Drop in Central-Line Infection Rates Linked to Disinfection Caps

Clinicians at NorthShore University HealthSystem's three hospitals near Chicago have found a method of reducing bloodstream infections by half.

Using a tiny alcohol-impregnated cap on central line hubs prevented four CLABSI deaths and prevented 21 patients from infections, they calculated during the study year, a result sustained with proven cost-effectiveness during the 18 months following their experiment.

The cap method differs from the traditional 15-second "scrub the hub" practice.

"Our trial demonstrates with evidence for the first time that these caps actually work, and we did so in a very convincing study," explains Marc-Oliver Wright, director of Infection Control for the 975-bed, NorthShore University HealthSystem in Evanston, IL.

Today, "most hospitals use these [needle-free] connectors, which were developed to prevent needlestick injuries," he says. "But the problem with these is how they're designed. They have these grooves where bacteria can just sit there and fester. And if you don't get it out by scrubbing, really, really well, then that's just an easy access port for bacteria to crawl inside that catheter hub and work its way down the line into the catheter and the patient's bloodstream."

To be sure of killing these bacteria, nurses or doctors must "scrub the hub" for a full 15 seconds, and Wright acknowledges that "when your patient is in need of medication, and you have to stand there for 15 seconds scrubbing the hub, well, you must might hurry it up a little bit and not give it that full 15 seconds."

"Even if you're really good, it's probably not going to happen 100% of the time," he says.

In a paper published in the American Journal of Infection Control, Wright and NorthShore colleagues showed the results of a three-phase trial in which each of three of NorthShore's hospitals experimented with three phases of intervention with the cap, with results showing "sharp," and "very statistically significant," reductions in infections during the phase in which they used the special alcohol impregnated cap.

In Phase 1, which ran during various months in 2010, nursing staff and physicians were instructed to use standard "scrub-the-hub" techniques, in which an alcohol pad is used to scrub the catheter hub for a recommended 15 seconds.

That technique is what is commonly used at most hospitals around the country today, Wright says.

But in the Phase 2, which ran during parts of 2010 and 2011, clinicians used a tiny bright orange disinfection cap, sold under the brand name SwabCap. The manufacturer paid for the cost of the study under a testing protocol, which obtained human subject review approval, but NorthShore hospitals purchased the caps.

The cap acts as a hood for an even tinier sponge that's saturated with 70% isopropyl alcohol. When twisted onto the IV catheter, the cap squeezes the alcohol in the sponge into the connector, killing any bacteria within five minutes.

The percentage of catheters sampled with contamination went from 12.4%, 12.7% and 13.3%, respectively in each of the three hospitals during Phase 1, to 6.5%, 3.6% and 3.2% in Phase 2.

For Phase 3, which ended in 2011, Wright and colleagues wanted to be sure that some other infection control initiative wasn't responsible for the improvement. So the largest facility, Evanston Hospital, continued the study by going back to the standard "scrub the hub" technique used in Phase 1.

Contamination rates resumed to 12.6%, or about where they were in Phase 1, and NorthShore ended the study.

When the trial ended 18 months ago, the hospitals were sold on the strategy, especially after a cost analysis revealed that the caps, which cost .20 to .30 a piece, at a total cost per day of $2 per day per catheterized patient, cost NorthShore's four facilities a total of only $60,000 per year. "It was a slam dunk," Wright says.

Using conservative estimates of the cost of caring for those patients with hospital-acquired infections for an additional three days, Wright says, the hospital number crunchers estimated that the savings equals an increased ability to admit more patients.

"With a literature-based estimate of 2.7 days in attributable length of stay, 56.7 bed-days are made available," the authors wrote in the AJIC paper. "Our average length of stay for a hospitalized patient is 4.5 days, suggesting that with the disinfection cap we could admit nearly 13 more patients per year."

He adds that the results were particularly surprising because NorthShore's CLABSI rates weren't that high to begin with, and it's harder to show a 50% reduction when numbers are already low.

Wright says he was originally skeptical, but now believes that the caps work to prevent infections and stop the formation of bacterial colonies inside these catheters. But he's not yet advising all hospitals to try them.

The NorthShore experience needs replication at other facilities first. "This is just one piece of evidence for it," he says.