The risk factors for deep and superficial chest surgical-site infections after coronary artery bypass graft surgery are different

Retrospective analysis of never events in panniculectomy and abdominoplasty patients and their financial implications

In 2008, the Centers for Medicare and Medicaid Service adapted a list from the National Quality Forum consisting of 10 hospital-acquired conditions, also known as never events. Deeming such events as preventable in a safe-hospital setting, reimbursement is no longer provided for treatments arising secondary to these events. A retrospective chart review identified 90 panniculectomy and abdominoplasty patients. The hospital-acquired conditions examined include surgical-site infections (SSI), vascular-catheter associated infections, deep venous thrombosis/pulmonary embolism, retained foreign body, catheter-related urinary tract infection, manifestations of poor glycemic control, falls and trauma, air embolism, pressure ulcers (stages III and IV), and blood incompatibility. Information regarding age, American Society of Anesthesiologists (ASA) classification, body mass index, smoking, and chemotherapy were collected. Patients were divided into 2 groups, namely, those who developed never events and those with no events. Of the 90 patients, 14 (15.5%) developed never events because of SSI. No events occurred in the remaining 9 categories. Statistically significant risk factors included American Society of Anesthesiologists classification, age, and diabetes mellitus. The most common never event was SSI. In light of the obvious prevalence of the risk factors in patients who develop these events, the question of whether never events are truly unavoidable arises. Despite this, awareness of the impact on patient care, health care and hospital reimbursement is vital to understanding the new paradigm of the "one size fits all."

Differences in risk factors associated with surgical site infections following two types of cardiac surgery in Japanese patients

BACKGROUND

Differences in the risk factors for surgical site infection (SSI) following open heart surgery and coronary artery bypass graft surgery are not well described.

AIM

To identify and compare risk factors for SSI following open heart surgery and coronary artery bypass graft surgery.

METHODS

SSI surveillance data on open heart surgery (CARD) and coronary artery bypass graft surgery (CBGB) submitted to the Japan Nosocomial Infection Surveillance (JANIS) system between 2008 and 2010 were analysed. Factors associated with SSI were analysed using univariate modelling analysis followed by multi-variate logistic regression analysis. Non-binary variables were analysed initially to determine the most appropriate category.

FINDINGS

The cumulative incidence rates of SSI for CARD and CBGB were 2.6% (151/5895) and 4.1% (160/3884), respectively. In both groups, the duration of the operation and a high American Society of Anesthesiologists' (ASA) score were significant in predicting SSI risk in the model. Wound class was independently associated with SSI in CARD but not in CBGB. Implants, multiple procedures and emergency operations predicted SSI in CARD, but none of these factors predicted SSI in CBGB.

CONCLUSIONS

There was a remarkable difference in the prediction of risk for SSI between the two types of cardiac surgery. Risk stratification in CARD could be improved by incorporating variables currently available in the existing surveillance systems. Risk index stratification in CBGB could be enhanced by collecting additional variables, because only two of the current variables were found to be significant for the prediction of SSI.

Improving Risk-Adjusted Measures of Surgical Site Infection for the National Healthcare Safely Network

Background.

The National Healthcare Safety Network (NHSN) has provided simple risk adjustment of surgical site infection (SSI) rates to participating hospitals to facilitate quality improvement activities; improved risk models were developed and evaluated.

Methods.

Data reported to the NHSN for all operative procedures performed from January 1, 2006, through December 31, 2008, were analyzed. Only SSIs related to the primary incision site were included. A common set of patient- and hospital-specific variables were evaluated as potential SSI risk factors by univariate analysis. Some ific variables were available for inclusion. Stepwise logistic regression was used to develop the specific risk models by procedure category. Bootstrap resampling was used to validate the models, and the c-index was used to compare the predictive power of new procedure-specific risk models with that of the models with the NHSN risk index as the only variable (NHSN risk index model).

Results.

From January 1, 2006, through December 31, 2008, 847 hospitals in 43 states reported a total of 849,659 procedures and 16,147 primary incisional SSIs (risk, 1.90%) among 39 operative procedure categories. Overall, the median c-index of the new procedure-specific risk was greater (0.67 [range, 0.59–0.85]) than the median c-index of the NHSN risk index models (0.60 [range, 0.51–0.77]); for 33 of 39 procedures, the new procedure-specific models yielded a higher c-index than did the NHSN risk index models.

Conclusions.

A set of new risk models developed using existing data elements collected through the NHSN improves predictive performance, compared with the traditional NHSN risk index stratification.

Safety and efficacy of percutaneous mitral valve repair using the MitraClip® system in patients with diabetes mellitus

BACKGROUND

Patients with diabetes mellitus show a negative outcome in percutaneous coronary intervention, aortic valve replacement and cardiac surgery. The impact of diabetes on patients undergoing treatment of severe mitral regurgitation (MR) using the MitraClip system is not known. We therefore sought to assess whether percutaneous mitral valve repair with the MitraClip system is safe and effective in patients with diabetes mellitus.

METHODS AND RESULTS

We included 58 patients with severe and moderate-to-severe MR in an open-label observational single-center study. Ninteen patients were under oral medication or insulin therapy for type II diabetes mellitus. MitraClip devices were successfully implanted in all patients with diabetes and in 97.4% (n = 38) of patients without diabetes (p = 0.672). Periprocedural major cardiac adverse and cerebrovascular events (MACCE) occurred in 5.1% (n = 2) of patients without diabetes whereas patients with diabetes did not show any MACCE (p = 0.448). 30-day mortality was 1.7% (n = 1) with no case of death in the diabetes group. Short-term follow up of three months showed a significant improvement of NYHA class and quality of life evaluated by the Minnesota Living with Heart Failure Questionnaire in both groups, with no changes in the 6-minute walk test.

CONCLUSIONS

Mitral valve repair with the MitraClip system is safe and effective in patients with type II diabetes mellitus.

TRIAL REGISTRATION

MitraClip Registry NCT02033811.

Use of incisional negative pressure wound therapy on closed median sternal incisions after cardiothoracic surgery: clinical evidence and consensus recommendations

Negative pressure wound therapy is a concept introduced initially to assist in the treatment of chronic open wounds. Recently, there has been growing interest in using the technique on closed incisions after surgery to prevent potentially severe surgical site infections and other wound complications in high-risk patients. Negative pressure wound therapy uses a negative pressure unit and specific dressings that help to hold the incision edges together, redistribute lateral tension, reduce edema, stimulate perfusion, and protect the surgical site from external infectious sources. Randomized, controlled studies of negative pressure wound therapy for closed incisions in orthopedic settings (which also is a clean surgical procedure in absence of an open fracture) have shown the technology can reduce the risk of wound infection, wound dehiscence, and seroma, and there is accumulating evidence that it also improves wound outcomes after cardiothoracic surgery. Identifying at-risk individuals for whom prophylactic use of negative pressure wound therapy would be most cost-effective remains a challenge; however, several risk-stratification systems have been proposed and should be evaluated more fully. The recent availability of a single-use, closed incision management system offers surgeons a convenient and practical means of delivering negative pressure wound therapy to their high-risk patients, with excellent wound outcomes reported to date. Although larger, randomized, controlled studies will help to clarify the precise role and benefits of such a system in cardiothoracic surgery, limited initial evidence from clinical studies and from the authors' own experiences appears promising. In light of the growing interest in this technology among cardiothoracic surgeons, a consensus meeting, which was attended by a group of international experts, was held to review existing evidence for negative pressure wound therapy in the prevention of wound complications after surgery and to provide recommendations on the optimal use of negative pressure wound therapy on closed median sternal incisions after cardiothoracic surgery.

Baseline body mass index does not significantly affect outcomes after pulmonary thromboendarterectomy

BACKGROUND

Obesity is a common comorbidity of patients with chronic thromboembolic pulmonary hypertension referred for pulmonary thromboendarterectomy, yet the effect of obesity on pulmonary thromboendarterectomy outcomes has not been well described.

METHODS

We conducted a retrospective cohort study in which 476 consecutive operations over a 3.5-year period were examined to determine the effects of obesity on outcomes. Patients were grouped into four categories based on body mass index (BMI): less than 22 kg/m2, 22 to 30 kg/m2, 30 to 40 kg/m2, and more than 40 kg/m2.

RESULTS

There were important differences in baseline pulmonary hemodynamics, with obese patients having significantly lower pulmonary vascular resistances than nonobese patients. All patients achieved a significant reduction in pulmonary vascular resistance, although the improvement was greatest in the lower BMI groups. The overall in-hospital mortality was 0.8%, and there were no differences in risk among BMI groups. Among the BMI groups, there were no differences in incidence of postoperative complications, including atrial fibrillation (overall 24.8%), reperfusion lung injury (overall 23.1%), and surgical site infection (overall 4.4%) or in median lengths of stay (including ventilator days, intensive care unit days, and postoperative length of stay).

CONCLUSIONS

Pulmonary thromboendarterectomy outcomes have continued to improve, and this surgery can safely be completed in obese patients, previously deemed to be at high risk for poor outcomes.

Strategies to prevent surgical site infections in acute care hospitals: 2014 update

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format designed to assist acute care hospitals in implementing and prioritizing their surgical site infection (SSI) prevention efforts. This document updates “Strategies to Prevent Surgical Site Infections in Acute Care Hospitals,”1 published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.2

Implementation of bundled interventions greatly decreases deep sternal wound infection following cardiovascular surgery

OBJECTIVE

Surgical site infection (SSI), particularly deep sternal wound infection (DSWI), is a serious complication after cardiovascular surgery because of its high mortality rate. We evaluated the effectiveness of an SSI bundle to reduce DSWI and identify the risk factors for DSWI.

METHODS

During the period January 2004 to February 2012, 1374 consecutive patients undergoing cardiovascular surgery via sternotomy were included. The cohort was separated into periods from January 2004 through February 2007 (period I, 682 patients) and March 2007 through February 2012 (period II, 692 patients). During period II, all preventive measures for DSWI were completed as an SSI bundle. We compared the DSWI rate between the 2 periods. Univariate and multivariate analyses were performed for the entire period to identify the risk factors for DSWI.

RESULTS

DSWI occurred in 13 patients (1.9%) during period I and in 1 patient (0.14%) during period II. The DSWI rate during period II was significantly decreased by 93%, compared with period I (P=.001). Independent risk factors for DSWI included obesity (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.00-11.75; P=.049), the use of 4 sternal wires (OR, 8.2; 95% CI, 1.39-48.14; P=.020), long operative time (OR, 4.4; 95% CI, 1.20-16.23; P=.026), and postoperative renal failure (OR, 9.0; 95% CI, 2.44-33.30; P=.001).

CONCLUSIONS

Complete implementation of simple multidisciplinary prevention measures as a bundle can greatly decrease the incidence of DSWI.

Sternal closure following negative pressure wound therapy: a safe approach with a new titanium device

BACKGROUND

The application of negative pressure wound therapy (NPWT) in patients with deep wound infection after cardiac surgery has steadily increased worldwide. Following NPWT, in patients with concomitant sternal diastasis, preparation of the substernal structures for the sternal wires application is mandatory, with increased risk of severe complications, such as laceration of the right ventricle. The aim of this study is to present an innovative technique for sternal closure after NPWT, using the ASCS® System (ASCS atraumatic Sternum Closure System; KS Handelsvertretung Produktinovation, Bad Homburg, Germany).

METHODS

Between January 2009 and August 2012, 88 patients (mean age 64.2 ± 12.4 years) with deep wound infection and sternal diastasis received NPWT; 16 of these patients (18.2%) underwent sternal closure after NPWT with ASCS®.

RESULTS

In all 16 cases, neither sub-sternal dissection nor placement of trans- or peristernal wires was necessary. No damage to the aortocoronary bypass and ventricular rupture occurred. Minimal post-operative bleeding from Redon drains (mean 40 ± 10 ml) was present. At follow-up, deep wound infection and sternal diastasis did not occur.

CONCLUSIONS

The ASCS® System combined with NPWT in patients with postoperative deep wound infection and sternal diastasis is a feasible and safe procedure. Because preparation of the substernal structures is not necessary, this device might prevent the occurrence of severe complications. Our experience, however, is limited and larger case series are necessary to fully evaluate this new and innovative technique.

Epidemiology and outcomes of deep surgical site infections following lung transplantation

We conducted a retrospective study of deep surgical site infections (SSIs) among consecutive patients who underwent lung transplantation (LTx) at a single center from 2006 through 2010. Thirty-one patients (5%) developed SSIs at median 25 days after LTx. Empyema was most common (42%), followed by surgical wound infections (29%), mediastinitis (16%), sternal osteomyelitis (6%), and pericarditis (6%). Pathogens included Gram-positive bacteria (41%), Gram-negative bacteria (41%), fungi (10%) and Mycobacterium abscessus, Mycoplasma hominis and Lactobacillus sp. (one each). Twenty-three percent of SSIs were due to pathogens colonizing recipients' native lungs at time of LTx, suggesting surgical seeding as a source. Patient-related independent risk factors for SSIs were diabetes and prior cardiothoracic surgery; procedure-related independent risk factors were LTx from a female donor, prolonged ischemic time and number of perioperative red blood cell transfusions. Mediastinitis and sternal infections were not observed among patients undergoing minimally invasive LTx. SSIs were associated with 35% mortality at 1 year post-LTx. Lengths of stay and mortality in-hospital and at 6 months and 1 year were significantly greater for patients with SSIs other than empyema. In conclusion, deep SSIs were uncommon, but important complications in LTx recipients because of their diverse microbiology and association with increased mortality.

Prevention of poststernotomy wound infections in obese patients by negative pressure wound therapy

OBJECTIVE

The majority of wound infections after median sternotomy in obese patients are triggered by the breakdown of skin sutures and subsequent seepage of skin flora. The purpose of this study was to evaluate negative pressure wound dressing treatment for the prevention of infection. We hypothesized that negative pressure wound dressing treatment for 6 to 7 days applied immediately after skin closure reduces the numbers of wound infections.

METHODS

In a prospective study, 150 consecutive obese patients (body mass index ≥ 30) with cardiac surgery performed via median sternotomy were analyzed. In the negative pressure wound dressing treatment group (n = 75), a foam dressing (Prevena, KCI, Wiesbaden, Germany) was placed immediately after skin suturing, and negative pressure of -125 mm Hg was applied for 6 to 7 days. In the control group (n = 75), conventional wound dressings were used. The primary end point was wound infection within 90 days. Mann-Whitney U test and Fisher exact test were used. Freedom from infection was estimated by Kaplan-Meier analysis.

RESULTS

Three of 75 patients (4%) with continuous negative pressure wound dressing treatment had wound infections compared with 12 of 75 patients (16%) with conventional sterile wound dressing (P = .0266; odds ratio, 4.57; 95% confidence interval, 1.23-16.94). Wound infections with Gram-positive skin flora were found in only 1 patient in the negative pressure wound dressing treatment group compared with 10 patients in the control group (P = .0090; odds ratio, 11.39; 95% confidence interval, 1.42-91.36).

CONCLUSIONS

Negative pressure wound dressing treatment over clean, closed incisions for the first 6 to 7 postoperative days significantly reduces the incidence of wound infection after median sternotomy in a high-risk group of obese patients.

An update review on risk factors and scales for prediction of deep sternal wound infections

Surgical site infections are the most common nosocomial infections in surgical patients. The preventable and the unmodifiable risk factors for deep sternal wound infections (DSWI) have been amply assessed in the literature. The aim of this review was to describe the results of the numerous published studies to describe all the DSWI risk factors and the scales devised to predict SWI, with a view to providing an update on this issue. A comprehensive search of the Medline and Embase databases was performed (considering studies from January 1995 to April 2011); and a manual search was also conducted using references cited in original publications and relevant review articles. There are several risk factors associated with DSWI, which could be classified in four categories as demographic (e.g. sex and age), behavioural (e.g. smoking and obesity), baseline clinical conditions (e.g. diabetes, hypertension and COPD) and surgical operative risk factors (e.g. duration of operation and emergency operation). Six scales for predicting the risk of DSWI are described in the literature: they vary not only in accuracy but also in ease of application and they are applied at different times (some only preoperatively and others also postoperatively). This study provides a broad update on our knowledge of the risk factors for DSWI and the scales for prediction with a view to improving the management of infections at cardiosurgery units.

Efficiency of antibacterial suture material in cardiac surgery: a double-blind randomized prospective study

OBJECTIVE

Postoperative surgical site infections (SSI) still greatly affect mortality and morbidity in cardiovascular surgery. SSI may be related to the suture material. In this prospective, randomized, controlled, and double-blinded study, the effect of antibacterial suture material on SSI in cardiac surgical patients was investigated.

METHODS

We randomly allocated 510 patients into 2 groups. Antibacterial suture materials were used for wound closure in 170 patients (triclosan-coated suture group), and routine suture materials were used in 340 patients (noncoated suture group). All patients were evaluated for SSI on days 10, 20, and 30 following cardiac surgery.

RESULTS

Preoperative risk factors and laboratory findings were comparable for the 2 groups. Sternal infection occurred in 4 (2.4%) of the patients in the triclosan-coated suture group and in 3.5% of the noncoated suture group (P > .05). Leg wound infection occurred in 5 (3.5%) of the patients in the triclosan-coated suture group and in 3.8% of the noncoated suture group (P > .05). Only diabetes mellitus was an independent predictor of SSI.

CONCLUSION

Both noncoated and triclosan-coated suture materials are safe. Larger studies may be needed to show the benefit and cost-effectiveness, if any, of triclosan-coated materials over noncoated materials.

Obesity and the risk and outcome of infection

The interactions between obesity and infectious diseases have recently received increasing recognition as emerging data have indicated an association between obesity and poor outcome in pandemic H1N1 influenza infection. Obesity is an established risk factor for surgical-site infections, nosocomial infections, periodontitis and skin infections. Several studies indicate that acute pancreatitis is more severe in the obese. Data are controversial and limited as regards the association between obesity and the risk and outcome of community-acquired infections such as pneumonia, bacteremia and sepsis and obesity and the course of HIV infection. As the cause-effect relationship between obesity and infection remains obscure in many infectious diseases, further studies are warranted. The consequences of obesity may have substantial effects on the global burden of infectious diseases.

Improved risk adjustment in public reporting: coronary artery bypass graft surgical site infections

OBJECTIVE

The objective was to develop a new National Healthcare Safety Network (NHSN) risk model for sternal, deep incisional, and organ/space (complex) surgical site infections (SSIs) following coronary artery bypass graft (CABG) procedures, detected on admission and readmission, consistent with public reporting requirements.

PATIENTS AND SETTING

A total of 133,503 CABG procedures with 4,008 associated complex SSIs reported by 293 NHSN hospitals in the United States.

METHODS

CABG procedures performed from January 1, 2006, through December 31, 2008, were analyzed. Potential SSI risk factors were identified by univariate analysis. Multivariate analysis with forward stepwise logistic regression modeling was used to develop the new model. The c-index was used to compare the predictive power of the new and NHSN risk index models.

RESULTS

Multivariate analysis independent risk factors included ASA score, procedure duration, female gender, age, and medical school affiliation. The new risk model has significantly improved predictive performance over the NHSN risk index (c-index, 0.62 and 0.56, respectively).

CONCLUSIONS

Traditionally, the NHSN surveillance system has used a risk index to provide procedure-specific risk-stratified SSI rates to hospitals. A new CABG sternal, complex SSI risk model developed by multivariate analysis has improved predictive performance over the traditional NHSN risk index and is being considered for endorsement as a measure for public reporting.

Risk factors for coronary artery bypass graft chest surgical site infections in New York State, 2008

BACKGROUND

All hospitals in New York State (NYS) are required to report surgical site infections (SSIs) occurring after coronary artery bypass graft surgery. This report describes the risk adjustment method used by NYS for reporting hospital SSI rates, and additional methods used to explore remaining differences in infection rates.

METHODS

All patients undergoing coronary artery bypass graft surgery in NYS in 2008 were monitored for chest SSI following the National Healthcare Safety Network protocol. The NYS Cardiac Surgery Reporting System and a survey of hospital infection prevention practices provided additional risk information. Models were developed to standardize hospital-specific infection rates and to assess additional risk factors and practices.

RESULTS

The National Healthcare Safety Network risk score based on duration of surgery, American Society of Anesthesiologists score, and wound class were not highly predictive of chest SSIs. The addition of diabetes, obesity, end-stage renal disease, sex, chronic obstructive pulmonary disease, and Medicaid payer to the model improved the discrimination between procedures that resulted in SSI and those that did not by 25%. Hospital-reported infection prevention practices were not significantly related to SSI rates.

CONCLUSIONS

Additional risk factors collected using a secondary database improved the prediction of SSIs, however, there remained unexplained variation in rates between hospitals.

Negative microbiological results are not mandatory in deep sternal wound infections before wound closure

OBJECTIVES

To define the outcome of treatment for deep sternal wound infections (DSWIs) using direct wound closure (DC) or vacuum-assisted therapy (VAT) based on negative vs. positive microbiological results.

METHODS

Between 1999 and 2008, 7746 patients underwent median sternotomy for cardiac surgery at our institution. Patients were screened for DSWI and out of the cohort 159 were identified (2%). These patients were treated, either using DC or VAT with delayed wound closure. Outcomes were retrospectively analysed to determine the effect of negative cultures at the time of closure.

RESULTS

The indication for sternotomy was CABG 51%, isolated valve 18%, CABG/valve 18% and other related cardiovascular procedures 14%. Sixty-five percent of the wound infections was diagnosed during rehabilitation period. One hundred and five (66%) patients were treated with VAT vs. 54 (34%) patients with direct closure. Coagulase negative staphylococci were found in 48% of bacterial cultures. In 75% of the patients, the microbiological results were positive at time of wound closure (69.2% VAT vs. 87.0% direct closure, P = 0.014). Out of 159 patients, 5.0% were with positive microbiological results at the time of closure readmitted vs. 5.1% with negative microbiological results (P = 1.0). Patients with VAT stayed significantly longer in the hospital (mean 21 ± 16 vs. 13 ± 12, P = 0.002).

CONCLUSIONS

Negative microbiological results are not mandatory before wound closure, as the rate of readmissions for recurrence of infection showed no difference between groups. Our results also suggest that shortening of VAT despite positive microbiological results may be feasible.

Risk analysis and outcome of mediastinal wound and deep mediastinal wound infections with specific emphasis to omental transposition

BACKGROUND

To report our experience, with Deep mediastinal wound infections (DMWI). Emphasis was given to the management of deep infections with omental flaps

METHODS

From February 2000 to October 2007, out of 3896 cardiac surgery patients (prospective data collection) 120 pts (3.02%) developed sternal wound infections. There were 104 males & 16 females; (73.7%) CABG, (13.5%) Valves & (9.32%) CABG and Valve.

RESULTS

Superficial sternal wound infection detected in 68 patients (1.75%) and fifty-two patients (1.34%) developed DMWI. The incremental risk factors for development of DMWI were: Diabetes (OR = 3.62, CI = 1.2-10.98), Pre Op Creatinine > 200 μmol/l (OR = 3.33, CI = 1.14-9.7) and Prolong ventilation (OR = 4.16, CI = 1.73-9.98). Overall mortality for the DMWI was 9.3% and the specific mortality of the omental flap group was 8.3%. 19% of the "DMWI group", developed complications: hematoma 6%, partial flap loss 3.0%, wound dehiscence 5.3%. Mean Hospital Stay: 59 ± 21.5 days.

CONCLUSION

Post cardiac surgery sternal wound complications remain challenging. The role of multidisciplinary approach is fundamental, as is the importance of an aggressive early wound exploration especially for deep sternal infections.

Does duration of perioperative antibiotic prophylaxis matter in cardiac surgery? A systematic review and meta-analysis

OBJECTIVE

We aimed to compare the efficacy of short-term (<24 hours) versus longer-term antibiotic prophylaxis (≥24 hours) in open heart surgery.

BACKGROUND

The optimal duration of antibiotic prophylaxis for adults undergoing cardiac surgery is unknown and guideline recommendations are inconsistent.

METHODS

We searched MEDLINE, EMBASE, CINAHL, and CENTRAL for parallel-group randomized trials comparing any antibiotic prophylaxis administered for <24 hours to any antibiotic prophylaxis for ≥24 hours in adult patients undergoing open heart surgery. Reference lists of selected articles, clinical practice guidelines, review articles, and congress abstracts were searched. Study selection, data extraction and assessment of risk of bias were performed independently by 2 reviewers.

RESULTS

Of the 1338 citations identified by our search strategy, 12 studies involving 7893 patients were selected. Compared with short-term antibiotic prophylaxis, longer-term antibiotic prophylaxis reduced the risk of sternal surgical site infection (SSI) by 38% (risk ratio 1.38, 95% confidence interval (CI) 1.13-1.69, P = 0.002) and deep sternal SSI by 68% (risk ratio 1.68, 95% CI 1.12-2.53, P = 0.01). There were no statistically significant differences in mortality, infections overall and adverse events. Eleven of the trials were at high risk for bias due to limitations in study design.

CONCLUSIONS

Perioperative antibiotic prophylaxis of ≥24 hours may be more efficacious in preventing sternal SSIs in patients undergoing cardiac surgery compared to shorter regimens. The findings however are limited by the heterogeneity of antibiotic regimens used and the risk of bias in the published studies.

Surgical wound complications after heart transplantation

Surgical wound complications are more frequent in patients undergoing heart transplantation than in other heart surgery patients. This is probably attributed to the presence of additional risk factors in these patients, such as immunosuppression, mechanical support through assist devices and generally poor health. Analyses of wound infections in heart transplantation are based on smaller patient population than those for general heart surgery, and the reported incidences vary largely. The identification of specific risk factors in heart transplant recipients to date is mainly based on retrospective case-control studies in small patient cohorts, the results are controversial, and the comparability of data is limited because of the lack of application of consistent definitions. The impact of immunosuppression and especially immunosuppression with mammalian target of rapamycin (mTOR) inhibitors on the development of surgical wound complications has been widely discussed following reports of increased occurrence with sirolimus. However, nonheart-transplant specific risk factors should also be considered to develop risk profiles and treatment algorithms for individual patients. Data on surgical wound complications in general heart surgery patients and in heart transplant recipients are compared, the impact of modern immunosuppression reviewed, and areas for further investigation discussed.

Laser Doppler flowmetry assessment of peristernal perfusion after cardiac surgery: beneficial effect of negative pressure therapy

Negative pressure therapy has been successfully applied to clean, closed incisions in patients at high-risk for wound complications. Using laser Doppler flowmetry, we evaluated peristernal perfusion after cardiac surgery via median sternotomy, assessing the influence of mammary artery harvesting and the impact of negative pressure therapy. Twenty adult patients underwent median sternotomy for cardiac surgery followed by routine closure. Negative pressure was applied at 125 mm Hg for 4 days postoperatively in patients with increased risk for wound complications (n = 10, negative pressure group); standard dressings were applied to control incisions postoperatively (n = 10). Presternal perfusion was determined at baseline and daily for 4 days postoperatively using laser Doppler flowmetry. Results within and between groups were compared with analysis of variance. No wound complications were encountered in either group. Perfusion increased among the patients who underwent negative pressure therapy and decreased among the controls (P = 0.004). Mammary artery harvesting reduced peristernal perfusion by 25.7% in the controls, but negative pressure increased perfusion by 100% after mammary harvesting (P = 0.04). Negative pressure therapy increased perfusion relative to controls and compensated for reduced perfusion rendered by mammary artery harvesting, providing additional support for 'well wound therapy' in high-risk patients.

A simple risk score for predicting surgical site infections in inflammatory bowel disease

PURPOSE

Patients with inflammatory bowel disease are often at highest risk for surgical site infections. We sought to define the predictors of surgical site infections and to develop a risk score for predicting those at highest risk.

METHODS

Patients undergoing a bowel resection for Crohn's disease or ulcerative colitis were identified from National Surgical Quality Improvement Program 2008. Univariate and multivariate analyses were conducted to identify predictors of surgical site infections. Clinically relevant prediction categories were developed and the predictive behavior of the model was validated by use of National Surgical Quality Improvement Program 2007. An integer-based scoring system risk score was created proportional to the logistic regression coefficients, grouping patients into categories of similar risk.

RESULTS

We identified 271,368 patients; 3981 of these patients underwent an operation for Crohn's disease (n = 2895) or ulcerative colitis (n = 1086). Nine hundred (22.6%) patients developed surgical site infections. Predictors included weight loss, smoking, emergent surgery, wound class, operative time (minutes), and an ASA score >2. A risk score was developed by stratifying patients into low (0-5), 15.6%; medium (6-8), 25.2%; and high (>8), 36.1% risk.

CONCLUSIONS

Patients with inflammatory bowel disease are at high risk for surgical site infections. Preoperative factors including weight loss, smoking, emergent surgery and an ASA score >2 are strong predictors of surgical site infections. Operative time and wound class are important intraoperative predictors. A risk score, based on pre- and intraoperative variables, can be used to identify patients at highest risk of developing surgical site infections. This may allow for appropriate process measures to be implemented to prevent and lessen the impact of surgical site infections in this high-risk population.

Obesity increases the risk of recurrent herniated nucleus pulposus after lumbar microdiscectomy

BACKGROUND CONTEXT

Recurrent herniation of the nucleus pulposus (HNP) frequently causes poor outcomes after lumbar discectomy. The relationship between obesity and recurrent HNP has not previously been reported.

PURPOSE

The purpose of this study was to investigate the association of obesity with recurrent HNP after lumbar microdiscectomy.

STUDY DESIGN

Retrospective Cohort.

PATIENT SAMPLE

We reviewed all cases of one- or two-level lumbar microdiscectomy from L2-S1 performed by a single surgeon with a minimum follow-up of 6 months.

OUTCOME MEASURES

The primary clinical outcomes were evidence of recurrent HNP on magnetic resonance imaging (MRI) and need for repeat surgery.

METHODS

All patients with recurrent radicular pain or new neurological deficits underwent a postoperative MRI scan. Recurrent HNP was defined as a HNP at the same side and same level as the index procedure.

RESULTS

Seventy-five patients were included in the study. The average body mass index (BMI) was 27.6+/-4.6. Thirty-two patients received an MRI scan. The time from operation to repeat MRI scan varied widely (3 days to 15 months). Eight patients (10.7%) had recurrent HNP. Four patients had persistent symptoms requiring reoperation (5.3%). The mean BMI of patients with recurrent HNP was significantly higher than that of those without recurrence (33.6+/-5.1 vs. 26.9+/-3.9, p<.001). In univariate analysis, obese patients (BMI >or=30) were 12 times more likely to have recurrent HNP than nonobese patients (odds ratio [OR]: 12.46, 95% confidence interval [CI]: 2.25-69.90). Obese patients were 30 times more likely to require reoperation (OR: 32.81, 95% CI: 1.67-642.70). Age, sex, smoking, and being a manual laborer were not significantly associated with recurrent HNP. A logistic regression analysis supported the findings of the univariate analysis. In a survival analysis using a Cox proportional hazards model, the hazard ratio of recurrent HNP for obese patients was 17 (OR: 17.08, 95% CI: 2.85-102.30, p=.002).

CONCLUSIONS

Obesity was a strong and independent predictor of recurrent HNP after lumbar microdiscectomy. Surgeons should incorporate weight loss counseling into their preoperative discussions with patients.

The use of autologous platelet gel (APG) for high-risk patients in cardiac surgery -- is it beneficial?

BACKGROUND

Wound healing in cardiac surgery has become a major problem due to the impaired risk profile of many patients. The aim of this study was to prove the influence of autologous platelet gel (APG) on wound healing in a special group of high-risk patients undergoing coronary surgery.

PATIENTS AND METHODS

We performed a prospective, double-blind study in 44 patients with a special risk constellation relating to wound complications (obesity, diabetes, smoker, New York Heart Association (NYHA) III-IV and peripheral vascular disease). The study group was treated with APG, prepared using the Magellan platelet separator, the control group underwent conventional wound treatment.

RESULTS

The incidence of major and minor wound complications at the thoracotomy, as well as in the area of saphenous vein harvesting, was not pronounced in either of the groups. Blood loss and pain sensations did not differ significantly either. Stay in the intensive care unit (ICU) and the in-hospital mortality were also comparable. The duration of the entire operation and the time until removing the chest-tubes were prolonged in the study group.

CONCLUSION

Despite promising results in other fields of surgery, APG shows no beneficial effect in high-risk patients undergoing cardiac surgery. Probably, it depends on different types of microcirculation in atherosclerotic patients, which are quite different from those of other surgical areas. This factor may offset the existing beneficial platelet effects which could be observed, for example, in maxillo-facial surgery.

Risk factors for endometritis after low transverse cesarean delivery

OBJECTIVE

To determine independent risk factors for endometritis after low transverse cesarean delivery.

STUDY DESIGN

We performed a retrospective case-control study during the period from July 1999 through June 2001 in a large tertiary care academic hospital. Endometritis was defined as fever beginning more than 24 hours or continuing for at least 24 hours after delivery plus fundal tenderness in the absence of other causes for fever. Independent risk factors for endometritis were determined by means of multivariable logistic regression. A fractional polynomial method was used to examine risk of endometritis associated with the continuous variable, duration of rupture of membranes.

RESULTS

Endometritis was identified in 124 (7.7%) of 1,605 women within 30 days after low transverse cesarean delivery. Independent risk factors for endometritis included age (odds ratio [OR] for each additional year, 0.93 [corrected] [95% confidence interval {CI}, 0.90-0.97]) and anemia or perioperative blood transfusion (OR, 2.18 [CI, 1.30-3.68]). Risk of endometritis was marginally associated with a proxy for low socioeconomic status, lack of private health insurance (OR, 1.72 [CI, 0.99-3.00]); with amniotomy (OR, 1.69 [CI, 0.97-2.95]); and with longer duration of rupture of membranes.

CONCLUSION

Risk of endometritis was independently associated with younger age and anemia and was marginally associated with lack of private health insurance and amniotomy. The odds of endometritis increased approximately 1.7-fold within 1 hour after rupture of membranes, but increased duration of rupture was only marginally associated with increased risk. Knowledge of these risk factors can guide selective use of prophylactic antibiotics during labor and heighten awareness of the risk in subgroups at highest risk of infection.

Antibacterial prophylaxis in dermatologic surgery: an evidence-based review

Clean, non-contaminated skin surgery is associated with low rates of surgical site infection (SSI), bacterial endocarditis, and joint prosthesis infection. Hence, antibacterial prophylaxis, which may be associated with adverse effects, the emergence of multidrug-resistant pathogens, and anaphylaxis, is generally not recommended in dermatologic surgery. Some body sites and surgical reconstructive procedures are associated with higher infection rates, and guidelines for SSI antibacterial prophylaxis have been proposed for these cases. Large prospective, controlled trials are needed to ascertain the role of oral SSI prophylaxis for these surgical sites and procedures especially in patients with diabetes mellitus who are intrinsically at greater risk of SSI. Topical antibacterial ointment and sterile paraffin appear to make no difference to healing or the incidence of SSIs in clean wounds. Although further research is needed, preliminary studies have shown that intraincisional antibacterials, which may be associated with fewer adverse effects and a lower risk of multidrug-resistant bacteria, could potentially be helpful for SSI prophylaxis. Trials using honey- and silver-impregnated dressings have found no advantage in the healing of chronic wounds. However, several case studies, which need corroboration in larger studies, suggest that these dressings may be helpful in preventing and treating SSIs. Bacterial endocarditis and joint prosthesis infection prophylaxis are not routinely recommended in cutaneous surgery. The updated 2007 American Heart Association guidelines now advocate bacterial endocarditis prophylaxis for high-risk cardiac patients having surgery involving the oral mucosa or infected skin. The latest American Dental Association/American Academy of Orthopaedic Surgery guidelines recommend considering antibacterial prophylaxis for oral procedures where bleeding is anticipated and for surgery involving acute orofacial skin infections if the patient has had a total joint replacement within 2 years or is in a high-risk group and has had a joint replacement at any time.

Developing a risk stratification model for surgical site infection after abdominal hysterectomy

OBJECTIVE

The incidence of surgical site infection (SSI) after hysterectomy ranges widely from 2% to 21%. A specific risk stratification index could help to predict more accurately the risk of incisional SSI following abdominal hysterectomy and would help determine the reasons for the wide range of reported SSI rates in individual studies. To increase our understanding of the risk factors needed to build a specific risk stratification index, we performed a retrospective multihospital analysis of risk factors for SSI after abdominal hysterectomy.

METHODS

Retrospective case-control study of 545 abdominal and 275 vaginal hysterectomies from July 1, 2003, to June 30, 2005, at 4 institutions. SSIs were defined by using Centers for Disease Control and Prevention/National Nosocomial Infections Surveillance criteria. Independent risk factors for abdominal hysterectomy were identified by using logistic regression.

RESULTS

There were 13 deep incisional, 53 superficial incisional, and 18 organ-space SSIs after abdominal hysterectomy and 14 organ-space SSIs after vaginal hysterectomy. Because risk factors for organ-space SSI were different according to univariate analysis, we focused further analyses on incisional SSI after abdominal hysterectomy. The maximum serum glucose level within 5 days after operation was highest in patients with deep incisional SSI, lower in patients with superficial incisional SSI, and lowest in uninfected patients (median, 189, 156, and 141 mg/dL, respectively; P = .005). Independent risk factors for incisional SSI included blood transfusion (odds ratio [OR], 2.4) and morbid obesity (body mass index [BMI], >35; OR, 5.7). Duration of operation greater than the 75th percentile (OR, 1.7), obesity (BMI, 30-35; OR, 3.0), and lack of private health insurance (OR, 1.7) were marginally associated with increased odds of SSI.

CONCLUSIONS

Incisional SSI after abdominal hysterectomy was associated with increased BMI and blood transfusion. Longer duration of operation and lack of private health insurance were marginally associated with SSI.

Safety and Efficacy of Cefazolin Sodium in the Management of Bacterial Infection and in Surgical Prophylaxis

Cefazolin sodium is a first-generation cephalosporin antibiotic and has been used worldwide since the early 1970s. It is used for the treatment of bacterial infections in various organs, such as the respiratory tract, skin and skin structure, genital tract, urinary tract, biliary tract, and bone and joint infections. It has also been used for septicemia due to susceptible gram-positive cocci (except Enterococcus), some gram-negative bacilli including E. coli, Proteus, and Klebsiella may be susceptible, and for perioperative prophylaxis. After the introduction of penicillins and other cephalosporins, occasional outbreaks of methicillin-resistant Staphylococcus aureus were noted. As a result, vancomycin use was increased; however, very recently and most alarmingly, vancomycin-resistant strains have been described. In this setting, to avoid the risk of the development of vancomycin-resistant strains further, vancomycin use should be curtailed. In consideration of this historical background, the appropriate use of antibiotics, such as dosage, dosage intervals, and the duration of administration is required not only for the protection of patients’ health but also for the prevention of the development of drug resistance. Cefazolin has been used in clinical practice for about 40 years, and a large body of evidence has been accumulated, and its efficacy and safety are well established compared with other antibiotics. Therefore, cefazolin has been chosen as a first-line anti-microbial for prophylaxis after various surgical procedures, including cardiovascular surgery, hysterectomy, arthroplasty and so on. Based on these facts, especially for the prophylaxis of surgical site infections, the first-generation cephalosporin, cefazolin, is now being “re-visited”.

Cost effectiveness of local collagen-gentamicin as prophylaxis for sternal wound infections in different risk groups

OBJECTIVES

In a randomized trial addition of local collagen-gentamicin in the sternal wound reduced the rate of sternal wound infection (SWI) to about 50% compared to intravenous prophylaxis alone. The aim of the present study was to evaluate the economic rationale for its use in every-day clinical practice. This includes the question whether high-risk groups that may have particular benefit should be identified.

DESIGN

For each patient with SWI in the trial the costs attributable to the SWI were calculated. Risk factors for SWI were identified and any heterogeneity of the effect of the prophylaxis examined.

RESULTS

The mean cost of a SWI was about 14500 Euros. A cost effectiveness analysis showed that the prophylaxis was cost saving. The positive net balance was even higher in risk groups. Assignment to the control group, overweight, diabetes, younger age, mammarian artery use, left ventricular ejection fraction <35% and longer operation time were independent risk factors for infection.

CONCLUSION

The addition of local collagen-gentamicin to intravenous antibiotic prophylaxis was dominant, i.e. resulted in both lower costs and fewer wound infections.

Does negative pressure wound therapy have a role in preventing poststernotomy wound complications?

BACKGROUND

Sternal wound infection (SWI) remains a devastating complication after cardiac surgery, decreasing long-term and short-term survival. In treating documented SWI, negative pressure wound therapy (NPWT) reduces wound edema and time to definitive closure and improves peristernal blood flow after internal mammary artery (IMA) harvesting. The authors evaluated NPWT as a form of "well wound" therapy in patients at substantial risk for SWI based on existing risk stratification models.

METHODS

Records of 57 adult cardiac surgery patients (September 2006 to April 2008) were reviewed. After preoperative risk assessment, NPWT was instituted on the clean, closed sternotomy immediately after surgery and continued 4 days postoperatively. Adverse postoperative events, including SWI, need for readmission, and other complications, were documented.

RESULTS

Mean age was 60.4 +/- 10 years, and 89.5% were male; 77.2% were obese (mean body mass index 35.3 +/- 6.7), 54.4% were diabetic, and 29 (50.9%) were both obese and diabetic. Coronary artery bypass (CAB) with single IMA was performed in 50.9% of the patients followed in frequency by combined CAB/valve, non-CAB surgery, and CAB with bilateral IMA. Estimated risk for SWI was 6.1 +/- 4%. All patients tolerated NPWT to completion. Thirty-day and in-hospital mortality was 1.8% and unrelated to DSWI. No treatment of SWI was required.

CONCLUSIONS

In this high-risk cohort, 3 postoperative SWI cases were anticipated but may have been mitigated by NPWT. This is an easily applied and well-tolerated therapy and may stimulate more effective wound healing. Among patients with increased SWI risk, strong consideration should be given to NPWT as a form of "well wound" therapy.

Risk analysis of deep sternal wound infections and their impact on long-term survival: a propensity analysis

The objectives of this study are to determine risk factors associated with deep sternal wound infections (DSWIs) following cardiac surgery, and to describe their impact on long-term survival. Data was obtained from a departmental database. Analysis included 7,978 consecutive patients who underwent cardiac surgery between 1997 and 2003. To identify risk factors for DSWI, regression analysis was performed. The probability scores obtained from logistic regression were used for propensity analysis of 2 groups. Kaplan-Meier analysis with log-rank test and Cox proportional hazard models were then used in survival analysis. DSWI developed in 123 of 7,978 patients (1.5%). Preoperative predictors of DSWI were body mass index >30 kg/m(2) (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1 to 2.4; P < 0.05), diabetes mellitus (OR, 2.4; 95% CI, 1.6 to 3.4; P < 0.001), urgent operation (OR, 1.7; 95% CI, 1.2 to 2.6; P < 0.05), smoking history within past year (OR, 2.7; 95% CI, 1.5 to 4.9; P < 0.001), smoking history within past 2 weeks (OR, 2.6; 95% CI, 1.5 to 4.5; P < 0.001), and a history of stroke (OR, 1.9; 95% CI, 1.1 to 3.1; P < 0.005). In addition, total length of hospital stay (OR, 1.01; 95% CI, 1.01 to 1.02; P < 0.05) and sepsis and/or endocarditis following surgery (OR, 5.1; 95% CI, 2.9 to 9.0; P < 0.001) were also predictive of DSWI. Patients with DSWI had a prolonged total length of hospital stay (40.3 days versus 16.1 days; P < 0.001), and higher 30-day mortality (1.6% versus 7.3% in DSWI group, P < 0.05). There were no differences between groups in 4-year and 8-year survival rates, with 77.2% and 61.8%, respectively, in patients with DSWI compared with 78.0% and 67.5% in patients without DSWI (P = 0.16). After adjustments for preoperative, intraoperative, and postoperative factors, the adjusted hazard ratio of long-term mortality for patients with DSWI was 0.9 (95% CI, 0.6 to 1.2, P = 0.39). Though DSWIs are associated with increased early mortality, patients undergoing cardiac surgery complicated by DSWI do not experience worse long-term survival.