Indwelling time and risk of colonization of peripheral arterial catheters in critically ill patients

Objective: Despite the lack of evidence to support routine scheduled replacement of peripheral arterial catheters this practice continues to be widely used in many intensive care units (ICU). This study evaluated whether additional risks of catheter colonization are incurred with a conservative attitude in severely ill patients. Design and setting: Observational study over a 18-month period in a 15-bed surgical ICU of a 1,000-bed French university-affiliated hospital. Catheters: A total of 295 peripheral arterial catheters were inserted in 295 patients. Measurements and main results: Hazard rates of catheters colonization (defined as quantitative culture of a catheter tip showing at least one microorganism at a concentration of 1,000 or more colony-forming units per milliliter) according to indwelling time were determined over 5-day periods by survival analysis. The mean indwelling time was 8 +/- 6 days (median 6 days). Overall, 47 (16%) colonization episodes were diagnosed, leading to catheter colonization incidence density of 19.9 per 1,000 catheter-days. Risk factors for catheters colonization increase in proportion to the duration of catheter use. Hazard rates of catheter colonization were 1.0, 1.9, 3.5, 7.0, 6.0 and 5.7%, for the 111 arterial catheters left in place for 4 days or less, 5-9 days (87 catheters), 10-14 days (55 catheters), 15-19 days (27 catheters), 20-24 days (10 catheters) and more than 24 days (5 catheters). Conclusions: Systematic replacement of peripheral arterial catheters might be useful in preventing catheter-related colonization, especially after 2 weeks of use.