Does Elective Sternal Plating in Morbidly Obese Patients Reduce Sternal Complication Rates?

BACKGROUND

Although the literature shows rigid plate fixation has superior outcomes over wire cerclage techniques, a patient population clearly benefitting from initial sternal plating over standard closure has not been identified. Data on plating as primary sternal closure in the morbidly obese patient remains sparse.

METHODS

A single-center retrospective study was performed on 564 consecutive patients undergoing complete median sternotomy from July 2014 to July 2017. Postoperative outcomes of patients with a body mass index of 35 kg/m² or more were compared between sternotomies with standard wire cerclage closure and those with sternal plate reinforcement. The primary endpoint was postoperative sternal complication defined as deep sternal wound infection, acute sternal dehiscence, chronic sternal disunion, or noninfectious sternal wound complication requiring operative intervention.

RESULTS

In all, 32.6% of sternotomies (184 of 564) were performed on patients with a body mass index of 35 kg/m² or greater. Of this group, 31.5% (58 of 184) underwent sternal closure with titanium plate reinforcement and 68.5% (126 of 184) underwent traditional chest closure. The overall sternal complication rate was 4.9% (9 of 184), consisting of 6 of 126 nonplated patients and 3 of 58 plated patients (4.8% vs 5.2%, P = .80).

CONCLUSIONS

Sternal plate reinforcement for sternotomy closure of patients with a body mass index 35 kg/m² or greater produced no difference in postoperative sternal complication rates.

Surgical Site Infection After Cardiac Surgery: A Simplified Surveillance Method

We report the results of a 2-year, 7-center program of surveillance of deep sternal wound infection (DSWI) after cardiac surgery. DSWI was defined as the need for reoperation. Stratification data were abstracted from computerized files. The incidence of DSWI was 2.2% (198 of 8,816 cardiac surgery procedures). The risk factors identified were obesity, age, coronary artery bypass grafting, postoperative mechanical ventilation, and early surgical reexploration. The resource efficiency of this simplified surveillance method is discussed.

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.

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.

Investigation of mediastinitis due to coagulase-negative staphylococci after cardiothoracic surgery

Six cases of coagulase-negative staphylococcal mediastinitis were identified in the latter half of 1999. A new preoperative cleansing solution was suspected by hospital staff to be a factor in the outbreak. We evaluated this possible risk factor along with other known and suspected surgical site infection risk factors in this case-control study.

Surgical-site infection after cardiac surgery: incidence, microbiology, and risk factors

OBJECTIVE

To identify risk factors associated with surgical-site infection according to the depth of infection, the cardiac procedure, and the National Nosocomial Infections Surveillance System risk index.

DESIGN

Prospective survey conducted during a 12-month period.

SETTING

A 48-bed cardiac surgical department in a teaching hospital.

PATIENTS

Patients admitted for cardiac surgery between February 2002 and January 2003.

RESULTS

Surgical-site infections were diagnosed in 3% of the patients (38 of 1,268). Of the 38 surgical-site infections, 20 were superficial incisional infections and 18 were mediastinitis for incidence rates of 1.6% and 1.4%, respectively. Cultures were positive in 28 cases and the most commonly isolated pathogen was Staphylococcus. A National Nosocomial Infections Surveillance System risk index score of 2 or greater was associated with a risk of surgical-site infection (relative risk, 2.4; P < .004). Heart transplantation, mechanical circulatory assistance, coronary artery bypass graft with the use of internal mammary artery, and reoperation for cardiac tamponade or pericard effusion were independent risk factors associated with surgical-site infection.

CONCLUSIONS

Data surveillance using incidence rates stratified by cardiac procedure and type of infection is relevant to improving infection control efforts. Risk factors in patients who developed superficial infection were different from those in patients who developed mediastinitis. Coronary artery bypass graft using internal mammary artery was associated with a high risk of surgical-site infection, and independent factors such as reoperation for cardiac tamponade or pericard effusion increased the risk of infection.

Risk factors for surgical site infection after cardiac surgery: the role of endogenous flora

OBJECTIVE

The study's objective was to assess predictors of surgical site infection (SSI) after cardiac surgery and the relationship of perioperative nasal carriage of Staphylococcus species with the development of SSI.

METHODS

Surveillance for infections was performed, and anterior nares cultures of patients who underwent cardiac surgery were obtained. Preoperative risk factors were analyzed, and staphylococcal isolates from nares and SSI were compared using pulsed-field gel electrophoresis.

RESULTS

Twelve patients had 14 SSIs (5.7 infections/100 surgeries). Two risk factors were significantly associated with SSI: smoking (P = .002, confidence interval(95) 1.1-1.4, relative risk = 1.3) and increased body mass index (P = .003, confidence interval(95) 2.8-99.8, relative risk = 16.8). A total of 5 of 8 infected patients (62.5%) for whom nares cultures were available had identical strains in their nares and SSI.

CONCLUSION

Smoking and body mass index were predictors of SSI. Approximately 2 of 3 infected patients for whom nares cultures were obtained had an SSI that was likely from an endogenous source.

Prophylactic use of vancomycin in adult cardiology and cardiac surgery

The recent appearance of Staphylococcus aureus and Staphylococcus epidermidis strains that have reduced susceptibility to vancomycin, and the spread of vancomycin-resistant enterococci, raise the specter of endovascular infections that will be difficult or impossible to cure with available drugs. We review issues concerning the prophylactic use of vancomycin in adult cardiology and cardiac surgery with special attention to dosing and indications. There is no indication for the routine use of prophylactic vancomycin in pacemaker implantations, cardiac catheterization, and transesophageal echocardiography. In institutions with a high incidence of methicillin-resistant S. aureus and S. epidermidis, vancomycin may be used for antibiotic prophylaxis in place of cephalosporins for pacemaker or defibrillator implantation. The strongest evidence in support of the prophylactic use of vancomycin is during cardiac surgeries, particularly valvular surgeries in institutions with a high prevalence of methicillin-resistant S. aureus and S. epidermidis. When vancomycin is used prior to open heart surgery, the dose should be 15 mg/kg rather than the standard 1 g dose that is often recommended in the literature and used by 85% of institutional pharmacists who responded to our survey. Cardiologists and cardiac surgeons should assume leadership roles in promoting its responsible use.

Risk factors for leg harvest surgical site infections after coronary artery bypass graft surgery

OBJECTIVE

Harvest site infections are more common than chest surgical infections after coronary artery bypass surgery, yet few studies detail risk factors for these infections. We sought to determine independent risk factors for leg surgical site infections using our institutional Society of Thoracic Surgeons database.

METHODS

We retrospectively analyzed data collected from 1980 coronary artery bypass patients undergoing surgery at our institution from January 1, 1996, through June 30, 1999, using The Society of Thoracic Surgeons database. Independent risk factors for leg harvest site infection were identified by multivariate logistic regression.

RESULTS

Seventy-six patients (4.5%) were coded as having had a leg harvest site infection, of which 67 were confirmed by infection control. The length of hospital stay after surgery was significantly longer in patients with leg harvest site infection (mean 10.1 days) compared with that of patients without infection (mean 7.1 days, P <.001), and infected patients were more likely to be readmitted to the hospital within 30 days of surgery. Independent risk factors for leg harvest site infection included previous cerebrovascular accident (odds ratio, 2.9), postoperative transfusion of 5 units or more of red blood cells (odds ratio, 2.8), obesity (odds ratio, 2.5), age 75 years or older (odds ratio, 1.9), and female gender (odds ratio, 1.8).

CONCLUSIONS

Consistent with previous studies, female gender and obesity were identified as independent risk factors for leg harvest site infection, while previous cerebrovascular accident, postoperative transfusion, and older age are newly described risk factors. The Society of Thoracic Surgeons database is a useful tool for identification of predictors of leg harvest site infections.

Preoperative skin preparation of cardiac patients

Nurses at a large southwestern hospital undertook an initiative to optimize the preoperative skin preparation of patients undergoing open heart surgery. After an extensive review of the literature, a proposal was submitted to and accepted by the surgeons and internal review board of the hospital. High-risk patients were identified before surgery and randomized into groups to receive one of four different skin preps. The incidence of infection was lower in the two groups of patients who were prepped with insoluble iodine, indicating that the type of surgical skin prep could affect whether patients develop surgical site infections. The clinical practice of skin preparation in this hospital changed based on the results.

Use of radial artery graft reduces the morbidity of coronary artery bypass graft surgery in patients aged 65 years and older

BACKGROUND

The use of the radial artery graft in patients aged 65 years and older could prevent the occurrence of leg wound infection, which is known to increase the morbidity of coronary artery bypass grafting surgery.

METHODS

We reviewed, retrospectively, 261 patients aged 65 years and older (age range 65 to 93 years), who underwent coronary artery bypass grafting surgery between February 1998 and August 2001. All the patients received at least one radial artery graft in addition to either a left internal thoracic artery, right internal thoracic artery, or saphenous vein graft as required. Saphenous vein grafts were used in 141 (54.1%) patients (group 1), and these were compared to 120 (45.9%) patients (group 2) who received only arterial conduits. Angiography was performed on 26 consecutive patients. The aim of the study was to review the clinical and angiographic outcomes in this population.

RESULTS

The mean number of distal anastomoses performed was 2.98. Mean global operating time was 204 minutes. This time dropped to 201 minutes in group 1 versus 231 minutes in group 2; p = 0.009. Sixteen (11.3%) patients receiving saphenous vein grafts had leg wound infection whereas only 1 (0.3%) patient of the global population had a forearm infection. The mean global hospital stay was 9.81 days; this duration increased to 13 days when leg wound infection occurred versus 9.1 days when infection did not occur; p = 0.008. Twenty-six (10%) patients underwent an early angiographic study. Twenty-four (92.3%) radial artery grafts were patent.

CONCLUSIONS

The routine use of radial artery grafts in patients aged 65 years and older is feasible, safe, and does not increase mortality, morbidity, or the complexity of coronary artery bypass grafting surgery.

Nonrandom selection and the attributable cost of surgical-site infections

OBJECTIVE

To study the extent to which selection bias poses problems for estimating the attributable cost of deep chest surgical-site infection (SSI) following coronary artery bypass graft (CABG) surgery.

DESIGN

Reanalysis of a prospective case-control study.

SETTING

A large, Midwestern community medical center.

PATIENTS

Cases were all patients who had an SSI (N = 41) following CABG and CABG and valve surgery between April 1996 and March 1998. Controls were every tenth uninfected patient (N = 160).

METHODS

Estimates of the attributable cost of deep chest SSI were computed using unmatched comparison, matched comparison, linear regression, and Heckman's two-stage approach.

RESULTS

The attributable cost of deep chest SSI was estimated to be $20,012 by unmatched comparison, $19,579 by matched comparison, $20,103 by linear regression, and $14,211 by Heckman's two-stage method. Controlling for selection bias substantially reduced the cost estimate, but the coefficient capturing selection bias was not statistically significant.

CONCLUSIONS

Deep chest SSI significantly increases the cost of care for patients who undergo CABG surgery. Unmatched comparison, matched comparison, and linear regression estimated the attributable cost to be approximately $20,000. Although controlling for selection bias with Heckman's two-stage method resulted in a substantially smaller estimate, the coefficient for selection bias was not statistically significant, suggesting that the estimates derived from the other models should be acceptable. However, the magnitude of the difference between the models shows that the effect of selection bias can be substantial. Some exploration for selection bias is recommended when estimating the attributable cost of SSIs.

Superficial and deep sternal wound complications: incidence, risk factors and mortality

OBJECTIVES

Sternal wound complications often have a late onset and are detected after patients are discharged from the hospital. In an effort to catch all sternal wound complications, different postdischarge surveillance methods have to be used. Together with this long-term follow-up an analysis of risk factors may help to identify patients at risk and can lead to more effective preventive and control measures.

METHODS

This retrospective study of 3008 adult patients who underwent consecutive cardiac surgery from January 1996 through September 1999 at Linköping University Hospital, Sweden, evaluated 42 potential risk factors by univariate analysis followed by backward stepwise multivariate logistic regression analysis.

RESULTS

Two-thirds of the 291 (9.7%) sternal wound complications that occurred were identified after discharge. Of the 291 patients, 47 (1.6%) had deep sternal infections, 50 (1.7%) had postoperative mediastinitis, and 194 (6.4%) had superficial sternal wound complications. Twenty-three variables were selected by univariate analysis (P<0.15) and included in a multivariate analysis where eight variables emerged as significant (P<0.05). Preoperative risk factors for deep sternal infections/mediastinitis were obesity, insulin-dependent diabetes, smoking, peripheral vascular disease, and high New York Heart Association score. An intraoperative risk factor was bilateral use of internal mammary arteries, and a postoperative risk factor was prolonged ventilator support. Risk factors for superficial sternal wound complications were obesity, and an age of <75 years. The 30 day mortality was 2.7% for patients without sternal wound complications and 2/291 (0.7%) for all patients with sternal wound complications, 0.5% for superficial sternal wound complications, and 1.0% for deep sternal infections/mediastinitis. The 1 year mortality rate was 4.8% for patients without sternal wound complications and 11/291 (3.8%) for patients with sternal wound complications, 2.1% for superficial sternal wound complications, and 7.2% for deep sternal infections/mediastinitis.

CONCLUSIONS

The risk factors found in this study have been detected and reported in previous studies. The predictive ability was stronger though for deep sternal infections/mediastinitis (those needing surgical revisions) than for superficial sternal wound complications. Earlier recognition of sternal wound complications and aggressive treatment have probably contributed to the relatively low mortality rate seen in this study.

Impact of active monitoring of infection control practices on deep sternal infection after open-heart surgery

BACKGROUND

Deep-sternal infection is a devastating complication after open-heart surgery. However, the association between infection control practices and deep-sternal infection rates is unclear.

METHODS

To identify contributors to increased deep-sternal infection rates in our institution, consecutive open-heart surgery patients were prospectively studied during two periods (75 and 40 days), including 66 and 40 patients, respectively. Active monitoring including 149 infection control practices was performed in the operating room and intensive care unit. End-points were deep-sternal infection rates and their relation to infection control practices.

RESULTS

Mean age was 62+/-11 years and 68% were males. Coronary bypass was performed in 82%. Clinical and surgical features were comparable, except that patients in period 2 were more likely to have heart failure (15% vs 1.5%, p = 0.01) and had a longer mean duration of surgery (277 vs 217 minutes, p < 0.005). Only 57 practices (38%) were adequately performed. The main categories showing inadequate practices were disinfection, traffic, hand-washing, and surgical attire of nonscrubbed personnel, anesthesiologists, and pump technicians. Many categories showed a statistically significant improvement between periods. Deep-sternal infection rates in prestudy and poststudy periods were 10% and 2.8%, respectively (p = 0.007).

CONCLUSIONS

Active monitoring among personnel involved in open-heart surgery resulted in a significant and sustained decrease in deep-sternal infection rates, through modification of human behavior and improvement of performance standards, probably mediated by the Hawthorne effect. Periodic active monitoring may be a valuable tool to achieve and even sustain such a decrease with tremendous implications on morbidity, costs, and quality of care.

Intranasal mupirocin reduces sternal wound infection after open heart surgery in diabetics and nondiabetics

BACKGROUND

This study was designed to determine whether decreasing nasal bacterial colonization by applying Mupirocin (MPN) intranasally decreases sternal wound infections.

METHODS

We prospectively followed 992 consecutive open heart surgery (OHS) patients who did not receive MPN prophylaxis (group I) from January 1, 1995 to October 31, 1996. Group II consisted of 854 consecutive patients followed prospectively from December 1, 1997 to March 31, 1999 treated with intranasal MPN given on the evening before, the morning of OHS, and twice daily for 5 days postoperatively.

RESULTS

There was a significant difference in the rate of overall sternal wound infections between the untreated (group I) and the treated group (group II): 2.7% (27 of 992) versus 0.9% (8 of 854) (p = 0.005). The difference was also significant in the diabetic subgroup: 5.1% (14 of 277) (group I) versus 1.9% (5 of 266) (group II) (p = 0.04) and the nondiabetic group: 1.8% (13 of 715) (group I) versus 0.5% (3 of 588) (group II) (p = 0.03). The cost of MPN treatment was $12.47 per patient compared with $81,018 +/- $41,567 for a deep wound infection with no antibiotic-related complications recorded.

CONCLUSIONS

Prophylactic intranasal MPN is safe, inexpensive, and very effective in reducing the overall sternal wound infections by 66.6%.

Comparison between closed drainage techniques for the treatment of postoperative mediastinitis

BACKGROUND

It is not clear which closed drainage technique is preferred as initial therapy for mediastinitis as soon as it is detected after cardiac surgery. A comparison is made between a continuous irrigation system and vacuum drainage using redon catheters.

METHODS

A retrospective cohort study of patients undergoing cardiac surgery between January 1, 1989 and January 1, 1997 was made. Patients who developed a deep surgical site infection at the sternotomy site and who were treated with one of the two closed drainage techniques were included. Patient characteristics and procedure-related variables were analyzed. Also, variables related to the drainage procedure were included. Outcome parameters were treatment failure, total hospital stay, postoperative hospital stay and in-hospital mortality.

RESULTS

The study population consisted of 11,488 patients, of whom 102 developed a deep surgical site infection (0.89%). The final study population consisted of 60 patients who fulfilled the inclusion criteria. From those, 29 were treated with continuous irrigation and 31 were treated with vacuum drainage. Both groups were comparable for patient characteristics and procedure-related variables. Treatment failure was more than three times as likely in the continuous irrigation group (relative risk: 3.2, 95% confidence interval: 1.3 to 7.7). Also, postoperative (p = 0.03) and total hospital stay (p = 0.03) were significantly longer in the group treated with continuous irrigation (mean prolongation of 14 and 13 days, respectively). After correcting for confounding, using multivariate analysis, the treatment method employed was found to be an independent and statistically significant variable associated with treatment failure (p = 0.04).

CONCLUSIONS

Closed drainage using vacuum-drainage system is the initial therapy of choice for patients with mediastinitis after cardiac surgery, because it is associated with significantly less treatment failure and a shorter stay in hospital.

The clinical and economic impact of deep chest surgical site infections following coronary artery bypass graft surgery

STUDY OBJECTIVES

To examine how deep chest surgical site infections following coronary artery bypass graft (CABG) surgery impact hospital inpatient length of stay (LOS), costs, and mortality.

SETTING

A large, Midwestern community medical center.

DESIGN

All CABG patients who developed deep chest infection (n = 41) were compared to a set of control subjects (n = 160) systematically selected as every tenth uninfected CABG patient. Clinical data were abstracted from patient records, and cost information was obtained from the cost accounting database of the hospital.

RESULTS

Variables that significantly increased the risk of deep chest surgical site infection included obesity (odds ratio [OR], 11; p = 0. 0001), renal insufficiency (OR, 8.9; p = 0.0001), connective tissue disease (OR, 25.4; p = 0.0003), reexploration for bleeding (OR, 8.2; p = 0.0015), and the timing of antibiotic prophylaxis (> 60 min before incision; OR, 5.3; p = 0.0128). Within 1 year postoperatively, patients with deep chest surgical site infection had a mortality rate of 22%, vs 0.6% for uninfected patients (p = 0.0001). Infected patients also incurred an average of 20 additional hospital days (p = 0.0001). Univariate analysis indicated that patients who developed deep chest surgical site infection incurred $20,012 in additional costs in the first year (p = 0.0001). Infected patients who died incurred on average $60,547 more than infected patients who survived (p = 0.034). Multivariate analysis confirmed the magnitude of the estimate of the cost for deep chest surgical site infection ($18, 938; p = 0.0001).

CONCLUSIONS

Deep chest surgical site infections following CABG surgery are associated with significant increases in LOS, hospitalization costs, and mortality. These results suggest the need for improved infection control measures to reduce deep chest surgical site infection rates.

Guideline for prevention of surgical site infection, 1999. Hospital Infection Control Practices Advisory Committee

The “Guideline for Prevention of Surgical Site Infection, 1999” presents the Centers for Disease Control and Prevention (CDC)'s recommendations for the prevention of surgical site infections (SSIs), formerly called surgical wound infections. This two-part guideline updates and replaces previous guidelines.

Part I, “Surgical Site Infection: An Overview,” describes the epidemiology, definitions, microbiology, pathogenesis, and surveillance of SSIs. Included is a detailed discussion of the pre-, intra-, and postoperative issues relevant to SSI genesis.