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.

To accomplish phlebotomy, withdraw the dead space solution, reclamp it, and use a separate syringe to remove the desired amount of blood.²⁸ If clots are withdrawn, continue withdrawing blood until it is clot free. Inject bolus medications and infuse IV solutions through the catheter, and clamp it whenever it is unattached. Deliver a 5-mL normal saline flush between medications through a 10-mL syringe. On completion of either blood withdrawal or medication infusion, inject 3 to 4 mL of saline to flush it and then inject 3 to 5 mL of heparin (1000 U/mL). Clamp the line and reposition the cap.²⁸ Note that 1000 U/mL of heparin should be used; less concentrated solutions may promote clotting. Do not inject larger amounts because it can heparinize the patient systemically. Groshong catheters need not be flushed with heparin but instead may be flushed briskly with 5 to 10 mL of saline. Multilumen central catheters have one port for each lumen, so access each one in the same manner. After antiseptic preparation, gain access either by inserting a needle or a syringe into the protective cap or by removing the cap entirely. Flush with 5-mL normal saline or sterile water, and verify backflow before all subsequent procedures. Perform phlebotomy through the proximal lumen to prevent mixing with medications being delivered through the other ports. Deliver IV infusions in similar fashion, and inject a normal saline flush between medications. Terminate the procedure by flushing 3 to 5 mL of heparin (1000 U/mL) through each port.

Accessing TIVADs

The procedure for accessing TIVADs is unique because these devices are not external. Instead, a circular reservoir (cylinder) lies subcutaneously on the anterior chest wall. First, palpate the cylinder and then prepare the overlying skin with povidone-iodine solution. Fill a 10-mL syringe with normal saline and attach it to connecting tubing. Attach this to a 19- to 22-gauge, 90-degree tapered (Huber) needle. The Huber needle is a specialized needle designed for use with TIVADs to prevent damage to the portal septum. It has a 90-degree bend with a slightly curved tip and the opening on the side rather than on the end. Most importantly, the Huber is a noncoring needle. This avoids damage to the Silastic septum and allows up to 2000 punctures. Do not access the TIVAD with a standard needle unless an arrest is in progress and a Huber needle is not immediately available. Apply a clamp to the connecting tubing whenever the system is open. Expel the air and insert the Huber needle through the septum of the reservoir. Insert the needle slowly and steadily through the diaphragm until it contacts the back of the reservoir. Be aware that although incomplete perforation of the septum will block flow, substantial pressure may also damage the back of the device and bend the tip of the needle. Remove the clamp slowly, and inject 5 mL of solution to ensure patency. If patency is not easily demonstrated, consider using alteplase (recombinant tissue plasminogen activator) as a fibrinolytic agent for catheter occlusion.²⁹

Once the solution has been injected, apply gentle negative pressure to demonstrate backflow of blood. Stabilize the Huber needle by building a 4- × 4-inch gauze pad about the needle and further reinforce it with 2.54-cm (1-inch) silk tape. First, remove 8 to 9 mL of blood with a separate syringe and waste it, and then perform phlebotomy through the extension tubing. If necessary, deliver IV solutions through extension tubing, but remember that the rate of flow will be limited by the smaller radius of the Huber needle. Deliver a 5-mL normal saline flush between medications. Complete the procedure with a 3- to 5-mL heparin (1000 U/mL) flush, and remove the Huber needle.²⁸

Accessing AV Fistulas, Shunts, and HD Catheters

AV fistulas, shunts, and temporary dialysis catheters are placed in patients who require HD, and they represent the sole access for that purpose. Consequently, routine use of these sites for phlebotomy and fluid administration is strongly discouraged. In fact, venipuncture in the same extremity as a patent AV fistula is not recommended, except for the veins in the dorsum of the ipsilateral hand. When standard IV access cannot be obtained under emergency circumstances, however, fistulas, shunts, and catheters may all be used to administer IV solutions and medications (Fig. 24-12). Though avoided whenever possible, the option to access these sites is based on clinical judgement by the clinician. If possible, ascertain patency of the fistula by noting a bruit and palpable thrill, although these signs may not be appreciable if the patient is in extremis.

Prepare the area overlying the fistula with antiseptic solution and access the fistula with the smallest-gauge needle that is appropriate.³⁰ Puncture 1 to 2 cm from the end of the anastomosis nearest the venous side, and avoid aneurysmal sites.³⁰ Access AV shunts similarly by placing the smallest needle possible in the catheter and bridging the arterial and venous circulations. Apply local pressure for at least 5 minutes after the procedure is completed and monitor subsequently for hemorrhage. Access the Uldall and Mahurkar catheters in much the same way that multilumen central catheters are accessed. Remove or inject through the retaining cap on each arm. Up to 5000 units of heparin is present within the two lumens, and so it is imperative to aspirate before administering fluid or medications. After use, flush each catheter arm with 10 mL of normal saline and instill 1.5 mL of heparin solution (1000 U/mL) into each one.

Infection

Infection is the most common complication leading to removal of VADs and potentially the most serious. Infection can also result in shunt thrombosis, rupture, or massive hemorrhage. An estimated 250,000 to 500,000 cases of nosocomial VAD-related bacteremia occur annually in the United States with an associated 10% mortality rate.³³ Infectious complications include endocarditis, septic arthritis, pulmonary emboli, osteomyelitis, and spinal epidural abscess. The definitions of VAD-related infections are not uniform, which makes it difficult to compare the results of various investigations. However, it is generally agreed that risk factors for infection include the site of insertion, hospital size, duration of catheter placement, type of catheter, and patient factors. Most studies show a lower incidence of infection for TIVADs than for external systems, presumably because of lack of direct access by cutaneous organisms. Rates of VAD infection tend to be highest in the first 3 months after insertion, with skin flora being most common.^31,34 The rate of infection decreases significantly and reaches a plateau after 5 to 6 months.³⁴ The most common infecting organisms are listed in Box 24-2.

Clinical findings are unreliable in the diagnosis of infection secondary to VADs. Fever, rigors, and an elevated white blood cell count are nonspecific, whereas purulent drainage at the insertion site is specific but not sensitive. Therefore, evaluation beyond physical examination alone is essential when infection is suspected, including Gram stain of purulent material at the site, blood cultures, and culture of catheter segments. In addition, transesophageal echocardiography is indicated if valvular vegetations are suspected by blood cultures positive for Staphylococcus aureus, persistent bacteremia or fungemia after removal of the catheter, or lack of clinical improvement.

Draw two sets of blood for culture, with one set through the catheter itself and one from a peripheral site. Positive blood cultures for S. aureus, coagulase-negative staphylococci, or Candida species, in the appropriate patient setting and in the absence of another identifiable source of infection, should increase suspicion for catheter-related bloodstream infection.³¹ In most studies, blood obtained from a VAD yielding a colony count at least 5- to 10-fold greater than that for blood obtained from a peripheral site suggests a catheter-related source of infection.³⁵ Similarly, catheter infection should be assumed if cultures of peripherally derived blood are negative and the VAD-derived cultures are positive.³⁴ Not only is blood drawn from the catheter more likely to yield a positive culture, but it may also occur earlier in the course of infection. One study demonstrated high sensitivity and specificity for diagnosing a VAD-related infection if cultures of blood drawn from the access device became positive 2 or more hours before cultures of peripherally drawn blood.³⁶

Infusate-related bloodstream infection is uncommon and defined as isolation of the same organism from both the infusate and separate percutaneous blood cultures, along with no other source of infection. When this diagnosis is suggested, cultures of the infusate should be performed in addition to catheter and peripheral blood cultures.³¹

When a catheter-related infection is suspected, an important management decision is required to determine whether to remove the catheter. Removal is recommended in patients who have a catheter placed solely for short-term use. In patients with long-term catheters, remove the catheter in the setting of severe sepsis, suppurative thrombophlebitis, endocarditis, or persistent positive blood cultures (longer than 72 hours) while on appropriate antibiotics. Also, remove the catheter if the infection is due to S. aureus, Pseudomonas aeruginosa, fungi, or mycobacteria. For patients who require long-term vascular access for survival or have no other vascular access options, salvage of the catheter may be attempted if the infecting agent is not Bacillus, Micrococcus, or propionibacteria, in addition to the previously listed organisms. If the catheter is left in place, obtain blood for repeated cultures and remove the catheter promptly if they remain positive following 72 hours of appropriate antibiotic therapy.³⁷

If a VAD is removed, culture it to determine the offending organism. Place the catheter in a sterile tube (red top) and send it to the laboratory for culturing. The most widely used laboratory technique for the clinical diagnosis of catheter-related infection is the semiquantitative method, in which a segment of the catheter is rolled across the surface of an agar plate and colony-forming units (CFUs) are counted after incubation overnight. Quantitative culture of the catheter segment requires either flushing the segment with broth or vortexing in broth, followed by serial dilutions and surface plating on blood agar. A yield of 15 CFUs or more from a catheter by semiquantitative culture or a yield of 10² or more from a catheter by quantitative culture with accompanying signs of local or systemic infection is indicative of a catheter-related infection.³¹

HD catheters deserve special consideration. The process of HD requires several connections to the graft, thereby increasing the risk for infection. The rate of bacteremia in HD patients attributed to the graft varies from 48% to 73%. The incidence is highest when central venous dialysis catheters are used. Native AV fistulas carry the lowest risk for infection. Unfortunately, AV grafts are more commonly used in the United States.³⁸ As with other VADs, initiate empirical antibiotic therapy based on epidemiologic and patient factors, followed by narrowed-spectrum therapy after isolation and determination of sensitivities. The most common infecting organism is S. aureus. There has been an association between nasal carriage of S. aureus in HD patients and catheter infection. Reducing carriage rates has resulted in a decreased incidence of bloodstream infections.³¹

Thrombus Formation

It has been estimated that 2% to 42% of VADs are associated with deep venous thrombosis (DVT).⁴⁶ Risk factors for catheter-related DVT include the composition, diameter, and position of the VAD; elevated intraluminal pressure; turbulent blood flow; vascular calcification; endothelial injury; and increased levels of fibronectin.^46,47 Polyurethane and silicone catheters have a lower rate of VAD-related DVT than do polyethylene or Teflon-coated catheters. A catheter with an external diameter of less than 2.8 mm has a lower incidence of DVT. Incorrect placement of the VAD in the SVC, as opposed to the junction of the SVC and right atrium, results in a higher incidence of catheter-related DVT.⁴⁶

DVTs may be asymptomatic and not recognized because of the underlying condition of the patient. The incidence of central venous catheter–related DVT, as assessed by venography, has been found to range from 27% to 66%. The majority of these thromboses are asymptomatic. The incidence of clinically overt DVT has been found to range from 0.3% to 28.3%, with most studies finding the incidence to be less than 5%. The first 6 weeks after catheter insertion presents the greatest risk for thromboembolic complications.⁴⁸

Most HD access failures (80%) are related to thrombosis, with greater than 90% of these thromboses associated with venous outflow stenosis.¹⁴ Histologically, hyperplasia of the endothelium and fibromuscular vessel wall occurs. Over time, fibrin deposits build up on the tip of the VAD. This may continue to the point of complete occlusion and prevent infusion or aspiration from the VAD. Early detection may be enhanced by maintaining a high index of suspicion and noting prolonged bleeding after withdrawal of the cannula or a change in the bruit over the device, or both. Prompt consultation with a nephrologist and vascular surgeon is indicated. Heparin or local thrombolytic agents, such as alteplase, may be tried (see the next section).

Catheter Occlusion

Occlusion of the catheter or low flow can be caused by improper positioning, kinking, or compression of the catheter; intraluminal thrombi; extraluminal thrombi; fibrin deposits at the tip of the catheter; or intraluminal precipitation of infusate. Pinch-off syndrome occurs when the line (most often a PICC) is compressed between the clavicle and the first rib. It is manifested clinically as difficulty injecting that is posturally related.¹⁶ Overzealous withdrawal of the syringe will collapse the catheter and cause occlusion. Chest radiographs may reveal scalloping of the catheter. Maneuvers to facilitate flow include the Valsalva maneuver, the reverse Trendelenburg position, slight tension on the catheter, placement of the catheter more laterally, IV hydration, and extension of the arms above the head.^28,49

If these measures are unsuccessful, the occlusion may be caused by clot formation. The clinician should be familiar with local institutional recommendations for thrombolysis in the setting of recent VAD occlusion attributed to a fibrin plug. Admission and consultation are usually required, and maneuvers to address clotted or occluded catheters are not a standard ED procedure but may be performed under proper circumstances and according to local guidelines. Alteplase has been shown to be both effective and safe in treating central venous catheter occlusions caused by clot.⁵⁰ If attempted, first withdraw any mobile clot by aspiration with a syringe. Instill 2 mL of alteplase (1 mg/mL) and allow it to dwell for up to 120 minutes. If it remains occluded, the dose may be repeated once.

Embolization

A serious but uncommon complication of VAD use is embolization with air, a catheter fragment, or thrombotic emboli.51–54 Air emboli develop when the lumen of the catheter is left open to air or the catheter is fractured, perforated, or cut. The one-way valve in the Groshong catheter prevents this complication. Be careful to maintain a closed system by clamping the catheter appropriately to prevent delivery of air into the venous circulation. Should the externalized portion of a catheter be damaged, immediately place an appropriate clamp between the damaged portion and the skin.²⁸ Be suspicious for air embolism if an open or damaged catheter is found in association with tachypnea and hypotension.⁵¹ Place the patient in a left lateral decubitus and Trendelenburg position to reduce ventricular outflow obstruction by air pockets. Initiate supportive measures, including high-flow oxygen. If this is unsuccessful, attempt aspiration with the catheter advanced into the right ventricle, if possible. Emergency thoracotomy to aspirate air (see Chapter 18) and cardiothoracic surgical consultation may also be warranted.

Embolization of a catheter fragment is a potentially life-threatening complication that can cause acute dyspnea, palpitations, atypical chest pain, hypoxia, and atrial fibrillation. As with any foreign-body embolus, sequelae include sepsis, lung abscess, dysrhythmias, vascular or cardiac perforation, and sudden death. Catheter fragments may be identified radiographically or potentially by ultrasonography and may be removed either surgically or by intravascular retrieval methods.⁵²

Embolization of thrombi with potentially lethal sequelae may occur during routine flushing and injection of solutions through the catheter. Anderson and coworkers prospectively evaluated the size and frequency of catheter thrombi in 43 patients by aspirating after a urokinase flush.⁵³ Clots were noted in 40 of 43 subjects and in 153 of 508 total specimens. Thrombi varied in size from small fragments to 5 cm in length. Burns and McLaren reported one case of a hemodynamically significant pulmonary embolus associated with PICC placement in a 77-year-old man.⁵⁴

Hemorrhagic Complications

Bleeding may be seen with any indwelling VAD or AV fistula but more commonly occurs with nontunneled VADs or temporary dialysis catheters. It is often related to mechanical trauma, transient or preexisting thrombocytopenia, uremia- or drug-induced platelet dysfunction, and infection. Repeated cannulation of the fistula or graft weakens the wall of the device. Many fistulas will develop aneurysms from repeated use; synthetic grafts can develop pseudoaneurysms from frequent punctures (Fig. 24-13). Severe life-threatening hemorrhage from this high-pressure system may occur and necessitates rapid control. The primary goal should be to control bleeding and prevent exsanguination; however, take care to minimize damage to the VAD that would prevent future use. Use full universal precautions because there is an increased risk for communicable disease in this patient population (2.4% for hepatitis B virus and 7.4% for hepatitis C virus in the United States).⁵⁵ When the bleeding stops, observe the patient for 2 hours for evidence of rebleeding and to detect graft thrombosis. Treatment can be divided into mechanical modalities and correction of coagulopathy.

Coagulopathy

Control of hemorrhage may require treatment of an underlying coagulopathy. HD patients are generally considered to be at increased risk for bleeding because of uremic platelet dysfunction. The incidence of major bleeding in these patients is increased with the concomitant use of anticoagulant medications.⁵⁶ Perform laboratory testing for evaluation: complete blood count, blood urea nitrogen, prothrombin time, international normalized ratio (INR), partial thromboplastin time, and other tests depending on the patient’s medical history or signs. Consult nephrology, vascular surgery, or both if possible before reversing therapeutic anticoagulation given the potential for graft thrombosis and the need for close follow-up.

Catheter Displacement, Migration, or Malposition

Catheter displacement may occur accidentally secondary to patient movement, iatrogenically, or both. The catheter should be firmly secured with sutures, sterile tape strips (with care taken to avoid direct contact with the catheter itself), and premanufactured devices.¹⁹ Even with these measures, migration may still occur. With regard to TIVADs, malposition of the intravascular portion may occur as a result of incorrect initial positioning or secondarily from forceful flushing, neck flexion, obesity, severe coughing, emesis, or upper extremity movement. Malposition of the port body may occur intentionally or by unintentional manipulation of the port (twiddler’s syndrome). Obtain a computed tomography scan of the chest to diagnosis this condition. Surgical intervention is usually necessary.⁵⁸

Catheter Fracture

Fracture of a VAD can occur either subcutaneously or in the externalized portion.⁵⁹ It may take place with certain physical activities that involve repetitive and excessive motion, such as golfing, swimming, and weight lifting. Subcutaneous fractures cause pain and swelling and require removal of the line. Fractures in the externalized portion may be repaired with commercially available kits and do not always have to be replaced.

Steal Syndrome

Vascular steal syndrome is an uncommon (1% to 3% incidence) but serious complication of AV fistulas that is difficult to predict and often leads to access failure. It occurs because of preferential flow through the low-resistance fistula at the expense of the distal circulation. The syndrome is manifested by classic arterial insufficiency symptoms with exacerbation during dialysis: pain, pallor, numbness, motor weakness, and diminished or absent pulses distal to the fistula.⁶⁰ Steal syndrome must be differentiated from diabetic or uremic neuropathy because it may lead to the development of irreversible neuromuscular dysfunction and tissue necrosis. Prompt recognition and correction of hand ischemia lead to increased salvage and use of functioning fistulas. Steal syndrome usually requires ligation or removal of the VAD with placement of a new access device in the opposite extremity.

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