Impact of multiple concurrent central lines on central-line-associated bloodstream infection rates.

BACKGROUND

The current methodology for calculating central-line-associated bloodstream infection (CLABSI) rates, used for pay-for-performance measures, does not account for multiple concurrent central lines.

OBJECTIVE

To compare CLABSI rates using standard National Healthcare Safety Network (NHSN) denominators to rates accounting for multiple concurrent central lines.

DESIGN

Descriptive analysis and retrospective cohort analysis.

METHODS

We identified all adult patients with central lines at 2 academic medical centers over an 18-month period. CLABSI rates were calculated for intensive care units (ICUs) and non-ICUs using the standard NHSN methodology and denominator (a patient could only have 1 central-line day for a given patient day) and a modified denominator (number of central lines in 1 patient in 1 day count as number of line days). We also compared characteristics of patients with and without multiple concurrent central lines.

RESULTS

Among 18,521 hospital admissions, there were 156,574 central-line days and 239 CLABSIs (ICU, 105; non-ICU, 134). Our modified denominator reduced CLABSI rates by 25% in ICUs (1.95 vs 1.47 per 1,000 line days) and 6% (1.30 vs 1.22 per 1,000 line days) in non-ICUs. Patients with multiple concurrent central lines were more likely to be in an ICU, to have a longer admission, to have a dialysis catheter, and to have a CLABSI.

CONCLUSIONS

Using the number of central lines as the denominator decreased CLABSI rates in ICUs by 25%. The presence of multiple concurrent central lines may be a marker of severity of illness. The risk of CLABSI per lumen of a central line is similar in ICUs compared to wards.