A fifteen-year wound surveillance study after coronary artery bypass

A review of the best method of leg wound closure following open harvesting of the long saphenous vein for coronary artery bypass grafting

Uncertainty exists around the optimal method of leg wound closure following open long saphenous vein harvesting in adults undergoing coronary artery bypass graft surgery (CABG). Such is evident from the variety observed in the closure approach utilised. Consequently, a best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was ‘following open long saphenous vein harvesting in adults undergoing CABG, is single-layer leg wound closure superior to multiple-layer closure in terms of post-operative complications encountered? ‘. Altogether 382 papers on Ovid Embase and Ovid Medline, 301 papers on PubMed and 11 papers on the Cochrane database were found using the reported search. From the screened articles, 6 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that the best method of leg closure following open saphenous vein harvesting for CABG is single-layer cutaneous closure. The use of a suction drain to eliminate the dead space should be considered on a case-to-case basis by the lead operating surgeon with the patient's characteristics and their own expertise in mind.

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Uncertainty exists around the best closure method after open harvesting of the long saphenous vein for CABG in adults.

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Various options include single-layer and multiple-layer closure.

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Therefore, we conducted a literature review to identify the best closure technique.

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We conclude that the best method is single-layer cutaneous closure.

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The use of a suction drain to eliminate the dead space should be considered.

Deep sternal infections after in situ bilateral internal thoracic artery grafting for left ventricular myocardial revascularization: predictors and influence on 20-year outcomes

Background

The incidence and potential factors influencing deep sternal wound infection (DSWI) in a cohort of patients undergoing coronary artery bypass grafting (CABG) using skeletonized bilateral internal thoracic artery (BITA) was explored. Furthermore, we studied influence of DSWI on long-term survival, major adverse cardiac events (MACEs) and repeat coronary revascularization (RCR).

Methods

The study cohort consisted of 1,325 consecutive patients who were divided in two groups: patients experiencing DSWI (n=33, group 1) and those who did not have sternal infection (n=1,292, group 2). A logistic regression model was employed to find predictors of DSWI whereas Cox regression and a competing risk models were carried out to test predictors of late death, MACE and RCR, respectively. Follow up was 100% complete and ranged from 1 to 245 months. Median follow-up was 103 months (IQR, 61 to 189 months). Cumulative follow-up was 16,430 patient years.

Results

The incidence of DSWI was 2.4%. Multivariable logistic regression analysis found any single independent predictor of DSWI. However, the association of peripheral vascular disease (PVD) and diabetes increased the risk by 1.4 and 1.6 times. When DM was associated with obesity the risk increased by 2.1 and 2.6 times compared to the single factors, respectively. Obese female patients were at a 1.6-fold higher risk when compared to the association of DM with obesity. DSWI was not an independent predictor of long-term survival (HR, 2.31; 95% CI: 0.59-9.12), RCR (SHR, 2.89; 95% CI: 0.65-10.12), or MACE (SHR, 1.98; 95% CI: 0.44-8.56).

Conclusions

With an accurate patient selection (i.e., exclusion of obese diabetic females) and strict DM control BITA represents a first choice for most of CABG patients, even at high risk for DSWI. The occurrence of DSWI does not influence long-term survival and late outcomes. Our findings should be confirmed by further larger research.

Secondary surgical-site infection after coronary artery bypass grafting: A multi-institutional prospective cohort study

OBJECTIVE

To analyze patient risk factors and processes of care associated with secondary surgical-site infection (SSI) after coronary artery bypass grafting (CABG).

METHODS

Data were collected prospectively between February and October 2010 for consenting adult patients undergoing CABG with saphenous vein graft (SVG) conduits. Patients who developed a deep or superficial SSI of the leg or groin within 65 days of CABG were compared with those who did not develop a secondary SSI.

RESULTS

Among 2174 patients identified, 65 (3.0%) developed a secondary SSI. Median time to diagnosis was 16 days (interquartile range 11-29) with the majority (86%) diagnosed after discharge. Gram-positive bacteria were most common. Readmission was more common in patients with a secondary SSI (34% vs 17%, P < .01). After adjustment, an open SVG harvest approach was associated with an increased risk of secondary SSI (adjusted hazard ratio [HR], 2.12; 95% confidence interval [CI], 1.28-3.48). Increased body mass index (adjusted HR, 1.08, 95% CI, 1.04-1.12) and packed red blood cell transfusions (adjusted HR, 1.13; 95% CI, 1.05-1.22) were associated with a greater risk of secondary SSI. Antibiotic type, antibiotic duration, and postoperative hyperglycemia were not associated with risk of secondary SSI.

CONCLUSIONS

Secondary SSI after CABG continues to be an important source of morbidity. This serious complication often occurs after discharge and is associated with open SVG harvesting, larger body mass, and blood transfusions. Patients with a secondary SSI have longer lengths of stay and are readmitted more frequently.

Highest core temperature during cardiopulmonary bypass and rate of mediastinitis

Temperature control during cardiopulmonary bypass (CPB) may be related to rates of bacterial infection. We assessed the relationship between highest core temperature during CPB and rates of mediastinitis in 6955 consecutive isolated coronary artery bypass graft (CABG) procedures in northern New England.

The overall rate of mediastinitis was 1.1%. The association between highest core temperature and mediastinitis was different for diabetics than for nondiabetics. A multivariate model showed that there was a significant interaction between diabetes and temperature in their association with mediastinitis ( p = 0.015). Diabetic patients showed higher rates of mediastinitis as highest core temperature increased, from 0.7% in the ≤37°C group to 3.3% in the ≥38°C group ( ptrend = 0.002). Adjusted rates were similar. Nondiabetic patients did not show this trend ( ptrend = 0.998).

Among diabetic patients, a peak core body temperature > 37.9°C during CPB is a significant risk factor for development of mediastinitis. Avoidance of higher temperatures during CPB may lower the risk of mediastinitis for diabetic patients undergoing CABG surgery.

Closed incision negative pressure therapy: international multidisciplinary consensus recommendations

Surgical site occurrences (SSOs) affect up to or over 25% of patients undergoing operative procedures, with the subset of surgical site infections (SSIs) being the most common. Commercially available closed incision negative pressure therapy (ciNPT) may offer surgeons an additional option to manage clean, closed surgical incisions. We conducted an extensive literature search for studies describing ciNPT use and assembled a diverse panel of experts to create consensus recommendations for when using ciNPT may be appropriate. A literature search of MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials using key words ‘prevention’, ‘negative pressure wound therapy (NPWT)’, ‘active incisional management’, ‘incisional vacuum therapy’, ‘incisional NPWT’, ‘incisional wound VAC’, ‘closed incisional NPWT’, ‘wound infection’, and ‘SSIs’ identified peer‐reviewed studies published from 2000 to 2015. During a multidisciplinary consensus meeting, the 12 experts reviewed the literature, presented their own ciNPT experiences, identified risk factors for SSOs and developed comprehensive consensus recommendations. A total of 100 publications satisfied the search requirements for ciNPT use. A majority presented data supporting ciNPT use. Numerous publications reported SSI risk factors, with the most common including obesity (body mass index ≥30 kg/m²); diabetes mellitus; tobacco use; or prolonged surgical time. We recommend that the surgeon assess the individual patient's risk factors and surgical risks. Surgeons should consider using ciNPT for patients at high risk for developing SSOs or who are undergoing a high‐risk procedure or a procedure that would have highly morbid consequences if an SSI occurred.

Perioperative hyperglycemia and risk of adverse events among patients with and without diabetes

OBJECTIVE

To study the association between diabetes status, perioperative hyperglycemia, and adverse events in a statewide surgical cohort.

BACKGROUND

Perioperative hyperglycemia may increase the risk of adverse events more significantly in patients without diabetes (NDM) than in those with diabetes (DM).

METHODS

Using data from the Surgical Care and Outcomes Assessment Program, a cohort study (2010-2012) evaluated diabetes status, perioperative hyperglycemia, and composite adverse events in abdominal, vascular, and spine surgery at 53 hospitals in Washington State.

RESULTS

Among 40,836 patients (mean age, 54 years; 53.6% women), 19% had diabetes; 47% underwent a perioperative blood glucose (BG) test, and of those, 18% had BG ≥180 mg/dL. DM patients had a higher rate of adverse events (12% vs 9%, P < 0.001) than NDM patients. After adjustment, among NDM patients, those with hyperglycemia had an increased risk of adverse events compared with those with normal BG. Among NDM patients, there was a dose-response relationship between the level of BG and composite adverse events [odds ratio (OR), 1.3 for BG 125-180 (95% confidence interval (CI), 1.1-1.5); OR, 1.6 for BG ≥180 (95% CI, 1.3-2.1)]. Conversely, hyperglycemic DM patients did not have an increased risk of adverse events, including those with a BG 180 or more (OR, 0.8; 95% CI, 0.6-1.0). NDM patients were less likely to receive insulin at each BG level.

CONCLUSIONS

For NDM patients, but not DM patients, the risk of adverse events was linked to hyperglycemia. Underlying this paradoxical effect may be the underuse of insulin, but also that hyperglycemia indicates higher levels of stress in NDM patients than in DM patients.

Risk Features for Surgical-Site Infections in Coronary Artery Bypass Surgery

OBJECTIVE: To identify preoperative and perioperative features that may lead to a risk of surgical-site infection (SSI) after coronary artery bypass surgery.

DESIGN: 884 patients who underwent coronary artery bypass grafting in 1992 and 1993 were studied. The associations between 23 preoperative and perioperative features and the presence of SSI at the donor site or in the chest area were evaluated by univariate analysis followed by multivariate logistic regression analysis.

SETTING: A university hospital.

RESULTS: 172 patients (19.5%) either had an SSI recorded before discharge or had received antibiotics prescribed for a suspected SSI during the 1-month surveillance period after discharge. Multivariate logistic regression analysis showed an extreme body mass index (BMI;P=.015), female gender (P=.023), and chronic obstructive pulmonary disease (COPD;P=.030) to be independent risk features for SSI. The donor site was infected in 136 patients (15.4%), an event for which female gender (P=.003) was the only independent risk feature. Forty-seven patients (5.3%) had an SSI of the chest area, with diabetes (P=.003) and extreme BMI (P=.010) as independent risk features.

CONCLUSION: Extreme BMI, female gender, and COPD are highly significant independent predictors of the development of SSI. Female gender is a risk feature specifically for SSI at the donor site, whereas diabetes and extreme BMI predict it in the chest area.

Comparison of Vancomycin and Cefuroxime for Infection Prophylaxis in Coronary Artery Bypass Surgery

OBJECTIVE: To investigate clinically significant differences between vancomycin and cefuroxime for perioperative infection prophylaxis in coronary artery bypass surgery.

DESIGN: A total of 884 patients were randomized prospectively to receive either cefuroxime (444) or van-comycin (440) and were assessed for infectious complications during hospitalization and 1 month postoperatively.

SETTING: A university hospital.

RESULTS: The overall immediate surgical-site infection rate was 3.2% in the cefuroxime group and 3.5% in the vancomycin group (difference, −0.3; 95% confidence interval, −2.6-2.1).

CONCLUSIONS: The data suggest that vancomycin has no clinically significant advantages over cephalosporin in terms of antimicrobial prophylaxis. We suggest that cefuroxime (or first-generation cephalosporins, which were not studied here) is a good choice for infection prophylaxis in connection with coronary artery bypass surgery in institutions without methicillin-resistantStaphylococcus aureusproblems. In addition to the increasing vancomycin-resistant enterococci problem, the easier administration and usually lower price of cefuroxime make it preferable to vancomycin.

A Protracted Outbreak ofStaphylococcus epidermidisInfections Among Patients Undergoing Valve Replacement

Objective:

To investigate aStaphylococcus epidermidisoutbreak among patients undergoing cardiac surgery.

Design:

Retrospective cohort study.

Setting:

A 260-bed community referral center.

Patients:

Case-patients were patients withS. epidermidismediastinals, endocarditis, or both after valve implantation at Hospital de La Ribera from January to June 2002. The study population included patients undergoing valve surgery at Hospital de La Ribera from January 2000 to June 2002.

Results:

From January to June 2002, 8 cases of mediastinals, endocarditis, or both occurred among 53 patients undergoing cardiac surgery. In the same months of 2000, there had been no cases among 22 patients, and in 2001, only 1 case among 47 patients (P= .095 andP= .034, respectively). In 2002, there were 4 cases of mediastinitis and endocarditis, 3 cases of medi-astinitis, and 1 case of endocarditis, all following aortic valve replacement. The epidemic curve suggested a protracted outbreak. Patients with chronic obstructive lung disease were sixfold more likely to be case-patients (95% confidence interval, 1.6-23.8). The mean duration of surgery tended to be longer in non-case-patients (161.4 ± 57.9 minutes) than in case-patients (123.7 ± 23.7 minutes) (P= .06).

Conclusion:

The cause of this protracted outbreak was likely multifactorial. Reemphasis of existing policies was associated with resolution of the outbreak.

Efficacy of a dual-ring wound protector for prevention of incisional surgical site infection after Whipple's procedure (pancreaticoduodenectomy) with preoperatively-placed intrabiliary stents: protocol for a randomised controlled trial

INTRODUCTION

Among surgical oncology patients, incisional surgical site infection is associated with substantially increased morbidity, mortality and healthcare costs. Moreover, while adults undergoing pancreaticoduodenectomy with preoperative placement of an intrabiliary stent have a high risk of this type of infection, and wound protectors may significantly reduce its risk, no relevant studies of wound protectors yet exist involving this patient population. This study will evaluate the efficacy of a dual-ring wound protector for prevention of incisional surgical site infection among adults undergoing pancreaticoduodenectomy with preoperatively-placed intrabiliary stents.

METHODS AND ANALYSIS

This study will be a parallel, dual-arm, randomised controlled trial that will utilise a more explanatory than pragmatic attitude. All adults (≥18 years) undergoing a pancreaticoduodenectomy at the Foothills Medical Centre in Calgary, Alberta, Canada with preoperative placement of an intrabiliary stent will be considered eligible. Exclusion criteria will include patient age <18 years and those receiving long-term glucocorticoids. The trial will employ block randomisation to allocate patients to a commercial dual-ring wound protector (the Alexis Wound Protector) or no wound protector and the current standard of care. The main outcome measure will be the rate of surgical site infection as defined by the Centers for Disease Control and Prevention criteria within 30 days of the index operation date as determined by a research assistant blinded to treatment allocation. Outcomes will be analysed by a statistician blinded to allocation status by calculating risk ratios and 95% CIs and compared using Fisher's exact test.

ETHICS AND DISSEMINATION

This will be the first randomised trial to evaluate the efficacy of a dual-ring wound protector for prevention of incisional surgical site infection among patients undergoing pancreaticoduodenectomy. Results of this study are expected to be available in 2016/2017 and will be disseminated using an integrated and end-of-grant knowledge translation strategy.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier NCT01836237.

Radial artery as graft for coronary artery bypass surgery: Advantages and disadvantages for its usage focused on structural and biological characteristics

Radial artery (RA) is the most popular arterial graft after the left internal thoracic artery in both low- and high-risk patients undergoing coronary artery bypass grafting. Various arterial grafts such as the right internal thoracic artery, the right gastroepiploic artery, and the inferior epigastric artery have also gained ground over the past 30 years because of the intimal hyperplasia and atherosclerosis of the saphenous vein leading to late graft occlusion. In this review article we would like to present the utility of the RA as a graft, focused mainly on its structural and biological characteristics.

The association between perioperative allogeneic transfusion volume and postoperative infection in patients following lumbar spine surgery

BACKGROUND

Perioperative allogeneic red blood cell transfusion is a risk factor for surgical site infection. The purpose of this study was to determine if the volume of perioperative allogeneic red blood cell transfusion influences the risk of surgical site infection following lumbar spine procedures.

METHODS

A retrospective matched case control study was performed by reviewing all patients who had undergone lumbar spine surgery at our institution from 2005 to 2009. Surgical site infections (spinal or iliac crest) were identified, all within thirty days of the procedure. Controls were matched to the infection cohort according to age, sex, body mass index, diabetic status, smoking status, Charlson Comorbidity Index, length of surgery, and procedure. A conditional logistic regression was performed to examine the association between transfusion volume and surgical site infection. The results were summarized by an odds ratio.

RESULTS

A total of 1799 lumbar procedures were identified with an infection rate of 3.1% (fifty-six cases). On the basis of the numbers, there was no significant difference in the matched variables between the infection cohort and the matched controls. The volume of transfusion was significantly associated with surgical site infection (odds ratio, 4.00 [95% confidence interval, 1.96 to 8.15]) after adjusting for both unmatched variables of preoperative hemoglobin level and volume of intraoperative blood loss.

CONCLUSIONS

In this retrospective matched case control study, the association between surgical site infection following lumbar spine surgery and volume of perioperative allogeneic red blood cell transfusion was supported.

Unprotected left main coronary artery disease after revascularization : effect of diabetes on patient outcomes

OBJECTIVE

It is unknown whether the effect of diabetes on patients with unprotected left main coronary artery (LMCA) disease differs according to the different revascularization strategies. This study was conducted to evaluate the impact of diabetes on patients with unprotected LMCA disease treated with either percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG).

PATIENTS AND METHODS

We prospectively enrolled 823 consecutive patients with unprotected LMCA disease who had drug-eluting stent (DES; n = 331) implantation or underwent CABG (n = 492) in the study. We compared the effects of diabetes on clinical outcomes according to different revascularization strategies.

RESULTS

Among 823 eligible patients enrolled, 226 had diabetes. In the DES population, no significant differences were observed in occurrences of death, cardiac death, repeat revascularization, stroke, and major adverse cardiac and cerebrovascular events. However, the risks of the composite of death/myocardial infarction (MI)/stroke (21.5 % DM vs. 7.2 % non-DM; p = 0.001) and MI (15.4 % DM vs. 1.6 % non-DM; p = 0.000) were significantly higher in the diabetic patients than those without diabetes. In the CABG population, similar rates of all clinical endpoints were observed between the diabetic and nondiabetic group.

CONCLUSION

Diabetes was associated with worse outcome in patients undergoing DES implantation for the treatment of unprotected LMCA disease. However, its negative prognostic impact was not found among patients undergoing CABG.

Assessing the Perioperative Safety of Common Femoral Endarterectomy in the Endovascular Era

Introduction:

Common femoral endarterectomy (CFE) has historically been the preferred treatment for atherosclerotic lesions involving the common femoral artery. The objectives of this study are to delineate the safety of this open procedure in the endovascular era, establish contemporary benchmarks for morbidity and mortality after CFE, and identify the subgroup of patients at increased risk of postoperative adverse events.

Methods:

Patients undergoing elective CFE in the 2007 to 2010 National Surgical Quality Improvement Project database were examined. Univariate analyses were used to identify the factors associated with major morbidity and mortality. Significant variables by univariate analysis were used to create multivariate logistic regression models for morbidity and mortality.

Results:

A total of 1513 patients underwent elective CFE. The 30-day mortality rate was 1.5%. Postoperative morbidities included cardiac (1.0%), pulmonary (1.9%), renal (0.4%), urinary tract infection (1.7%), thromboembolic (0.5%), neurologic (0.4%), sepsis (2.7%), superficial (6.3%), and deep surgical site complications (2.0%). At least 1 complication, including major and minor, was seen in 7.9% of the patients. By multivariate analysis, partial- and total-dependent functional status (odds ratio [OR] 9.0, 95% confidence interval [CI] 2.8-28.4 and OR 21.3, 95% CI 3.3-139.4) and dyspnea at rest (OR 8.2, 95% 1.2-58.8) predicted mortality. Independent predictors of morbidity include steroid use (OR 2.4, 95% 1.4-4.1), diabetes (OR 1.8, 95% CI 1.3-2.4), and obesity (OR 1.6, 95% CI 1.1-2.4).

Discussion:

Overall, CFE is tolerated well by the majority of patients with peripheral arterial disease. These results affirm the safety of CFE and can still be used as standard first-line therapy in most patients. Long-term results for endovascular interventions need to be studied to see whether high-risk patients that we identified for CFE would benefit more from an endovascular approach.

Current British veterinary attitudes to the use of perioperative antimicrobials in small animal surgery

A questionnaire was sent to 2951 mixed and small animal veterinary practices to examine the use of perioperative antimicrobials in cats and dogs in the UK. The percentage of respondents who always used antimicrobials in two surgical procedures classified according to NRC criteria as 'clean' was 25.3 per cent for removal of a 1&emsp14;cm cutaneous mass and 32.1 per cent for routine prescrotal castration. Factors considered important in decision-making about when to use antimicrobial agents included immunosuppression, presence of a drain, degree of wound contamination, potential for spillage of visceral contents and implantation of prosthesis. The most common antimicrobial agents mentioned were potentiated amoxicillin (98.0 per cent), amoxicillin (60.5 per cent), clindamycin (21.8 per cent), enrofloxacin (21.7 per cent), cephalexin (18.6 per cent) and metronidazole (12.7 per cent). Forty-three per cent of all responding veterinarians listed a long-acting preparation for perioperative use. The routes used were subcutaneous (76.1 per cent), intravenous (25.8 per cent), intramuscular (19.8 per cent), oral (13.5 per cent) and topical (7.7 per cent). Antimicrobials were given before surgery (66.6 per cent), during surgery (30.2 per cent), immediately after surgery (12.0 per cent) and after surgery (6.3 per cent). This survey has identified the suboptimal use of perioperative antimicrobials in small animal surgery with improvements needed with respect to timing, duration, choice of antimicrobial and a more prudent selection of surgical cases requiring prophylaxis.

Prospective comparative study of single-layer versus double-layer closure of leg wounds after long saphenous vein harvest in coronary artery bypass graft operations

INTRODUCTION

Wound infection is one of the major complication post CABG that leads to prolonged length of stay and cost post surgery. Coronary artery bypass grafting is one of the most commonly performed operations in the world. The long saphenous vein harvested by traditional techniques is still widely used and caries a risk of wound infection.

OBJECTIVE

The purpose of this study is to ascertain if a single-layer closure result in better wound healing and functional outcome as compared with the traditional two-layer closure after harvest of saphenous vein.

METHODS

Sixty-seven consecutive patients undergoing CABG were prospectively randomized to have their leg wound closed by either a single-layer technique with a suction drain or double layers without suction drain. All wounds were assessed for the presence of serous discharge, inflammation, edema, purulent exudates, infection of the deep tissues, and pain postoperatively and two weeks after discharge.

RESULTS

There were trends towards increased rates of wound related outcomes in patients in double layer group when compared with single layer group. Out of 77 patients in our study, 52 patients underwent single layer closure (males, n = 37; females, n= 15) and 25 patients underwent double layer closure (males, n = 21; females, n = 04). There was significant statistical difference between the treatment groups with single layer group having lower average scores (4.038) compared to double layer group (9.467), P- value 0.001. Patients whose legs were closed with the single layer technique had less post operative edema (23.07% vs 53.30) and pain (44.2 vs 73.33) compared with the double layer group.

CONCLUSIONS

Single-layer leg wound closure over a suction drain has shown a better wound outcome compared to traditional double-layer closure. A possible mechanism of better wound healing in the former technique might be through decreased tissue handling and a reduction in leg edema.

Assessing the impact of antibiotic prophylaxis in outpatient elective hand surgery: a single-center, retrospective review of 8,850 cases

PURPOSE

Prophylactic antibiotics have been shown to prevent surgical site infection (SSI) after some gastrointestinal, orthopedic, and plastic surgical procedures, but their efficacy in clean, elective hand surgery is unclear. Our aims were to assess the efficacy of preoperative antibiotics in preventing SSI after clean, elective hand surgery, and to identify potential risk factors for SSI.

METHODS

We queried the database from an outpatient surgical center by Current Procedural Terminology code to identify patients who underwent elective hand surgery. For each medical record, we collected patient demographics and characteristics along with preoperative, intraoperative, and postoperative management details. The primary outcome of this study was SSI, and secondary outcomes were wound dehiscence and suture granuloma.

RESULTS

From October 2000 through October 2008, 8,850 patient records met our inclusion criteria. The overall SSI rate was 0.35%, with an average patient follow-up duration of 79 days. The SSI rates did not significantly differ between patients receiving antibiotics (0.54%; 2,755 patients) and those who did not (0.26%; 6,095 patients). Surgical site infection was associated with smoking status, diabetes mellitus, and longer procedure length irrespective of antibiotic use. Subgroup analysis revealed that prophylactic antibiotics did not prevent SSI in male patients, smokers, or diabetics, or for procedure length less than 30 minutes, 30 to 60 minutes, and greater than 60 minutes.

CONCLUSIONS

Prophylactic antibiotic administration does not reduce the incidence of SSI after clean, elective hand surgery in an outpatient population. Moreover, subgroup analysis revealed that prophylactic antibiotics did not reduce the frequency of SSI among patients who were found to be at higher risk in this study. We identified 3 factors associated with the development of SSI in our study: diabetes mellitus status, procedure length, and smoking status. Given the potential harmful complications associated with antibiotic use and the lack of evidence that prophylactic antibiotics prevent SSIs, we conclude that antibiotics should not be routinely administered to patients who undergo clean, elective hand surgery.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

Effects of perioperative blood product use on surgical site infection following thoracic and lumbar spinal surgery

STUDY DESIGN

Retrospective case-control review.

OBJECTIVE

This retrospective study explored the hypothesis that the perioperative administration of blood products is an identifiable risk factor of increased surgical site infections (SSIs) after thoracic and lumbar spine surgical procedures.

SUMMARY OF BACKGROUND DATA

Surgical site infections are a significant cause of postoperative morbidity and mortality. According to the Center for Disease Control's National Nosocomial Infections Surveillance system, which monitors the rate of hospital-acquired infections in the United States, SSIs represent the third most commonly reported type of nosocomial infection, accounting for 14% to 16% of all nosocomial infections. The incidence of SSIs after spinal surgery is influenced by both preoperative and intraoperative risk factors. The relationship between blood products and SSIs has been a matter of debate for more than 2 decades. Several studies have supported the association between the use of blood products and the development of postoperative surgical site infections.

METHODS

A retrospective case-control study was performed. We reviewed the charts of all patients who had undergone thoracic and/or lumbar spinal surgery at the NYU Hospital for Joint Diseases between 2002 and 2007. All patients who had developed surgical site infections following spine surgery in this 5-year period were identified.

RESULTS

Data for 61 cases and 71 controls were included in this study. The analysis of the preoperative risk factors was performed for the entire population of patients. Body mass index and blood transfusions were found to be statistically significant risk factors for increased surgical site infections for this population.

CONCLUSION

Our findings support current theories that blood transfusions may have modulatory effects on the immune system of the recipients. Our specific study in spine patients may contribute to the expanding literature on allogeneic blood transfusions and the risk of nosocomial infections and encourage surgeons to favor a more restrictive policy with regard to transfusions.

Is the use of Steri-StripTM S for wound closure after coronary artery bypass grafting better than intracuticular suture?

Several methods have been used in wound closure after coronary artery bypass grafting (CABG). In this study, the safety and efficacy of one of these methods, Steri-Strip S is compared with the traditional intracuticular suture method. Eighty-one patients undergoing CABG were prospectively randomized into two groups according to the method of skin closure: Steri-Strip S group and traditional suture group. Comparison between the two methods was done with regards to the length of the wound and the time needed to close it. The median closure time with Steri-Strip S was 5.45+/-3.35 min vs. 7.53+/-3.41 min in the suture group. A pain score of >or=6 at the first postoperative day was found in 30% of the patients in the suture group vs. 14% of the patients in the Steri-Strip S group (P=0.07). Cosmetic evaluation showed a non-significant difference in the linear visual analogue score in favor of Steri-Strip S group compared to the intracuticular suture group (73.1 vs. 70.1) (P=0.07). Steri-Strip S is a fast, safe alternative for wound closure of the sternotomy incision and graft harvesting site. A larger study is needed to establish the potential beneficial effect of Steri-Strip S on wound infection prevention.

Positive nasal culture of methicillin-resistant Staphylococcus aureus (MRSA) is a risk factor for surgical site infection in orthopedics

BACKGROUND

Although nasal carriage of MRSA has been identified as one of the risk factors for surgical site infection (SSI) with MRSA, there have been no reports of this in the orthopedics field.

METHODS

This prospective observational cohort study included 2,423 consecutive patients who were admitted to our department over 26 months and who underwent orthopedic surgery. We examined the relationship between pre-existing nasal MRSA and subsequent occurrence of SSI with MRSA.

RESULTS

63 patients (2.6%) had a positive nasal MRSA culture. 15 patients (0.6%) developed SSI with MRSA. The occurrence of SSI with MRSA in nasal MRSA carriers was significantly higher than that in non-carriers (4 out of 63 (6.3%) vs. 11 out of 2,360 (0.5%); p < 0.001) (adjusted OR: 11; 95% CI: 3-37; p = 0.001).

INTERPRETATION

We recommend appropriate treatment of patients who are nasal carriers of MRSA before orthopedic surgery.

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.

A national survey of antimicrobial prophylaxis in adult cardiac surgery across Canada

OBJECTIVE

To characterize national and regional patterns of antimicrobial prophylaxis in adult cardiac surgery across Canada.

DESIGN

Retrospective, cross-sectional analysis.

SETTING

Thirty-three adult cardiac surgical centres across Canada.

INTERVENTIONS

A one-page questionnaire collecting information regarding institutional demographics and antimicrobial prophylaxis regimens for adult cardiac surgical procedures was mailed to all adult surgical centres across Canada. If a response was not received within one month, a second survey was mailed, followed by a telephone reminder within two weeks of the second mailing.

MAIN RESULTS

The Overall response rate was 100%. Prophylactic antimicrobials were used in all the adult cardiac centres; single-agent prophylaxis was used in 97% (32 of 33) of centres; Single-dose antimicrobial prophylaxis was used in only 3% (one of 33) of centres. Preoperative and postoperative antimicrobial prophylaxis regimens varied both between provinces and within provinces across Canada. Cefazolin was the antimicrobial used in 88% (38 of 43) and 87% (33 of 38) of the reported pre-operative and post-operative prophylaxis regimens, respectively. Antimicrobial prophylaxis was initiated in the operating room 72% (26 of 36) of the time and intra-operative supplemental antimicrobial doses were administered for cardiac procedures longer than a median of 4 hours (range 4 to 8 hr). Overall, the median duration of antimicrobial prophylaxis was 36 hours (range 8 to 96 hr).

CONCLUSIONS

Despite the availability of various published guidelines, our survey identified several areas for improvement with respect to antimicrobial prophylaxis in adult cardiac surgery across Canada.

Retrospective analysis of local sensorimotor deficits after radial artery harvesting for coronary artery bypass grafting

OBJECTIVES

The radial artery (RA) has gained widespread acceptance as a conduit for coronary artery bypass. We analyze patient-based data to determine risk factors for long-term upper limb morbidities associated with RA harvest for coronary artery bypass grafting.

STUDY DESIGN/METHODS

Between April 1997 and March 2004, a total of 1030 patients underwent RA harvesting for coronary artery bypass grafting for a total of 1704 harvest sites. Patients were contacted by telephone and asked to report any ongoing severe sensory and functional motor deficits for each harvest site since surgery. Retrospective chart review was performed and preoperative risk factors were evaluated. Patient-based risk factors were evaluated for development of significant long-term local sensorimotor deficits including gender, elderly age (>70 y), diabetes, smoking, and whether the RA was harvested from the dominant hand.

RESULTS

Successful evaluation of 629 patients for a total of 1048 RA harvest sites was completed. The mean follow-up time was 48.3 mo (range, 2 to 86 mo). The mean age of the patients analyzed was 62.2 y. On statistical analysis, diabetics and elderly did not report significantly greater functional or sensory deficits than nondiabetics and nonelderly, respectively. There was a significantly higher incidence of sensory deficits in smokers compared with nonsmoker patients (4.2% versus 1.4%; P = 0.005) but no difference in their functional impairment was noted. Harvesting from the dominant hand did not influence the occurrence of sensory or motor functional deficits.

CONCLUSIONS

RA harvesting for coronary artery bypass grafting can be done with minimal serious long-term upper limb morbidity in higher risk patients. Based on our findings, harvesting of the RA from the dominant hand is not contraindicated in these patients.

In vivo measurement of levofloxacin penetration into lung tissue after cardiac surgery

Nosocomial pneumonia is a severe complication after cardiac surgery (CS). Levofloxacin, a fluoroquinolone, qualifies for the therapy of postoperative pneumonia. However, penetration properties of levofloxacin into the lung tissue could be substantially affected by CS: atelectasis, low cardiac output after CS, high volume loads, and inflammatory capillary leak potentially influence drug distribution. The aim of our study was to gain information on interstitial antibiotic concentrations in lung tissue in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass. Therefore, six patients undergoing elective CS participated in this prospective study. A dose of 500 mg of levofloxacin was administered intravenously in addition to standard antibiotic prophylaxis immediately after the end of surgery. Time versus concentration profiles of levofloxacin in the interstitial lung tissue and plasma were determined. A microdialysis technique was used for lung interstitial concentration measurements. The microdialysis procedure was well tolerated in all patients and no adverse events were observed. The median area under the concentration curve (AUC) of levofloxacin in interstitial lung fluid was 18.6 microg.h/ml (range, 10.1 to 33.6). The median AUC for tissue (AUC(tissue)) of unbound levofloxacin/AUC(total) in plasma was 0.6 (range, 0.4 to 0.9). The median unbound AUC(tissue)/MIC was 2.4 (range, 1.3 to 4.2) for Pseudomonas aeruginosa. Our study demonstrated the feasibility and safety of microdialysis in human lung tissue in vivo after CS. The unbound AUC/MIC ratio revealed that levofloxacin used in the described manner was borderline sufficient for the treatment of nosocomial pneumonia caused by Klebsiella pneumoniae and insufficient for the treatment of pneumonia caused by Pseudomonas aeruginosa, because the breakpoint of 30 to 40 for AUC/MIC could not be reached by the conventionally used dosage schema in our post-CS setting. Penetration was lower than in previous reports.

Single-Layer Versus Multiple-Layer Closure of Leg Wounds After Long Saphenous Vein Harvest: A Prospective Randomized Trial

BACKGROUND

The long saphenous vein harvested by traditional techniques is an important conduit for coronary artery bypass grafting (CABG). The purpose of this study was to determine if a single-layer closure over a drain improved wound healing compared with the traditional two-layer closure after harvest.

METHODS

Seventy-eight consecutive patients undergoing CABG were prospectively randomized to have their leg wound closed by either a single-layer technique with a suction drain or multiple layers. All wounds were assessed using the additional treatment, presence of serous discharge, erythema, purulent exudate, and separation of the deep tissues, isolation of bacteria, and the duration of inpatient stay (ASEPSIS) score postoperatively and 6 weeks later.

RESULTS

Forty-four patients (5 females) had their wound closed by the single-layer technique and 34 (6 females) closed in multiple layers. The ASEPSIS scores were significantly lower (p = 0.001) in those patients closed with a single layer (mean, 4.4) than those with multiple layers (mean, 6.8). Patients whose legs were closed with the single-layer technique had less peripheral edema compared with the multiple-layer group (chi2, p < 0.001). Using univariate analysis there was no correlation between ASEPSIS scores and length of wound incision (p = 0.49), whereas increasing age was found to have a weak positive correlation (r =0.24; p = 0.04).

CONCLUSIONS

Single-layer leg wound closure over a suction drain is superior to the traditional multiple-layer closure. A possible mechanism of better wound healing in the former technique might be through decreased tissue handling and a reduction in leg edema.

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.

The Impact of Deep Sternal Wound Infection on Long-term Survival After Coronary Artery Bypass Grafting

OBJECTIVES

To identify the impact of deep sternal wound infection (DSWI) on long-term survival after coronary artery bypass grafting (CABG).

BACKGROUND

DSWI following CABG is an infrequent, yet devastating complication with increased morbidity and mortality. However, little has been published regarding the impact of DSWI on long-term mortality.

METHODS

We studied 3,760 consecutive patients who underwent isolated CABG between 1992 and 2002. Patients with CABG and no DSWI were compared with those in whom DSWI developed. Long-term survival data (mean follow-up, 5.2 years) were obtained from the National Death Index. Groups were compared by Cox proportional hazard models and Kaplan-Meier survival plots. The propensity for DSWI was determined by logistic regression analysis, and each patient with DSWI was then matched to 10 patients without DSWI.

RESULTS

DSWI developed in 40 of 3,760 patients (1.1%). Independent predictors for DSWI were diabetes (odds ratio [OR], 5.5; 95% confidence interval [CI], 2.7 to 11.6; p < 0.001), hemodynamic instability preoperatively (OR, 4.0; 95% CI, 1.2 to 13.9; p = 0.026), preoperative renal failure on dialysis (OR, 3.4; 95% CI, 1.0 to 13.6; p = 0.049), use of bilateral internal thoracic arteries (OR, 2.6; 95% CI, 1.3 to 5.3; p = 0.010), and sepsis and/or endocarditis after CABG (OR, 29.9; 95% CI, 11.7 to 76.4; p < 0.001). Patients with DSWI had prolonged length of stay (35.0 days vs 16.4 days; p < 0.001); however, there was no difference in early mortality between matched groups. After adjustment for preoperative, intraoperative, and postoperative factors, the adjusted hazard ratio of long-term mortality for patients with DSWI was 2.44 (95% CI, 1.51 to 3.92; p < 0.001). Patients without DSWI had a better 5-year survival rate (72.8 +/- 2.4% vs 50.8.6 +/- 8.5% [mean +/- SE]; p = 0.0007 between matched groups).

CONCLUSIONS

We found that DSWI following CABG was associated with increased long-term mortality during a 10-year follow-up study.

Multivariate analysis of risk factors for deep and superficial sternal infection after coronary artery bypass grafting at a tertiary care medical center

Identification of modifiable risk factors for sternal infection is essential for the development and institution of practices that decrease the incidence of these infections. This study analyzed 4004 consecutive patients undergoing coronary artery bypass grafting performed at a single institution between January 1996 and May 2003. Specific risk factors for both superficial and deep sternal wound infection were identified by univariate and multivariate analysis. The incidence of superficial sternal wound infections was 2.2% (N = 87) while the incidence of deep sternal wound infections was 1.8% (N = 73). Risk factors for superficial sternal infection identified by multivariate analysis include increasing body mass index (BMI) (OR 1.089, 95% CI 1.057-1.122, P < 0.001), female gender (OR 1.412, 1.108-1.717, P = 0.036), active smoking (OR 1.856, 1.079-3.193, P = 0.025), utilization of bilateral internal mammary arteries (OR 7.546, 3.175-17.935, P < 0.001), and transfusion of > or =4 units of packed red blood cells postoperatively (OR 2.009, 1.158-3.485, P = 0.013). Risk factors for deep sternal infection include increasing BMI (OR 1.077, 1.042-1.114, P < 0.001), diabetes mellitus (OR 2.412, 1.376-4.231, P = 0.002), and transfusion with > or =2 units of platelets postoperatively (OR 2.787, 1.279-6.071, P = 0.010). These data suggest that cessation of smoking, improved blood glucose management, preoperative weight loss, limitation of transfusions, and discriminate use of bilateral internal mammary arteries are all practices that may decrease the incidence of postoperative wound complications following coronary revascularization.

An Insulin Infusion Protocol in Critically Ill Cardiothoracic Surgery Patients

BACKGROUND:

Critically ill cardiothoracic patients are prone to hyperglycemia and an increased risk of surgical site infections postoperatively. Aggressive insulin treatment is required to achieve tight glycemic control (TGC) and improve outcomes.

OBJECTIVE:

To examine and report on the performance of an insulin infusion protocol to maintain TGC, defined as a blood glucose level of 80–150 mg/dL, in critically ill cardiothoracic surgical patients.

METHODS:

A nurse-driven insulin infusion protocol was developed and initiated in postoperative cardiothoracic surgical intensive care patients with or without diabetes. In this before—after cohort study, 2 periods of measurement were performed: a 6–month baseline period prior to the initiation of the insulin infusion protocol (control group, n = 174) followed by a 6–month intervention period in which the protocol was used (TGC group, n = 168).

RESULTS:

Findings showed percent and time of blood glucose measurements within the TGC range (control 47% vs TGC 61%; p = 0.001), AUC of glucose exposure >150 mg/dL versus time for the first 24 hours of the insulin infusion (control 28.4 vs TGC 14.8; p < 0.001), median time to blood glucose <150 mg/dL (control 9.4 h vs TGC 2.1 h; p < 0.001), and percent blood glucose <65 mg/dL as a marker for hypoglycemia (control 9.8% vs TGC 16.7%; NS).

CONCLUSIONS:

An insulin infusion protocol designed to achieve a goal blood glucose range of 80–150 mg/dL efficiently and significantly improved TGC in critically ill postoperative cardiothoracic surgery patients without significantly increasing the incidence of hypoglycemia.

Staphylococcus aureus types 5 and 8 capsular polysaccharide-protein conjugate vaccines

BACKGROUND

Staphylococcus aureus, the first or second most common pathogen isolated from patients, is capsulated; there are at least 12 capsular types, and types 5 and 8 comprise approximately 85% of blood. Types 5 and 8, composed of a trisaccharide repeat unit including a mannose uronic acid and 2 fucoses, are non-immunogenic. As protein conjugates, they induce opsonophagocytic antibodies that confer type-specific active and passive protection in mice.

METHODS

A phase II study of patients with end-stage renal disease showed that these conjugates induced approximately one third of the immunoglobulin G antibody of healthy individuals. Increasing the dose to 100 microg of polysaccharide induced levels similar to that in healthy individuals injected with 25 microg.

RESULTS

In a double-blinded randomized and controlled study of patients undergoing renal dialysis, the conjugates induced statistically significant protection against bacteremia for as long as 10 months after immunization. The estimated protective level was 80 microg Ab/mL. At re-injection approximately 2 years later, 83 of 83 recipients responded with protective levels.

CONCLUSIONS

Conjugate vaccine-induced antibodies to the types 5 and 8 capsular polysaccharide antibodies of S aureus prevent bacteremia caused by this pathogen. The extent and duration of conjugate-induced immunity can be extended by re-immunization approximately 1 year later. Studies of patients undergoing cardiovascular surgery who would be immunized with the staphylococcus conjugates when they are immunologically intact are planned.

Plastic iodophor drape during liver surgery operative use of the iodophor-impregnated adhesive drape to prevent wound infection during high risk surgery

We retrospectively investigated factors associated with wound infection after liver resection for hepatocellular carcinoma (HCC), with special reference to use of a plastic adhesive drape impregnated with iodophor. The subjects were 296 patients undergoing liver resection for HCC. Wound infection was defined as purulent drainage from the superficial incision with or without laboratory confirmation. One or more of the following signs was required: pain or tenderness, localized swelling, or redness or heat. Wound infection developed in 25 patients. Regression analysis indicated that low body mass index (BMI), smoking, long preoperative hospital stay, and nonuse of iodophor drapes were risk factors for wound infection. Wound infection was significantly less likely with the use of iodophor drapes (3.1%) than for surgery without iodophor drapes (12.1%). By multivariate regression analysis, BMI, smoking, and lack of drape use were independent risk factors. Most of the bacteria isolated were skin bacteria, including Staphylococcus aureus and Staphylococcus epidermidis. In conclusion, low BMI, smoking, a long preoperative hospital stay, and the lack of iodophor drape use were risk factors for wound infection after liver resection for HCC. The drapes presumably prevented contamination from the skin during the operation.

Percutaneous coronary intervention versus coronary bypass graft surgery for diabetic patients with unstable angina and risk factors for adverse outcomes with bypass: outcome of diabetic patients in the AWESOME randomized trial and registry

OBJECTIVES

This study compared survival after percutaneous coronary intervention (PCI) with survival after coronary artery bypass graft surgery (CABG) among diabetics in the Veterans Affairs AWESOME (Angina With Extremely Serious Operative Mortality Evaluation) study randomized trial and registry of high-risk patients.

BACKGROUND

Previous studies indicate that CABG may be superior to PCI for diabetics, but no comparisons have been made for diabetics at high risk for surgery.

METHODS

Over five years (1995 to 2000), 2,431 patients with medically refractory myocardial ischemia and at least one of five risk factors (prior CABG, myocardial infarction within seven days, left ventricular ejection fraction <0.35, age >70 years, or an intra-aortic balloon being required to stabilize) were identified. A total of 781 were acceptable for CABG and PCI, and 454 consented to be randomized. The 1,650 patients not acceptable for both CABG and PCI constitute the physician-directed registry, and the 327 who were acceptable but refused to be randomized constitute the patient-choice registry. Diabetes prevalence was 32% (144) among randomized patients, 27% (89) in the patient-choice registry, and 32% (525) in the physician-directed registry. The CABG and PCI survival rates were compared using Kaplan-Meier curves and log-rank tests.

RESULTS

The respective CABG and PCI 36-month survival rates for diabetic patients were 72% and 81% for randomized patients, 85% and 89% for patient-choice registry patients, and 73% and 71% for the physician-directed registry patients. None of the differences was statistically significant.

CONCLUSIONS

We conclude that PCI is a relatively safe alternative to CABG for diabetic patients with medically refractory unstable angina who are at high risk for CABG.

Perioperative hyperglycemia is a strong correlate of postoperative infection in type II diabetic patients after coronary artery bypass grafting

This study was planned to assess the relationship of perioperative glycemic control to the subsequent risk of infectious complications and to compare early clinical outcomes of coronary artery bypass surgery in diabetics with nondiabetics in a single center. A total of 1090 adults who underwent coronary artery surgery in a five year period were included in a retrospective cohort study based on available chart review. Of 1090 patients, 400 had type II diabetes mellitus. Intraoperative and postoperative blood glucose levels in diabetic group were manipulated by means of a continuous insulin infusion. Data of pre- and postoperative blood glucose levels were evaluated with respect to postoperative infection risk for diabetics. Risks of early mortality, cerebrovascular accident, and postoperative infection in diabetic patients were compared with the nondiabetic group. High preoperative mean glucose levels were the main risk factor for the development of postoperative infection (p = 0.012 and p = 0.028 for the mean glucose levels 1 and 2 days before operation, respectively). For diabetic group, of 400 patients 20 (5%) were diagnosed to have postoperative infection (superficial sternal wound in 3 (0.75%), donor site infection in 4 (1%), mediastinitis in 5 (1.25%), urinary tract infection in 6 (1.5%), and lung infection in 2 (0.5%) patients). The diabetic group had significantly higher prevalence of mediastinitis, donor site infection, urinary tract infection and total infection (p values were 0.048, 0.013, 0.009, and 0.044, respectively). Early mortality was higher among diabetics than in nondiabetics (1.73% vs 3%, p = 0.048) but the risk of cerebrovascular accident in diabetics was not greater than in nondiabetics in early period. In patients with diabetes who undergo coronary artery bypass surgery, preoperative hyperglycemia is an independent predictor of short-term infectious complications and total length of stay in hospital.

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

OBJECTIVE

We sought to determine risk factors for deep and superficial chest wound infections after coronary artery bypass graft surgery to develop predictive models.

METHODS

We retrospectively analyzed data collected on 1980 consecutive patients undergoing coronary artery bypass surgery at our institution between January 1, 1996, and June 30, 1999, by using the Society of Thoracic Surgery database. Independent risk factors for surgical-site infection were identified with multivariate logistic regression.

RESULTS

There were 37 (1.9%) deep chest and 46 (2.3%) superficial chest surgical-site infections. Obese diabetic patients had a 7.7-fold increased risk of deep chest infections after controlling for intra-aortic balloon pump use (odds ratio, 3.1) and postoperative transfusion (odds ratio, 2.3). Independent risk factors for superficial surgical-site infections included obesity (odds ratio, 3.1), diabetes in persons 65 years of age or older (odds ratio, 2.7), and current smoking (odds ratio, 2.5). Use of antiplatelet drugs was associated with a lower risk of superficial infections (odds ratio, 0.4). Predicted operative mortality as a marker of severity of illness was not clearly predictive of deep or superficial surgical-site infection. Mortality in the year after the operation was increased in patients with deep chest infections compared with that seen in uninfected control subjects (8/37 [21.6%] vs 114/1612 [7.1%], P =.004) but not in patients with superficial chest infections (7/47 [15.2%] vs 114/1612 [7.1%], P =.075).

CONCLUSIONS

Risk factors for deep and superficial chest surgical-site infections after coronary artery bypass surgery differ, suggesting different mechanisms of pathogenesis. Appropriate risk stratification models specific to these important outcomes must be developed.

Endoscopic greater saphenous vein harvesting reduces the morbidity of coronary artery bypass surgery

BACKGROUND

Most coronary artery bypass grafting (CABG) operations still involve the use of greater saphenous vein (GSV) for one or more grafts, even with the increasing use of arterial conduits for coronary revascularization. Wound complications from GSV harvesting are common, and sometimes severe. In order to reduce the morbidity of this procedure, we adopted a technique of endoscopic vein harvesting (EVH). EVH allows nearly complete harvest of the GSV, with excellent visualization, through minimal incisions. At our institution, a physician's assistant routinely performs EVH, usually while a cardiothoracic surgeon harvests an arterial conduit. In 1997, all GSV harvesting was performed by open technique. During a transition period in 1998 and 1999 we used several different endoscopic techniques. By the beginning of 2000, our technique of EVH was standardized and used routinely.

METHODS

To determine whether EVH reduced the morbidity associated with conventional open vein harvesting (OVH), we reviewed the charts of all patients having primary coronary artery bypass operations utilizing GSV during the years 1997 and 2000.

RESULTS

The two groups were comparable in risk factors for leg incision complications. The year 2000 EVH group had a marked reduction in the number of wound complications compared with the year 1997 OVH group (7.1% versus 26.1%, P < 0.00001). There were no significant differences between the two groups in total operative time (OVH 224 minutes, EVH 223 minutes, number of distal coronary anastomoses (OVH 3.38 +/- 0.90, EVH 3.38 +/- 0.94), or the rate of clinically apparent early graft failure. There was a significant increase in the use of sequential grafting techniques in the 2000 group (OVH 21.9%, EVH 43.6%, P < 0.00001).

CONCLUSIONS

EVH reduced the morbidity associated with GSV harvesting. EVH was associated with an increased use of sequential coronary grafting techniques. EVH does not prolong operative time when performed by experienced personnel. We believe EVH should become the standard of care.

Morbidity after procurement of radial arteries in diabetic patients and the elderly undergoing coronary revascularization

BACKGROUND

The use of radial arteries for coronary revascularization is increasing. There remain concerns regarding alteration of upper extremity function after radial artery procurement. This study evaluates the functional morbidity in higher risk patients.

METHODS

Between April 1997 and September 1999, 374 patients underwent unilateral or bilateral radial artery procurement. A questionnaire was used to evaluate symptoms related to motor and sensory function and changes in appearance after radial artery harvest.

RESULTS

Two hundred eighty-nine patients were successfully interviewed. The average age was 63 years. Median follow-up was 9.5 months (range, 2 to 23 months). No patient suffered limb loss. Altered gross and fine motor function, residual pain, paresthesias, numbness, pallor, swelling, and altered temperature sensation were compared among diabetic patients, patients older than 70 years, and patients without these characteristics.

CONCLUSIONS

Radial artery procurement for elective coronary revascularization can be done with minimal serious morbidity in higher risk patients. The most common symptoms were numbness and paresthesia. Despite the finding of greater residual pain in diabetic patients, we do not believe the use of radial artery conduits is contraindicated in these patients.

Association of bacterial infection and red blood cell transfusion after coronary artery bypass surgery

BACKGROUND

Previous studies have shown an association between red blood cell transfusions (RBC) and bacterial infections following coronary artery bypass graft (CABG) surgery. We sought to assess whether there is an independent effect of RBC on the incidence of bacterial infections.

METHODS

This was a prospective cohort study of 533 CABG patients over a 7-month period. Subjects were followed from time of CABG until 30 days postoperatively. Data were collected on patient and treatment characteristics, surgical management, and transfusion incidence.

RESULTS

Seventy-five (14.1%) of 533 patients developed a bacterial infection. After controlling for patient and disease characteristics, invasive treatments, surgical time, and the transfusion of other substances, the adjusted rates of bacterial infection were 4.8% for no RBC transfusion, 15.2% with one to two units, 22.1% with three to five units, and 29.0% with greater than or equal to six units, (p(trend) < 0.001). Diabetes was the only patient or disease factor significantly associated with bacterial infection (p < 0.001).

CONCLUSIONS

RBC transfusions were independently associated with a higher incidence of post-CABG bacterial infections. The risk of infection increased in proportion to the number of units of RBC transfused.

The association of diabetes and glucose control with surgical-site infections among cardiothoracic surgery patients

OBJECTIVE

To assess the importance of diabetes, diabetes control, hyperglycemia, and previously undiagnosed diabetes in the development of surgical-site infections (SSIs) among cardiothoracic surgery patients.

SETTING

A 540-bed tertiary-care university-affiliated hospital.

DESIGN

Prospective cohort and case-control studies.

PATIENTS

All patients having cardiothoracic surgery between November 1998 and September 1999 were eligible for participation. One thousand patients had preoperative hemoglobin A1c determinations. Seventy-four patients with SSIs were identified.

RESULTS

Diabetes (odd ratio [OR], 2.76; P<.001) and postoperative hyperglycemia (OR, 2.02; P=.007) were independently associated with development of SSIs. Among known diabetics, elevated hemoglobin A1c values were not associated with a statistically significantly increased risk of infection; the mean A1c value was 8.44% among those with infections compared with 7.80% for those without (P=.09). Forty-two (6%) of 700 patients without prior diabetes history had evidence of undiagnosed diabetes; their infection rate was comparable to that of known diabetics (3/42 [7%] vs 17/300 [6%]; P=.72). An additional 30% of nondiabetics had elevated hemoglobin A1c determinations or perioperative hyperglycemia.

CONCLUSIONS

Postoperative hyperglycemia and previously undiagnosed diabetes are associated with development of SSIs among cardiothoracic surgery patients. Screening for diabetes and hyperglycemia among patients having cardiothoracic surgery may be warranted to prevent postoperative and chronic complications of this metabolic abnormality.

Postoperative management of the diabetic patient

Diabetic patients are at increased risk for adverse outcomes of surgery. These adverse outcomes are related to pre-existing complications of diabetes, especially atherosclerotic disease, nephropathy (and perhaps increased susceptibility to other renal toxins), and peripheral and autonomic neuropathy. Hyperglycemia is associated with likely risks for poorer wound healing, increased susceptibility to infection, and probable loss of administered nutrients through glycosuria. Insulin use has the flexibility of timing and dose in the postoperative management of most diabetic patients. The combinations of intermediate-acting and long-acting insulins and short-acting insulins usually are related to the experience and preferences of the treating physicians and allied health professionals. Intravenous insulin (always R) may be limited to administration in the ICU because of the need for frequent blood glucose monitoring and rapidity of glucose response to intravenous insulin. The use of short-acting insulin analogues has been shown to work well as premeal insulin or for rapidly treating marked hyperglycemia in the outpatient setting. Meal delivery in the hospitalized patient may not be timed as precisely as in the home situation. Nurses may be responsible for many patients. The rapid-acting analogues may be associated with increased risk for hypoglycemia in the hospitalized patient if insulin cannot be given immediately before a meal. These rapid-acting insulin analogues usually are limited to circumstances in which the patient can determine the dose and self-administer just before ingestion of the meal. The long-acting insulin analogues may not afford enough flexibility in many situations in which daily dosages changes are occurring in intermediate-acting and long-acting insulins. Oral glucose-lowering agent use in the postoperative state usually is limited to selected patients, including patients who have been on such agents before surgery, who have only mild elevations of blood glucose, who are able to ingest oral medications, and who do not have significant comorbid conditions (or significant risk for such conditions) that may be contraindications to use of such agents (see Table 3). Sulfonylureas and other insulin secretagogues (e.g., meglitinide, nateglinide) lower glucoses acutely. The risk for hypoglycemia is slightly less with the nonsulfonylurea agents. Efficacy and side effects limit the use of carbohydrase inhibitors for hospitalized patients. The glucose-lowering effects of biguanides and thiazolidinediones usually are not rapid enough for hospitalized patients who have never taken these medications. For patients who have been on a biguanide or thiazolidinedione before admission, these agents often are restarted in the postoperative period when oral intake of medications is possible and hepatic and renal function are stable. The hospital period affords an opportunity to review long-term management issues related to diabetes and its complications. Instruction on the importance of medical nutrition therapy, glycemic control, management of hypertension, dyslipidemia, and aspirin use as well as basic guidelines for foot care should be carried out during the hospitalization and at the time of discharge. Similarly, appropriate arrangements for medical nutrition therapy, general diabetes education (especially for newly diagnosed diabetic patients), and regular medical follow-up are important to ensure long-term, excellent surgical and medical outcomes.

Sternal Wound Infection Prediction Scale: a test of the reliability and validity

The purpose of the present study was to determine the reliability and validity of the Sternal Wound Infection Prediction Scale. The tool was developed to fill the need for a quick and easy way to determine which patients are at risk of developing a sternal wound infection in order that preventive measures can be instituted. Data were collected by a retrospective chart review of 56 patient records, 27 who developed a sternal wound infection and 29 who did not. In this group of patients, obesity and diabetes were found to be statistically significant risk factors. Pharmacological support was found to be a clinically significant factor. Of the infected group, 68.4% of patients who developed a sternal wound infection were predicted to do so by the tool.