RESUMO
Infections related to central venous cannulation present first-magnitude problems in recovery rooms and intensive care units. Catheter-related bloodstream infection (CRBSI) is the most serious complication because of its high frequency and a mortality rate that averages around 3%. Although infections arise for various reasons, point-of-insertion contamination is the main cause when catheters are implanted for periods of less than 10 days. Contaminating microorganisms (especially Staphyloccocus epidermidis) find refuge from the host's defenses in a biofilm that covers the catheter. Several factors participate in the formation of this biofilm, such as catheter composition, proteins of the host or type of microorganism. Biofilm bacteria are resistant to both antibiotics and the host's own defenses (e.g. phagocytes and antibodies). The microorganism can then begin to reproduce, possibly leading to bloodstream infection. The measures designed to prevent this process include recommendations for both catheter insertion and maintenance. Recent meta-analyses have led to certain conclusions but no unanimity among authors. Thus, there is agreement on the adoption of strict aseptic technique during catheter insertion, on the use of chlorhexidine as a skin antiseptic and on choice of the subclavian vein. Such measures significantly decrease the frequency of CRBSI. Maintenance techniques that have been shown to be effective are the use of connectors impregnated with antiseptic, catheters impregnated with antiseptics or antibiotics, and permeable dressings. Additionally, building an experienced infusion-therapy team to insert and maintain central venous catheters has been shown to be one of the most effective measures for preventing CRBSI.
