Catheter Disinfection Caps Cut Infection Rates

Larry Hand

January 04, 2013

Central line–associated bloodstream infections (CLABSIs) declined sharply during a study that tested alcohol-impregnated disinfection caps with catheters in place of the standard scrubbing protocol. The suburban Chicago hospitals involved in the study have since adopted the use of the cap as standard practice.

Marc-Oliver Wright, MT, MS, CIC, from the Department of Infection Control, NorthShore University Health Systems, Evanston, Illinois, and colleagues reported their results in an article published in the January issue of the American Journal of Infection Control.

The investigators conducted a 3-phase quasi-experimental study of adults with central lines installed at 3 hospitals in 2009: first with standard scrub protocol, second (intervention) with the cap used, and third with standard scrub used again. At a fourth hospital, they tested just the intervention because of limited resources. The plastic-threaded cap houses a sponge saturated with 70% isopropyl alcohol.

The researcher found that contamination of the lines declined from 12.7% (32/252 patients) during the first phase to 5.5% (20/364 patients; P = .002) during the intervention and rose back to 12.0% (22/183 patients; P = 0.88 vs phase 1 and P = .01 vs phase 2) in the third phase (P = .001 vs intervention).

The researchers also found that the median colony-forming units per milliliter amounted to 4 for the first baseline period, 1 for the intervention (P = .009), and 2 for the second baseline period (P = .05 vs intervention).

CLABSI rates declined from 1.43 per 1000 line-days (16/11,154 days) in the first baseline to 0.69 (13/18,972 days) in the intervention (P = .04) and rose back up to 1.31 (7/5354 days) in phase 3, when all 4 hospitals are included in the analysis (risk ratio, 0.48; 95% confidence interval, 0.23 - 0.98; P = .04).

As a control measure, the researchers calculated catheter-associated urinary tract infection rates, which were stable during the first 2 phases (1.42 and 1.41, respectively; P = .90) but declined in the third phase (1.04; P = .03 vs the first 2 phases).

"Not surprisingly, among the patients with intraluminal contamination the most commonly recovered organism was coagulase-negative Staphylococcus species (18/32, 12/20, P = 1.00), a skin colonizer and frequent cause of CLABSI," the researchers write.

Cost Analysis

The researchers also conducted an economic analysis, calculating the total cost of the disinfection cap at $60,233 per year and using the above risk ratio to propose a 52% reduction in infections for all 4 hospitals. "For a cost of $2.07 per catheterized patient per day, we avoid 21 infections and 4 deaths and make enough beds available for 13 new admissions," the researchers write.

"Preventing catheter hub contamination can take many forms," the researchers write. "The approach of using a continuously applied alcohol impregnated sponge as a cap on the hub for a standard approach to catheter care may eliminate the problem of teaching health care providers one additional disinfection process they need to use as part of their busy patient care schedule."

Limitations of the study include the use of surveillance-based CLABSI results that may overestimate clinical disease occurrence, as well as the inclusion of results from the fourth hospital that conducted the intervention phase only, the researchers write.

In fact, when the investigators do not include the intervention-only site, the difference in CLABSI rates per 1000 central line days lacks significance in the remaining 3 hospitals (P = .11), despite a 49% decline compared with baseline rates.

"We think it is reasonable to include the data from this hospital because it is part of our health care organization and practices there are the same as at our other 3 facilities. The only reason it was not part of the formal investigation was that we did not have sufficient resources to collect samples at that site, and so we implemented the disinfection cap as a standard practice at the onset. Measurement of CLABSI was identical at this hospital as it was for the other 3 in the formal study." they explain.

The researchers conclude, "At the conclusion of this investigation, our Infection Control Committee approved the permanent introduction of this device for use with central lines, and it is now the standard of practice for the organization."

The authors have disclosed no relevant financial relationships.

Am J Infect Cont. 2013;41:33-38. Full text