In the United States, the Surgical Care Improvement Project (SCIP) was an initiative led by stakeholder organizations with the common goal of significantly reducing surgical morbidity and mortality. The original intent of SCIP was to improve hospital compliance with the use of prophylactic antibiotics for elective surgery and later extended to broader SSI prevention measures as well as other surgical harm. Hospital-level compliance is publically reported on the hospitalcompare.gov website and tied to value based purchasing. SCIP measures related to SSI prevention include:

Although level 1 evidence supports each measure, hospital compliance has failed to translate into reduced SSI rates [5–7]. As of January 1, 2015, in the United States, the SCIP measures are no longer part of the Medicare value based purchasing program.

Redosing of antimicrobial surgical prophylaxis during procedures is an important strategy to prevent surgical site infection (SSI). Intraoperative redosing is supported by clinical and pharmacological studies and recommended by the Therapeutic Guidelines on Antimicrobial Prophylaxis in Surgery—a consensus document developed by multiple specialty societies (http://​www.​ajhp.​org/​content/​70/​3/​195.​full.​pdf+html). The goal is to achieve and maintain adequate serum and tissue levels of the antimicrobial agent for the entire period during which the wound is open [8]. Antimicrobial agents need to be redosed if the procedure time exceeds two half-lives of the antimicrobial agents or if there is excessive blood loss (>1500 ml) [8–12]. Intraoperative redosing may also be warranted if factors such as extensive burns shorten the half-life of the antimicrobial agent. Intraoperative redosing may NOT be warranted if factors such as renal failure prolong the half-life of the antimicrobial agent. Recommended intraoperative redosing intervals (from the initiation of the preoperative dose) of some commonly utilized agents are:

Certain agents do not require intraoperative redosing (e.g., ertapenem, gentamicin [5 mg/kg], metronidazole) due to their pharmacokinetic properties.

Weight-based dosing of Cephalosporin preoperative antimicrobial prophylaxis for obese patients aims to achieve adequate serum and tissue levels to prevent SSI. This strategy is supported by clinical and pharmacological studies, recommended by the CDC in the HICPAC (Healthcare Infection Control Practices Advisory Committee) Guidelines for Prevention of Surgical Site Infection (2004) [8], and suggested in the latest version of the Therapeutic Guidelines on Antimicrobial Prophylaxis in Surgery. The preoperative antimicrobial prophylaxis dose of cefazolin should be increased from 1 to 2 g for patients with weight >80 kg and to 3 g for patients with weight >120 kg. Preoperative doses of 1 g cefazolin may not be sufficient to achieve serum and tissue concentrations greater than the MIC for common gram-negative and gram-positive pathogens [13, 14]. Whether to use ideal body weight or actual body weight for these dosing calculations remains to be determined. Doubling the normal dose of cephalosporins produces concentrations in obese patients similar to those achieved with normal doses in normal-weight patients [15]. For simplification, some hospitals have implemented a standardized preoperative prophylaxis dose of Cefazolin 2 g for all adult patients and 3 g for patients with weight >120 kg and administer Cefotetan and Cefoxitin antimicrobial prophylaxis (when indicated) at a dose of 2 g for all adult patients.

Careful skin preparation with the appropriate agent is a critical step for prevention of surgical site infections. The skin harbors approximately 10¹² bacteria. Common skin organisms include Staphylococcus spp., Streptococcus spp., Propionibacterium acnes, Corynebacterium spp., and Acinetobacter spp. The goal of a surgical skin preparation is to reduce the burden of skin microorganisms prior to incision [16]. The most commonly used preparations are chlorhexidine, povidone-iodine, and/or alcohol. To optimize efficacy, either chlorhexidine or povidone-iodine should be combined with alcohol solution because alcohol is the most effective strategy to reduce skin bacteria, but without another agent the effect is not durable. Commercially available combination preps include Chloraprep [2 % chlorhexidine gluconate and 70 % isopropyl alcohol] and DuraPrep [iodine povacrylex and isopropyl alcohol] [17]. A randomized controlled study of patients undergoing clean-contaminated procedures compared chloraprep and povidone-iodine scrub and paint. The chloraprep group had a lower overall, superficial and deep space infection rates but there was no difference in organ space infections (overall 9.5 % vs. 16.1 %) [18]. Recommendations for the use of alcohol-based skin preparations:

Preoperative bathing with chlorhexidine (CHG) 4 % to prevent SSI is becoming more common. CHG bathing preoperatively as compared to soap significantly reduces the microbiological burden of the skin, but it has been challenging to demonstrate an associated reduction in SSI. Studies from Hayek et al. (cluster randomized controlled trial) and Wihlborg et al. (randomized controlled trial) totaling 3500 patients reported reductions in SSI with chlorhexidine bathing [19, 20] while all other studies, totaling 6900 patients, found no decrease in SSI. Despite the lack of evidence, adoption of CHG bathing is widespread, likely because it is a simple intervention to implement and relatively low cost—between 1 and 12 dollars per patient depending on the formulation selected. Most protocols recommend bathing with CHG the night before and morning of surgery with either packages of CHG soap or impregnated washcloths. Alternatively, to improve compliance, some hospitals have advocated CHG use only prior to surgery with supervised application in the preoperative area of the operating room. Providers should consider using CHG bathing if they note an increase in a significant number of wound infections associated with skin bacteria such as Staphylococcus spp. or Streptococcus spp. as is commonly seen in cardiac and orthopedic surgery and in some instances in gastrointestinal surgery.

Hyperglycemia in hospitalized patients is common. In a survey of patients admitted to a community teaching hospital, hyperglycemia was present in 38 % of medical and surgical admissions (26 % had a known history of diabetes and 12 % had no preoperative history). In cardiac surgery, degree of postoperative hyperglycemia correlates with SSI [21, 22]. Although tight glucose control has not been studied with the same rigor in the general surgery patient, case series and analyses of state-wide surgical collaboratives have identified an association between hyperglycemia and postoperative complications. Diabetic patients undergoing colorectal surgery had a 15 % rate of SSI; on multivariate analysis, higher glucose levels were associated with increased risk of SSI. However, implementation of SSI prevention bundles including glucose control (<200 mg/dl (11.1 mmol/l) or <180 mg/dl (10 mmol/l)) has not demonstrated improvements in SSI [23–25]. A Cochrane review of the topic found that there was insufficient evidence to support perioperative strict glycemic control for SSI prevention [26]. Based on the draft version of the revised HICPAC guidelines, perioperative glycemic control should be aimed at maintaining glucose levels less than 200 mg/dl (<11.1 mmol/l) in diabetic and nondiabetic patients. To achieve this in the perioperative area, the Canadian program, Safer Health Care Now, recommends:

There are also several interventions included in Enhanced Recovery programs that aim to preserve perioperative insulin sensitivity, such as preoperative carbohydrate drinks and avoidance of prolonged fasting, afferent neural blockade, and early resumption of oral intake.

The use of oral antibiotics to decontaminate the colon was one of the earliest strategies to reduce infectious complications in colorectal surgery patients. For the past 20 years, much of the surgical infection research has focused on the role of preoperative intravenous antibiotics to reduce SSI rates and based on well-designed randomized studies this has become standard of care in the perioperative period and included as a SCIP measure. The combination of preoperative intravenous antibiotics combined with oral antibiotics with or without mechanical bowel has not been studied with the same rigor.

The use of oral antibiotics for colon surgery was first described in the 1940s. Small follow-up reports with different combinations of oral antibiotics (varying amounts of aerobic and anaerobic bacteria coverage) demonstrated that this treatment resulted in marked decontamination of the colon and decreased SSI. Washington et al. conducted the first randomized trial comparing oral neomycin/tetracycline plus mechanical bowel preparation with placebo plus mechanical bowel preparation and demonstrated decreased infectious complications in group receiving oral antibiotics (43 % placebo, 41 % neomycin, 5 % neomycin and tetracycline) [27]. Subsequent work by Nichols, Condon, and Clark popularized the use of neomycin and erythromycin with mechanical bowel preparation [28, 29]. These studies were criticized because intravenous antibiotics were not administered. In 2002, Lewis et al., conducted a randomized controlled trial comparing oral neomycin and metronidazole plus systemic antibiotics to systemic antibiotics alone (17 % placebo and 5 % neomycin and metronidazole) [30]. Oral antibiotics were associated with a decreased SSI rate and this finding was corroborated by a meta-analysis of 13 other trials demonstrating that oral antibiotic use was associated with decreased SSI. Most recently, evaluation of the Michigan Surgical Quality Collaborative (MSQC) data (NSQIP methodology) using a propensity matched analysis found that patients who received oral antibiotics and mechanical bowel preparation as compared to those receiving mechanical bowel preparation alone had a lower rate of superficial and organ space infections [31]. Similar results were found with analysis of the Veterans Affairs Hospital data. A recent Cochrane review of perioperative antibiotic prophylaxis found that use of preoperative oral antibiotics was associated with reduction in SSI [32].

Although there are still unanswered questions about the optimal use of oral antibiotics and mechanical bowel preparation, the evidence supports the addition of oral antibiotics when mechanical bowel preparation is used. The consensus guidelines endorsed by the American Society of Hospital Pharmacists support their use in colorectal surgery. Mechanical bowel preparation without oral antimicrobials does not reduce the risk of SSI. A Cochrane review from 2011 comparing mechanical bowel preparation to no bowel preparation found no difference in SSI rates in the two groups for open colon surgery; however these studies did not include oral antibiotics with the mechanical preparations. Nonetheless, guidelines from the ERAS Society state that mechanical bowel preparation should not be used routinely for colonic surgery. There is less data available for rectal surgery, laparoscopic surgery, or when a diverting ileostomy is planned (see Chap. 3).

Historical inquiry into surgical site infections has suggested that these infections occur during a “decisive period” intraoperatively when soft tissue is directly exposed to skin and enteric flora while the tissue is concurrently stressed [33]. Improving wound edge tissue oxygenation, maintaining euvolemia, and preventing intraoperative hypothermia are suggested to reduce the physiologic stress of surgery.