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 ...