1. 
   

   How many different types of central lines exist?

   
   
2. 
   

   What is the role for using ultrasound in the placement of central lines?

   
   
3. 
   

   Is there a preferred vein for the placement of a central line?

   
   
4. 
   

   Are there any absolute contraindications to central line placement?

   
   
5. 
   

   What is considered to be the best “skin prep” for site sterilization in preparation for central line insertion?

   
   
6. 
   

   What are the three critical elements of proper sharps safety?

The practice of hospital-based internal medicine has traditionally required proficiency in the insertion of central venous catheters (CVCs) for intravenous access. Athough the requirement that physicians-in-training become proficient in the placement of CVCs has been questioned by some, the fact remains that CVCs are a mainstay of inpatient medical care and many hospitals in the United States frequently rely on residents and hospitalists to place CVCs. This chapter reviews a number of key elements related to CVC placement, maintenance, and removal; indications and contraindications for CVC placement, procedure set-up and insertion techniques, and potential complications of CVCs. Lastly, we will comment on the essential nature of using real-time ultrasound guidance for optimal CVC placement.

A central line, or central venous catheter, is any vascular access device whose tip terminates in a large blood vessel of the body (most commonly the superior vena cava or inferior vena cava). On rare occasions (due to proximal thrombosis or stenosis) central lines will terminate in the subclavian vein; these “midline” catheters are also considered to be CVCs.

Almost any peripheral or central vessel can be the entry point for a CVC; the most commonly used veins for the insertion of CVCs include the internal jugular (IJ), subclavian (SC), and femoral veins. PICCs (peripherally inserted central catheters) are also considered to be CVCs and are inserted into a peripheral mid-arm vein such as the basilic vein or cephalic vein.

CVCs are made of either polyurethane or silicone. Some CVCs are designed to withstand the pressures required for the power injection of IV contrast for CT scans, and others have been impregnated with antibiotics (either chlorhexidine/silver sulfadiazine or rifampin/minocycline) in order to prevent catheter-related bloodstream infection (CR-BSI). CVCs range widely in diameter, from 3-Fr single lumen PICCs to 7-Fr 5-lumen CVCs to 15-Fr double-lumen dialysis catheters. The required diameter depends in part on the desired flow rate, which varies based on the indication, eg, 3 cc/min for CT contrast infusion, 70 cc/min for pheresis, or >300 cc/min for hemodialysis. Some CVCs have a natural safety lifespan of 10 to 14 days, while others can safely remain in place for years.

Ports are a unique type of CVC. Ports are canisters (made of plastic or metal) that are implanted into a subcutaneous pocket in either the chest (Port-a-cath) or arm (PAS-port). The canister is attached to a polyurethane catheter which is inserted into the vascular space; the internal jugular, subclavian, or basilic veins are most commonly utilized for this purpose. Because the device is implanted and the catheter cut to length, fluoroscopic guidance is used to ensure proper positioning at the time of insertion. In order to infuse or draw blood through a port, the canister is accessed using a special, noncoring needle (Huber) that extends the life of the canister and reservoir. The main advantage of ports is that all elements of the device are buried underneath the skin, such that no dressing or covering is required when the device is not being used. This configuration minimizes the risk of infection, thereby distinguishing it from PICCs, nontunneled central lines, or tunneled catheters (discussed below), all of which protrude from the skin and have greater risk of infection from skin flora and require a sterile, occlusive dressing. Ports are typically used in patients who will need intermittent but recurrent, long-term (>3 months) vascular access for infusion and/or phlebotomy, such as chemotherapy for cancer patients. More frequent port access increases the risk of port site infection, as the skin overlying the port is limited in its ability to tolerate repeated (or continuous) access while retaining integrity as a barrier to infection.

Virtually any central line can be tunneled or nontunneled. Nontunneled central lines are commonly placed in intensive care units, operating rooms, and emergency departments. These lines (for example, a 7-Fr triple-lumen catheter) are designed for short-term access and involve the insertion of a catheter directly from the skin into a vessel below. A tunneled central line, by contrast, exits the skin at a site distant from where it enters the vascular space, traveling through a subcutaneous “tunnel” from venotomy to skin exit.

Tunneled catheters are typically used for longer-term access (> 2 weeks). The insertion procedure, similar to port implantation, is usually aided by real-time fluoroscopic guidance. Most tunneled CVCs are inserted into the internal jugular or subclavian veins and are routed through a subcutaneous tunnel 8 to 10 cm long on the chest wall, resulting in an exit site on the anterior chest. They characteristically possess a dacron cuff on the distal aspect of the catheter that is positioned within the tunnel. This cuff scars into the subcutaneous tissue over time and functions both to secure the catheter in place and as a mechanical barrier to bacterial migration. Insertion and removal of tunneled catheters are inherently more invasive than for nontunneled CVCs. Because of this, and due to their suitability for long-term use, the insertion of tunneled CVCs should be performed in patients who are free from active infections so as to minimize the chances that they become seeded with bacteria and require early removal.

Patients can be safely discharged from the hospital and live for extended periods with tunneled CVCs in place—another important difference between tunneled and many nontunneled CVCs. Outpatient hemodialysis is the most common use for these catheters, and various brand names are associated with them (Hickman, Quinton, or Permacath). Groshong catheters are of smaller diameter than dialysis catheters, but are otherwise similar. In addition, cuffed PICCs (usually < 7-Fr) can either be tunneled from the IJ or SC to the anterior chest or from the axilla to the mid-arm; these latter two tunneled CVCs are designed to meet long-term infusion and phlebotomy needs if arm veins are no longer usable.

Common indications for central line placement include

1. 
   

   Infusion of medications that would otherwise be caustic, toxic, or cause sclerosis of peripheral vessels if given through a peripheral IV. Common examples include chemotherapy, vasoactive medications, and some antibiotics (ie, vancomycin)

   
   
2. 
   

   Recurrent and/or difficult phlebotomy, typically in hospitalized patients or for patients requiring frequent outpatient lab draws over extended periods

   
   
3. 
   

   Performing ultrafiltration, hemodialysis, plasmapheresis, or any other blood filtering process

   
   
4. 
   

   A need for long-term vascular access (PICC lines, ports, and tunneled catheters)

   
   
5. 
   

   Infusing IV medications for patients in whom peripheral IV access is difficult or impossible to obtain

   
   
6. 
   

   Hemodynamic monitoring, ie, pulmonary artery (Swan-Ganz) catheters for left ventricular end diastolic pressure and cardiac output monitoring

Given the severity of illness generally associated with the requirement for a CVC, establishing adequate venous access is frequently a matter of life and death. An actively hemorrhaging gastrointestinal bleed, for example, may require immediate placement of a large bore catheter regardless of INR or platelet levels. Similarly, a patient in intensive care may need immediate central access for antibiotics, vasoactive medications, and/or blood products, despite being severely coagulopathic and at high risk of internal or external bleeding from invasive procedures. In essence, there are no absolute contraindications to CVC placement provided that the likelihood and severity of potential complications are outweighed by the benefits of immediate venous access.

In less urgent situations, it is common practice to evaluate coagulation parameters (INR, PTT, platelets) and correct abnormalities (target INR <1.5, PTT <40, platelets >50,000) prior to line insertion, although no randomized studies exist to support this approach. In reality, many CVCs can be safely placed in coagulopathic patients, and the likelihood of mechanical complication depends more upon the skill and experience of the operator in using ultrasound for guidance (discussed below) than it does on any single laboratory value. In experienced hands, the use of ultrasound guidance may be a more reliable predictor of complications than coagulopathy.

Bacteremic patients present a unique dilemma in that IV access is required for parenteral antibiotics, yet these patients are at high risk for developing secondary CR-BSI due to the seeding of the central line from circulating bacteria. In ideal circumstances bacteremic patients should be kept “line-free” (without any central lines) for at least 48 hours and/or until the bacteremia clears prior to placing a new central line. During this period, clinicians should rely on peripheral IV access for parenteral antibiotics. However, some patients inevitably will require central venous access during their bacteremic phase, and in those cases it is still acceptable to place a CVC in order to ensure the patient receives proper treatment and/or monitoring. In these patients, antibiotic-impregnated catheters are highly recommended along with the prompt removal of the CVC as soon as it is no longer required.

In summary, the indications and necessity for central venous access in all patients must be reviewed critically before proceeding with a CVC insertion. Indwelling lines pose definite risks to patients, and once inserted, the CVC should be regularly assessed for ongoing necessity with the goal of prompt CVC removal as soon as the risks eclipse the benefits. A broad assessment of a patient’s clinical status, planned future interventions, operator expertise, and the appropriateness of the overall treatment plan should be considered in all patients prior to line insertion, as these risks and needs determine the optimal procedure for any given patient.

Central line complications can be divided into three categories spanning the life of the catheter (from insertion to removal): insertion complications; persistence-related complications; and removal complications. During the insertion of a CVC, potential complications include the following:

• Arterial puncture and/or arterial cannulation
  
• Arteriovenous (AV) fistula creation
  
• Bleeding
  
• Hematoma
  
• Pneumothorax
  
• Hemothorax
  
• Bladder injury
  
• Nerve injury
  
• Introduction of bacteria to the circulation, with resultant bacteremia
  
• Retained foreign object (most commonly a guidewire)
  
• Operator needle stick injury
  
• Line malposition (eg, incorrect length, or tip placement in a vessel other than the SVC)

Complications related to the persistence of an indwelling CVC include

• Line dislodgement
  
• Line associated deep venous thrombosis (DVT)
  
• Rash or allergic reaction to dressing adhesive
  
• Catheter-related bloodstream infection

Complications associated with the removal of a CVC include

• Bleeding
  
• Air embolism
  
• Catheter fracture, with or without embolism of the retained fragment