, presence of pleural effusions, lung metastases, mediastinal adenopathy, mediastinal tumors) that can modify selection of a site for LTCVA device placement.
Contraindications and Precautions
A neutrophil count < 1,000/µL is a relative contraindication to placement of an LTCVA device, given that patients with neutropenia may have a higher incidence of septic episodes. Use of prophylactic antibiotics may reduce the incidence of infection in patients with a low absolute neutrophil count.
Thrombocytopenia and platelet dysfunction are frequently encountered in the cancer patient. Preoperative platelet transfusion to approximately 50,000/µL may allow the central venous catheter to be safely placed with a reduction in the risk of bleeding complications. In patients with thrombocytopenia refractory to platelet transfusions, venous cutdown may be a safer approach for central venous catheter placement.
Clotting Factor Abnormalities
Many cancer patients have abnormalities in their clotting factors secondary to malnutrition or chemotherapy. Correction with vitamin K or fresh frozen plasma may be necessary.
The presence of an active infection represents an absolute contraindication to placement of an LTCVA device. In patients with an active infection who require long-term antibiotic treatment, a temporary percutaneous CVA catheter or a peripherally inserted central venous catheter is preferable.
LTCVA Device Selection
Two types of LTCVA devices are available. There are percutaneous tunneled external catheters that are accessible above the skin surface (eg, Hickman, Broviac, Leonard, Groshong, Quinton). Likewise, there are subcutaneous implanted ports (eg, Port-A-Cath, Infusaport, Mediport). Both types of LTCVA devices are available with different lumen diameters and numbers of lumens. Peripherally placed central venous access devices, such as the PICC (peripherally inserted central catheter) line and the PAS (peripheral access system) port, have now become more commonplace because of their ease of placement.
Important differences between percutaneous tunneled external catheters and subcutaneous implanted ports are outlined in Table 1.
An important general consideration in the selection of an appropriate LTCVA device is that the infusion flow resistance depends on the catheter length and lumen diameter. Likewise, catheters with a split valve at the tip (Groshong catheter) are less reliable for blood drawing.
Frequency of Device Access
Subcutaneous implanted ports are preferred in patients who require intermittent device access for treatment or blood drawing. Percutaneous tunneled external catheters are preferred in patients who require continuous or frequent device access for treatment, blood drawing, or delivery of supportive therapies (eg, intravenous fluid hydration, parenteral nutrition, blood product transfusion, pain medication) or who are receiving therapy that would be potentially toxic if extravasated into the subcutaneous tissues. Additionally, peripherally placed central venous access devices can be useful in patients who require single, continuous, infusional therapy (eg, systemic antibiotics, intravenous fluid hydration, pain medication), as is seen frequently in cancer palliative care.
Number of Lumens
The choice of the number of lumens should be based on the intensity and complexity of the therapy.
Specially Designed Catheters
There are specially designed catheters for hemodialysis or apheresis treatment. These catheters are shorter and have a lumen that is larger in diameter and is staggered at the tip of the catheter to prevent recirculation. These catheters have a higher incidence of kinking, so care should be taken to avoid sharp angles at the skin exit site. In patients who already have an LTCVA device in place and require short-term access for apheresis or stem cell collection, consideration should be given to placing a temporary percutaneous hemodialysis or apheresis catheter on the contralateral side, rather than replacing the existing LTCVA device.
Methods of Insertion of LTCVA Devices
Placement of LTCVA devices (eg, percutaneous tunneled external catheters, subcutaneous implanted ports, and PAS ports) is generally best performed under sterile conditions in a surgical suite or an interventional radiology suite, to minimize the incidence of infections. Most procedures are performed on an outpatient basis or immediately prior to a scheduled admission. Local anesthesia and short-acting barbiturates and sedatives are safe and provide excellent patient comfort and sedation. The use of peri-procedural fluoroscopy during LTCVA device placement is strongly recommended: (1) to allow the operator to observe the course of the guidewire and catheter as they pass down through the thorax region under fluoroscopy, as this enables identification of any aberrancies in the catheter pathway suggesting congenital, treatment-induced, or disease-induced alterations in venous anatomy; (2) to help select final catheter tip location; and (3) to help prevent potential procedural complications. PICC lines can be placed by specially trained nurses under sterile conditions on the hospital wards or in dedicated procedure rooms.
The most common technique used in LTCVA device placement is the percutaneous method of Seldinger, using the subclavian vein or the internal jugular vein. Venous ultrasound can be very useful for guiding successful placement of the venipuncture needle into the initial point of entry of the subclavian vein or the internal jugular vein. Alternatively, a venous cutdown approach to the cephalic, external jugular, internal jugular, or saphenous vein can provide appropriate access for LTCVA device placement. Use of a venous cutdown approach (instead of a percutaneous venipuncture approach) for LTCVA device placement can essentially eliminate the risk of significant peri-procedural complications, such as pneumothorax or injury to a major vascular structure.
A post-procedural upright chest x-ray is highly recommended after LTCVA device placement to document successful central venous catheter placement, to document catheter tip location, and to help recognize any potential peri-procedural complications.
Subcutaneous Implanted Ports
Subcutaneous implanted ports require minimal to no care when they are not accessed. Subcutaneous implanted ports should be flushed after each use with heparin solution (3-5 mL; 100 U/mL), as well as monthly during periods of nonuse. Nevertheless, there are no prospective randomized data supporting the need for monthly flushing vs longer durations of time between flushing during periods of nonuse for subcutaneous implanted ports. During continuous infusion therapy via a subcutaneous implanted port, the percutaneous non-coring (Huber) access needle should be replaced every third to fifth day, using sterile technique, and an occlusive dressing should be re-applied. However, continuous use of subcutaneous implanted ports for a duration of greater than 3 to 5 days should generally be discouraged, as subcutaneous implanted ports are intended for individuals who require only intermittent device access. Instead, an intervening interval of de-access of the subcutaneous implanted port should be considered prior to re-access of the subcutaneous implanted port, in order to minimize the risk of infectious complications.
Percutaneous Tunneled External Catheters
Percutaneous tunneled external catheters require more frequent care. Hickman-type catheters are generally recommended for flushing after each use with a heparin solution (3-5 mL; 100 U/mL), as well as biweekly to weekly during periods of nonuse. Groshong-type catheters are generally recommended for flushing after each use with normal saline solution (5-10 mL), as well as biweekly to weekly during periods of nonuse. The protective caps on all percutaneous tunneled external catheters can be replaced biweekly to weekly. In addition, the skin exit site around all percutaneous tunneled external catheters should be cleansed with an antiseptic agent biweekly to weekly, and an occlusive dressing should be reapplied.