Impact of Avoiding Central Vascular Catheter-Drawn Blood Samples for Culture in a Large Tertiary Care University Hospital

Background: Uncertainty regarding the significance of central line blood culture results prompted the CDC to recommend avoiding their use unless absolutely necessary. The effectiveness and safety of enforcing this policy in a hospital that cares for immunocompromised hosts is unknown.

Methods: We examined the impact of avoiding the use of catheter-drawn blood samples for culture unless absolutely necessary at a tertiary care hospital that also cares for patients with cancer, stem cell transplants and solid-organ transplants. Hospital-wide enforcement began in September 2013. The pre-implementation era was defined from August 2012 to July 2013, and the post-implementation era was defined from January 2014 to December 2015. The following outcomes were compared between eras: 1) number of blood cultures per 1,000 inpatient days; 2) number of blood cultures from central lines per 1,000 inpatient days; 3) number of positive blood cultures per 1,000 inpatient days; 4) number of central-line associated bloodstream infections (CLABSIs) meeting National Healthcare Safety Network (NHSN) definitions per 1,000 central line days; 5) length of stay; 6) inpatient death.

Results:  The number of blood cultures decreased two-fold from 144 to 72 per 1,000 inpatient days, and the number of blood cultures drawn from central lines decreased eight-fold from 24 to 3 per 1,000 inpatient days between pre- and post-implementation eras. The number of positive blood cultures decreased by a third from 14 to 9 per 1,000 inpatient days, whereas the number of CLABSIs meeting NHSN definitions decreased three-fold from 3 to 1 per 1,000 central line days between eras. The mean length of stay was unchanged at 3.8 and 4.0 days (p=0.316), and the number of inpatient deaths per 1,000 admissions was stable at 8.5 and 9.2 (p=0.240) between eras. The mean length of stay for patients admitted to cancer and transplant units was unchanged at 6.4 and 6.5 days (p=0.609), and the number of inpatient deaths per 1,000 admissions at cancer, transplant and intensive care units was stable at 41.2 and 47.1 (p=0.131) between eras.

Conclusion:  Avoiding the use of catheter-drawn blood samples for culture can effectively decrease CLABSIs meeting NHSN criteria without adversely impacting patient outcomes.