Abstract
Abstract
Background:
Surgical site infection (SSI) is unequivocally morbid and costly. The estimated 300,000 SSIs annually in the United States represent the second most common infection among surgical patients, prolong hospitalization by 7–10 days, and have an estimated annual incremental cost of $1 billion. The mortality rate associated with SSI is 3%, with about three quarters of deaths being attributable directly to the infection. Prevention is possible for the most part, and concerted effort has been made to limit these infections, arguably to little effect.
Methods:
Review of pertinent English-language literature.
Results:
Numerous risk factors for SSI and tactics for prevention have been described, but efforts to bundle these tactics into an effective, comprehensive prevention program have been disappointing. Numerous studies now demonstrate that the Surgical Care Improvement Program (SCIP), which focused on process improvement rather than outcomes, has been ineffective despite governmental support, financial penalties for non-compliance, and consequent widespread implementation.
Conclusion:
Required reporting has increased awareness of the problem of SSI, but just as the complexity of SSI risk, pathogenesis, and preventions reflects the complexity of the disease, many other factors must be taken into account, including the skill and knowledge of the surgical team and promulgation of a culture of quality and safety in surgical patient care.
Pathogenesis of SSI
Both endogenous and exogenous sources contribute to the development of SSI. Endogenous sources include the patient skin flora or organisms colonizing the mucous membranes or the gastrointestinal tract, depending on the procedure being performed. Seeding from a distant focus of infection also occurs. Exogenous sources include soiled attire of the surgical team, breaks in aseptic technique, or inadequate hand hygiene. Poor management of the operating room physical environment, including air handling, as well as inadequate sterilization of equipment and materials brought into the operative field are other exogenous sources contributing to SSI. In addition to the direct exposure to bacterial sources, several risk factors have been associated with a higher risk of SSI, including obesity, advanced age, diabetes mellitus, malnutrition, smoking, immunosuppressive medications, inappropriate antibiotic use, poor peri-operative temperature control, inadequate post-operative glycemic control [3], intra-operative blood transfusion [4], and protracted surgery [5]. These and several other risk factors have been enumerated recently and succinctly by Fry [6].
Approaches to Prevention
Several prevention tactics have been reported to decrease SSIs. These tactics are divided into core interventions, which are supported by high-quality evidence, are highly feasible, and can be implemented readily, and supplemental strategies, which are supported by less scientific evidence and have various degrees of feasibility. The majority of these approaches are reported with recommendations and supporting evidence in the Hospital Infection Control Practices Advisory Committee guidelines by Mangram et al. [7], which are slated to be updated later in 2012.
The core interventions are:
1. Timely administration of appropriate antimicrobial prophylaxis within 1 h of surgery, followed by timely discontinuation of the antibiotic within 24 h; 2. Identification of any remote infections whenever possible, and treatment of that infection to resolution prior to proceeding with elective surgery; 3. No removal of hair at the operative site unless necessary, and if necessary, use of hair clipping rather than shaving with a razor; 4. Use of appropriate antiseptic agents and techniques for skin preparation; 5. Maintenance of immediate post-operative normothermia; 6. Minimizing operating room traffic by keeping the doors closed during surgery, except as needed for passage of equipment and personnel; 7. Protection of primary closure incisions with a sterile dressing for 24–48 h post-operatively; 8. Control of blood glucose <200 mg/dL during the immediate post-operative period (for cardiac patients); and 9. Mechanical preparation of the colon and administration of non-absorbable oral antimicrobial agents for colorectal surgery [5,7–9].
Supplemental preventive tactics include:
1. Nasal screening and decolonization of Staphylococcus aureus carriers with pre-operative topical mupirocin treatment of the nares [10,11]; 2. Redosing of antibiotics at the 3-h intervals in procedures with a duration >3 h, depending on the antibiotic and its half-life [12]; 3. Adjusting antimicrobial prophylaxis dose for obese patients (body mass index >30 mg/kg) [12–14]; and 4. Use of at least 50% fraction of inspired oxygen intra-operatively and immediately post-operatively [15–17]).
From “SIP” to “SCIP”
Following the published guidelines by Mangram et al. for the prevention of SSI [7] and the inconsistent implementation by hospitals of those proved measures, the Centers for Medicare and Medicaid Services (CMS) collaborated with the U.S. Centers for Disease Control and Prevention (CDC) on the Surgical Infection Prevention Project (SIP) with the goals of standardizing quality improvement measures that could be applied nationally, with better compliance, in an effort to decrease SSIs. Initial reports after implementation of this initiative demonstrated significant reductions in the rates of SSI [18]. However, baseline results from the SIP project demonstrated that compliance with the recommendations of prophylactic antibiotics within 1 h before surgery, an antibiotic selected in accordance with current guidelines, and timely discontinuation of the antibiotic within 24 h after surgery was unsatisfactory, with only 28% of patients having all three measures completed correctly [12].
In 2006, the SIP transitioned to the Surgical Care Improvement Project (SCIP), created through a national quality partnership of 10 professional organizations interested in reducing preventable surgical complications by 25% by 2010 [19]. Of the several SCIP performance measures, seven apply to the peri-operative period (Table 1), each of which is supported by good evidence [8]. To increase the incentive for compliance, CMS has required reporting by hospitals if they are to receive full Medicare payment. Hospitals not reporting will receive 2% less [20]. Specifically for SSI, CMS mandated reporting of compliance starting January 1, 2012 [21].
Adherence to SCIP and SSI
Institution level
Institution-level reports of compliance with the SCIP guidelines, especially INF-1 through INF-3, normoglycemia, and INF-10, have demonstrated a significant reduction of SSI in colorectal surgery patients. Hedrick et al. reported a decrease in the SSI rate in colorectal surgery patients, from 25.6% pre-implementation of a peri-operative protocol to 15.9% post-implementation, as a result of better compliance with the three prophylactic antibiotic measures, as well as attention to normothermia and normoglycemia [22]. Similarly, Nguyen et al. reported a significant decrease in the SSI rate, from 21.7% to 3.4%, but the only significant association was with the improvement in the timely administration of the antibiotic prophylaxis [23]. In another study by Hedrick et al., prospective analysis of SSI rates in patients undergoing intra-abdominal operations demonstrated a trend toward a lower rate after improvement in compliance with the prophylactic antibiotic measures, as well as attention to normothermia and normoglycemia in diabetic patients. A significant decrease was demonstrated in the subset of patients who underwent laparotomy, upper gastrointestinal, hepatobiliary, and colorectal operations [24]. Berenguer et al. also demonstrated that after a significant increase in compliance with the SCIP guidelines, from 38% to 92%, there was a significant reduction in the superficial incisional infection rate, from 13.3% to 8.3%, in colorectal surgery patients. It is noteworthy that these results were achieved during their first two years of participation in the National Surgical Quality Improvement Program (NSQIP), raising the possibility that factors besides adherence to SCIP contributed to the decline in SSI rate [25].
National level
The question of whether adherence to SCIP measures decreases SSI rates across multiple hospitals was addressed recently in three published studies. Stulberg et al. investigated the SSI rates from 400 SCIP-reporting hospitals representing nearly 405,000 patients [26]. The investigators looked at two composite measures, the S-INF and the S-INF-Core. Both of these are “all-or-none.” In the S-INF analysis, all patients with at least two of the SCIP INF-1 through INF-7 measures demonstrated a decrease in the SSI rate from 14.2 to 6.8/1,000 discharges (adjusted odds ratio [AOR] 0.85; 95% confidence interval [CI] 0.76-0.95). In the S-INF-Core analysis, all patients with the first three SCIP infection measures (INF-1 through INF-3) demonstrated a change in the SSI rate from 11.5 to 5.3/1,000 discharges (AOR 0.86; CI 0.74-1.01). In addition, reported adherence to individual SCIP measures was not associated with a decrease in the SSI [26].
Hawn et al. studied the SCIP INF-1 measure in 9,000 patients to determine if incorrect timing of antibiotics impacted SSI [27]. Incorrect timing of antibiotics produced no difference in the SSI rate (5.8% vs. 4.6%; OR 1.29; 95% CI 0.99-1.67) compared with timely antibiotic prophylaxis. The study highlighted the fact that although compliance with administration of an antibiotic within 60 min, giving the antibiotic at 59 min prior to incision (meeting the measure) versus 61 min (failing the measure), may in fact have no clinical impact on SSI [27]. Attention to achieving the proper antibiotic concentration prior to incision may be more important than meeting the 1-h time frame of the measure.
In another study by Hawn et al., national Veterans Affairs (VA) Medical Center data from 2005 to 2009 (60,853 operations at 112 VA hospitals) on adherence to five SCIP measures (INF-1, 2, 3, 6, and 10) were linked to Veterans Affairs Surgical Quality Improvement Project (VASQIP) SSI outcome data [28]. The effect of SCIP adherence and year of surgery on SSIs was evaluated, as well as hospital correlations of SCIP adherence and SSI rates. Although SCIP adherence improved substantially for all measures over the study period, none of the five SCIP measures was associated significantly with lower adjusted odds for SSI. In addition, hospital SCIP performance did not correlate with the SSI rate. This study demonstrated that SCIP measures were not linked tightly to the occurrence of an SSI at the patient level, and did not impact hospital SSI rates [28].
The results by Stulberg et al. and Hawn et al., which found no relation between SCIP adherence and outcomes, highlight the fact that public reporting of SCIP adherence to process measures as a surrogate for a given hospital's quality of care and outcomes may be invalid [29–31]. In fact, it may lead patients to select the wrong institution for their care.
Where Do We Stand with SCIP?
Whereas there is some evidence that compliance with the SCIP measures decreases SSIs, this has not been corroborated by large-scale national studies. In view of these recent reports, should the SCIP measures be ignored, or, more realistically, should the required reporting be discontinued? [29]. It is relevant that these analyses depend on self-reported rates of compliance. The increasing pressure from payors such as CMS, which link reporting with reimbursement, have placed more emphasis on collecting the required data than on identifying or addressing true quality improvement measures that would contribute meaningfully to the lower SSI rates that have been reported at the institutional level. Studies of self-reported compliance rates, even at the institutional level, have demonstrated that actual compliance with mandated measures is discordant with what is “checked” on a data sheet and reported.
The required reporting has raised awareness of some of the evidence-based practices that impact SSI, but the required SCIP measures are by no means all-inclusive of what can be done for SSI prevention. In fact, they are just a start. Postoperative complications such as SSIs are influenced by many factors independent of SCIP measures [26,32]. These include the skill and knowledge of the surgical team, a clean working environment, and an overall culture of safety and quality [26,33]. The emphasis placed on collecting the required data for reporting could be used to augment SCIP with more meaningful measures, which may accomplish the desired goal, namely, fewer SSIs [34].
Further work needs to be performed on defining “metrics that matter.” Rather than focus on a single risk-reduction strategy, future efforts to improve surgical outcomes should embrace a multi-faceted strategy based on the best available evidence that can be tailored to the patient populations at risk for SSI. The challenge that lies ahead will be in developing pertinent metrics that focus on outcomes rather than mundane adherence reporting.
Footnotes
Author Disclosure Statement
No competing financial interests exist.