The More Things Change, the More They Stay the Same

Even in modern times infection after surgery still occurs

/ Author:  / Reviewed by: Joseph V. Madia, MD

Being naked and unconscious on a table surrounded by total strangers isn't the only thing that can make an operation a frightening experience.

There's the danger of anesthesia, the fear of what put you in the operating room in the first place, and don't forget the general stress of being cut open! Unfortunately, another big stress associated with surgery can be surgical site infections.

Surgical infections are not a new problem in medicine. Until the discovery of germ theory by Louis Pasteur, surgical wounds would routinely get infected and cause great sickness and death among those unfortunate enough to need surgery. But even now with sterile operating rooms, strict antiseptic precautions for surgeons and nurses, and incredibly advanced antibiotics, the problem of infection after surgery still affects modern medicine.

A surgical site infection occurs when any of the tissues that have been manipulated during surgery become infected with germs from our own bodies or from the operating room. Usually the pathogen is bacteria like Staphylococcus aureus (which lives on our skin and in our nose) or Escherichia coli and enterococcus species (which live in our colon). In addition, surgical site infections can come from outside of our bodies, such as contaminated surgical equipment or operating room staff, or even bacteria in the air if the ventilation system is not functioning properly. Surgical infection routinely prolongs for seven to ten days the length of a hospital stay, which increases the risk for another hospital acquired infections like pneumonia.

The worst-case scenario of any infection is sepsis, a condition in which bacteria grows in the bloodstream and inflames the organs. Sepsis is so serious an illness that 50 percent of patients who become septic will not survive.

But if the operating room and surgical environment is clean and sterile, how do patients still get infections? Surgical wounds can actually be classified into four categories: clean, clean-contaminated, contaminated and dirty/infected.

Clean wounds are cases where a patient has surgery and there is no entry of the respiratory, gastrointestinal or urinary tracts. In these cases, the infection source is usually from the bacteria that live on the patient's skin, like S. aureus. When proper sanitary procedure is not followed, and the wound dressing is not changed enough, or nurses or patients touch the wound with dirty hands, an infection can occur.

Clean-contaminated wounds are when the respiratory, GI or GU tracts are operated on. These systems have natural bacteria that live happily in these organs, but when exposed to an open wound, they can cause infection. The most common example would be a patient who has bowel surgery and the natural bacteria from the colon somehow makes it to the skin or underlying tissues. Contaminated and dirty wounds occur in cases of accidental spillage of bowel contents and operating on a previously infected area, respectively. Current treatment involves heavy doses of intravenous antibiotics, and, if the infection is serious enough to cause necrosis (death of the surrounding tissue), surgeons will operate again and debride the dead tissue by cutting it away to allow the underlying healthy tissue a chance to grow.

On the bright side, most surgical patients do not get an infection. Current statistics show that 2 percent to 5 percent of surgical patients will be affected. That comes to around 500,000 cases per year. And among those who do become infected, a majority of surgical patients’ own immune systems are able to overcome the infection. Unless there's a major break in sterile procedure with a large number of contaminating organisms, the risk of infection is low. However, there are some patients who are more at risk. These patients have poor nutritional status, uncontrolled diabetes, are smokers, are obese or all of the above. Patients who have HIV or other states of poor immunity are also at risk.

The best thing a surgical patient can do to prevent infection is avoid known risk factors. Smokers should obviously quit for a multitude of reasons but should particularly try to cease smoking at least thirty days before having surgery. Nicotine constricts blood vessels and retards the healing process. Strict control of diabetes is encouraged all the time, but especially after an operation. A new study in the Archives of Surgery presents strong evidence of the danger of post-operative hyperglycemia. Ashar Ata, MBBS, MPH, from Albany Medical College writes “It has been well established that patients with diabetes mellitus are more prone to surgical and other nosocomial infections. ... We found postoperative hyperglycemia to be the most important risk factor for [surgical site infection] in general and colorectal cancer surgery patients, and serum glucose levels higher than 110 mg/dL were associated with increasingly higher rates of postsurgical infection.”

Another risk factor is the length of preoperative stay. The longer a patient spends in the hospital before a surgery is performed is directly related to an increased risk of a surgical site infection. And while obesity is something that can't be solved quickly before an operation, chalk the risk of surgical site infection up as one of the many other reasons patients should try to shed those extra pounds and maintain a healthy weight. Thicker layers of abdominal fat make wound healing more difficult, as well as making the surgery itself harder for the surgeon to perform in a sterile and precise manner.

Surgery can be a scary and sometimes risky procedure. But a little knowledge of how infections happen and how they can be prevented can go a long way in ensuring a speedy and healthy recovery.

Reviewed by: 
Review Date: 
October 5, 2010