One Preop Antibiotic Dose Is as Good As Several Postop

RIBEIRO PRETO, Brazil, Nov. 20 -- A single preop dose of antibiotics is as effective at preventing infection as is 24-hour coverage after surgery, researchers here said.

A hospital protocol to replace 24-hour dosing with a single preop dose cut costs without an increase in surgical site infections, reported Silvia Nunes Szente Fonseca, M.D., M.P.H., of the Hospital So Francisco here, and colleagues, in the November issue of the Archives of Surgery.

For the 6,140 consecutive elective surgery patients treated in eight months at the hospital before the protocol, the infection rate was 2% compared to 2.1% for the 6,159 consecutive patients included in the study during the nine months after implementation (P=0.67).

Infection prophylaxis with the antibiotic Ancef (cephazolin) stayed at 99% compliance but the amount used by the hospital dropped by 63% (467 versus 1,259 vials) for a monthly savings of ,980.

"Numerous guidelines for the correct use of prophylactic antibiotics have been published in recent years," the authors wrote. "Those guidelines and publications show that one-dose prophylaxis is efficacious for most procedures, Misuse of antibiotics is not harmless; increasing adverse effects, bacterial resistance, and costs are among a few problems commonly associated with antibiotic use."

"Unfortunately," they added, "experience has shown that surgeons' compliance with these recommendations can be hard to obtain."

At the tertiary private general hospital where the study was conducted, the protocol for most surgeries was 1 g of Ancef administered at anesthesia induction and no antibiotic dosing after the end of surgery.

The study included orthopedic, gastrointestinal, urology, vascular, lung, head and neck, heart, gynecologic, oncology, colon, neurologic, and pediatric surgeries. It excluded patients with infection at the time of surgery or who were immunosuppressed.

High compliance was encouraged with educational presentations to anesthesiologists, residents, nursing personnel, and medical staff of all clinics as well as administrative measures that reduced access to extra doses or different antibiotics unless preoperative forms were completed by the surgeon.

These efforts paid off where other institutions have failed, said Martin A. Makary, M.D., M.P.H., of Johns Hopkins, in an invited critique of the study published in the same journal issue.

"In my opinion, the most impressive aspect of this research is the successful implementation of a hospital-wide process change, which overnight standardized antibiotic administration for every operation in every specialty," he said.

"Their strategy was based on evidence from practice guidelines, a dedicated team in charge of implementing a protocol, and a physician champion--three ingredients important to any successful quality improvement endeavor," he added.

The researchers measured the rate of surgical site infections by consulting all antibiotic prescription forms and culture results daily as well as visiting the intensive care units and wards regularly, seeking infections. Postdischarge surveillance by the infection control nurse included telephoning patients 10 to 15 days after discharge to ask about symptoms or signs of infection. Surgical site infections were defined according to CDC criteria.

The researchers found that no difference in postdischarge infections before and after the protocol change. There were 90 infections with 24-hour antibiotic dosing (71%) and 97 infections with single dosing (73%).

This was despite the increased number of patients reached by telephone in the post-implementation period (3,066 patients, 50% of total, versus 2,717 patients, 44% of total, P<0.001).

To compare costs, the researchers simply compared the number of Ancef vials used since the antibiotic is used only for prophylaxis at their hospital. The price for each vial was estimated at .50 to attain the ,980-monthly savings figure from 792 fewer vials used.

"It is important to notice that our savings referred only to decreasing surgical prophylaxis from 24 hours to [single dosing prophylaxis], which meant decreasing two to three doses per surgery," the researchers wrote. They noted that hospitals that use antibiotic prophylaxis for longer than 24 hours after surgery would see even larger savings, which can have a big impact in resource-limited countries like Brazil.

Dr. Makary said the study was limited by the follow-up surveillance, which was complete for only 47% of patients and performed as early as 10 days after discharge. He cautioned that the results of the study should not be generalized to immunocompromised or infected patients, who were excluded from the study.

Dr. Makary recommended giving prophylactic antibiotics based on criteria of the National Nosocomial Infections Surveillance System, which include factors such as the patient's American Society of Anesthesiologists score, contamination, length of case greater than the 75th percentile, and type of operation.

The study was supported by the Waldemar Barnsley Pessoa Foundation and Maternidade Sinh Junqueira Foundation.