A 3-year prospective study was performed that included all patients admitted to the 24-bed intensive care unit (ICU) of the Hospital Universitario de Canarias (Tenerife), between 1 May 2000 and 30 April 2003. The study was approved by the institutional review board.
The catheters used were not antimicrobial-coated, but were radiopaque polyurethane catheters (Arrow, Reading, PA, USA). The placement and maintenance of catheters were performed according to the following protocol. The catheters were inserted by physicians with the following sterile-barrier precautions: use of large sterile drapes around the insertion site, surgical antiseptic hand wash, and sterile gown, gloves, mask and cap. The skin insertion site was first disinfected with 10% povidone-iodine and anesthetized with 2% mepivacaine. The catheters were percutaneously inserted using the Seldinger technique and were fixed to the skin with 2-0 silk suture. After the line insertion, the area surrounding the catheter was cleaned with a sterile gauze soaked with povidone-iodine and a dry sterile gauze occlusive dressing covered the site. No topical antimicrobial ointment was applied to insertion sites.
The percutaneous entry sites were examined for the presence of local inflammation and purulence, and were cared for in the same manner daily by the ICU nurse assigned to the patient. Catheter dressings were changed every 24 h, or sooner at the discretion of the nurse caring for the patient if the dressing was contaminated. The connecting lines were changed every 48 h and disposable traducer components were replaced every 96 h.
Also, the percutaneous entry sites were examined daily by the ICU nurse assigned to the patient to avoid accidental catheter removals [32
] in order to minimize infection risk associated with the reinsertion of the catheter.
The decision to remove the catheter was made by the patient's physician. Catheters were removed when they were no longer needed or if a systemic or local complication occurred. CVCs were routinely replaced every 14 days. We routinely used the guidewire technique to replace catheters, but in patients suspected of having a catheter-related infection the insertion site for the new catheter was changed. All catheter tips removed were routinely cultured. The catheters were removed using a sterile technique by an ICU nurse. The distal 5 cm segment of the catheters was cut with sterile scissors, placed in a sterile transport tube and cultured using the semi-quantitative method described by Maki et al
The following data were collected: age, sex, diagnosis, APACHE-II score, ICU admission and discharge dates, catheter access, catheter insertion and removal dates, cause of catheter removal, development of CRLI and CRBSI. The following three groups of CVCs were studied: femoral, jugular and subclavian.
Catheter-related infection was defined according to catheter tip colonization, CRLI or CRBSI. Catheter tip colonization was the significant growth of a microorganism (>15 colony-forming units) from the catheter tip. CRLI was any sign of local infection (induration, erythema, heat, pain, purulent drainage) and catheter tip colonization. CRBSI was a positive blood culture obtained from a peripheral vein, and signs of systemic infection (fever, chills, and/or hypotension), with no apparent source of bacteremia except the catheter, and catheter tip colonization with the same organism.
Statistical analysis was performed with SPSS 11.0 (SPSS Inc., Chicago, IL, USA) and LogXact 4.1 (Cyrus Mehta and Nitin Patel, Cambridge, MA, USA). Continuous variables are reported as means and standard deviation, and categoric variables as percentages. The CRLI and CRBSI rates are reported as: the percentage of catheters that developed CRLI; the number of CRLIs per 1,000 catheter-days; the percentage of catheters that developed CRBSI; the number of CRBSIs per 1,000 catheter-days. Comparison of the densities of incidence per 1,000 catheter-days, of CRLI and CRBSI, and between the different accesses were done using Poisson Regression and analyses were corrected for multiple testing with a Bonferroni correction. According to Bonferroni's adjustment, a p < 0.017 was considered statistically significant.