Risk factors and clinical impact of central line infections in the surgical intensive care unit

Objective: To determine the risk factors and clinical impact of central line infections in critically ill surgical patients. Design: Retrospective study. Setting: The surgical intensive care unit of a large tertiary care university hospital. Patients: A total of 232 consecutive central line catheters sent for culture from patients in a surgical intensive care unit during 1996 and 1997. Catheters were sent for microbiologic analysis when the patient was clinically infected and the central line was a possible source. Interventions: None. Main Outcome Measures: Risk factors associated and clinical impact of a positive catheter culture. Results: Of 232 consecutive catheters from 93 patients sent for microbiologic analysis, 114 catheters (49%) had no growth, 40 (17%) were colonized (<15 colonies), and 78 (34%) were considered infected (greater than or equal to 15 colonies). Univariate analysis showed that site (internal jugular vs subclavian, P<.001), catheter use (monitoring > dialysis > fluid > nutrition, P = .006), placement in the operating room vs the intensive care unit (P = .02), and placement of a new catheter (> guide wire, > new site, P = .003) were all significant factors. Surprisingly, neither the number of lumens nor the duration of the catheter in situ were predictors when a catheter was suspected and not proved infected compared with a suspected and proved catheter infection. In the multiple regression model, the placement of the catheter in the internal jugular position was the single most important predictor of a catheter infection (P<.001; odds ratio, 1.83; 95% confidence interval [CI], 1.41-2.37). The presence or absence of a specific clinical sign of infection was not predictive of a proved catheter infection. Eighty-six percent of patients had gram-positive bacteria identified on the culture, while the remaining patients had gramnegative bacteria or Candida identified. Of the catheter infections, 68% were monomicrobial, whereas 32% were polymicrobial. Of the catheters sent for microbiologic analysis, 209 (90%) had concurrent peripheral blood cultures for analysis. Nineteen (32%) with no growth from the catheter, and 14 (23%) of colonized catheters had concurrent bacteremia; all had another identifiable cause of infection. Twenty-seven (45%) of infected catheters had a concurrent bacteremia, and 9 of 27 had a second site positive for the same organism. Death related to the infection occurred in 15 patients, 2 in the first 72 hours and 13 in the following 14 days. Conclusions: Central line infections remain an important cause of morbidity and mortality. Comprehensive review of hospital practices may show a directed focus for performance improvement practices. At our institution, internal jugular catheters have the highest rate of infection. This may suggest breaks in technique during catheter insertion or during catheter maintenance and care.