Cuffed, Tunneled RA Catheters (Broviac, Hickman, Hemocath, Leonard, Raaf)

Several cuffed, tunneled RA catheters are available, each with differences tailored to specific applications (Fig. 24-1A). The Broviac is an all-Silastic single-lumen catheter with a 1.0-mm internal diameter (ID). It is 90 cm long with a thin intravascular segment (55 cm). The Hickman, also a Silastic catheter, has a 1.6-mm ID. It allows more frequent blood sampling without jeopardizing luminal patency.¹² Single-, double- and triple-lumen variations exist. Hemocath/Permacath has the largest bore of the RA catheters, 2.2 mm ID. Quinton Instrument Company manufactures these catheters for HD, plasmapheresis, long-term nutritional support, and pain control. The main advantage of a cuffed catheter is that it can be used immediately, but it is not recommended for long-term access in patients undergoing dialysis if an AV fistula or graft is possible. Long-term dialysis with tunneled catheters has been associated with an increased risk for death, a 5- to 10-fold increase in the risk for infection, and a decreased likelihood of adequate dialysis.¹³ Ideally, these catheters should be used only as a bridge to longer-term devices.¹⁴

Nonemergency insertion of RA catheters is typically done in an operating room or interventional radiology suite. The device is introduced via the upper anterior chest wall and tunneled subcutaneously to enter the superior vena cava (SVC) system via the cephalic, subclavian, internal, or external jugular vein (Fig. 24-2). The distal tip of the flexible catheter is advanced to the distal SVC or into the mid-RA area. The subcutaneous tunnel isolates the venous puncture site from the skin and decreases the potential for bacterial contamination. Dacron cuffs (one near the venous entrance site and one near the skin exit site) anchor the catheter and are believed to inhibit colonization of the SVC by skin organisms.¹⁵ However, no study has been able to support this belief. Advantages of an RA catheter include ease of insertion and use, minimal interference with patient activity, low incidence of major complications or unintended dislodgment, ease of removal, and potential repair via a kit. Disadvantages include the need for regular maintenance and the potential for unacceptable cosmesis.

Groshong Catheter

In contrast to the Broviac and Hickman catheters, the Groshong catheter has slitlike openings just proximal to the end of the intravascular portion of the catheter (see Fig. 24-1B). This functions as a one-way valve to stop backbleeding and prevent air entry and embolism from the negative intrathoracic pressure. This feature obviates the need to use a heparin lock (saline may be used). In addition, external catheter clamping is not necessary. Disadvantages are its high cost and requirement for pressurized infusion systems.¹⁶

TIVADs/Ports (Port-A-Cath, Proport, Infuse-A-Port, Mediport)

Since 1983, implanted ports have become the mainstay for long-term cancer therapy. TIVADs are tunneled RA catheters, but they differ from Broviac and Hickman catheters in that they have a subcutaneous titanium or plastic portal with a self-sealing septum (Fig. 24-3) that may be accessed by puncturing a specially designed needle (90-degree angled Huber needle) through intact skin (Fig. 24-4). Cosmetically, they are superior to external tunneled catheters, require less maintenance, and afford patients greater freedom of movement and activities such as swimming or bathing.

TIVADs may be inserted on an outpatient basis under local anesthesia via a subcutaneous tunnel or open cutdown. The cutdown technique offers potential speed (mean placement time, 15 minutes), safety (negligible risk for pneumothorax), along with avoidance of early and late complications.¹⁷ Placement is typically in the nondominant arm with the portal in the upper part of the arm or chest unless a vein is occluded or radiation therapy is planned on that side.

Disadvantages of this type of device include increased cost, the need for a specific noncoring Huber access needle, and the small gauge (20 to 22) of the access needle, which limits fluid infusion rates.¹⁶

PICC (Nontunneled, Noncuffed)

PICC lines are centrally placed lines that were first described in the 1970s and originally developed for the neonatal population. Subsequently, their use expanded into the adult arena for prolonged antibiotic therapy, IV fluids, chemotherapy, TPN, and delivery of medications that are irritating to peripheral vessels. PICCs (Fig. 24-5) are made of two substances, either polyurethane (Intracath) or silicone (Intrasil), are radiopaque, and measure 50 to 60 cm in length with an outside diameter of 2 to 7 Fr. The catheter may have a single- or double-lumen configuration and can be open or closed ended or valved (e.g., Groshong). An open-ended PICC cannot prevent feedback of blood into the catheter and therefore must be flushed one or more times daily with heparinized saline. The Groshong valve reduces backup of blood into the catheter and therefore requires flushing as infrequently as once a week. The most common type of PICC line in use today is the 5-Fr, double-lumen, closed-ended catheter.

Selection of the device should be based on the number of lumens necessary for therapy. Selection of the access site depends on many factors, including the suitability of target vessels, body habitus, handedness, ability to manage self-care, comorbid conditions, desired infusion rate, number and compatibility of concurrent infusions, infusate characteristics, and the estimated duration of therapy. Infusate that is hyperosmolar (e.g., TPN) or vesicant requires rapid dilution. Accordingly, the tip must be in the SVC, where the estimated flow rate is 2000 mL/min. PICC lines are most frequently placed in the superficial veins proximal to the antecubital fossa (usually the basilic or cephalic vein) (Fig. 24-6). However, they may also be placed via a transhepatic or translumbar approach when the SVC is thrombosed or occluded.¹⁸

Advantages of PICC lines include usefulness in a wide variety of clinical situations, ease of placement, and ease of use and maintenance. They do not require surgical insertion and may be placed in an outpatient setting. A PICC line is an excellent vehicle for medium- to long-term IV therapy. With proper care, PICCs can remain in place for long periods, even months to years.¹⁹ To remove a PICC line, simply withdraw it from the vein and apply pressure and a sterile bandage.

Midline Peripheral Catheters

Midline catheters are often confused with PICC lines. They are also placed peripherally in the superficial veins of the antecubital fossa or upper part of the forearm. They differ from PICCs in that they are peripheral, not central catheters. Midlines are typically shorter (20 cm), with the tip terminating near the axillary vein. Placement above the axillary vein results in a higher risk for thrombosis. They are designed for short- to medium-term use, a shorter period than with a PICC. Because midline catheters do not enter the central circulation with high flow, delivery of medication and infusion types are limited, and routine blood withdrawal is not recommended. Differentiating between these two catheters in situ may be difficult because their outward appearance is similar. Obtaining an x-ray film for visualization of tip placement will help in determining catheter type.

HD VADs

Vascular access, which is often referred to as the Achilles heel of renal patients, remains problematic. From the moment that the first access is created, an ongoing process is started that will end with loss of all access sites if the patient survives long enough.²⁰ Clinical practice guidelines of the National Kidney Foundation—Disease Outcomes Quality Initiative (NKF-DOQI) recommend early construction of an AV fistula and avoidance of catheters for permanent or prolonged vascular access,^17,21 with less than 10% of permanent access being in the form of catheters.²² However, one study demonstrated that more than half the patients began dialysis with a central catheter because a well-developed AV fistula was not available.²³ The risk of requiring three or more vascular access sites is almost double in patients who start HD with a central catheter.

Temporary Dialysis Catheters (Quinton, Mahurkar, Tessio, Vascath, Uldall)

Temporary vascular access catheters (Fig. 24-7) are used for emergency HD or for temporary HD access if a more permanent dialysis route (AV fistula or graft) is not available or has recently been placed and has not matured yet. The advantage of tunneled catheters is the ability to provide immediate access or temporary access while a more permanent structure matures, but this carries a long-term risk for infection, dysfunction, and central venous stenosis. The majority of bacteremia episodes in patients undergoing HD are caused by HD catheters, with an approximate 20% to 25% risk over the average duration of use.

These large-bore catheters allow the necessary blood flow rate of 300 mL/min for dialysis. The Quinton catheter has two ports, one to deliver the patient’s blood to the dialysis machine and another to return the blood to the patient’s circulation (see Fig. 24-2B). These catheters are placed in a central vein, either the internal jugular, subclavian, or femoral. The right internal jugular approach is preferred, even if permanent access is to be created on the right side, because it has the lowest thrombosis rate. The NKF-DOQI recommends avoiding the subclavian vein unless no other options exist or the ipsilateral arm has no more permanent access sites. For patient comfort, a special 180-degree catheter can be used (Fig. 24-8). There are two avenues to place this catheter: percutaneously or surgically. Emergency percutaneous placement may be performed by the emergency clinician at the bedside. Using sterile technique and after injection of a local anesthetic, insert the catheter by following the same procedure for placing a central line into one of the central veins.

The second technique uses a slightly larger catheter (Quinton, Hickman) and is performed in the operating room under local anesthesia with or without general sedation. This catheter is placed in much the same fashion as the tunneled RA catheters described previously. Surgically implanted catheters are preferred if more than temporary use is anticipated because the risk for infection is decreased and they can be used for a longer time.

Chronic HD Vascular Access

The goal of chronic HD vascular access is to provide safe, effective, and repeated easy access to the circulation. The three principal types of access are native AV fistulas, synthetic grafts, and double-lumen tunneled cuffed catheters (described above). The access types differ in failure rates, patency, complications, and other morbidity. In general, fistulas are preferred over grafts because of superior long-term patency and lower complication rates. However, fistulas are more likely than grafts to experience primary failure, defined as being unable to provide reliable access. Both fistulas and grafts must mature before they can be used for HD, a process that may take several weeks to several months. HD is often performed via a Quinton catheter during this hiatus, so a patient in the emergency department (ED) with both a catheter and a shunt either has a nonfunctioning fistula or graft or the access site is still immature. Grafts can usually be cannulated earlier than fistulas, often within weeks of placement. The minimum time for fistula maturation is at least 1 month. Complications common to both grafts and fistulas are thrombosis, infection, steal syndrome, aneurysms, venous hypertension, seromas, and local bleeding (Fig. 24-9). Overall, grafts are more likely to experience infection and thrombosis requiring thrombectomy or require other types of access intervention. The risk for infection with HD grafts is about 10% over prolonged use and 1% to 2% with HD fistulas. Graft infection requires complete excision to eradicate an infection of the foreign material, whereas fistula infections may resolve with IV antibiotic use.

It may be difficult to distinguish a fistula from a graft by gross inspection alone. Grafts are rarely placed in the forearm, which is the preferred site for fistulas. Fistulas tend to be more tortuous and serpentine, whereas synthetic grafts are straighter or C shaped. Both grafts and fistulas are subject to vascular perturbation and integrity issues from the high flow rates and repeated access. Grafts are subject to pseudoaneurysms when there is a breach in the integrity of the graft and are more likely to rupture. Fistulas are also subject to bulging of the vessel walls to form a true aneurysm. Dilated veins in a fistula can simulate an aneurysm. Both types of vascular deformities can rupture. Multiple defects may require a replacement access.

Edema of the arm, breasts, neck, or face can result from complications of HD access. Causes include venous outflow obstruction in various areas, thrombosis, or infection.

AV Fistulas

An AV fistula is a direct subcutaneous anastomosis of an artery and vein without prosthetic material and is the preferred means of vascular access for HD (see Fig. 24-9). Historically, the percentage of patients with AV fistulas fell well below the recommended goal, with most patients receiving AV grafts or long-term vascular access catheters. The most recent data from the Dialysis Outcomes and Practice Patterns Study (DOPPS) show that from 1996 to 2007, AV fistula use in the United States almost doubled (24% to 47%) and AV graft use fell by 50%.²⁴ Use of an autogenous fistula is associated with the longest period of patency with relative freedom from thrombotic and infectious complications. Once a fistula matures, long-term patency is high (48% of AV fistulas versus 14% of AV grafts at 5 years), with low infection rates relative to grafts.²⁵

An autogenous AV fistula is constructed by anastomosing an artery to a vein (see Fig. 24-9), preferably a nearby one. Various configurations are possible, but AV fistulas are typically an end-to-side vein-to-artery anastomosis. The radial-cephalic (Brescia-Cimino forearm) fistula in the forearm is the most frequently used (Fig. 24-10), with the brachial-cephalic, brachial-basilic, and rarely the proximal part of the thigh being alternatives. Over time, the venous portion of the shunt is subjected to high pressure, and flow becomes arterialized (hypertrophied and dilated), which renders it suitable for repeated vascular access. Full epithelialization of the shunt does not occur for 3 to 6 months, thus necessitating anticipatory placement as renal function worsens.

AV Grafts

If a forearm radiocephalic fistula cannot be constructed or has failed, an AV bridge graft using a donor vein or synthetic material is a well-accepted alternative. Several synthetic materials are used for grafts. Polytetrafluoroethylene (PTFE) is the most commonly used but takes 3 weeks to mature. An available polyurethane graft (Vectra) has the ability to be accessed within 24 hours. A standard graft is 6 to 8 mm in diameter and usually positioned in a U-shaped subcutaneous tunnel in the forearm. The graft is attached by end-to-side anastomoses to the brachial artery and antecubital vein. If no suitable antecubital vein is available, a straight bridge graft between the brachial artery and either the axillary or the basilic vein is often used. Multiple configurations are possible (Fig. 24-11). The characteristic C shape of the graft can aid in differentiating a graft from a more tortuous fistula. A jump graft between opposite extremities with creation of a loop across the chest or anastomosis of the axillary artery to the iliac vein is a possibility if all other sites have been exhausted. When compared with AV fistulas, AV grafts have a significantly higher incidence of thrombosis, infection, pseudoaneurysm formation, and limb loss. PTFE grafts have a low primary patency rate (29% at 1 year according to one study).²⁶ However, they have a low incidence of aneurysm formation and are comparatively easy to revise. The estimated life span of a PTFE graft in clinical practice is often less than 2 years.

Accessing Long-Term Venous Access Catheters

To access the catheter (with the exception of Groshong catheters, which have backflow valve protection), first clamp it to prevent air embolism. Patients usually carry their own clamps, but if not available, use a hemostat without teeth. A hemostat with teeth will suffice in an emergency, in which case wrap sterile tape or tubing around the teeth of the hemostat. Remove the cap of the catheter and withdraw any mobile clots with a syringe. Remove about 3 to 5 mL of blood and then attach a 10-mL syringe to a single-dose vial of normal saline. Smaller syringes generate greater amounts of pressure for infusion, which can lead to increased intraluminal pressure and rupture of the catheter. Inject 3 to 5 mL of solution and then again withdraw it to ensure patency. Flush again with saline. More pronounced infusion might be necessary to ensure the patency of Groshong catheters.