Why timing is everything with prophylactic antibiotics and surgery
New data show that many patients are still receiving the drugs too soon before–and too long after–surgery by Deborah Gesensway
Published in the April 2005 issue of Today's Hospitalist
When it comes to administering prophylactic antibiotics before and after major surgery, timing is everything. That’s the consensus of a growing body of research—and a project that aims to reduce infection in patients undergoing surgery by the end of the decade.
Nearly all patients undergoing major surgery these days receive an antibiotic, and many of those patients are receiving the specific drugs recommended by national guidelines. In too many cases, however, antibiotics are given to patients too soon before they go under the knife, reducing the drugs’ ability to prevent infections, or they
“Fever alone is not a good reason to continue antibiotics postoperatively.”
Dale W. Bratzler, DO, MPH Oklahoma Foundation for Medical Quality
are continued for too long after surgery, contributing to concerns about antimicrobial resistance.
A new study of Medicare patients published in the February 2005 issue of Archives of Surgery, for example, found that only slightly more ht]than half of patients undergoing surgery received their antibiotic dose in the hour before incision, and that only 40 percent of them stopped taking an antimicrobial within 24 hours following surgery.
Dale W. Bratzler, DO, MPH, principal clinical coordinator at the Oklahoma Foundation for Medical Quality and lead author of the study, says his is just the latest study to point out that the timing of antibiotics both before and after surgery is suboptimal.
On the front end of the process, he says, research has proven that antibiotics must be present in the patient when the wound is open to provide the most protection against infections acquired during surgery. That means that most antibiotics are ideally given no more than one hour before an incision is made, and not after the incision has been made, as sometimes occurs.
“We found that surgeons order antibiotics consistently,” Dr. Bratzler says. “But the fact that only 56 percent of these antibiotics were started within an hour before the incision represents a problem with the hospital system’s ability to ensure delivery within that critical timeframe. Studies show giving antibiotics too early or too late can result in higher infection rates in these patients.”
On the back end of the process, he adds, studies show that while giving antibiotic prophylaxis for more than 24 or even 48 hours after surgery does nothing to reduce infection rates, it can contribute to antimicrobial resistance issues. “There is pretty clear evidence that prolonging the use of prophylactic antibiotics is associated with hospital bacterial resistance,” Dr. Bratzler explains.
The window before surgery
Dr. Bratzler’s study is just the latest to come out of a large national project sponsored by the Centers for Medicare and Medicaid Services (CMS) and the CDC.
That initiative, known as the Surgical Care Improvement Project, aims to reduce surgical complications by 25 percent by 2010. About 40 percent of the more than 42 million operations performed each year result in complications that include infections, adverse cardiac events, venous thromboembolism and respiratory difficulties.
Dr. Bratzler says that hospitalists who work in the institutions that will participate in the part of the project that focuses on surgical site infections can potentially play a role in at least two areas related to reducing surgical site infection rates: the proper use of prophylactic antibiotics and postoperative blood sugar control.
(Other components of the project will focus on operating room procedures that can reduce infections, along with the increased use of perioperative beta-blockers and deep vein thrombosis prophylaxis. More information about the project is online at www.medqic.org/scip.)
Surgical site infections alone cost U.S. health care about $1.5 million each year. About 2 percent of the 30 million operations performed in U.S. hospitals each year are complicated by these infections, according to Dr. Bratzler’s study. A patient who develops a surgical site infection is twice as likely to die and five to six times more likely to require readmission to the hospital than a similar patient undergoing the same surgery.
The evidence for tighter use of antibiotics before surgery may be overwhelming, but making sure all patients going in for major surgery receive prophylactic antibiotics is complicated by the simple fact that operations don’t always occur on schedule.
“There are so many things that happen to patients when they are going to an operating room today,” Dr. Bratzler explains, “that giving that antibiotic within the hour is challenging. We need a systems approach with standardized protocols that includes all the people who have ownership of the patient’s care just before the operation.”
Dr. Bratzler’s research found that patients undergoing cardiac and orthopedic surgery were most likely to receive their antibiotics on time. Patients undergoing hip or knee arthroplasty were more likely to receive antibiotics approximately one hour before surgery, compared to patients undergoing colorectal surgery.
The authors credited this achievement to the fact that these specialists were the most likely to use “preprinted care plans or order forms.” These tools were present in the charts of 50 percent of patients undergoing arthroplasty, compared to only 4 percent of patients undergoing colon surgery.
While systems issues may hamstring the delivery of antibiotics before surgery, Dr. Bratzler says the big barrier to cutting off drugs 24 hours after a procedure has to do with the attitudes of physicians and nurses.
Many doctors and nurses, he explains, simply are unfamiliar with the evidence supporting this best practice. “We have a lot of people tell us that they don’t have a problem with infection rates,” he says, “so they are not going to change their practice.”
While it’s true that stopping antibiotics earlier will not change infection rates—studies have shown that infection rates don’t go up or down by keeping patients on prophylactic antibiotics for more than 24 hours following surgery—there are other big benefits. Dr. Bratzler points to studies that show when infections occur in patients who have received antibiotics for more than 48 hours after surgery, the incidence of resistant infection increases.
“In cardiac literature,” Dr. Bratzler explains, “there are good data that once antibiotics go beyond 48 hours, the incidence of resistant infection—when infections occur—goes up fairly dramatically.”
Making matters worse, Dr. Bratzler explains, clinicians often prescribe antibiotics for common reactions to surgery that are not infections. Consider, for example, that 20 percent to 30 percent of all patients who have surgery will have a fever on the first day following their operation.
“That doesn’t necessarily mean an infection,” he says, “but that’s not always understood. In fact, we think it’s one of the reasons that clinicians frequently continue to give patients antibiotics. But fever alone is not a good reason to continue antibiotics postoperatively.”
Moreover, Dr. Bratzler adds, when patients do develop a surgical site infection, the evidence shows that merely treating it with antibiotics is usually ineffective. “If you have a patient with a real wound infection,” he says, “you can give antibiotics until the cows come home, and it won’t cure the problem. You need to open the incision back up and drain it.”
While he acknowledges that there is still some controversy about a hard 24-hour cutoff for postoperative prophylactic antibiotics, almost no one disputes the idea of using a 48-hour cutoff. Nevertheless, his study found that an alarming 27 percent of patients continued to receive antibiotics after 48 hours.
Choosing an agent
While the timing of antibiotics before and after surgery is important, so is physicians’ choice of antibiotics.
Dr. Bratzler’s study found that while more than 90 percent of the surgical patients in the study received an antibiotic consistent with published guidelines, physicians often prescribed other antibiotics for good measure.
When the researchers looked for patients who received only the recommended drug, and nothing more, the percentage dropped to 79 percent. “Some patients are receiving additional antibiotics that are not necessary,” Dr. Bratzler says.
He notes that all published guidelines on the topic recommend using older, narrow-spectrum agents and saving the newer, broad spectrum drugs for when infections do occur.
Because many hospitalists sit on their institution’s pharmacy and therapeutics committees, Dr. Bratzler thinks “there is a role for hospitalists to work with their colleagues to come up with standardized protocols for prophylaxis.” Perhaps even more importantly, he adds, hospitalists can play a key role in changing how physicians view the role of antibiotics in surgical patients.
He acknowledges, however, that it may be a challenging task. “Every doctor can remember the patient who got an infection,” Dr. Bratzler says. “Unquestionably, it’s a terrible complication. These are the patients you remember, so there is a tendency to think that giving more is better. But the literature hasn’t borne that out.”
Deborah Gesensway reports on U.S. health care from Toronto, Canada.