Infections caused by aterial catheters used for hemodynamic monitoring.

Utilizing a semiquantitative technique for culturing vascular catheters, we prospectively studied the risk and profile of infection caused by arterial catheters used for hemodynamic monitoring in 95 patients with a high risk of nosocomial infection. Of 130 catheters, 23 (18 per cent) produced local infection (larger than or equal to 15 colonies on semi-quantitative culture) and five septicemia (4 per cent). Sixteen of the 23 local infections and all septicemias occurred with catheter placements exceeding four days (p less than 0.001). Other factors associated with an increased risk of infection included insertion by surgical cut-down rather than percutaneously (ninefold increased rate of bacteremia, p = 0.008) and the presence of local inflammation (12-fold increase, p = 0.009). Systemic antimicrobial therapy (given to 80 per cent of the entire group and to four of the five with septicemia) did not protect against catheter-related infection but may account for the predominance of enterococci, Candida and gram-negative bacilli in these infections. Twelve per cent of all nosocomial bacteremias occurring in this critical care unit population originated from an arterial catheter. Indwelling arterial catheters pose a significant risk of bacteremic infection to ctirically ill patients. The percutaneous mode of placement is preferred; when prolonged arterial cannulation is required, the site should be rotated every four days. Local pain or inflammation, or clinical signs of sepsis without an obvious source should prompt removal and culture of the catheter.