Intrawound vancomycin application after spinal surgery: a propensity score-matched cohort analysis.

OBJECTIVE: Surgical site infection (SSI) following spine surgery is associated with increased morbidity and healthcare costs. In an effort to reduce SSI rates, the application of intrawound vancomycin powder has gained popularity. However, there is limited high-quality evidence to support the safety and efficacy of this practice. The authors sought to determine if intrawound application of vancomycin powder improves 90-day overall SSI rates. METHODS: The authors performed a retrospective, vancomycin exposure-matched cohort study at a single tertiary care hospital over 21 months. They included all patients undergoing elective spinal surgery and stratified the patients into two groups: those who received intrawound vancomycin powder application and those who received no application of vancomycin powder. The primary outcome of interest was the 90-day overall SSI rate. Secondary outcomes included rates of superficial SSI, deep SSI, wound disruption, and a post hoc analysis of the microbiology and minimum inhibitory concentrations. Baseline patient demographics, clinical presentation, comorbidities, perioperative factors, and 90-day postoperative outcomes were manually abstracted from patient charts. To mitigate bias, we performed 1:1 matching after calculating propensity scores and identified 1 patient from the no-vancomycin cohort for each patient in the vancomycin cohort. RESULTS: A total of 997 patients met our inclusion criteria (473 patients receiving vancomycin and 524 patients not receiving vancomycin). Propensity score matching produced 221 matched pairs. Risk-adjusted analysis demonstrated similar overall SSI rates between the groups (OR 1.9, p = 0.329). On unadjusted analysis, the overall 90-day SSI rate was greater in the vancomycin group (n = 10 [4.5%]) than in the no-vancomycin group (n = 5 [2.3%]) (p < 0.001), as were the superficial SSI rate (7 [3.2%] vs 4 [1.8%], p < 0.001), deep SSI rate (3 [1.4%] vs 1 [0.5%], p < 0.001), and wound disruption rate (5 [2.3%] vs 1 [0.5%], p < 0.001). No cultured isolate demonstrated vancomycin resistance. CONCLUSIONS: The authors observed no difference in SSI rates after the intrawound application of vancomycin powder during spine surgery. Vancomycin use did not contribute to antimicrobial resistance; however, it may select out gram-negative bacteria and increase rates of wound disruption.

Electronically Triggered Sepsis Alert in Non-Intensive Care Inpatients Using Modified Systemic Inflammatory Response Syndrome Criteria: A Retrospective Observational Study with In-Depth Analysis of Surgical Patients.

Background: Our center initiated an electronic Sepsis Best Practice Alert (sBPA) protocol to aid in early sepsis detection and treatment. However, surgery alters peri-operative physiology, which may trigger an sBPA for noninfectious causes. This study aimed to provide early evaluation of automated sBPA utility in surgical patients. Methods: This study was a retrospective review of the outcomes of patients admitted to the University of Minnesota Medical Center (but not to the intensive care unit) from August 2015-March 2016 and compared how the sBPA performed in those having and not having surgery. An sBPA prompted nursing to draw blood for an immediate lactate assay if two modified systemic inflammatory response syndrome (mSIRS) criteria or three mSIRS criteria within 24 hours after surgery were met. Physicians were notified if the lactate concentration was >2 mmol/L. Further review was performed of data collected prospectively on the surgical patients. Results: A total of 10,335 patients were admitted (2,158 surgery and 8,177 non-surgery). Of these, 33% of the surgery patients and 35% of the patients not having surgery triggered sBPAs. In surgery patients, 13% of lactate concentrations were >2 mmol/L versus 25% in patients not having surgery. An sBPA was triggered more frequently after procedures with a wound class of 4 (5% vs. 2%), emergency operation (23% vs. 10%), and longer operations (280 min vs. 222 min (p < 0.05 for all). Surgery patients triggering sBPAs had longer hospital stays (9.6 vs. 4.4 days; p < 0.05), more surgical site infections (7% vs. 2%; p < 0.05), and a similar mortality rate (3% vs. 4%; p = 0.15) than those who did not trigger an sBPA. Conclusion: An sBPA fired in a third of all inpatients, and an sBPA that prompted lactate measurements was less likely to be abnormal in surgery patients than in those not having surgery. There was no difference in the mortality rate in surgical patients who fired and those who did not; however, the sBPA did identify patients with a more complicated post-operative course. Further refinements of the electronic trigger should increase BPA specificity.

Single-setting endoscopic retrograde cholangiopancreatography (ERCP) and cholecystectomy improve the rate of surgical site infection.

INTRODUCTION: Cholecystectomy is a common surgical procedure. The presence of common bile duct stones complicates treatment, often requiring a second procedure for stone retrieval. For such patients, endoscopic retrograde cholangiopancreatography (ERCP) provides adequate therapy, and can be performed before, after, or at the same time as cholecystectomy. In 2013, duodenoscopes were implicated by the Centers for Disease Control and Prevention in transmission of carbapenem-resistant Enterobacteriaceae. In this study, we sought to determine if the addition of ERCP to cholecystectomy was associated with higher rates of surgical site infections and microbial resistance. HYPOTHESIS: Adding ERCP to cholecystectomy increases the SSI rate. METHODS: For this retrospective review, we used the SSI surveillance database at our tertiary-care academic hospital. Cholecystectomy cases between 2010 and 2015 were included in the analysis. SSI was diagnosed using criteria of CDC's National Healthcare Safety Network (NHSN). We applied a logistic regression model to our data (SAS Studio software, v3.4, Enterprise Edition). RESULTS: Our 6-year study period included 2201 cholecystectomies. The SSI rate was 4.1 times higher for patients who underwent open cholecystectomy as compared with laparoscopic cholecystectomy (95% CI 1.61-10.24). When adjusted for wound class and procedure type, the SSI rate was significantly higher for patients who underwent ERCP within 60 days before cholecystectomy (P = 0.04; OR 2.2; CI 1.04-4.49). Rates of resistant pathogens were significantly higher in patients who underwent ERCP in addition to cholecystectomy (1.1% vs. 0.2%, P = 0.02, Fisher's exact test). CONCLUSIONS: ERCP performed in the same setting as cholecystectomy carries no increased risk of SSI and should be the treatment of choice in patients with choledocholithiasis. ERCP performed separately within 60 days before cholecystectomy doubles the risk of SSI. Contaminated equipment might play a role, but other factors are likely at play, and should be taken into account when selecting treatment pathways for patients with choledocholithiasis.

Risk Adjustment for Determining Surgical Site Infection in Colon Surgery: Are All Models Created Equal?

BACKGROUND: Colon surgical site infections (SSIs) are being utilized increasingly as a quality measure for hospital reimbursement and public reporting. The Centers for Medicare and Medicaid Services (CMS) now require reporting of colon SSI, which is entered through the U.S. Centers for Disease Control and Prevention's National Healthcare Safety Network (NHSN). However, the CMS's model for determining expected SSIs uses different risk adjustment variables than does NHSN. We hypothesize that CMS's colon SSI model will predict lower expected infection rates than will NHSN. METHODS: Colon SSI data were reported prospectively to NHSN from 2012-2014 for the six Fairview Hospitals (1,789 colon procedures). We compared expected quarterly SSIs and standardized infection ratios (SIRs) generated by CMS's risk-adjustment model (age and American Society of Anesthesiologist [ASA] classification) vs. NHSN's (age, ASA classification, procedure duration, endoscope [including laparoscope] use, medical school affiliation, hospital bed number, and incision class). RESULTS: The patients with more complex colon SSIs were more likely to be male (60% vs. 44%; p = 0.011), to have contaminated/dirty incisions (21% vs. 10%; p = 0.005), and to have longer operations (235 min vs. 156 min; p < 0.001) and were more likely to be at a medical school-affiliated hospital (53% vs. 40%; p = 0.032). For Fairview Hospitals combined, CMS calculated a lower number of expected quarterly SSIs than did the NHSN (4.58 vs. 5.09 SSIs/quarter; p = 0.002). This difference persisted in a university hospital (727 procedures; 2.08 vs. 2.33; p = 0.002) and a smaller, community-based hospital (565 procedures; 1.31 vs. 1.42; p = 0.002). There were two quarters in which CMS identified Fairview's SIR as an outlier for complex colon SSIs (p = 0.05 and 0.04), whereas NHSN did not (p = 0.06 and 0.06). CONCLUSION: The CMS's current risk-adjustment model using age and ASA classification predicts lower rates of expected colon SSIs than does NHSN. This may lead to financial penalties because of the use of limited risk factors. Further efforts at elucidating appropriate risk adjustment measures without unnecessarily burdening hospitals with expensive data collection are necessary.

Obstructive Sleep Apnea: A Risk Factor for Surgical Site Infection following Colectomy.

BACKGROUND: Obstructive sleep apnea (OSA) is associated with increased systemic oxidative stress, endothelial dysfunction, and activation of pro-inflammatory cascades, which increase host susceptibility to infection. OSA has not been evaluated as a risk factor for surgical site infection (SSI) following colectomy. We hypothesized that OSA increases the risk for SSI after colectomy. METHODS: We performed a retrospective review of 507 colectomies that took place between August 2011 and September 2013. Forty-two patients carried the diagnosis of OSA prior to surgery. These 42 patients were matched to 68 patients with no OSA for age, body mass index (BMI), diabetes mellitus (DM), reason for surgery and surgical approach. RESULTS: The rate of SSI was 28.6% (12 of 42) in the patients with and 10.3% (7 of 68) in the patients without OSA (p=0.03). Using logistic regression, the predictors of SSI following colectomy were found to be OSA (odds ratio [OR] of 3.98, 95% confidence interval [CI]=1.29-12.27), and DM (OR of 7.16, 95% CI=2.36-21.96). The average hospital stay after colectomy for patients with OSA complicated with SSI was 16.7 d whereas patients with OSA without SSI stayed 7.4 d (p<0.001). The rate of organ space infections was 9.5% (4 of 42) in the patients with OSA compared with 0 (p=0.02) in patients without OSA. CONCLUSIONS: OSA is an independent risk factor for SSI following colectomy. Patients with OSA have substantially greater rates of organ space SSI and longer hospital stay.

Abdominal Hysterectomy: Reduced Risk of Surgical Site Infection Associated with Robotic and Laparoscopic Technique.

BACKGROUND: Hysterectomy is one of the most common procedures performed in the United States. New techniques utilizing laparoscopic and robotic technology are becoming increasingly common. It is unknown if these minimally invasive surgical techniques alter the risk of surgical site infections (SSI). METHODS: We performed a retrospective review of all patients undergoing abdominal hysterectomy at our institution between January 2011 and June 2013. International Classification of Diseases, Ninth edition (ICD-9) codes and chart review were used to identify patients undergoing hysterectomy by open, laparoscopic, or robotic approach and to identify patients who developed SSI subsequently. Chi-square and analysis of variance (ANOVA) tests were used to identify univariate risk factors and logistic regression was used to perform multivariable analysis. RESULTS: During this time period, 986 patients were identified who had undergone abdominal hysterectomy, with 433 receiving open technique (44%), 116 laparoscopic (12%), 407 robotic (41%), and 30 cases that were converted from minimally invasive to open (3%). Patients undergoing laparoscopic-assisted hysterectomy were significantly younger and had lower body mass index (BMI) and American Society of Anesthesiologists (ASA) scores than those undergoing open or robotic hysterectomy. There were no significant differences between patients undergoing open versus robotic hysterectomy. The post-operative hospital stay was significantly longer for open procedures compared with those using laparoscopic or robotic techniques (5.1, 1.7, and 1.6 d, respectively; p<0.0001). The overall rate of SSI after all hysterectomy procedures was 4.2%. More SSI occurred in open cases (6.5%) than laparoscopic (0%) or robotic (2.2%) (p<0.0001). Cases converted to open also had an increased rate of SSI (13.3%). In both univariate and multivariable analyses, open technique, wound class of III/IV, age greater than 75 y, and morbid obesity were all associated with increased risk of SSI. CONCLUSION: Laparoscopic and robotic hysterectomies were associated with a significantly lower risk of SSI and shorter hospital stays. Body mass index, advanced age, and wound class were also independent risk factors for SSI.

Pre-operative antiseptic shower and bath policy decreases the rate of S. aureus and methicillin-resistant S. aureus surgical site infections in patients undergoing joint arthroplasty.

BACKGROUND: Surgical site infection (SSI) following joint arthroplasty increases length of stay, hospital cost, and leads to patient and healthcare provider dissatisfaction. Due to the presence of non-biologic implants (the prosthetic joint) in these procedures, infection is often devastating and treatment of the infection is more difficult. For this reason, prevention of SSI is of crucial importance in this population. Staphylococcus aureus colonizes the nares of approximately 30-40% of the population, is the most common pathogen causing SSI, and is associated with high morbidity and mortality rate. A pre-operative shower or bath with an antiseptic is an inexpensive and effective method of removal of these transient skin pathogens prior to the procedure and may be used to decrease SSI. HYPOTHESIS: We hypothesize that a preoperative antiseptic shower or bath will decrease the rate of SSI. METHODS: A retrospective review was performed at two affiliated hospitals within the same system, one with a hospital-wide policy enforcing pre-operative antiseptic shower or bath and the other with no policy, with cases included from January 2010 to June 2012. International Classification of Disease-Ninth Revision-Clinical Modification (ICD-9-CM) codes and chart review were used to identify patients undergoing joint arthroplasty and to identify those with SSI. RESULTS: Two thousand three-hundred forty-nine arthroplasties were performed at the University of Minnesota Medical Center, a tertiary-care hospital with a pre-operative antiseptic shower or bath policy in place. An additional 1,693 procedures were performed at Fairview Ridges Hospital, a community hospital with no pre-operative policy. There was no difference in the rate of SSI between the two hospitals (1.96% vs. 1.95%; p=1.0). However, the rate of SSI caused by S. aureus was significantly decreased by pre-operative antiseptic shower/bath (17% vs. 61%; p=0.03), as was the rate of methicillin-resistant S. aureus (MRSA) infections (2% vs. 24% p=0.002). CONCLUSIONS: A pre-operative antiseptic shower and bath policy was associated with a significant decrease in S. aureus and MRSA SSI, but did not decrease the total incidence of SSI. This intervention may decrease the morbidity of S. aureus SSI in this population.