Arterial catheter-related bloodstream infection: incidence, pathogenesis, risk factors and prevention.

BACKGROUND Arterial catheters are essential in critical care for haemodynamic and blood gas monitoring. The risk of infection remains ill defined. AIMS To delineate the incidence, pathogenesis and risk factors for arterial catheter-related bloodstream infection (BSI). METHODS Arterial catheters in two randomized trials in 1998-2000 were studied prospectively. One trial studied the effect of a 1% chlorhexidine-75% alcohol solution for cutaneous antisepsis for intravascular catheters, and the other trial studied the efficacy of a chlorhexidine-impregnated sponge dressing, both for prevention of catheter-related BSI. At catheter removal, skin of the insertion site, catheter segments, hub and infusate were cultured quantitatively in all cases. Catheter-related BSI was confirmed by concordance between isolates from the catheter and from blood cultures by restriction-fragment DNA subtyping. Risk factors for arterial catheter-related BSI were determined using univariate analysis. FINDINGS Of 834 arterial catheters studied (3273 catheter-days), 109 (13%) were colonized and 11 caused bacteraemia (1.3%, 3.4 per 1000 catheter-days). The majority of catheter-related BSIs were acquired extraluminally from skin of the insertion site (63%). The risk of arterial catheter-related BSI was comparable with that for short-term non-cuffed central venous catheters (2.7%, 5.9 per 1000 CVC-days). CONCLUSION In patients in intensive care with cryptogenic sepsis or bacteraemia, arterial catheter-related BSI must also be suspected and excluded. The most common route of infection is extraluminal; as such, novel technologies shown to prevent bloodstream infection with CVCs, such as chlorhexidine for cutaneous antisepsis and chlorhexidine-impregnated dressings, may also be of benefit with arterial catheters.