Central venous catheters: Can we control the infections?

Abstract

Central line infections resulting in bacteremia are associated with a substantial increase in hospital costs, morbidity, and mortality. Approximately 3%–7% of the 3 million central venous catheters inserted annually in the United States result in the 150,000 to 250,000 nosocomial bacteremias that occur every year, associated with the presence of an intravascular catheter. Mortality rates of 10%–20% are reported, and hospital stay is prolonged by an average of 7 days. Strategies to reduce infections have been recently recommended by the Centers for Disease Control and Prevention. These guidelines include maximal sterile barrier precautions and avoidance of catheter exchanges over a guidewire. Additional ways to reduce central line infections include routinely inspecting the insertion site, minimizing the duration of catheterization, and using the subclavian vein insertion site. Because it is postulated that the majority of infections occur because of microorganisms that adhere to the surface of the skin, novel strategies have been developed. These include applying cutaneous antiseptic or antimicrobial agents at the insertion site, attaching a subcutaneous silver-impregnated cuff, or impregnating the catheter itself with antiseptics or antibiotics. The scientific basis for preparing catheters coated with these agents may be their ability to prevent the development of biofilm formation and the subsequent adherence of bacteria. Certain patients may be at higher risk of catheter-related bacteremia and may justify the increased costs of using impregnated central line devices. These include patients who have their central line placed in the intensive care unit, patients immunocompromised because of malignancy, corticosteroids, or immunosuppression, patients with pulmonary artery catheters, and patients requiring long-term catheter use for parenteral nutrition. Given the wide application of central venous catheter use throughout the world, it is important that studies evaluating these new devices demonstrate reduction in catheter-related blood-stream infections and that proper cost-benefit analysis indicates true financial savings. It is also important that patients be able to tolerate the antimicrobial substances impregnated on these catheters and that the substances do not contribute to the ever-increasing problem of bacterial resistance in intensive care units. The reviewed studies appear to show that catheters impregnated with chlorhexidine and silver sulfadiazine or minocycline and rifampin reduce the rate of catheter colonization and probably bloodstream infections in well-designed, controlled conditions. This was achieved with excellent patient safety, as it appears that the agents used were barely detectable in the systemic blood and catheters were well tolerated. The minocycline and rifampin-impregnated catheter may provide better protection from catheter colonization and systemic bacteremia. Antimicrobial resistance thus far does not appear to be a problem, but continued surveillance is necessary. Will these devices benefit all patients requiring central venous access, or should they be used only for patients determined to be at “high risk?” These questions so far have not been clearly answered and, therefore, clinical judgment is required to identify the patient at high risk. Additional cost-benefit analysis using patient-specific hospital costs is necessary. It appears that antiseptic-impregnated central venous catheters may help to reduce the incidence of costly nosocomial bloodstream infections by decreasing the rate of catheter colonization. However, they should not replace careful consideration of the indications for insertion and removal, diligent inspection and dressing of the insertion site, strict sterile barrier precautions during insertion, proper line maintenance, and use of protocols to determine how often and through which technique central venous catheters are replaced.