Study Says Antimicrobials Are Used Properly Only About Half the Time

Antimicrobial medications intended to prevent surgical site infections are appropriately administered to patients (within one hour before incision) only 55.7 percent of the time, according to a study published in the February 2005 issue of Archives of Surgery.

Surgical site infections (SSIs) are a major contributor to patient injury, mortality and health care costs, increasing mortality rates by two to three times, length of hospital stay by an average of seven days and charges by approximately $3,000, according to background information in the article. The effectiveness of antimicrobials administered shortly before skin incision for prevention of SSIs was established in the 1960s and has been repeatedly demonstrated since, the authors report. Antimicrobial prophylaxis (preventive treatment) to prevent SSI is one of the most widely accepted practices in surgery.

Dale W. Bratzler, DO, MPH, of the Oklahoma Foundation for Medical Quality, Inc., Oklahoma City, and colleagues report baseline results of an assessment of use antimicrobials to prevent SSIs for a national sample of Medicare patients undergoing five types of major surgery during 2001. The study included a random sample of 34,133 patients from 2,965 hospitals from every state, the District of Columbia and Puerto Rico. The medical records were examined to determine if the use of antimicrobials met three parameters of published guidelines for their use to prevent SSIs: whether they were given within one hour before the surgical incision; the selection of safe and effective antimicrobials consistent with current published guidelines; and their discontinuation 24 hours after surgery when the patient is no longer receiving a benefit.

"Overall, 55.7 percent of patients received prophylactic antimicrobials during the 60 minutes before incision, the authors write. Prior studies have demonstrated that timing is critical to the effectiveness of prophylaxis, and current guidelines recommend dosing within one hour before incision. It is of interest that 9.6 percent of the patients in our assessment received their first dose more than four hours after incision when little if any benefit would be expected based on these previously published guidelines.

"Most (92.6 percent) of the patients in this assessment received a prophylactic antimicrobial regimen consistent with current guidelines, according to the study. However, only 78.7 percent received regimens that were limited to the recommended agents, suggesting that a substantial amount of antimicrobials are used unnecessarily.

The results of this study raise additional concerns regarding antimicrobial resistance. Our data suggest that vancomycin continues to be used excessively for surgical prophylaxis, the authors write. In addition, 59.3 percent of patients received prophylaxis for more than 24 hours after the end of surgery. There is evidence that use of new, broad spectrum antimicrobials and prolonged use of antimicrobials can promote antimicrobial-resistant bacteria and increase the incidence of antibiotic-associated complications, according to the article.

Substantial opportunities remain to improve the use of prophylactic antimicrobials for patients undergoing major surgery, the authors conclude. Achieving high rates of performance for appropriate antimicrobial prophylaxis to prevent SSIs will require the development of systems in which the knowledge from years of research and recommendation from clinical practice guidelines are routinely incorporated into practice.

Source: American Medical Association