Patients are used to signing consent forms that identify infection as a routine risk of surgery. But they probably don’t grasp the scope of the problem: Each year, more than 40 million major operations are performed in U.S. hospitals, and 800,000 to 2 million patients develop surgical site infections.¹

An SSI is defined as “an infection related to the operative procedure that occurs at or near the surgical incision (incisional or organ/space) within 30 days of an operative procedure or within one year if an implant is left in place.¹ SSIs complicate the recovery of 2% to 5% of patients with clean extraabdominal surgeries (e.g., thoracic and orthopedic surgeries) and of up to 20% of patients with intraabdominal procedures. SSIs account for nearly 40% of all hospital-associated infections among surgical patients and are the second most commonly reported hospital-associated infections, making up 22% of all such infections.^2,3 Patients with an SSI have longer hospital stays (seven to 10 days), increased costs, and higher morbidity. They are 60% more likely to spend time in ICUs, five times more likely to be readmitted to the hospital, and twice as likely to die as other postoperative patients.⁴ When surgical patients die, 75% of the deaths are attributable to a surgical wound infection.¹ SSIs also contribute significantly to U.S. healthcare expenses, costing an estimated $130 million to $845 million each year.²

25% by 2010

These shockingly high numbers have raised concerns about patient safety and have led a number of national organizations to work together with the goal of reducing surgical complications by 25% by 2010.⁵ A partnership that includes the Centers for Medicare and Medicaid Services (CMS), The Joint Commission, the Centers for Disease Control and Prevention (CDC), the American College of Surgeons, and the American Hospital Association has developed performance measures as part of the Surgical Care Improvement Project (SCIP) to reduce the morbidity and mortality associated with postop SSIs.⁵ As an added incentive for preventing SSIs, beginning in October 2008, the CMS will no longer pay hospitals the extra costs of treating patients with some of the hospital-associated infections that reasonably could be prevented by following evidence-based guidelines. When this happens, private insurers will probably follow Medicare’s lead in withholding payments.^5,6

Monetary penalties may be what’s needed to ensure that every hospital follows the SCIP initiatives for reducing SSIs. Nearly 10 years ago, the CDC issued guidelines for the prevention of SSIs. These were followed by guidelines from the Surgical Infection Prevention project in 2002 and then by the SCIP performance measures in 2005. Yet despite evidence showing the effectiveness of the guidelines, many providers ignore them. As an illustration, a recent survey of 1,256 U.S. hospitals found that only 32% were in full adherence with recommended measures to prevent SSIs.⁷ This module will provide nurses the latest information about four of the SCIP performance measures to reduce SSIs:

1. The prevention of infection through proper selection, timing, and administration of antimicrobial prophylaxis
2. The control of blood glucose postoperatively in cardiac surgery patients to 200 md/dL or less
3. Proper hair removal
4. Maintenance of the patient’s body temperature between 36 C and 38 C within one hour of leaving the OR

By following these recommendations, an estimated 40% to 60% of SSIs can be prevented.² 

Inevitable contamination

SSIs occur despite the best surgical techniques, the thoroughness of skin disinfection, and the OR staff’s preventive strategies. At the time of incision, every surgical site becomes contaminated with bacteria inward from the skin or outward from the internal organ being operated on.³ Most contamination is due to the patient’s endogenous flora present at the surgical site on the skin, on mucosal membranes, or in the hollow viscera. Other contamination can come from exogenous sources, such as the OR staff and environment, including the air and surgical instruments.⁸ But for most patients, bacteria in a wound does not result in infection. Usually, innate host defenses can eliminate the contaminating organisms.^9-11

When SSIs do develop, among the most important contributing factors are the amount of bacteria inoculated into the wound, virulence of bacteria, and local blood flow — the delivery of oxygen, inflammatory cells, cytokines, and nutritional components to the surgical site. Also important are the administration of antibiotics and the adequacy of host immune defenses — innate or acquired. Patient-related risk factors also influence the development of SSIs, including advanced age, obesity, diabetes, malnutrition, poor tissue perfusion, the use of steroids or other immunosuppressant drugs, a preoperative stay in a hospital (more than four days), colonization with Staphylococcus aureus, or remote infection at the time of surgery.^9-11

Obviously, however, the amount of bacteria in the wound at the end of surgery is the major determinant of SSIs. Over 40 years ago, a clinical estimate of the amount of bacteria likely to be encountered in the operative site during surgery was used to develop a surgical wound classification system. Four classes of surgical procedures were identified: clean, clean-contaminated, contaminated, and dirty — each with a distinctive infection rate:^11,12

• Clean procedures: an uninfected operative wound without inflammation; respiratory, GI, biliary, or genitourinary tracts not entered; 1% to 2% infection rate without prophylactic antibiotics.
• Clean-contaminated procedures: operative wounds in which respiratory, gastrointestinal, bilary, and genitourinary tract are entered under controlled conditions with minimal spillage and no encounter with infected urine or bile; 6% to 9% infection rate without prophylactic antibiotics.
• Contaminated procedures: open, fresh, accidental wounds and surgeries with major breaks in sterile technique (e.g., open cardiac massage) or gross spillage from the GI tract; also includes incisions in which acute, nonpurulent inflammation is encountered; 13% to 20% infection rate without prophylactic antibiotics.
• Dirty/infected procedures: purulent inflammation present. Includes old traumatic wounds with retained dead tissues and those that involve existing clinical infection or perforated viscera; about 40% infection rate without prophylactic antibiotics

Surgical risk was further defined by three additional risk factors that played a significant role in wound infections: an operation lasting more than two hours, one involving the abdomen, or one performed on a patient having three or more underlying diagnoses (indicative of the patient’s clinical status). The addition of these three factors to the wound classification system made predicting the risk of a wound infection twice as helpful as the traditional wound classification alone.^9,11

Developing a way to calculate the risks of infection for different surgeries was easier than finding ways to prevent infection. With the introduction of antibiotics in the 1950s, many thought treating wound infections with antibiotics after surgery might be the answer. However, the hoped-for reduction in infections did not occur. Since then, it has taken hundreds of clinical trials to understand the most effective and appropriate methods of using antibiotics to prevent SSIs.

Knowledge vs. practice

The efficacy of antibiotics against SSIs was established in the 1960s, when studies determined they were most effective in preventing wound infections when given before the inoculation of bacteria into the wound and  ineffective if given three hours after inoculation.^9,10 Studies also confirmed that giving antibiotics for more than 24 hours after wound closure offered no additional benefits.⁵ Although this important information resulted in good evidence-based guidelines, physicians have continued to use and time antibiotics inappropriately in 25% to 50% of operations in U.S. hospitals.²

Surgical errors, hospital-acquired infections, medication errors, and adverse drug events are common in U.S. hospitals. According to the Institute for Healthcare Improvement (IHI), 15 million incidents of medical harm occur each year in the U.S. — more than 40,000 incidents per day. Clearly, major opportunities exist to save lives and lessen the chances for medical harm. The IHI urges all hospitals to reduce surgical complications by adopting the SCIP recommendations.¹³ Surgeons, nurses, anesthesiologists, infection control practitioners, pharmacists, and hospital administrators can work together to improve patient safety by providing care consistent with medical evidence and clinical practice guidelines. The following SCIP performance measures can serve as a framework to monitor progress in improving surgical patient safety:

SCIP — Inf 1: Prophylactic antibiotic received within one hour prior to surgical incision or within two hours before incision if vancomycin (Vanocin) or a fluoroquinolone (Ciprofloxacin) is required for prophylaxis

Improving the timing of antibiotic administration is a crucial first step in preventing SSIs. Antibiotics should be given as close to the time of incision as clinically practical and no more than 60 minutes prior to surgery unless the use of a fluoroquinolone or vancomycin is indicated.⁸

When a surgical incision disrupts tissue integrity, an inflammatory exudate (neutrophils, macrophage, blood cells, coagulation cascade proteins, and fibrin strands) begins filling the space around the wound, embedding the contaminating bacteria in a fibrin clot matrix. To be able to penetrate the fibrin clot matrix, the antibiotic must be present at the time of fibrin formation. To ensure a therapeutic level of antibiotic at the time of incision and during the surgical procedure, the patient should receive the antibiotic just before incision time.

After an incision is closed, antibiotics have no appreciable effect on preventing infections.⁴ In addition, after the wound is closed, the increased hydrostatic pressure secondary to edema formation makes it difficult for antibiotics to gain access to the area around the wound space.¹²

Hospitals need standard protocols to ensure that prophylactic antibiotics are delivered no more than one hour before the surgical incision is made. Patients should receive antibiotics when they reach the preop area or the OR rather than “on-call.” With “on-call” dosing, case delays can result in patients’ not receiving preoperative doses within the recommended time frame. 

SCIP — Inf 2: Prophylactic antibiotic selection for surgical patients

Surgical patients should receive prophylactic antibiotics in accord with current published guidelines for each type of procedure.² For most surgeries, cephalosporins are the drugs of choice, and first or second-generation cephalosporins, such as cefazolin (Ancef, Kefzol) or cefoxitin (Mefoxin) for colon surgeries, are ideally suited for prophylaxis. Cephalosporins have a broad spectrum of activity against both Gram-positive and Gram-negative bacteria and a wide ratio of therapeutic to toxic dosages. Cephalosporins are also inexpensive and easy to administer, and allergic reactions are rare.^1,9 

To ensure that appropriate antibiotics are used for prophylaxis, hospitals should follow recommendations from the American Society of Health-System Pharmacists, Infectious Diseases Society of America, Medical Letter, Sanford Guide to Antimicrobial Therapy, or Surgical Infection Society.⁵ Hospitals with epidemiologists on staff should consult with them for recommendations on endemic pathogens and antimicrobial prophylaxsis.

Vancomycin should not routinely be used for surgical procedures.¹ But sometimes it may be the best choice for prophylaxis. For example, vancomycin may be used when a patient has a documented beta-lactam allergy, is colonized with methicillin-resistant S. aureus (MRSA), is at high risk for MRSA because of an acute inpatient hospitalization or nursing home stay within a year prior to admission, has an inpatient stay of over 24 hours before the surgery, or is in a facility with a high rate of MRSA infections.⁴ The number of patients with MRSA has increased significantly in U.S. hospitals, rising from fewer than 2,000 in 1993 to 368,800 in 2005 (the latest  data available).¹⁴

SCIP — Inf 3:  Prophylactic antibiotics discontinued within 24 hours after surgery end time

Discontinuing prophylactic antibiotics within 24 hours after surgery (except cardiothoracic surgery, when 48 hours is appropriate) is recommended. Evidence shows that continuing antibiotic prophylaxis beyond 24 hours after the incision is closed offers no additional benefits. In fact, prolonged use of antibiotics can lead to infection with Clostridium difficile and the emergence of antibiotic-resistant organisms.^5,9 Clinicians can use protocols and standard order sets to ensure that antibiotics are stopped after 24 hours.

SCIP — Inf 4:  Cardiac surgery patients with controlled 6 AM postoperative serum glucose

Surgical patients with a preop blood glucose level of 200 mg/dL or more have a greater risk of SSI. Hyperglycemia results in impaired host defenses by impairing polymorphonuclear leukocyte functions, including adherence, chemotaxis, phagocytosis, and bactericidal activity. In a study of cardiothoracic patients, hyperglycemia was associated with a 102% increase in the risk for wound infection.¹¹ Additionally, patients with diabetes undergoing cardiac surgery have a two to three times greater risk of infection than patients without diabetes. Hyperglycemia is also risky for noncardiac surgery patients. It appears that the risk of infection increases fourfold if the patient becomes hyperglycemic at any time on the first postop day.³ The risk of surgical wound infections can be reduced by using insulin therapy to maintain tight blood glucose concentrations between 80 mg/dL and 110 mg/dL.¹¹ While this performance measure is limited to cardiac surgery, maintaining blood glucose levels less than 200 mg/dL is key for other postop patients, as well.

Hospitals should have a standardized glucose management protocol for all patients undergoing surgery.

SCIP — Inf 6: Appropriate hair removal

The nicks and scrapes from preop shaving are linked to an increased risk of SSIs from skin-associated bacteria. Even with conscientious skin preparation, up to 20% of skin-associated bacteria remain on the skin beneath the surface in hair follicles and sebaceous glands. Shaving allows these bacteria to penetrate the microscopic cuts in the skin.^8,11 To reduce SSIs, current practice recommends no hair removal, or if hair removal is necessary, removal in the immediate preop period with electric clippers and a disposable, single-patient-use cutting head. Razors should be removed from OR supply carts and surgical prep kits so they are not used on patients. RNs should educate patients not to shave operative sites before surgery.^1,5,10

SCIP — Inf 7: Colorectal surgery patients with immediate postoperative normothermia (36 C to 38 C) within the first hour after leaving the OR

Hypothermia (a core body temperature less than 36 C) almost always occurs in unwarmed patients during surgery. It develops from exposure to the relatively cool OR environment and the effects of anesthesia. General or major regional anesthesia impairs the body’s normal thermoregulation and causes a shift of heat from the body’s core to its periphery. In the first hour after induction, the core temperature drops by 1.0 C to 1.5 C. It drops another 1.1 C during the subsequent two to three hours of anesthesia time, reaching a plateau at about 34 C. As the body becomes hypothermic, vasoconstriction reduces the perfusion of subcutaneous tissue. This reduces the oxygen supply to the wound and impairs immune function, including T-cell mediated antibody production and the oxidative killing of pathogenic bacteria by neutrophils. As an illustration, in colon resection patients, a 1.9 C. drop in core temperature (core temperature of 34.7 C) triples the incidence of surgical wound infections and increases the length of stay by a week or longer.¹⁰ Mild hypothermia also increases time in the hospital for uninfected patients.

Although this performance measure applies to colorectal surgery, clinicians should make sure all patients maintain temperatures as close to 37 C as possible when they undergo surgery. This is done by keeping the OR warm and by using preoperative and intraoperative measures to warm the patient, such as warmed IV fluids.

Although some surgical complications are unavoidable, they can be significantly reduced and patient safety improved by following the SCIP performance measures and other evidence-based practice recommendations. Nurses, working with surgeons, infection control practitioners, and pharmacists, have a responsibility to follow these recommendations to make sure that patients receive the safest surgical care possible.

Note: More information is available on SCIP at www.medqic.org/scip.>