Most surgeons misuse antibiotics.
   That is the blunt warning from Robert Sawyer, MD, co-director of the surgical trauma intensive care unit at the University of Virginia Health System. The problem is not ignorance of appropriate use, he told the American College of Surgeons' Clinical Congress. The problem is that surgeons ignore appropriate use.
   "Knowledge alone does not alter behavior," he said. "We have known for 30 years what should be done with antibiotics in surgery and it is not happening. We need to be prompted and checked to ensure good practice."
   Almost every area of antibiotic use in surgery needs improvement, agreed Addison May, MD, associate professor of surgery and anesthesiology at Vanderbilt University in Nashville. Nearly 40% of surgical patients are given presurgical antibiotic prophylaxis at the wrong time, either too early or too late. A significant percentage of patients are given a broad-spectrum agent when they should receive a narrow spectrum agent. Other patients are given antibiotics in the absence of evidence of infection. Even patients for whom an antibiotic is appropriate are given too long a course.
   "We tend to use antibiotics too broadly and at the wrong time," Dr. May said. "That inappropriate use quickly increases the numbers of infections, complications, and deaths among our patients."
   Multiple studies agree that preop antibiotic prophylaxis is most effective when administered one hour before the first incision. Yet a recent study across 44 teaching hospitals found that 14% of patients received no antibiotic prophylaxis at all and 37% got their presurgical dose at the wrong time.
   Why the concern? The surgical infection rate among patients who received prophylaxis within an hour of first incision was 1%, Dr. May noted. The infection rate jumped to 4% when prophylaxis was given more than two hours before surgery began.
   "The consensus is clear that prophylactic antibiotics are useful in reducing surgical infections," said Thomas Gleason, MD, director of aortic surgery at Northwestern University in Chicago. Beta lactams may be slightly more effective than glycopeptides, he added, but there are data to support almost any antibiotic in current use. Single-dose prophylaxis is just as effective as multiple doses, at least in cardiac procedures.
   Patients who present with what appears to be an infection are often treated empirically. The strategy is appropriate for many patients, but appropriate drug choice is critical. Too many surgeons order a broad spectrum product in the mistaken belief that it is better to attack more bugs than fewer, Dr. May noted. The reality is that narrow spectrum agents are both more effective and less likely to induce resistance.
   A two-year study of ICP patients found that the use of broad-spectrum antibiotics was associated with a 4% infection rate. Switching to narrow spectrum agents cut the infection rate to 1.8%. Studies in the mid-1990s found that use of broad-spectrum agents increased the incidence of MRSA by three to four times.
   Other studies have found patients on antibiotics even though they did not have an infection, cautioned Soumitra Eachempati, MD, associate professor of surgery and public health at Cornell University. Surgeons saw a fever, assumed infection, and wrote an antibiotic order.
   "You've got to look for the source of fever," he said. "They are not all created equal and they are not all susceptible to antibiotic treatment."
   "Length of treatment is another problem area. Fully 24% of adverse drug events are related to antibiotic use," Dr. Sawyer said. Long-term use of antibiotics is associated with higher mortality. Prior antibiotic use is also among the most important risk factors for fungal and candidemia infection.
   "If a little antibiotic is good, more is not better. Patient exposure to antibiotics should be as limited as possible."