Zero risk for central line-associated bloodstream infection: are we there yet?

OBJECTIVE

Identify the longest period a central line remains free from central line-associated bloodstream infection during an 18-month insertion-bundle project.

DESIGN

Prospective cohort.

SETTING

New South Wales adult intensive care units at university teaching hospitals between July 2007 and December 2008.

PATIENTS

Intensive care unit adult patients whose central line was inserted in the intensive care unit.

INTERVENTION

Compliance with the insertion bundle for central lines during the first 12-month roll-out period and the last 6 months.

MAIN OUTCOMES

The cumulative line days that remained close to infection-free before the lowest probability of central line-associated bloodstream infection, 1 in 100 chances, was identified using conditional probability modeling. An adjusted central line-associated bloodstream infection rate was calculated for these cumulated line days and thereafter where the probability for infection increased with additional dwell time.

RESULTS

The lowest probability identified for central line-associated bloodstream infection was 1 in 100 chances regardless of the phase of the project or central line type. During the first 12 months of the project, the close to infection-free period finished by the end of day 7 giving an adjusted central line-associated bloodstream infection rate of 1.8 (95% confidence interval 0.9-3.3)/1000 line days. By the last 6 months of the project the close to infection-free period was extended by 2 additional line days to the end of day 9, giving an adjusted central line-associated bloodstream infection rate of 0.9 (95% confidence interval 0.5-1.5)/1,000 line days. For dialysis and unspecified central line types, the close to infection-free period was extended by 5 additional line days, from day 2 with a rate of 4.3 (95% confidence interval 0.9-12.5)/1,000 line days to day 7, giving a rate of 0.6 (95% confidence interval 0.2-2.4)/1,000 line days.

CONCLUSION

The success of the insertion bundle was identified by improved analysis that identified that the safest dwell time was extended to the first 9 days for centrally inserted lines and up to day 7 for dialysis, peripherally inserted central catheters, and unspecified central line types. Given that three quarters of intensive care unit patients have their central line removed by day 7, zero risk for central line-associated bloodstream infection should be achievable in the majority of patients where clinicians comply with the clinician and patient insertion bundles.