Beyond the bundle--journey of a tertiary care medical intensive care unit to zero central line-associated bloodstream infections

Abstract

Introduction: We set a goal to reduce the incidence rate of catheter-related bloodstream infections to rate of <1 per 1,000 central line days in a two-year period.

Methods: This is an observational cohort study with historical controls in a 25-bed intensive care unit at a tertiary academic hospital. All patients admitted to the unit from January 2008 to December 2011 (31,931 patient days) were included. A multidisciplinary team consisting of hospital epidemiologist/infectious diseases physician, infection preventionist, unit physician and nursing leadership was convened. Interventions included: central line insertion checklist, demonstration of competencies for line maintenance and access, daily line necessity checklist, and quality rounds by nursing leadership, heightened staff accountability, follow-up surveillance by epidemiology with timely unit feedback and case reviews, and identification of noncompliance with evidence-based guidelines. Molecular epidemiologic investigation of a cluster of vancomycin-resistant Enterococcus faecium (VRE) was undertaken resulting in staff education for proper acquisition of blood cultures, environmental decontamination and daily chlorhexidine gluconate (CHG) bathing for patients.

Results: Center for Disease Control/National Health Safety Network (CDC/NHSN) definition was used to measure central line-associated bloodstream infection (CLA-BSI) rates during the following time periods: baseline (January 2008 to December 2009), intervention year (IY) 1 (January to December 2010), and IY 2 (January to December 2011). Infection rates were as follows: baseline: 2.65 infections per 1,000 catheter days; IY1: 1.97 per 1,000 catheter days; the incidence rate ratio (IRR) was 0.74 (95% CI=0.37 to 1.65, P=0.398); residual seven CLA-BSIs during IY1 were VRE faecium blood cultures positive from central line alone in the setting of findings explicable by noninfectious conditions. Following staff education, environmental decontamination and CHG bathing (IY2): 0.53 per 1,000 catheter days; the IRR was 0.20 (95% CI=0.06 to 0.65, P=0.008) with 80% reduction compared to the baseline. Over the two-year intervention period, the overall rate decreased by 53% to 1.24 per 1,000 catheter-days (IRR of 0.47 (95% CI=0.25 to 0.88, P=0.019) with zero CLA-BSI for a total of 15 months.

Conclusions: Residual CLA-BSIs, despite strict adherence to central line bundle, may be related to blood culture contamination categorized as CLA-BSIs per CDC/NHSN definition. Efforts to reduce residual CLA-BSIs require a strategic multidisciplinary team approach focused on epidemiologic investigations of practitioner- or unit-specific etiologies.

Figure 1

Central line-associated bloodstream infections, compliance with central line insertion and dressing maintenance during the study period. NHSN, National Health Safety Network.

Figure 2

Intensive care unit layout; four patients with VRE central line-associated bloodstream infection were located in two rooms of pod B - two in one room and two in another room. One patient each was located in each of the other pods.

Figure 3

Rep-PCR analysis of VRE isolates from blood cultures and environmental cultures related to patients with VRE CLA-BSI. CLA-BSI, central line-associated blood stream infections; P, pattern number; VRE, vancomycin-resistant Enterococcus faecium. Control (row 19) = E.faecalis ATCC™ 51299 control strain.