Chapter 51. Troubleshooting Indwelling Central Venous Lines

Indwelling central venous lines are an essential part of the care of both the acutely and chronically ill patients. These patients may require implanted venous access devices due to their poor peripheral venous access or for long-term intravenous therapies. When an indwelling central venous line is malfunctioning, the Emergency Physician must act quickly and thoughtfully to diagnose and correct the malfunction without further damaging the device. Understanding the different etiologies and a thorough assessment are critical to the successful management of a central venous catheter malfunction.

Indwelling central venous catheters allow access to the central venous circulation from a peripheral site. This access to the central circulation is via the end of a partially implanted catheter that protrudes from the body or through the skin into a subcutaneous reservoir of a fully implanted catheter.1,2 The proximal tip of the central venous line will typically reside in either the superior vena cava, the inferior vena cava (less commonly), or the right atrium.

Indwelling central venous access devices can malfunction for a variety of reasons. The two most common types of vascular catheter complications are thrombotic occlusions and infections.3 The etiology of the malfunction can be divided into two main categories: external to the catheter and internal to the catheter. External malfunctions are for the most part mechanical malfunctions. Examples include catheter migration, the catheter tip abutting a vessel wall, a mural thrombus, and kinked catheters. Internal malfunctions can be further divided into thrombotic (e.g., intraluminal thrombus, fibrin sheath, and fibrin tail) and nonthrombotic (e.g., drug/drug precipitate, insoluble salts, lipid precipitate, and drug/solution precipitate).3–5 Phenytoin and diazepam cannot be given through silicone indwelling lines as they can crystallize and permanently obstruct the catheter lumen.4 Calcium and phosphate can form an insoluble precipitate within the catheter lumen. Infused lipids can form waxy casts within the catheter lumen.

Any catheter that cannot be easily flushed or aspirated requires further investigation. If peripheral venous access is readily available, and the patient is not acutely ill due to catheter sepsis or central venous thrombosis, catheter troubleshooting may be deferred to the Primary Care Provider. It is important to consider that delaying troubleshooting may make management more difficult and therefore necessitate line replacement. However, the Emergency Physician will have to address the problem if emergent or urgent access to the patient's central vascular system is required.

Any device that is obviously displaced from the central circulation is not salvageable and should not be used. Dislodging a clot or septic thrombus from a catheter tip can lead to a fatal pulmonary embolism. Catheter manipulation should be avoided if signs of sepsis or central venous thrombosis are present.6 The use of indwelling dialysis lines for purposes other than dialysis is discouraged. Manipulation of a dialysis line should only be undertaken in a true emergency or if the line is malfunctioning and is needed for hemodialysis.

• Povidone iodine or chlorhexidine solution
• Sterile alcohol prep pads
• Thrombolytic agent
• Syringes, 5 mL and 10 mL
• 18 gauge needles
• Noncoring (Huber) needle
• 70% ethanol solution
• 0.1 N hydrochloric acid (HCl) solution
• Sterile saline
• Heparinized saline flush solution (100 U/mL)
• Sterile gauze squares
• Sterile gloves

Repair kits are available to repair some externally damaged partially implanted catheters. The kits avoid the need to remove the device and implant a new catheter. If the external tubing of the device is damaged, apply a smooth catheter clamp proximal to the damaged area and arrange to have the device repaired. The use of these kits is beyond the scope of this chapter.

Thrombolytic Agents

The use of a specific thrombolytic agent is institution-specific and physician-specific. Streptokinase, recombinant tissue plasminogen activator (t-PA), Reteplase, and urokinase have all been successfully used to dissolve a clot within a central venous catheter.4,7–12 Volumes and doses of the drugs differ significantly and careful attention should be paid to the medication administration. Urokinase and recombinant tissue plasminogen activator are most commonly used. Streptokinase is more likely to lead to a hypersensitivity reaction, especially if the patient has prior exposure to it, and is therefore not recommended. Urokinase is the thrombolytic agent used by most institutions because it is much less expensive than t-PA. Urokinase may be purchased in concentrations of 5000 U/mL and 250,000 U/5 mL (50,000 U/mL). The concentration of 5000 U/mL is used for dissolving a clot within a catheter. Some institutions prefer to use t-PA for this process. The Pharmacist dilutes a 50 mg vial of t-PA with 50 mL of sterile water to produce 25 syringes containing 2 mg of t-PA in 2 mL (1 mg/mL). The syringes of t-PA are then frozen until needed. It is also available from the manufacturer in 2 mg single use vials. Standard dosing for catheter obstructions is 1 mL of urokinase (5000 U/mL), 2 mL of t-PA (1 mg/ml), or 0.4 units of Reteplase.15

Discuss the procedure with the patient and/or their representative. Most patients with indwelling central venous access devices are very familiar with their use and idiosyncrasies. The patient will often be able to tell the Emergency Physician if the line has had problems in the past and the method used to correct the problem. Some patients will be able to suggest postural changes (e.g., raising an arm or lying in the Trendelenburg position) that will help the catheter function better. Obtain a posteroanterior and lateral chest radiograph to confirm that the tip of the catheter is in a proper location.

The chest radiograph is a good screening tool that allows the Emergency Physician to often diagnose catheter complications. A malpositioned catheter or one with the tip abutting the vessel wall must be removed and replaced. A catheter whose flow changes with patient arm position may be subject to the “pinch-off” phenomenon. This may be visible as a kinking of the catheter as it passes between the clavicle and first rib. A series of chest radiographs with the arm at the patient's side and elevated may reveal the kinking or pinching-off of the catheter. These catheters require removal. A catheter may migrate intravascularly so that it is within the contralateral subclavian vein. An Interventional Radiologist may be able to insert a wire or snare into the femoral vein to grasp and reposition the catheter. Arrhythmias associated with a catheter tip positioned within the heart require the catheter to be removed and a new one inserted. The distal catheter can curve upward so that it lies within the jugular vein. An Interventional Radiologist may be able to reposition it. Otherwise, it must be removed and replaced.

Any manipulation, injection, or aspiration of a central venous line must be done using strict aseptic techniques. Clean any dirt and debris from the distal port of a partially implanted device or the skin overlying the reservoir of a fully implanted device. Apply povidone iodine or chlorhexidine and allow it to dry. Wipe off the iodine (if used) with a sterile alcohol prep pad. This process must be performed every time a needle is inserted into a central venous access device.

An algorithmic approach to the occluded indwelling central venous catheter is summarized in Figure 51-1.9,14 The key principle is that forced irrigation of the catheter, especially with a 1 mL syringe, is never performed as the catheter may rupture.

A catheter that flushes easily but cannot be aspirated may have a fibrin sheath around the catheter tip forming a one-way valve. The tip may also be lodged against the wall of the superior vena cava or the right atrium. Repositioning the patient may alleviate the problem. The catheter may be cautiously used for an infusion if there are no signs of infection (e.g., new heart murmur, fever, erythema, or discharge at the catheter or subcutaneous reservoir site) and the catheter tip is in good position. Refer the patient to their Primary Care Provider or a consultant for follow-up of the malfunction.

The problem is more serious if the catheter does not easily flush. Attempt to obtain peripheral intravenous access while attempting to correct the problem with the central venous catheter. If there are no signs of infection, and the catheter is not ruptured or malpositioned, the Emergency Physician must decide if a prolonged effort at resolving the occlusion is necessary. If so, proceed as described below and in Figure 51-1.

Partially Implanted Catheters

A clot or small amount of precipitate within the partially implanted catheter may be able to be aspirated if the catheter bore is large enough to permit passage. Remove the Luer-lock cap from the catheter. Connect a 10 mL syringe with 2 to 3 mL of sterile saline directly to the occluded port's Luer adapter. Any clot large enough to occlude the catheter will not pass through a needle. Apply negative pressure to the syringe. The catheter is probably occluded by a clot or a precipitate if the obstruction cannot be aspirated. Remove the syringe and attach a new Luer-lock cap.

If a precipitate is seen in the catheter aspirate, determine if it is waxy or solid. Waxy precipitates are due to the lipid component of parenteral nutrition fluids. Waxy precipitates may be dissolved with a solution of 70% ethanol in water. Inject 1 to 2 mL of this alcohol–water solution and allow it to dwell in the catheter for 1 hour. Aspirate the catheter to determine patency. If still occluded, inject 1 to 2 mL of 0.1 N hydrochloric acid solution. Allow the solution to dwell in the catheter for 20 minutes. Aspirate the catheter to determine patency. Attempt to infuse 0.1 N hydrochloric acid solution two more times. The next step is to infuse a thrombolytic agent, as described below, or to replace the catheter.

Solid precipitates are due to precipitation of medications or minerals. Dilute 0.1 hydrochloric acid solution may be used to dissolve precipitated calcium and phosphate crystals. Infuse 1 to 2 mL of 0.1 N HCl and allow it to dwell in the catheter 20 minutes. Aspirate the catheter to determine patency. The process may be repeated up to three times. If still occluded, inject 1 to 2 mL of 70% ethanol in water and allow it to dwell in the catheter for 1 hour. Aspirate the catheter to determine patency. The next step is to inject a thrombolytic agent, as described below, or to replace the catheter.

If no precipitate is present, or if efforts to clear the precipitate fail, a clot may be present within the catheter lumen. Clots probably form to some extent in the majority of implanted central venous catheters. The clots may obstruct the catheter lumen.13 Thrombosis of the central veins, superior vena cava, or right atrium may also occur. Suspect a major vein thrombosis if there is swelling, pain, or edema of anatomic structures that are drained by the cannulated vein(s).

Small clots may be dissolved by a bolus or infusion of a thrombolytic agent. Inject 1 mL of urokinase (5000 U/mL), 2 mL of t-PA (1 mg/mL), or 0.4 units of Reteplase into the catheter. Allow the solution to dwell in the catheter for 30 minutes. Aspirate the catheter to determine patency. This process may be repeated up to three times. For catheters with multiple occluded ports, the medication dosing should remain the same but divided into equal doses between the ports. If still occluded, inject 2 mL of intravenous contrast dye under fluoroscopy or inject the dye and obtain a radiograph. If no clot is present or if the contrast material will not infuse, attempt to clear the catheter with hydrochloric acid solution (up to three times) and 70% ethanol in water.

If a clot is present within the catheter, a continuous thrombolytic infusion may be considered. The infusion should occur through an intravenous line equipped with a 0.22 micron or 0.45 micron filter. A urokinase infusion may be begun over a 24-hour period. Administer the urokinase at a dose of 200 U/kg-hr mixed to run at a rate of at least 20 mL/h.8,9 A continuous t-PA infusion may also be started. Use 2 mg/20 mL as a low dose for ports, 4 mg/20 mL as a high dose for ports, or 5 mg/50 mL as a high dose for tunneled catheters. Set the t-PA infusion rate at 10 mL/h for low and high doses for ports or 20 mL/h for high dose tunneled catheters. Thrombolytic infusions should be undertaken in consultation with the patient's Primary Care Provider as the patient will require hospital admission.

Consider consulting an Interventional Radiologist if these methods do not successfully clear the catheter or if a thrombolytic infusion is contraindicated. They can perform percutaneous fibrin sheath stripping, exchange over a wire, or removal and replacement of the malfunctioning catheter. Alternatively, the Emergency Physician may place a new central venous catheter at another site if the patient requires immediate vascular access.

Fully Implanted Catheters

The procedure is the same for a fully implanted central venous access device with one exception. The subcutaneous reservoir will not be able to be initially cleared by aspiration. Any clot or precipitates large enough to occlude a catheter will not pass through a noncoring (Huber) needle. Always use a noncoring (Huber) needle when aspirating or injecting through a fully implanted catheter.

Indwelling central venous lines must be flushed with saline, followed by the appropriate heparin solution if necessary, after clearing the obstruction. Refer to Chapter 49 for the complete details. Patients given thrombolytics must be assessed for bleeding at the catheter site and elsewhere prior to discharge, if they do not require hospital admission. The success rate for thrombolytics restoring catheter patency are greater than 80%.16,17 Patients receiving prolonged thrombolytic infusions should be admitted for the infusion and for monitoring of potential bleeding complications. Patients and their care providers must be made aware of any catheter malfunctions and the attempts made at restoring catheter patency.

The complications associated with attempts to de-occlude a catheter include catheter rupture, disconnection of the catheter from any implanted reservoir, hemorrhage, and contamination of the catheter with subsequent infection. No major bleeding episodes or deaths have been associated with intracatheter thrombolysis.15–17 Assessment for these complications is discussed in Chapter 49.

In the course of their treatment, a number of patients with indwelling central venous access devices will present to the Emergency Department with malfunctioning catheters. Familiarity with the strategies for diagnosing and correcting the catheter dysfunction will enable the Emergency Physician to restore the function of some, but not all, indwelling lines. Early consultation with the patient's Primary Care Provider, Vascular Surgeon, or Interventional Radiologist is essential if the procedures outlined do not promptly restore the catheter's function.