[Effectiveness of Prophylactic Negative Pressure Wound Therapy after Cardiovascular Surgery through Median Sternotomy]

Negative pressure wound therapy( NPWT) is used primarily for tissue defects. In recent years, cardiovascular surgery via full sternotomy is increasingly performed through small incisions, but the rate of cardiovascular surgery through median sternotomy remains high in elderly patients, who frequently have complicated cardiovascular diseases. Mediastinitis, among other surgical site infections( SSIs), is a serious complication after cardiovascular surgery that must be resolved. Mediastinitis has a high mortality rate once it occurs, and cost of treatment and a negative impact on a patient are substantial. In some countries, NPWT is for the prophylaxis of mediastinitis, but only for cases with a significant risk of SSI. To avoid SSI, prophylactic NPWT is administered in all cardiovascular surgeries through median sternotomy at our hospital. Of 641 consecutive median sternotomy patients from March 2011 to March 2021, 601 cases were able to observe the wound for at least 30 days following the surgery. In the 601 cases, we found a statistically significant difference in the incidence of SSI. The results suggest that prophylactic NPWT significantly reduces SSI after cardiovascular surgery through median sternotomy.

Eradication of Staphylococcus aureus post-sternotomy mediastinitis following the implementation of universal pre-operative nasal decontamination with mupirocin: an interrupted time-series analysis

BACKGROUND

Although pre-surgical nasal decontamination with mupirocin (NDM) has been advocated as a measure for preventing post-surgical mediastinitis (PSM) due to Staphylococcus aureus, this strategy is not universally recommended due to the lack of robust supporting evidence. We aimed to evaluate the role of pre-operative NDM in the annual incidence of S. aureus PSM at our institution.

METHODS

An interrupted time-series analysis, with autoregressive error model, was applied to our single-center cohort by comparing pre-intervention (1990-2003) and post-intervention period (2005 to 2018). Logistic regression was performed to analyze risk factors for S. aureus PSM.

FINDINGS

12,236 sternotomy procedures were analyzed (6,370 [52.1%] and 5,866 [47.9%] in the pre-intervention and post-intervention periods, respectively). The mean annual percentage adherence to NDM estimated over the post-interventional period was 90.2%. Only four out of 127 total cases of S. aureus PSM occurred during the 14-years post-intervention period (0.68/1,000 sternotomies vs. 19.31/1,000 in pre-interventional period [p<0.0001]). Interrupted time-series analysis demonstrated a statistically significant annual reduction of S. aureus PSM trend of -9.85 cases per 1,000 sternotomies (-13.17 to -6.5, P-value< 0·0001) in 2005, with a decreasing trend maintained over the following five years with an estimated relative reduction of 84.8% (95% CI: 89·25 to 74·09). Chronic obstructive pulmonary disease was the single independent risk factor for S. aureus PSM (odds ratio: 3.7; 95% CI: 1.72-7.93) and was equally distributed in patients undergoing sternotomy during pre or post-intervention periods.

INTERPRETATION

Our experience suggests that the implementation of pre-operative NDM reduces significantly the incidence of S. aureus PSM.

[Prophylactic Effectiveness of Vacuum-assisted Closure for High-risk Patients Undergoing Cardiovascular Surgery through Median Sternotomy]

Vacuum-assisted closure(VAC) therapy is mainly used for tissue defects. VAC therapy can remove exudate that could impair the healing process. We applied VAC therapy in patients considered at high risk of surgical site infection who underwent cardiovascular surgery via standard median sternotomy. Risk factors included advanced heart failure, obesity, diabetes mellitus, steroid administration, immunosuppressant administration, and chronic renal failure, etc. VAC therapy was used in 134 patients. Only 3 of these patients (2.2%) developed surgical site infection caused by Staphylococcus epidermidis;2 patients fully recovered after prolonged VAC therapy for 2 weeks, and the other required an additional sternal fixation after the sternal wires were removed for wound infection control. No patient developed infective mediastinitis. Prophylactic VAC therapy can reduce postoperative wound infection in high risk patients undergoing open heart surgery via full sternotomy.

[Prevention and Treatment of Mediastinitis Following Cardiac Surgery]

Mediastinitis after cardiac surgery occurs about 1% of the time and is associated with adverse effects on both short- and long-term outcomes. Therefore, prevention of mediastinitis is very important. However, when this complication occurs, a radical cure should be performed using a safe and reliable method. Many pre-, intra-, and post-operative risk factors have been reported. Perioperative management based on an understanding of the pathological condition that causes this complication is an effective prevention strategy. Early detection and treatment are most important, and there should be close coordination with plastic surgeons. Recently, negative pressure wound therapy has been used widely and appears to be effective for this complication.

DIAGNOSTICS AND TREATMENT OF PATIENTS WITH TOOL ESOPHAGEAL PERFORATION

The article presents an experience of diagnostics and treatment in 21 patients with esophageal perforation at the period from 1995 to 2015. The perforation was often (13 patients) the complication of interventional surgery which was directed to reconstruction of esophagus passing (scarry stricture of the esophagus, esophageal cancer, achalasia of esophagus). There was noted an esophageal rupture of lower third part of esophagus in 14 cases. These complications were diagnosed in all cases and the patients underwent an operation. There was performed the opening and drainage of the mediastinum in order to prevent mediastinitis. Complications had one patient in postoperative period. There wasn’t observed lethal outcome.

[Comparative analysis of the results of using the method of elimination of sternal infection and standard methodology of cardiosurgical operations]

Postoperative mediastinitis belongs to one of the severest complications of cardiosurgical operations. There have been suggested many methods of pre- and intraoperative prevention of sternal infection. Summarizing the obtained experience, in 2006 specialists of the EurAsia Heart Foundation under the leadership of Professor P. Vogt (Im Park Clinic, Zurich, Switzerland) elaborated and suggested a methodology of eliminating sternal infection, which according to the author s opinion made it possible to decrease the frequency of the development of sternal infection from 5.6 to 0%. This methodology was implemented at the Federal Centre of Cardiovascular Surgery (city of Penza) in July 2012, thus leading to a decrease in the rate of wound complications from 4.05 to 0.3%.

Preventing deep wound infection after coronary artery bypass grafting: a review

The consequences of deep wound infections before, during, and after coronary artery bypass grafting have prompted research to clarify risk factors and explore preventive measures to keep infection rates at an irreducible minimum. An analysis of 42 studies in which investigators used multivariate logistic regression analysis revealed that diabetes mellitus and obesity are by far the chief preoperative risk factors. A 4-point preoperative scoring system based on a patient's body mass index and the presence or absence of diabetes is one practical way to determine the risk of mediastinitis, and other risk-estimate methods are being refined. Intraoperative risk factors include prolonged perfusion time, the use of one or more internal mammary arteries as grafts, blood transfusion, and mechanical circulatory assistance. The chief postoperative risk factor is reoperation, usually for bleeding. Unresolved issues include the optimal approach to Staphylococcus aureus nasal colonization and the choice of a prophylactic antibiotic regimen. We recommend that cardiac surgery programs supplement their audit processes and ongoing vigilance for infections with periodic, multidisciplinary reviews of best-practice standards for preoperative, intraoperative, and postoperative patient care.

Pneumomediastinum and subcutaneous emphysema due to blunt neck injury: a case report and review of the literature

Minor blunt neck injury from childhood trauma is a relatively common condition which can be potentially life-threatening in only rare circumstances. Pneumomediastinum may develop in up to 10% patients who have sustained blunt cervical or thoracic trauma and may be a significant cause of morbidity and mortality in affected individuals because of the associated damage to the oesophagus, larynx or trachea. Management of this condition varies from conservative approach with close observation and antibiotherapy to surgical interventions, depending on the extent and severity of aerodigestive injuries. We present a paediatric blunt neck trauma accompanied by subcutaneous emphysema and pneumomediastinum secondary to a bicycle accident (neck striking the handlebar). Its radiologic appearance, clinical presentation, and the options for initial management in the emergency department (ED) are reviewed.

[Esophageal perforation following anterior cervical fixation of posttraumatic spine fracture--case report]

Esophageal perforation by a fixed plate is a rare complication in cervical spine surgery. Its appearance can lead to mediastinitis, which is an important clinical problem. Diagnosis of this complication should to be recognized as quickly as possible to make causal treatment effective. Endoscopic picture of this kind of complication was presented in the paper.

A clinical trial to investigate the effect of silver nylon dressings on mediastinitis rates in postoperative cardiac sternotomy incisions

Mediastinitis is a rare but serious postoperative complication of cardiac surgery that increases mortality rates, hospital length of stay, and medical costs. A clinical trial was conducted to investigate whether the type of postoperative surgical dressing (silver nylon or standard gauze) affects the rate of mediastinal infections. The sample consisted of 1,600 surgical cardiac patients. Infection rates in the standard gauze group (control, n = 1,235) were collected retrospectively from 24 months of infection control records. In the prospective treatment arm of the study, the wounds of all consecutive surgical patients (n = 365) were covered with a silver nylon dressing and patients were assessed during the 3-week postoperative visit. Thirteen (13) patients in the control group (1%) and none of the patients in the treatment group developed mediastinitis (chi2 [1, N = 1,600] = 3.88, P <0.05). Study findings support the need for a large, prospective, controlled clinical study to confirm the effects of these dressings on mediastinitis, resultant morbidity, and costs of care.

Staphylococcus aureus poststernotomy mediastinitis: description of two distinct acquisition pathways with different potential preventive approaches

OBJECTIVE

Determining the acquisition routes of infection is crucial to designing specific preventive approaches against Staphylococcus aureus poststernotomy mediastinitis.

METHODS

From 2002 to 2004, a nasal sample was obtained from patients before cardiac surgery. We collected clinical and microbiologic data of all episodes of S aureus poststernotomy mediastinitis. A case-control study (3:1) was performed to confirm the role of previous preoperative nasal colonization by S aureus as a risk factor for S aureus poststernotomy mediastinitis. Pulsed field gel electrophoresis molecular analysis of nasal and surgical site S aureus isolates was performed to analyze their relatedness in each patient with poststernotomy mediastinitis and with other patients of the study cohort.

RESULTS

S aureus nasal cultures were positive in 228 (15.9%) of 1432 patients: methicillin-susceptible S aureus in 222 (15.5%) and meticillin-resistant S aureus in 6 (0.4%). S aureus poststernotomy mediastinitis was diagnosed in 17 (1.2%) of 1432 patients: 9 (3.95%) of 228 in colonized patients versus 8 (0.66%) of 1204 in noncolonized patients (P < .0001). Seven of 9 patients (1.2%) with methicillin-susceptible S aureus had an identical isolate by pulsed field gel electrophoresis in preoperative nasal and surgical-site cultures, but no clonal relatedness was shown among the isolates from these 9 patients. None of the 8 patients with methicillin-resistant S aureus poststernotomy mediastinitis had an identical isolate by pulsed field gel electrophoresis in preoperative nasal and surgical-site cultures, and the same clone of methicillin-resistant S aureus was responsible for all these cases.

CONCLUSIONS

Endogenous [corrected] nasal colonization often precedes methicillin-resistant S aureus poststernotomy mediastinitis, which suggests that preoperative [corrected] decontamination is adequate for preventing methicillin-susceptible [corrected] S aureus poststernotomy mediastinitis, whereas hospital infection control measures seem to be the major factor for preventing methicillin-resistant S aureus poststernotomy mediastinitis.

Healthcare-associated infection in pediatric patients on extracorporeal life support: The role of multidisciplinary surveillance

OBJECTIVE

To describe the use of a multidisciplinary approach to sepsis surveillance and evaluate impact on outcome.

DESIGN

Prospective clinical study or clinical audit cycle.

SETTING

Tertiary pediatric extracorporeal membrane oxygenation (ECMO) center.

PATIENTS

Patients were 215 children supported with ECMO January 1999 to December 2004.

INTERVENTIONS

A multidisciplinary team met monthly to evaluate cases of bloodstream infection and mediastinitis, review trends, and update unit policies. Changes in practice were made at the end of 2001 in order to address a perceived high rate of sepsis: a) reeducation; b) introduction of electively preprimed ECMO circuits; and c) preference for neck rather than chest cannulation in cardiac patients. Prophylactic antibiotics were used from preprocedure for 24 hrs only throughout the study.

MEASUREMENTS AND MAIN RESULTS

Over the entire study period, 39 children had 47 septic episodes, with a rate of 24.9 per 1000 ECMO days. Multiple logistic regression analyses indicated that infection was associated with duration of ECMO support (odds ratio 1.24; 95% confidence interval 1.15, 1.35 per day) and case type: Closed vs. open chest was protective in cardiac patients (odds ratio 0.08; 95% confidence interval 0.01, 0.50). Infection increased the odds of death by 2.01 (95% confidence interval 1.00, 4.05), but this effect was less important than case type and ECMO days. After policy changes were implemented, there was a reduction in sepsis from 29.3 to 20.1 episodes per 1000 ECMO days. There was reduced sepsis in respiratory patients: neonates from 28.0 to 6.6 and pediatric patients from 42.4 to 16.9 episodes per 1000 ECMO days. Despite policy changes, sepsis remained a problem in cardiac patients with open sternum: 65.1 per 1000 ECMO days.

CONCLUSIONS

ECMO support is a high-risk setup for nosocomial infection, in particular for cardiac patients with open sternum for whom antibiotic prophylaxis is justified. Multidisciplinary surveillance offers an excellent approach for quality improvement in this challenging field.

Topical Application of Bacitracin Ointment Is Associated with Decreased Risk of Mediastinitis after Median Sternotomy

BACKGROUND

The diagnosis of mediastinitis after open-heart surgery is infrequent but dreaded as it carries a high morbidity and mortality. The purpose of this study was to investigate the impact that topical antibacterials would have on the postoperative mediastinitis rate.

METHODS

Data were collected from 2455 consecutive patients who underwent sternotomy and cardiopulmonary bypass for both valvar and ischemic heart disease. Prior to 1999, patients (n = 1036) underwent surgery with standard perioperative intravenous antibiotics but no application of bacitracin. After 1999, patients (n = 1419) underwent surgery with intravenous antibiotics and application of bacitracin ointment to the sternotomy incision after closure.

RESULTS

Cases of mediastinitis occurred in 12 patients (1.2%) not treated with bacitracin, which required re-exploration, sternectomy, and soft tissue closure of the mediastinum. Alternatively, 3 patients (0.2%) in the group treated with bacitracin developed mediastinitis (P < .01). Therefore, the use of topical antibacterials was associated with a 6-fold reduction in the risk of mediastinitis after cardiac surgery. This significant difference in the infection rate was observed even though the percentage of patients with risk factors for mediastinitis was equal to greater than the group not treated with bacitracin. Non-bacitracin versus bacitracin: diabetics, 298 versus 484; emergency operations, 24 versus 50; bilateral internal thoracic grafts, 28 versus 29; and obesity (body mass index >30), 294 versus 396.

CONCLUSIONS

The use of topical antibacterials is associated with a decrease in the risk of mediastinitis after cardiac surgery.

Primary Closure of Median Sternotomy: A Survey of all German Surgical Heart Centers and a Review of the Literature Concerning Sternal Closure Technique

BACKGROUND

Sternal instability and mediastinitis are rare but serious complications following cardiac surgery with median sternotomy.

METHODS

This study presents the results of a questionnaire, which was sent to all 79 German surgical heart centers. The conventional sternal closure technique, the parameters considered to be risk factors for sternal instability, and the surgical strategy in the presence of risk factors were determined. In addition, a literature research with the key words "sternal closure technique" and "sternal dehiscence" was performed.

RESULTS

Conventional closure of primary sternotomy is done using many different methods, most often with surgical steel sutures (87 %) passed trans/peristernally (64 %). An osteoporotic or fractured sternum (70 x), and obesity (31 x) were the most frequently cited risk factors. The preferred osteosynthetic procedure for patients with an increased risk for sternal instability was the method of Robicsek (48 x).

CONCLUSION

There is no uniform osteosynthetic method for primary sternal closure and there is substantial variation in the perception of risk factors for sternal instability and possible surgical consequences among the surgical heart centers in Germany.

Cultures of sternal wound and mediastinum taken at the end of heart surgery do not predict postsurgical mediastinitis

The aim of the study was to assess of the role of intraoperative cultures taken at the end of major heart surgery (MHS) in the prediction of postoperative mediastinitis (PM) in patients undergoing MHS over a 6-month period in a tertiary university hospital. Just before wound closure, a sample of the sternal border was taken, swabbing back and forth the sternal border and the subcutaneous tissues. A second sample was taken after irrigation of the deep mediastinal structures with 10 mL of Ringer lactate. Swabs were processed semiquantitatively and the mediastinal fluid with a quantitative technique. The observation of one or more colonies per plate was considered a positive culture. Cultures obtained at the end of 229 surgical interventions (227 patients) were positive with the semiquantitative or with the quantitative procedures in 31.0% (95% confidence interval [CI], 25.1-37.4%) and 34.5% (95% CI, 28.4-41.0%) of the times, respectively (P = NS). The number of microorganisms isolated in the wound swab or mediastinal fluid was 91 and 110, respectively. Of the 227 patients, 7 developed an episode of PM (3.1%; 95% CI, 1.2-6.2%) after a median time of 11 days (range, 5-19 days). The microorganisms causing the 7 cases of mediastinitis were not isolated in the intraoperative cultures in any of the cases. The value of intraoperative cultures as a test for prediction of PM depending on the breakpoint chosen were as follows: sensitivity (0%), specificity (66.2-97.3%), and positive (0%) and negative predictive values (96.8-98.0%). We recommend against surveillance cultures taken intraoperatively in patients undergoing MHS.

Prophylaxis of sternal wound infections with gentamicin-collagen implant: randomized controlled study in cardiac surgery

Postoperative infections may lead to prolonged hospital stay and increased morbidity, mortality and hospital costs, especially in heart surgery. Finding new means to prevent infections would benefit both the patient and society. The aim of this study was to assess if locally administered gentamicin prevents sternal wound infections in coronary artery bypass (CABG) surgery. We randomized 542 consecutive CABG patients to two groups: those who received gentamicin-collagen implant under their sternum before closure (N=272) and controls (N=270). The subjects received routine intravenous antimicrobial prophylaxis (85% cefuroxime, 14% cefuroxime and vancomycin), and were followed-up for three months. The sternal wound infection rate was 4.0% (11/272) in the gentamicin group and 5.9% (16/270) in the control group. The mediastinitis rates were 1.1 and 1.9%, respectively. This treatment was safe and easy to administer, and no side-effects occurred. No statistically significant difference was demonstrated between infection rates in the two groups. This is the first study on the use of gentamicin-collagen sponge as prophylaxis in cardiac surgery. Our data show that infection was reduced slightly in the gentamicin-collagen group compared with the control group, but the study population was too small to draw conclusions. Further evaluation is needed, and the results may warrant another larger, better-powered study.

Primary sternal plating in high-risk patients prevents mediastinitis

OBJECTIVE

Sternal wound infection leading to post-operative mediastinitis is a devastating complication of cardiac surgery carrying nearly a 15% mortality rate despite current treatment methods. Instability of bone fragments pre-disposes a patient to have non-union, mal-union and can subsequently lead to deep sternal wound infections progressing to mediastinitis. Rigid plate fixation has been utilized for acquired and surgically created fractures of virtually every bone in the body to prevent instability. However, the current standard for sternotomy closure remains the method of wire-circlage. Application of rigid plate fixation for sternal osteotomies affords greater stability of the sternum. We report on our preliminary experience with this technique in high-risk patients.

METHODS

From July of 2000 to December 2001, rigid plate fixation was applied to 45 patients designated as having high risk for sternal dehiscence and subsequent mediastinitis. High risk was defined as patients having 3 or more established historical risk factors, including: COPD, Re-Operative Surgery, Renal Failure, Diabetes, Chronic Steroid Use, Morbid Obesity, Concurrent Infection and Acquired or Iatrogenic Immunosuppression. Intra-operative risk factors included off-midline sternotomy, osteoporosis, long cardio-pulmonary bypass runs (>2 h), transverse fractures of the sternum. Rigid plate fixation was performed using a combination of plates secured by bi-cortical screws, after the cardiac surgical procedure was complete and hemostasis was secured.

RESULTS

Rigid plate fixation was performed on 26 males and 19 females. The average age of patients was 63 (43-88) years. The average follow-up was 15 weeks (range 8-41 weeks). While there were 4 peri-operative deaths unrelated to sternal closure: one from aspiration pneumonia (post-operative day 9), one from a pulmonary embolus (post-operative day 29), one from overwhelming sepsis from pre-existing endocarditis (post-operative day 15), and one for primary respiratory failure (post-operative day 12). All others healed successfully. One patient who had a sterile dehiscence subsequently underwent successful re-operative rigid fixation. Comparing the cohort of patients who received rigid plate fixation to a matched population of high-risk patients during a similar time period who received wire closure, revealed a significant difference in the incidence of post-operative mediastinitis. The wire closed group (n = 207) had 18 deaths unrelated to sternal closure and had 28 patients who developed mediastinitis (14.8%). The rigid plate fixation group had no mediastinitis (Fisher's exact test, P = 0.006). The total incidence of post-operative mediastinitis during the designated study period was 4.2%.

CONCLUSION

Patients who benefited from sternal closure with rigid plate fixation showed a significant decrease in the incidence of post-operative mediastinitis when compared to similar population of patients whose sterna were closed with wire.

[The efficacy of function water (electrolyzed strong acid solution) on open heart surgery; postoperative mediastinitis due to methicillin-resistant Staphylococcus aureus]

Methicillin-resistant Staphylococcus aureus (MRSA) infection after cardiac surgery has recently increased. We compared the anti-inflammatory effect of an electrolyzed strong acid solution and a warm saline solution in patients with open heart surgery. These solutions were used for mediastinal irrigation before closing the sternum. Group A patients were irrigated by a warm saline solution, and group B patients were irrigated by an electrolyzed strong acid solution, administration of this water is safe, feasible, and easy for the prevention of MRSA infection. Postoperative infection was significantly decreased in the group B as compared in the group A. An electrolyzed strong acid solution may be effective on postoperative infection, particularly MRSA infection following open heart surgery.

Coronary artery bypass grafting and aortic valve replacement in a patient with a tracheostoma

We report a 67-year-old man with a tracheostoma who successfully underwent coronary artery bypass grafting and aortic valve replacement. He had received both a tracheostoma just above the sternal notch after total laryngectomy. As the standard full sternotomy might cause mediastinitis, we performed the operation through a lower half sternotomy with a limited skin incision. Postoperatively the wound was covered with a sterile plastic drape to prevent infection from the tracheostoma. The postoperative course was uneventful.

[Acute mediastinitis]

Causes, diagnosis, treatment and mortality about acute mediastinitis were described. Two cases of our experience were demonstrated with chest X-ray, computed tomography (CT) and operative findings. Prevention, recognition, prompt diagnosis and early treatment of the disease were emphasized.

Risk factors for postoperative mediastinitis due to methicillin-resistant Staphylococcus aureus

Risk factors for developing postoperative mediastinitis (POM) due to methicillin-resistant Staphylococcus aureus (MRSA) were analyzed in a case-case control study of patients who underwent median sternotomy during the period from 1994 through 2000. Three patient groups were studied. The first consisted of 64 patients with POM due to MRSA; the second consisted of 79 patients with POM due to methicillin-susceptible S. aureus (MSSA); and the third consisted of 80 uninfected control patients. In multivariable analysis, patients who were diabetic (adjusted OR, 2.86; 95% CI, 1.22-6.70), female (OR, 2.70; 95% CI, 1.25-5.88), and >70 years old (OR, 3.43; 95% CI, 1.53-7.71) were more likely to develop POM due to MRSA. In contrast, the only independent risk factor associated with POM due to MSSA was obesity (OR, 2.49; 95% CI, 1.25-4.96). Antimicrobial prophylaxis consisted primarily of cephalosporin antibiotics (administered to 97% of the patients). Changes in perioperative antimicrobial prophylaxis, in addition to other interventions, should be considered for prevention of POM due to MRSA in targeted, high-risk populations.

Prevention of Postoperative Mediastinitis

In a prospective study of more than 4,000 consecutive patients who underwent any cardiovascular procedure requiring sternotomy incision in a 650-bed tertiary care hospital, a gradual increase in deep sternal infections from 0.8% in 1995 to 2.1% in 1999 was noted. By using a Plan-Do-Check-Act process improvement model, several interventions to decrease the infection rate were planned and implemented based on hypotheses generated from the characteristics of infected patients. These interventions included chlorhexidine preoperative shower, discontinuation of shaving, administration of antibiotics in the holding area, segregation of instruments, and implementation of an insulin protocol. Findings included a decrease in deep sternal and leg infections after implementation of these interventions. Deep sternal infection rates decreased from 2.1% to 1.5% and leg infection rates, from 1.93% to 0.47%. Results were not statistically significant but were clinically relevant. Furthermore, a total of $200,000 was achieved in cost savings in 1 year.

[Surgical treatment and adjunct hyperbaric therapy to improve healing of wound infection complications after sterno-mediastinitis]

Although the incidence of wound complications after median sternotomy is less than 1%, it remains a serious complication in patients undergoing cardiac procedures. We suggest that the combination of hyperbaric oxygen therapy and aggressive surgical approach improves clinical outcomes in these patients. Between August 1997 and May 2002, 55 patients with postoperative sternal wound infection and/or mediastinitis were qualified for hyperbaric oxygen treatment in connection to surgical management. Surgical procedure included wound debridment and/or sternum rewiring, omental pedicle flap plasty or sternectomy. Hyperbaric oxygen therapy consisted of 20 to 40 expositions per patient and was carried before and after the surgery.

RESULTS

There was no in-hospital death. The total time between the admission and discharge from the hospital varied from 2 to 24 weeks (average 8 weeks). The infection has been cured in all patients treated for postoperative sternal wound infection. That has been confirmed by negative bacteriological tests, stabilization of the sternum and complete wound healing.

CONCLUSIONS

The combination of surgical treatment and hyperbaric oxygen therapy may improve clinical outcome in patients with sterno-mediastinis and poststernotomy wound infection after cardiac surgery.

Antibiotic concentrations in serum and wound fluid after local gentamicin or intravenous dicloxacillin prophylaxis in cardiac surgery

One important aim of antibiotic prophylaxis in cardiac surgery is preventing mediastinitis and thus it would appear to be relevant to study the antibiotic concentrations in pericardial/mediastinal fluid. Local administration of gentamicin in the wound before sternal closure is a novel way of antibiotic prophylaxis and could be effective against bacteria resistant to intravenous antibiotics. This study measured dicloxacillin concentrations in 101 patients in serum and wound fluid following intravenous administration of dicloxacillin. Similarly, concentrations of gentamicin in serum and wound fluid were determined in 30 patients after administration of 260 mg gentamicin in the wound at sternal closure. Median dicloxacillin concentrations in serum and wound fluid at sternal closure were 59.4 and 55.35 mg/l, respectively. Gentamicin levels in the wound were very high (median 304 mg/l), whereas serum concentrations were low (peak median 2.05 mg/l). Dicloxacillin, 1 g given intravenously, according to the clinical protocol, resulted in levels in serum and wound fluid at sternal closure likely to prevent Staphylococcus aureus infections. Locally administered gentamicin resulted in high local concentrations, potentially effective against agents normally considered resistant.

Topical vancomycin applied on closure of the sternotomy wound does not prevent high levels of systemic vancomycin

OBJECTIVE

Vancomycin is effective in reducing the risk of mediastinits and topical vancomycin has been hypothesised to give high local dose concentrations while avoiding high systemic levels, thus avoiding the risk of bacterial resistance to this second-line antibiotic. However, this theory has never been tested and the degree to which vancomycin is absorbed systemically is unknown.

METHODS

Fourteen patients undergoing elective coronary artery bypass grafts (CABG) received 500mg of topical vancomycin prior to sternotomy closure. Serum samples were taken at 30, 60, 120, 180 and 720min post-operatively. In addition, samples were taken from the drain bottles and urine samples taken daily for 5 days. Vancomycin levels were measured by fluorescence polarisation immunoassay, using the reverse dilution method to give a detection limit of 0.8mg/l.

RESULTS

Vancomycin was detected in almost all serum samples. Peak concentration was at 30min and the mean value was 2.96mg/l (range, 0.99-5.00mg/l). This mean fell to 1.32mg/l at 6h. Of the 500mg of vancomycin applied, a mean of only 8.8mg was found to have been lost into the drain bottles in the first 24h (range, 0.17-12.5mg). When 5 consecutive days of urine collection was achieved, a mean of 151mg of vancomycin was excreted (range, 40-195mg) and vancomycin was detectable in the urine till day 5. The mean concentration of vancomycin in the urine was maximal on day 1 and was 24.4mg/l (range, 4.49-44.98mg/l).

CONCLUSIONS

Topical vancomycin causes significant systemic concentrations in the 6h post-surgery and can be detected in the urine for up to 5 days post-surgery.

An outbreak of mediastinitis among heart transplant recipients apparently related to a change in the united network for organ sharing guidelines

OBJECTIVE

To describe an outbreak of mediastinitis in heart transplant recipients.

DESIGN

Retrospective and contemporaneous cohort

SETTING

Urban tertiary-care university hospital with a large cardiac transplantation program.

PATIENTS

Heart transplant recipients.

INTERVENTIONS

Modifications of donor harvest technique; procedures aimed at decreasing skin and mucosal bacterial colonization; strict aseptic technique in the intensive care unit; and aggressive policing of established infection control practices.

RESULTS

In April 1999, mediastinitis rates among heart transplant recipients increased abruptly from a baseline of 6 cases per 100 procedures to sequential quarterly rates of 22, 31, and 50 cases per 100 procedures, whereas infection rates in other cardiac operations were unchanged. Bacteria causing these infections were multidrug-resistant "nosocomial" organisms. The epidemic occurred 2 months after a change in the United Network for Organ Sharing organ allocation algorithm. This change resulted in an increase in the duration of preoperative hospitalization from a median of 52 to 79 days (P = .008) and may have promoted prolonged hospitalization of patients with high illness severity. Aggressive multidisciplinary interventions were temporally associated with a return to preoperative mediastinitis rates without changing length of hospitalization prior to transplantation.

CONCLUSIONS

Changes in organ allocation for transplant that prolong waiting time in the hospital and alter illness acuity may lead to increased rates of postoperative infection. Measures to limit bacterial colonization may be a helpful countervailing strategy.

Mediastinitis and cardiac surgery--an updated risk factor analysis in 10,373 consecutive adult patients

BACKGROUND

Deep sternal wound infection (DSWI) remains a serious complication after cardiac surgery. New evolving techniques including the utilization of internal mammary arteries (IMA), beating heart procedures, and minimal invasive surgery (MIC) require an updated risk factor analysis to identify high risk patients in order to improve perioperative treatment.

METHODS

10,373 consecutive patients receiving cardiac surgery between May 1996 and August 1999 were evaluated: 9,303 underwent full sternotomy whereas a minimally invasive (MIC) approach using partial sternotomy or lateral thoracotomy was used in 1,070 patients. DSWI was defined as the evidence of mediastinitis seen at reoperation along with one or more of the following: positive culture of mediastinal fluid, positive blood culture or temperature higher than 38 degrees C and/or leukocytosis.

RESULTS

The overall incidence of DSWI in the "full sternotomy" group was 1.44 % (134 of 9,303). Univariate risk factor analysis showed a significant influence of IMA use, ICU / IC treatment > 5 days, postoperative ventilator time > or = 72 h, need for reexploration, diabetes, surgery time > or = 180 min, assist device implantation (including use of IABP), peripheral vascular disease and increased body mass index. Multivariate analysis identified double IMA, ICU treatment > 5 days, single IMA, diabetes, reexploration and increased body mass as significant risk factors. No mediastinitis was observed in the MIC group.

CONCLUSION

As DSWI is related to sternotomy, a MIC approach should be considered for patients at high risk for DSWI. IMA takedown as a pedicled graft should be especially avoided in patients with diabetes since the risk for postoperative mediastinitis is unacceptably high in this patient group.

Rectus abdominis muscle flaps used successfully for median sternotomy wounds after ipsilateral internal mammary artery ligation

Use of the rectus abdominis muscle for reconstruction based on its superior blood supply has been said by some to be contraindicated if the ipsilateral internal mammary artery (IMA) has been divided for reasons such as coronary artery bypass grafting. The authors describe 5 patients in whom either both IMAs were used for coronary revascularization or in whom there was a contralateral subcostal incision, and they were thus compelled to perform sternal reconstruction using at least one rectus abdominis muscle ipsilateral to prior IMA ligation. In all patients the muscle flap was used to reconstruct an open median sternotomy wound successfully. An injection study as well as a fresh cadaveric dissection revealed rich collateral circulation to the superior epigastric vascular pedicle through the musculophrenic artery as well as through the lower intercostal arteries. This case report and the series of 5 patients indicate that if elevation of the rectus muscle and division of the lateral segmental vessels is done only up to the costal margin, one can reliably maintain a viable rectus muscle flap, even in the face of prior ipsilateral IMA ligation. This enables useful reconstruction to the lower half of a sternal wound using the rectus abdominis muscle, requiring a pectoralis major muscle flap for the superior part of the wound.

[Esophageal carcinoma: 2-stage operation for preventing mediastinitis in high risk patients]

Strict patient selection, standardization of the surgical technique and advances in peri- and postoperative management have in experienced centers resulted in a decrease in postoperative mortality after esophagectomy and reconstruction to less than 5% in recent years. The previously common and potentially lethal pulmonary and cardiac complications have lost their impact on outcome. Today, septic complications, which usually arise from the reconstruction phase, constitute the major morbidity and mortality factors in the surgical therapy of esophageal cancer. These complications pose a particular problem for patients with compromised organ function and patients after neoadjuvant combined radiochemotherapy. In these situations a surgical safety concept with a two-stage procedure, i.e., delay of reconstruction after resection for 8-10 days, can markedly reduce the otherwise substantial postoperative mortality. A two-stage procedure thus offers patients a chance of a potentially curative surgical therapy who would otherwise be excluded from resection.

[Comparison of 2 endoscopic surgery techniques for reliable therapy of Zenker diverticulum]

BACKGROUND

A mediastinitis or intraoperative bleeding are the most feared complications of the transoral laser assisted diverticulotomy of Zenker's diverticulum. To reduce these complications we developed a new endoscopic surgical technique and compared the results of this new method with the results of patients who we treated earlier.

PATIENTS AND METHODS

At the department of Otorhinolaryngology, Head and Neck Surgery, University of Luebeck 68 patients suffering from a hypopharyngeal diverticulum have been treated since 1987. In 64 patients we performed an endoscopic diverticulotomy using a CO2-Laser and the Weerda distending diverticuloscope. Four of the Zenker's diverticulua had to be removed by an external approach. From 1987 to 1994 a five millimeter bar between pouch and hypopharynx after diverticulotomy was left and sealed with fibrin glue in the first 38 patients. From 1995 to 1999 the spur of the hypopharyngeal pouch of the other 26 patients was completely separated. Afterwards we sutured the mucosa between the pouch and the hypopharynx to close the opened mediastinal space and sealed the former spur with fibrin glue.

RESULTS

Comparing both endoscopic methods we had to observe concerning our first method one mediastinitis, a rise of body temperature in 29 patients (76%) and we had to perform a revision diverticulotomy in three patients (8%). Our modified technique didn't cause any mediastinitis, a rise of body temperature did only occur in five patients (18%) and no patient had to undergo revision surgery.

CONCLUSIONS

The transoral complete separation of the spur of the hypopharyngeal pouch with suturing the mucosa of the pouch and the hypopharynx causes good functional results and means a further reduction of complications and a further improvement of the endoscopic diverticulotomy. Our new instruments (Fa. K. Storz, Tuttlingen) will be demonstrated.

A hospital-acquired outbreak of methicillin-resistant Staphylococcus aureus infection initiated by a surgeon carrier

Methicillin-resistant Staphylococcus aureus (MRSA) has become an important hospital-acquired pathogen, infection with which often leads to major morbidity and mortality. The principal mode of transmission for MRSA is transfer of the organism from a carrier or infected patient to uninfected patients by the hands or clothing of staff. From January 16 1997 to April 2 1997, five patients who had undergone open-heart surgery in a hospital located in northern Taiwan, developed surgical wound infections and mediastinitis caused by MRSA. All patients were hospitalized in two adjacent surgical intensive care units (ICUs) following their respective operations. Consequently, the hospital's infection control team commenced investigation of the outbreak. Pulsed-field gel electrophoresis (PFGE) has been shown to be a good technique for epidemiological typing. By analysing cultures taken from staff by PFGE, it was demonstrated that this outbreak was most likely to be initiated by a surgeon with MRSA carriage. After elimination of the carrier state using topical mupirocin treatment, the outbreak was controlled without further incident.

Mediastinitis after cardiac surgery--epidemiology and current treatment

Mediastinal infection is a feared complication observed after 0.4%-5% of cardiac operations. Even today the mortality remains as high as 20%-40%. We discuss the aetiology, mechanisms, prevention, diagnosis, and medical management. The staging system for mediastinal wound infections developed at a joint conference of German cardiac surgical centres is presented. The use of parenteral polyvalent immunoglobulins is also discussed.

The overall concept: immunoglobulins as adjuvants for mediastinitis--does it make sense?

Supportive intravenous immunoglobulin (ivIg) treatment may reduce the incidence and severity of infections in a well-defined group of patients in intensive care, including those who have had cardiac surgery. Sternal wound infections and mediastinitis after cardiac surgery are to be investigated in the ATMI study with Pentaglobin. In this article I focus on optimising ivIg dosage, on likely mechanisms, on reasons why ivIg might improve a primarily gram-positive infection, and on the use of serial scoring as an endpoint in a trial of immunoglobulin.

Considerations on the statistical design of the ATMI study

The ATMI study of prevention of mediastinitis after cardiac surgery uses the total amount of therapeutic interventions measured by the TISS-28 score as the primary endpoint. The study is designed as an adaptive group-sequential plan with three sequences, as experiences with the TISS-28 in cardiac intensive care units are scarce. According to the Bauer-Köhne method the sample sizes of the second and third sequences can be calculated in a data-driven manner after the results of the previous interim analyses are available. Thus the first trial phase can be considered as an internal pilot study.

The effect of thorough preoperative disinfection on the incidence of postoperative mediastinitis

This study was conducted to evaluate the effectiveness of scrubbing the skin of patients scheduled to undergo elective cardiac surgery with disinfectant solutions in an attempt to reduce the incidence of the potentially fatal postoperative complication of mediastinitis. Since April 1991, we have routinely disinfected the skin of all such patients three times preoperatively. A retrospective comparison of the incidence of mediastinitis before and after April 1991 was carried out. Microbiological examinations of the anterior chest were conducted in ten patients admitted for elective operations, and in four patients admitted for emergency surgery. Specimens were obtained before each scrubbing, before the operation, and just after skin closure. There was a significant decrease in the general incidence of mediastinitis after April 1991 (P < 0.01). Microbiologically, significant decreases in colony counts were also observed after the first (P < 0.05) and second scrubbing (P < 0.05) in the ten patients specifically studied before elective surgery. No colonies grew in the postoperative specimens from any of these patients, but colony formations were observed in two of the four patients who underwent emergency surgery (P = 0.066). Thus, we conclude that our thorough disinfection method effectively achieves adequate, prolonged suppression of the skin flora, which explains the marked decrease in the incidence of mediastinitis in our hospital since its institution.

Is mediastinitis a preventable complication? A 10-year review

BACKGROUND

The incidence of mediastinitis after cardiac surgical intervention is reported to be between 0.15% and 5% and is a major cause of postoperative morbidity. A number of risk factors have been identified, most of which are not modifiable. It is our contention that this complication can be reduced to a minimum by the consistent application of good operative technique and postoperative management.

METHODS

We reviewed the records of all 9,771 patients who underwent cardiac surgical procedures between 1987 and 1997. All operations were performed using a common skin preparation, draping, and antibiotic prophylaxis. Cases of mediastinitis were defined according to Centers for Disease Control and Prevention criteria and were identified from three sources: medical records database, hospital infection control, and the Society of Thoracic Surgeons database. Risk factors were assessed using chi2 and Fisher's exact tests.

RESULTS

Of 24 patients identified as having deep sternal wound infection (incidence, 0.25%), 2 died (mortality rate, 8.3%), 18 required reoperation (75%), and only 4 needed pectoral muscle flaps. Statistical analysis revealed only the presence of chronic obstructive pulmonary disease as a significant risk factor (p < 0.01). Other factors, including diabetes, renal failure, smoking, sex, age, reoperation, morbid obesity, and steroid use, were not significant. The use of internal mammary arteries (single or bilateral) was not associated with mediastinitis. Postoperative complications, including prolonged ventilation, inotropic support, and the need for blood products, were not significant risk factors. The patients who developed mediastinitis were more likely to be readmitted to the hospital (p < 0.005) and more likely to require reoperation (p < 0.005).

CONCLUSIONS

In a large patient series we found a low incidence of mediastinitis (0.25%) and an even lower incidence of required reoperation (0.19%). Except for the use of bone wax and the use of bilateral mammary arteries in diabetic patients, none of the previously identified risk factors are modifiable. We believe that with strict adherence to perioperative aseptic technique, attention to hemostasis, and precise sternal closure, a very low incidence of mediastinitis can be achieved.

Omental transfer as a method of preventing residual persistent subcutaneous infection after mediastinitis

Currently, poststernotomy mediastinitis frequently is being treated by debridement and immediate closure with omental drainage. This method is useful, but subcutaneous infection occasionally occurs. Divided omental transfer to the presternal space may be helpful in preventing this complication.

[Bacterial culture of the anterior chest skin for prophylaxis in cardiovascular operations: prospective study in two civilian hospitals]

Mediastinitis after median stermotomy is a significant complication for a cardiovascular surgery. Prospective study of bacterial cultures of the anterior chest skin in cardiac and aortic surgery was performed with the comparison of two civilian hospitals. There were many ABPC-resistant bacteria including 26 to 67 percent of Staphylococcus epidermidis (SE). ABPC could not be chosen for the first drug of prophylaxis. Although there was a few CEZ-resistant SE, the efficacy of first-generation cephalosporins was acceptable in this series. If methicillin-resistant Staphylococcus aureus (MRSA) is detected in patient's preoperative bacterial cultures, vancomycin should be selected for prophylaxis. In patients with poor risk who required emergent cardiac surgery, combinational use of an first-generation cephalosporin and an amikacin or a minocycline should be recommended in our data.

Sternal wound dressings--a research study into risk factors

Papworth Hospital is an internationally renowned centre for cardiothoracic surgery and cardiopulmonary transplantation. Each year approximately 2,000 procedures are carried out. In early 1994 staff had noticed an increase in the number of cardiac patients returning for debridement of sternal wounds following infection. This was obviously an area for concern, and consequently a research project was initiated to examine potential risk factors for sternal wound infection.