Severe sepsis, defined as acute organ dysfunction secondary to infection, is the most common cause of death in noncardiac intensive care units (ICUs) (22). Blood cultures serve as a reliable, if imperfect, test for detecting the bacteremia often associated with sepsis and as a vital tool in tailoring antibiotic therapy (8, 36). However, blood culture contamination (with organisms that do not reflect true bacteremia) frequently complicates the interpretation of blood culture results (30), leading to unnecessary antibiotic administration (20) and adding significantly to the length of hospital stay and the cost of care (1).Central lines are often inserted into unstable ICU patients when sepsis is suspected, in order to measure central venous pressure, direct fluid resuscitation, obtain venous oxygen saturation (33), and facilitate the safe administration of vasoactive drugs. The strict aseptic techniques and sterile-barrier precautions employed during central line insertion (in order to reduce the incidence of central line-associated bloodstream infections [28]) far exceed those taken when obtaining blood cultures from peripheral venipuncture. Since suspected sepsis is also an indication for obtaining blood cultures, and since central lines are inserted under strict sterile precautions, obtaining blood cultures during central line insertion presents an attractive opportunity to minimize the risk of culture contamination. Indeed, this is a common ICU practice.The principal hypothesis examined in this study was that the rate of contamination of blood cultures taken at central line insertion would be lower than that of blood cultures taken from peripheral venipuncture. This question is important in order to establish the validity of central line insertion blood cultures.(This work was presented in part as a poster at the International Symposium of Intensive Care and Emergency Medicine, Brussels, Belgium, 2011.)
MATERIALS AND METHODSSetting and data collection. The Hadassah-Hebrew University Medical Centre is a 775-bed academic tertiary care hospital. Data on all blood cultures taken from patients in the 12-bed adult general (mainly surgical) ICU (GICU) and the 9-bed medical ICU (MICU) between January 2005 and June 2010 were obtained retrospectively from the computerized microbiological laboratory database. Cultures taken from existing lines (not at the time of insertion) were excluded. A waiver of informed consent was granted by the institutional research ethics committee, as this was considered a quality control initiative, and there were no patients identified or treatments given.The following information was extracted for each blood culture: ICU of patient admission, date of specimen collection, culture result, and source of blood culture (peripheral venipuncture, central venipuncture during central venous catheter insertion, or arterial puncture during arterial catheter insertion). Central venous catheters included single-, double-, and triple-lumen catheters; temporary dialysis catheters; and pulmonary-artery cat...
