Tunneled Central Venous Catheters



Tunneled Central Venous Catheters


Peter R. Bream, Jr.


Tunneled central venous catheters (CVCs) fill a vital role in patient treatment, especially with new cancer-fighting regimens. The catheters are durable and fit nicely into interventionalists’ armamentarium alongside peripherally inserted central catheter (PICC) lines and chest or arm ports. There are many sizes, lengths, and technologic advancements that allow safe, long-term venous access. These catheters enable the physician to safely administer caustic medications centrally, draw blood for laboratory studies, and even perform pheresis or dialysis multiple times a week. They have become an indispensable tool in the modern-day treatment of patients.



Indications


One of the keys to successful, safe, long-term central venous access is placement of the most appropriate device at the initiation of therapy. The ordering physician and the proceduralist should maintain an open dialogue regarding the goals and duration of therapy so the device can be individualized for the patient. Generally, cuffed tunneled catheters are suited for intermediate (<6 months) to long (>6 months) use in patients who are not overly debilitated. The design is ideal for patients who need frequent to continuous access and two to three lumina. The ability of the patient (or appropriate caregiver) to care for this device is extremely important and crucial for its long-term success. Cuffed tunneled catheters are ideal for patients receiving continuous therapy, including epoprostenol sodium, dobutamine, and magnesium. The ease of placement and exchange also allows site preservation in these patients, who will need access for many years. These catheters can remain in place long term because of the nature of the tunnel. Tunneling under the skin allows the body’s natural defenses to ward off infection and prevents access of pathogens to the venous entry site. The addition of a Dacron cuff or one made of other fiber promotes the ingrowth of fibroblasts and scar tissue, which secures the catheter. Some catheters are designed with an “antimicrobial” cuff (Vitacuff [Vitaphore, Menlo Park, Calif.]) that is used in tandem (closer to the skin exit site) and intended as a temporary barrier until the Dacron cuff is secure.



Contraindications


Although there are no absolute contraindications to placement of a tunneled CVC, most proceduralists avoid placement in patients with active infection or proven bacteremia. If central venous access is needed in these patients, a nontunneled temporary line can be placed. In our institution, patients must be culture negative for 24 hours before considering placement of a tunneled line. Coagulopathy is a relative contraindication. A tunneled line is an elective procedure in the vast majority of patients, so acute correction of coagulopathy is rarely needed. If necessary, replacement of platelets or administration of fresh frozen plasma can be performed. A total platelet count of greater than 40,000/mm3 and an international normalized ratio (INR) of less than 1.5 are the standards we adhere to. If the patient is on a regimen of chronic anticoagulation, conversion to either standard or low-molecular-weight heparin (LMWH) is carried out before the procedure. The heparin is discontinued for the appropriate amount of time for each type (1-2 hours for standard heparin and 24 hours for LMWH). Patients taking antiplatelet medication (aspirin, clopidogrel bisulfate) should stop taking it 5 days before the procedure and can resume immediately afterward. Other relative contraindications are lack of a suitable vein for access and severe skin conditions that will not accommodate a tunnel (scleroderma, graft-versus-host disease, or Stevens-Johnson syndrome). Careful evaluation of the venous access needs must be weighed against the risk for infection or bleeding in such patients. Finally, allergy to the material the catheter is made of is rare but can result in replacement with a catheter made of different material.



Equipment


The history of CVCs dates back to 1733, where an English clergyman, Stephen Hales, inserted a glass tube into the jugular vein of a horse to measure pressure. The first prolonged use of catheters for central venous infusion was reported by B.J. Duffy in 1949, reporting on 72 catheters.1 The catheter we use most often today was created at the University of Washington by a team including Belding Scribner, John Broviac, and Robert Hickman in 1973.2 The basic design of the catheter has not changed, although new technologies have allowed different brands to distinguish themselves. Over the past years, valve technology was developed to reduce thrombosis and infection and eliminate the need for heparin packing. Recently, with the advent of faster computed tomography (CT) scanning, power injectibility has been introduced.


Valves have been used on catheters dating back to the Groshong catheter (Bard Access Systems, Salt Lake City, Utah). The Groshong has slits in the sides of the catheter near the tip. The tip is closed with an atraumatic rounded end. The slits are closed except during infusion or aspiration. The company claims this cuts down on infection and occlusion rates. Groshong catheters are flushed with heparin solution.


CT has become an irreplaceable technology for diagnosing all types of diseases. Newer protocols rely on rapid introduction of a bolus of contrast material for CT angiography and evaluation of tissue perfusion. Many patients with chronic disease undergo regularly scheduled CT scans to evaluate the effectiveness of treatment, and these same patients have some form of central venous access for that treatment. Rather than start a peripheral intravenous line each time the patient needs a CT scan, it would be desirable to use the patient’s existing access. This has been accomplished with newer power-injectable cuffed tunneled catheters. The use of polyurethane for the construction of the catheter has allowed larger inner lumens and faster flow rates. The Power Hickman (Bard Access Systems [Fig 119-1]) was the first such catheter. It is capable of injection rates up to 5 mL/s, which is clearly marked on the catheter’s hub. In addition, the catheter has a distinct purple color that has become a universal signal of power injectibility, present on PICC lines and ports from Bard as well as other manufacturers. Although there are many studies36 that have safely shown the use of regular catheters for power injection, these were done off-label, and the readily available power injection safe catheters today render this practice obsolete.




Technique


Anatomy and Approach


The right internal jugular (RIJ) vein is the preferred vessel for entry when all other variables are equal. The modern proceduralist will always use ultrasound to guide venous access. When ultrasound is used, the RIJ has been shown to have the lowest rate of complications, including thrombosis, arterial puncture, pneumothorax, and catheter malposition.7-13 Although some articles have recently settled on the subclavian vein (SCV) as the preferred entry site, this recommendation is for temporary catheters, not tunneled ones. The Kidney Disease Outcomes Quality Initiative (K/DOQI)14 clearly states that the RIJ is the primary site for dialysis catheters and that tunneled infusion catheters should follow suit. In a retrospective review of subclavian versus IJ tunneled catheters by Trerotola et al. in 2000,9 there was a 13% incidence of clinically significant central thrombosis when catheters were placed in the SCV (with fluoroscopic guidance) versus 3% when placed in the IJ (with ultrasound guidance). Of note, they did not identify a higher risk for infection in the IJ than in the subclavian site. When the RIJ is not available, the next vein of choice is somewhat controversial. Most interventionalists will proceed to the left internal jugular (LIJ) or resort to the SCV. However, a recent article by Cho et al. proposed that the right external jugular vein is the preferred second choice. They demonstrated an acceptable success rate and a low complication rate to reach their conclusion. This makes sense because of the tortuous route through the left brachiocephalic vein from an LIJ approach.


A careful history is essential to optimize site selection for each patient. Information such as previous catheters and surgeries and patient preference should be discerned. I have altered the exit or entry site of a catheter based on patient preference. If the patient has undergone a mastectomy or radical node dissection in either the axillary or neck region, that side should be avoided because of the devastating consequence of venous thrombosis on a side that has had the lymphatic system disrupted. After determining the optimal site, a thorough informed consent should be obtained. The consent form should indicate that the risks involved in placing the catheter have been discussed, including bleeding, infection, nerve or lung puncture, air embolism, infection, and cardiac ectopy (see Complications). It is crucial to include the risks associated with conscious sedation if it will be used.


The final step in patient preparation is a preliminary ultrasound scan of the proposed catheter site before the patient is sterilely prepared. The technique for prescanning includes identification of the jugular vein and its relationship to the carotid artery (Fig. 119-2). This is done in the transverse plane and carried down to below the clavicle until the vein cannot be visualized. Test the compressibility of the vein to identify it and exclude acute thrombosis. Note the location of the subclavian artery if it is present and its relationship to the IJ. Finally, look for valves in the jugular bulb. If these valves are moving back and forth with respiration, there is direct communication with the right atrium (RA), which helps assure the operator there is not a significant stenosis in the superior vena cava (SVC).



Hemodynamic monitoring, including noninvasive blood pressure, electrocardiography, and oxygen saturation, is then established. The site is prepared with 1% to 2% chlorhexidine and alcohol, and a full body drape is placed.


The technique for RIJ access (Fig. 119-3) is as follows. Position a linear 7- to 12-MHz transducer that has been placed in a sterile cover parallel to and touching the clavicle. Identify the RIJ, and palpate the sternal head of the sternocleidomastoid muscle. The puncture site should be just lateral to this muscle, which allows superolateral entry into the RIJ. Use liberal lidocaine with epinephrine and create a wheal. Make the incision appropriate for the catheter size. Use an angled hemostat to dissect the tissues down to the vein and in the direction of the tunnel. With the vein seen in transverse orientation and the needle in longitudinal orientation, advance the needle into the vein until it is seen tenting the wall. Make sure to angle the transducer to visualize the entire subcutaneous course of the needle. When tenting the wall, slowly advance until the wall release and the tip of the needle in the vein are seen (Fig. 119-4). We use a 21-gauge needle with a 0.018-inch wire for most accesses. If resistance is encountered while advancing the wire from the needle tip, pull the wire back until it is in the needle and then pull the needle back. Readvance the wire until no resistance is met. This maneuver can be repeated until the needle is out of the skin. If at any time resistance is encountered when pulling the wire back into the needle, stop and pull the needle and wire out as a unit. Mandrel-type wire tips can shear off and embolize to the lungs. Once the wire is safely in the vein, advance it several centimeters into the RA while being careful to listen for ectopy, remove the needle, and place a transitional dilator. I prefer the Cope Access Set (Cook Medical, Bloomington, Ind.), which includes a 6.3F dilator with a metal inner stiffener, a 0.018-inch stainless steel Cope mandrel wire, and a 0.035-inch Rosen wire.



Dec 23, 2015 | Posted by in INTERVENTIONAL RADIOLOGY | Comments Off on Tunneled Central Venous Catheters
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