Effective prophylactic drugs reduce surgery infections

March 1, 2007

Surgical site infections are a significant problem in hospitals today. They occur in 2% to 5% of patients who have clean operations outside the abdomen, and in up to 20% of patients with intra-abdominal procedures. They account for about 15% of hospital-acquired infections.

Appropriate antibiotics, given just before surgery, can substantially reduce the rate of these infections. "An effective prophylactic regimen should be directed against the most likely infecting organisms, but need not eradicate every potential pathogen. For most procedures, the first-generation cephalosporin, cefazolin (Ancef, and others), which is active against many staphylococci and streptococci, has been effective," says Mark Abramowicz, MD, editor of The Medical Letter on Drugs and Therapeutics, a non-profit newsletter that critically appraises drugs.

However, for procedures that might involve anaerobic bowel bacteria, including Bacteroides fragilis, the second-generation cephalosporin cefoxitin (Mefoxin, and others), is recommended because it is more active against these organisms. Because of high demand, cefoxitin availability has been limited. In this situation, cefazolin plus metronidazole (Flagyl, and others), or ampicillin/sulbactam (Unasyn, and others) alone, are reasonable alternatives.

Any local patterns of drug resistance should be taken into account when selecting an antibiotic.

"In institutions with frequent surgical site infections because of methicillin-resistant Staphylococcus aureus [MRSA] or methicillin-resistant coagulase-negative staphylococci, vancomycin can be used for prophylaxis," says Dr. Abramowicz. "However, routine use of vancomycin should be discouraged because it does not appear to be any more effective than cefazolin in these settings."

In 2004, the Institute for Healthcare Improvement (IHI), Cambridge, Mass., launched a campaign to save up to 100,000 lives over the next 18 months through improvements in care. They targeted six areas; one of them was surgical site infections. Hospitals participating in the campaign were encouraged to implement specific steps to substantially lower the rate of these infections.

Steps include: Use of the appropriate antibiotics; antibiotics given 60 minutes before the first incision; prophylactic antibiotics discontinued within 24 hours of the end of surgery; avoiding use of razors to remove body hair before surgery; maintaining normal blood glucose levels (in cardiac patients); and maintaining normal body temperature levels (in colorectal surgery patients).

Clinical studies have demonstrated that maintaining normal temperature and glucose levels benefit the defined populations by preventing infections, and it's likely they will benefit other surgical patients, too.

During the 100,000 Lives Campaign, IHI didn't require hospitals to submit data describing their progress on each intervention, so they can't say exactly how many lives were saved due to preventing surgical site infections. However, a landmark study by E. P. Dellinger and others, published in 2005 in the American Journal of Surgery, described the National Surgical Infection Prevention Collaborative, a demonstration project sponsored by CMS.

In this one-year study, 44 hospitals reported data on 35,543 surgical cases, using the suggested steps to prevent surgical site infections. They found that their infection rate decreased 27%, from 2.3% during the first three months, to 1.7% during the last three months.

"During the collaborative, hospitals did not reach 100% performance levels for all of these interventions," says Kenneth LaBresh, MD, chief medical officer at Masspro, Waltham, Mass. "This means the 27% improvement level doesn't reflect the maximum potential for these interventions, but it does demonstrate what is possible for hospitals that spend a year improving their processes."