Use of inappropriate regimens for antibiotic prophylaxis, both with respect to dosing issues and the agent used, represents the biggest problem area, says Dr. Camins, assistant professor of medicine, division of infectious diseases, Washington University School of Medicine, St. Louis.
In the absence of a contraindication to cephalosporin use (i.e., history of anaphylactic reaction to a beta-lactam antibiotic), IV cefazolin is considered the antibiotic of choice for preventing surgical-site infections. It should be given 30 to 60 minutes prior to making the incision using a dose of 1 gm for patients weighing less than 80 kg and 2 gm for heavier patients. An additional dose (1 gm) is needed only for procedures lasting longer than three hours or if there is significant blood loss (1500 mL or more), and treatment should not be continued after the surgical incision is closed, Dr. Camins says."These recommendations recognize that the key to effective antibiotic prophylaxis for surgical-site infections is to assure there is a bactericidal concentration of antibiotic against the common potential pathogens present at the surgical site when inoculation with microorganisms can occur, which is from creation of the first skin incision through closure," he says. "However, the reality of clinical practice is that there are surgeons who are starting prophylaxis treatment too early or too late, failing to adjust the dose based on patient weight or procedure length, continuing antibiotic treatment for an excessive time and using fluoroquinolones instead of cefazolin."
In terms of the timing of antibiotic prophylaxis administration, orders to give the antibiotic "on call to the OR," a common practice in the past, could result in the patient receiving the prophylactic dose several hours prior to when the incision is made. Still occurring is the error of administering the dose too close to the time the incision is made, which does not allow adequate time for the medication to be distributed to the target site.