How to reduce surgical site infections

Factors that place patients at SSI risk encompass a variety of causes, from preexisting conditions to patient characteristics.

Abort surgery if a pre-existing skin infection is present near the surgical site. Photo courtesy Phil Zeltzman
Abort surgery if a pre-existing skin infection is present near the surgical site.
Photo courtesy Phil Zeltzman

Considering the emergence of resistant bacteria, having a solid plan to decrease infection risk becomes increasingly important. A surgical site infection (SSI) is defined by the Centers for Disease Control and Prevention as an infection occurring at the surgical site within 30 days following a procedure, or within one year of placing an implant. You can significantly decrease risk in your practice by scrutinizing four factors that contribute to SSI incidence: patients, environmental and human factors, and miscellaneous risks.

Patient factors

Factors that place patients at SSI risk encompass a variety of causes, from preexisting conditions to patient characteristics.

Preexisting conditions include obesity, poor nutrition, and recent surgery.

Further, skin infection is a risk factor when the surgical incision is involved. If you notice an infection after clipping, you need to have the honesty and the guts to abort surgery rather than risk serious complications. TPLO and total hip surgeons occasionally are confronted with this frustrating decision. Even if you perform simpler procedures, you must hold yourself to the same ethical standards.

Patient characteristics include young age, old age, poor hygiene, and radiotherapy treatment near the surgical area. Other potential factors include diabetes, Cushing’s disease, hypoxia, ascites, and postoperative anemia.

Improper protection of the incision postop also can lead to infection. An Elizabethan collar or equivalent should always be used to prevent licking or chewing at the incision site. Dogs with allergies tend to lick their incisions more often, thereby increasing the risk of dehiscence and/or infection.

Environmental factors

Countless environmental factors can contribute to SSIs, but in theory, they may be easier to control than patient and human factors.

Contaminated multi-use  vials for medication along with contaminated injection ports may lead to an infection. It is important to swipe ports with alcohol—every single time.

Indeed, inadequate disinfection and sterilization of surgical equipment could easily cause an infection in a patient. Proper cleaning and sterilization of all surgical equipment is neccessary in order to ensure a successful surgery.

Paper and plastic pouches are easy to tear. Treat them with care and respect every time you handle them. (Hint: Throwing pouches around is not OK.) Remember to thoroughly inspect pouches for tiny holes or tears before opening them.

Ideally, always double-wrap sharp instruments in surgical-grade paper or cloth drapes (not in pouches). Don’t use pieces of curtains, blue hand towels, and other creative sources of cloth to wrap surgical equipment.

Improper preparation of the surgical site can result in a higher SSI incidence. Never perform clipping prior to the day of surgery. Ideally, shave the patient only after induction of anesthesia and immediately before surgery. Careful shaving can help lower SSI risk, as microtrauma caused by clippers can give opportunistic bacteria a place to grow.

After shaving, vacuum the hair, clean grossly soiled areas, and only then scrub aseptically to prep the patient. A patient’s own flora automatically becomes a suspect when a postsurgical infection arises.

Cover patients with a single-use, nonwoven, surgical-grade paper drape rather than a reusable cloth drape to reduce the risk of bacterial translocation. Such drapes provide a more effective barrier against fluids. Reusable cloth drapes typically are not changed often enough. Multiple washing cycles, holes created by towel clamps, and other physical insults make them less than ideal.

The operating room itself can increase SSI occurrence, depending on its setup and management. Clipping a patient inside the OR is less than ideal. Further, a poorly ventilated room can contribute to a higher number of postsurgical infections.

Human factors

Human error also can increase the chances of a patient developing a postop infection. Ensure surgical team members are reducing their contribution to SSI risk with proper antiseptic preparation of the hands and forearms. Every member of the team should wear caps, masks, and disposable (or well-maintained cloth) gowns.

Routinely check surgical gloves for perforations, especially during orthopedic surgery. Consider changing them regularly during long procedures to reduce the chance of a tear.

During surgery, handle tissue gently, maintain proper hemostasis, and minimize dead space. Remove foreign material and compromised or charred tissue, as both can impair the wound’s ability to resist infection.

Limit the number of people in the OR and minimize in-and-out traffic in order to help decrease the airflow of microbial organisms. Studies show that SSI risk increases 1.3 times for each additional person present.

Miscellaneous factors

Many other factors must be remembered to reduce SSI risk (Nelson, Vet Clinics, 2011).

Emergency procedures and prolonged hospitalization increase the potential for infection.

Duration of anesthesia and surgery impair a patient’s immune response. Each additional hour under anesthesia raises the risk of infection by 30 percent (Beal, Vet Surgery, 2000). The time under anesthesia can be much longer than the duration of surgery when you add the time it takes to place an IV catheter, clip hair, take radiographs, position the patient on the surgery table, scrub the skin, and patiently wait for the surgeon.

Long surgeries also can lead to hypothermia, which has shown an increased SSI correlation.

Proper patient oxygenation can help lower postop infection risk.

If a surgical drain must be placed, a closed or active system is ideal, with the drain placed through a separate incision. Always remove drains as soon as possible.

Poorly cleaned endotracheal tubes can carry serious respiratory pathogens, such as Streptococcus zooepidemicus and Bordetella bronchiseptic. Chlorhexidine was shown to work best to clean these tubes (Crawford et al, JAVMA, 2015). After cleaning, rinse them thoroughly to avoid mucosal irritation, especially in cats.

Depending on surgery type, wound condition, and overall patient health, prophylactic antibiotics may be an extra step toward preventing infection. A poorly chosen antibiotic protocol can increase bacterial resistance or worsen a patient’s SSI risk.

Dental cleaning performed in addition to a surgery leads to bacteremia, which can lead to surgical site infection. This is why some colleagues give antibiotics before a dental procedure. Ironically, bacteria may be protected by a biofilm. It may be wiser to avoid doubling up on procedures, especially if the surgeon uses an implant. Clearly, this is a delicate and controversial topic.

The day you decide to improve your protocols (Weese, VCOT, 2008) and simplify your life by improving factors for SSI risk, your patients and clients will thank you.

Dr. Phil Zeltzman is a board-certified veterinary surgeon and author. His traveling surgery practice takes him all over Eastern Pennsylvania and Western New Jersey. Visit his websites at and Kat Christman, a certified veterinary technician in Effort, Pa., contributed to this article.

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