Falling SSI rates yield substantial savings

Interventions lead to $400,000 in avoided costs

A concerted and cooperative effort by clinicians at Alta Bates Medical Center in Berkeley, CA, has led to a significant reduction in postoperative surgical-site infections and attendant costs in cardiac surgery, reports Mark Bresnik, MD, hospital epidemiologist at the facility.

Noting that infection rates were on the rise in the mid-1990s, Bresnik and colleagues initiated a quality improvement project. "We sat down with the cardiac surgeons and many other personnel in care of the cardiac surgery patient, including OR nurses, ICU nurses, cardiologists — anyone involved along the whole continuum of care," he tells Hospital Infection Control. "We had monthly meetings to look at everything involved in cardiac surgery to try to see how we could change our proactive patterns to lower our infection rates again."

As the meetings continued, a best practices model based on the medical literature emerged as a key component of the program. While it is not possible to report to what degree each change in practice contributed to the reduction in infection rates, that is indeed what happened. "In [some] infection control studies that show beneficial effect, they talk about the Hawthorne effect," he says, "which is that we don’t know why it worked, but just getting people together and addressing issues and raising people’s consciousness will often make problems go away or improve."

Some educated guesses about major contributing factors include: more consistent application of pre-op skin prep (including the elimination of pre-op shaving); correct timing of prophylactic antibiotic dosing (antibiotics were given within two hours of the skin incision in 66% of cases during the baseline period and 100% of cases in the post-intervention period); and improvements in aseptic techniques in the operating room, he reports.

Pre-op preparation made a difference

"The things that I think had the greatest impact included the pre-op preparation of the patient, where we made sure they were all going to get chlorhexidine showers or baths prior to surgery," Bresnik says. "We got consistency on the skin prepping, eliminating razors, and made sure that they were using chlorhexidine to preclean and then tincture of iodine for the skin prep."

The measures were applied to both the chest and the leg for bypass procedures, in which scalpels were changed between the skin incision and the vein incision when harvesting leg veins for bypass. "So you don’t use the same blade cutting through skin, which could then get contaminated, and then you bring it down into the deeper tissues, and that could provoke a wound infection," he says.

Surgical savings were shown through projected "cost avoidance" in 1997-1998, meaning the expected number of infections (42) was compared to the 22 infections that actually occurred. The 20 prevented infections resulted in savings of nearly $400,000, based on an estimated cost per infection of $19,616. A major portion of that cost results from an average of 15 extra days in each infected patient’s length of stay. "The patients with infections had an average length of stay post-op of 24 days, and patients without infections had 8.95 days," Bresnik explains. "[Cost data] came straight off the [hospital] computer. Just calculating the differences in the infected patient group compared to the non-infected group postoperatively, I was able to come up with the figures that characterize what the cost of infections were."