[Deep sternal wound infection after sternotomy - Report of the consensus workshop of the German-Speaking Society for Microsurgery of Peripheral Nerves and Vessels (DAM)]

Deep sternal wound infection (TSWI) is a potentially life-threatening complication that may occur after median sternotomy, contributing to prolonged hospital stay and increased health care costs. Bacterial infection is often characterized by biofilm formation on implant material and/or dead bone. Diagnosis is made upon clinical signs and symptoms of local and systemic infection. Early multidisciplinary decision making is needed for optimal patient care. Repeated surgical wound debridements accompanied by wound conditioning are performed until clean circumstances are achieved. Thereafter, wound closure and defect reconstruction are obtained using a variety of pedicled and microvascular flaps.

The cosmic ray shadow of the Moon observed with the ANTARES neutrino telescope

One of the main objectives of the ANTARES telescope is the search for point-like neutrino sources. Both the pointing accuracy and the angular resolution of the detector are important in this context and a reliable way to evaluate this performance is needed. In order to measure the pointing accuracy of the detector, one possibility is to study the shadow of the Moon, i.e. the deficit of the atmospheric muon flux from the direction of the Moon induced by the absorption of cosmic rays. Analysing the data taken between 2007 and 2016, the Moon shadow is observed with 3.5 σ statistical significance. The detector angular resolution for downward-going muons is 0 . 73 ∘ ± 0 . 14 ∘ . The resulting pointing performance is consistent with the expectations. An independent check of the telescope pointing accuracy is realised with the data collected by a shower array detector onboard of a ship temporarily moving around the ANTARES location.

An algorithm for the reconstruction of high-energy neutrino-induced particle showers and its application to the ANTARES neutrino telescope

A novel algorithm to reconstruct neutrino-induced particle showers within the ANTARES neutrino telescope is presented. The method achieves a median angular resolution of [Formula: see text] for shower energies below 100 TeV. Applying this algorithm to 6 years of data taken with the ANTARES detector, 8 events with reconstructed shower energies above 10 TeV are observed. This is consistent with the expectation of about 5 events from atmospheric backgrounds, but also compatible with diffuse astrophysical flux measurements by the IceCube collaboration, from which 2-4 additional events are expected. A [Formula: see text] C.L. upper limit on the diffuse astrophysical neutrino flux with a value per neutrino flavour of [Formula: see text] is set, applicable to the energy range from 23 TeV to 7.8 PeV, assuming an unbroken [Formula: see text] spectrum and neutrino flavour equipartition at Earth.

Sperm whale long-range echolocation sounds revealed by ANTARES, a deep-sea neutrino telescope

Despite dedicated research has been carried out to adequately map the distribution of the sperm whale in the Mediterranean Sea, unlike other regions of the world, the species population status is still presently uncertain. The analysis of two years of continuous acoustic data provided by the ANTARES neutrino telescope revealed the year-round presence of sperm whales in the Ligurian Sea, probably associated with the availability of cephalopods in the region. The presence of the Ligurian Sea sperm whales was demonstrated through the real-time analysis of audio data streamed from a cabled-to-shore deep-sea observatory that allowed the hourly tracking of their long-range echolocation behaviour on the Internet. Interestingly, the same acoustic analysis indicated that the occurrence of surface shipping noise would apparently not condition the foraging behaviour of the sperm whale in the area, since shipping noise was almost always present when sperm whales were acoustically detected. The continuous presence of the sperm whale in the region confirms the ecological value of the Ligurian sea and the importance of ANTARES to help monitoring its ecosystems.

Deep Surgical Site Infections after Open Radical Cystectomy and Urinary Diversion Significantly Increase Hospitalisation Time and Total Treatment Costs

INTRODUCTION

Deep surgical site infections (DSSI) usually require secondary treatments. The aim of this study was to compare the total length of hospitalisation (LOH), intensive care unit (ICU) duration, and total treatment costs in patients with DSSI versus without DSSI after open radical cystectomy (ORC) and urinary diversion.

MATERIAL AND METHODS

Prospective case-control study in a tertiary care hospital in patients after ORC with urinary diversion during April 2008 to July 2012. DSSI was defined based on Centers for Disease Control and Prevention criteria. Matched-pair analysis for patients with versus without DSSI was done in 1:2 ratios. Patients with superficial surgical site infections (SSI) were excluded from analysis.

RESULTS

In total, 189 operations were performed. Thirty-eight patients (20.1%) developed SSI of which 28 patients (14.8%) had DSSI. Out of 28 patients, 27 (96.4%) were with DSSI and required surgical re-intervention. Due to insufficient matching criteria, 11 patients with DSSI were excluded from analyses. Consequently, 17 patients with DSSI were matched with 34 patients without DSSI. Significant differences were seen for median overall LOH (30 vs. 18 days, p < 0.001), median ICU duration (p = 0.024), and median overall treatment costs (€17,030 vs. €11,402, p = 0.011).

CONCLUSIONS

DSSI significantly increases LOH (67%) and treatment costs (49%), adding up to a financial loss for the hospital of approximately €5,500 in patients with DSSI.

Intensive care physicians' and nurses' perception that hand hygiene prevents pathogen transmission: Belief strength and associations with other cognitive factors

Besides habituation, conscious decision-making remains important for healthcare workers' hand hygiene compliance. This study compared 307 physicians and 348 nurses in intensive care at a German university medical centre regarding their belief that hand disinfection prevents pathogen transmission. Physicians perceived less risk reduction ( p < 0.001; variance explained: 4%), a comparison outscored only by lower self-rated guideline knowledge (8%). In both groups, the transmission-preventive belief was associated with high response efficacy, behavioural intention and self-efficacy, but not with self-rated knowledge. Consistent with the Health Action Process Approach, hand hygiene interventions targeting risk reduction beliefs may promote high motivation, but not action control.

Percutaneous minimally invasive fetoscopic surgery for spina bifida aperta. Part III: neurosurgical intervention in the first postnatal year

OBJECTIVE

To evaluate the need for postnatal neurosurgical intervention after fetoscopic patch coverage of spina bifida aperta (SBA).

METHODS

This was a retrospective analysis of a cohort of 71 fetuses which underwent minimally invasive fetoscopic patch coverage of SBA between 21 + 0 and 29 + 1 weeks of gestation. Postnatal neurosurgical procedures were classified into two types: re-coverage of the SBA within the first 3 months following birth, and shunt placement as treatment of associated hydrocephalus within the first year.

RESULTS

Location of the SBA was lumbosacral in 59 cases, lumbar in seven, thoracic in three and sacral in two. In total, 20/71 (28%) patients underwent early postnatal neurosurgical intervention by means of re-coverage of the SBA. This was performed because of cerebrospinal fluid leakage in seven (35%), adhesions with functional deterioration in three (15%), incomplete coverage in five (25%) and skin defect in five (25%) cases. Ventriculoperitoneal shunt placement within 1 year was required in 32 (45%) cases and was preceded by ventriculostomy in two. Three (4%) infants needed Chiari decompression surgery in the first 12 months following birth, because of syringomyelia or gait disturbance.

CONCLUSIONS

Fetoscopic patch coverage of SBA may require postnatal re-coverage in some cases. In most cases, conservative wound treatment shows good results, without requiring neurosurgical intervention. The low 1-year-shunt rate is comparable to data of the Management of Myelomeningocele Study and lower compared with published data of patients with postnatal only coverage of SBA.

Psychosocial determinants of self-reported hand hygiene behaviour: a survey comparing physicians and nurses in intensive care units

BACKGROUND

Research applying psychological behaviour change theories to hand hygiene compliance is scarce, especially for physicians.

AIM

To identify psychosocial determinants of self-reported hand hygiene behaviour (HHB) of physicians and nurses in intensive care units (ICUs).

METHODS

A cross-sectional survey using a self-administered questionnaire that applied concepts from the Health Action Process Approach on hygienic hand disinfection was conducted in 10 ICUs and two haematopoietic stem cell transplantation units at Hannover Medical School, Germany. Self-reported compliance was operationalized as always disinfecting one's hands when given tasks associated with risk of infection. Using seven-point Likert scales, behavioural planning, maintenance self-efficacy and action control were assessed as psychological factors, and personnel and material resources, organizational problems and cooperation on the ward were assessed as perceived environmental factors. Multiple logistic regression analysis was employed.

FINDINGS

In total, 307 physicians and 348 nurses participated in this study (response rates 70.9% and 63.4%, respectively). Self-reported compliance did not differ between the groups (72.4% vs 69.4%, P = 0.405). While nurses reported stronger planning, self-efficacy and action control, physicians indicated better personnel resources and cooperation on the ward (P < 0.02). Self-efficacy [odds ratio (OR) 1.4, P = 0.041], action control (OR 1.8, P < 0.001) and cooperation on the ward (OR 1.5, P = 0.036) were positively associated with HHB among physicians, but only action control was positively associated with HHB among nurses (OR 1.6, P < 0.001).

CONCLUSION

The associations between action control (self-regulatory strategies where behaviour is evaluated continuously and automatically against guidelines) and compliance indicate that HHB is a habit in need of self-monitoring. The fact that perceived cooperation on the ward was the only environmental correlate of HHB among physicians stresses the importance of team-directed interventions.

Targeted ED-B fibronectin SPECT in vivo imaging in experimental atherosclerosis

AIM

The extracellular matrix protein ED-B fibronectin (ED-B) is upregulated in inflammatory atherosclerotic lesions. However, functional in vivo imaging of ED-B-containing plaques has not been explored. This study evaluated whether [(99m)Tc]-conjugated AP39 ([(99m)Tc]-AP39), a single-chain antibody specific to ED-B, can be used for in vivo detection of atherosclerotic plaques in Western diet (WD)-fed, apolipoprotein E-deficient (apoE-/-) mice as compared to wildtype (WT) control mice.

METHODS

Using SPECT, 12-month-old WD-fed apoE-/- and WT mice were studied 4 hours after injecting [(99m)Tc]-AP39 (148 MBq). Subsequently, mice were sacrificed, thoracic aortas measured in a g-counter, and plaques analyzed using histology, immuno-histochemistry, autoradiography, and morphometry.

RESULTS

In vivo [(99m)Tc]-AP39-SPECT imaging of apoE-/- mice demonstrated a significant signal activity in the plaque-ridden thoracic aorta (52.236 ± 40.646 cpm/cm³) that co-localized with the aortic arch and the supra-aortic arteries in MRI scans. Low signal activity (9.468 ± 4.976 cpm/cm³) was observed in WT mice. In apoE-/- mice, the strongest signals were detected in the aortic root, aortic arch and along the abdominal aorta. Autoradiography analysis of aortas from apoE-/- mice confirmed the in vivo observation by demonstrating signal localization in atherosclerotic plaques. The size of autoradiography-positive plaque areas correlated significantly with the size of ED-B-positive (r=0.645, P=0.044) or macrophage-infiltrated (r=0.84, P<0.002) plaques. A significant correlation was found between the sizes of ED-B-positive and macrophage-infiltrated plaque areas (r=0.93, P<0.01).

CONCLUSION

[(99m)Tc]-AP39-SPECT in vivo imaging detects inflammatory plaque lesions in WD-fed apoE-/- mice.

[Compliance with hand hygiene guidelines on intensive care units at a university medical centre with surgical focus]

BACKGROUND AND AIM

Hand hygiene practice is one of the most effective measures to prevent healthcare-associated infections. This study examines the trends of hand hygiene compliance among physicians and nurses on the intensive care units (ICU) and hematopoetic stem cell transplantation units (HSCTU) at Hannover Medical School. An observational study via repeated cross-sectional assessments was conducted during the first 6 years of the "AKTION Saubere Hände" (ASH), i.e. the German adaptation of WHO's "Clean Care is Safer Care" campaign.

METHODS

Compliance rates were directly observed in accordance with WHO definitions on the 10 ICU and two HSCTU. Overall, 13,175 hand hygiene opportunities were observed between 2008 and 2013.

RESULTS

In 2008, compliance rates of physicians and nurses did not differ significantly in statistical terms (53% vs. 57%, p=0.085). Physicians' compliance improved to 64% in 2011, but declined again to 48.4% in 2013 (p < 0.001). In contrast, hand hygiene compliance among nurses had increased to 71.3% as soon as 2009 /10 (p < 0.001). Their compliance dropped to 55.8% in 2013 and thus to baseline level (p=0.444), while remaining higher than that of physicians (p=0.003). Similar trends pertained to the surgical ICU.

CONCLUSIONS

These results indicate that during the ASH-campaign hand hygiene compliance increased initially both among physicians and nurses, albeit so far not in a sustainable fashion. This implies an increased demand for interventions which not only promote motivation, but also its translation into stable and sustained behavior in accordance with guidelines.

The prevalence of nosocomial and community acquired infections in a university hospital: an observational study

BACKGROUND

Nosocomial infections (NI) increase morbidity and mortality. Studies of their prevalence in single institutions can reveal trends over time and help to identify risk factors.

METHODS

In March and April 2010, data were prospectively recorded from all inpatients at the Hannover Medical School (Germany) except those treated in the pediatric, psychosomatic, and psychiatric services. The data were acquired systematically by chart review and by interviews with the medical staff. Infections were classified according to the definitions of the Centers for Disease Control and Prevention (CDC). Information was obtained on underlying diseases, invasive procedures, the use of antibiotics, devices (the application of specific medical techniques such as drainage, vascular catheters, etc.), and detected pathogens.

RESULTS

Of the 1047 patients studied, 117 (11.2%) had a total of 124 nosocomial infections, while 112 (10.7%) had 122 community-acquired infections. The most common NI were surgical site infections (29%), infections of the gastrointestinal tract (26%) and respiratory tract (19%), urinary tract infections (16%), and primary sepsis (4%). The most common pathogens were Escherichia coli, coagulase-negative staphylococci, Candida spp., Enterococcus spp., and Pseudomonas aeruginosa. Multivariable regression analysis revealed the following independent risk factors for NI: antibiotic treatment in the last 6 months (odds ratio [OR] = 2.9), underlying gastrointestinal diseases (OR = 2.3), surgery in the last 12 months (OR = 1.8), and more than two underlying diseases (OR = 1.7). Each additional device that was used gave rise to an OR of 1.4. Further risk factors included age, length of current or previous hospital stay, trauma, stay on an intensive care unit, and artificial ventilation.

CONCLUSION

In this prevalence study, NI were a common complication. Surgical site infections were the single most common type of NI because of the large number of patients that underwent surgical procedures in our institution. More investigation will be needed to assess the benefit of prevalence studies for optimizing appropriate, effective preventive measures.

Hand hygiene compliance in transplant and other special patient groups: an observational study

BACKGROUND

This study evaluates hand hygiene behavior of health care workers in a German university hospital stratified for treatment of special patient groups (eg, transplant patients).

METHODS

From 2008 to 2010, comprehensive education and training of all health care workers was implemented to improve hand hygiene compliance. Consumption rates of alcohol-based hand rub and gloves were collected and evaluated.

RESULTS

Of the 5,647 opportunities of hand disinfection evaluated, 1,607 occurred during care for transplant patients. To our knowledge, this is the largest survey of hand hygiene compliance in special patient groups on intensive care units in a university hospital in Germany. Health care workers on surgical intensive care units showed lower hand hygiene compliance compared with health care workers on other types of intensive care units. Compliance toward hand hygiene was significantly higher on hemato-oncologic and pediatric wards. In general, hand disinfection was performed significantly more frequently after an intervention than before (P < .05, 95% confidence interval: 1.24-1.84). Overall, there was no significant difference in hand hygiene compliance when caring for transplant patients or other patients (odds ratio, 1.16; 95% confidence interval: 0.95-1.42). Nurse's and physician's hand hygiene compliance improved because of education.

CONCLUSION

Hand hygiene compliance is not increased in the care for transplant patients (despite their predisposition for nosocomial infections) compared with other patients. Additional studies will be necessary to further investigate these findings.

Beliefs about hand hygiene: a survey in medical students in their first clinical year

Medical students were asked regarding knowledge and beliefs on hand hygiene before entering the clinical phase of education. By this, we noticed a lack of knowledge concerning the correct indications for hand disinfection. Regardless of previous experience in hospitals, the medical students expected that the compliance towards hand hygiene would be worse in more experienced physicians and senior consultants--who are often considered to be role models for medical students.

Differences in the implications of maternal lipids on fetal metabolism and growth between gestational diabetes mellitus and control pregnancies

AIMS

To evaluate the potential contribution of maternal glucose and lipids to fetal metabolic variables and growth in pregnancies with normal glucose tolerance in comparison with pregnancies with well-controlled gestational diabetes previously reported by us.

METHODS

In 190 pregnancies with normal oral glucose tolerance tests (controls), insulin, glucose and lipid components were determined in maternal and arterial cord blood serum. Birthweight and neonatal fat mass were obtained after delivery. Values were adjusted for maternal pre-pregnancy BMI, Caesarean section and gestational age. Measurements were compared with those of gestational diabetes previously reported.

RESULTS

Maternal serum glucose, triacylglycerol, free fatty acid and cholesterol levels did not differ between control pregnancies and those with gestational diabetes, whereas insulin, homeostasis model assessment and glycerol values were significantly lower in the former (2.6 vs. 5.6 μmol/l and 176 vs. 193 μmol/l, respectively). In contrast, cord blood glucose and free fatty acids were significantly lower in control pregnancies than in those with gestational diabetes (3.9 vs. 4.4 mmol/l and 80.7 vs. 137 μmol/l, respectively); the same was valid for insulin (0.03 vs. 0.05 nmol/l) and homeostasis model assessment (1.0 vs. 1.87). In control pregnancies, maternal serum glucose, free fatty acids and glycerol correlated with those in cord blood, but not with neonatal weight and fat mass, as seen for free fatty acids in those with gestational diabetes. The negative correlation between cord blood triacylglycerols and neonatal weight or fat mass previously reported in gestational diabetes could not be confirmed in control pregnancies, where all fetal lipids showed a positive correlation to neonatal anthropometrics.

CONCLUSION

In normal pregnancies, in contrast to those with gestational diabetes, maternal lipids do not influence neonatal weight. Similar levels of maternal lipids in pregnancies with gestational diabetes and control pregnancies, but higher free fatty acids in the cord blood of those with gestational diabetes, indicate their enhanced placental transport and/or enhanced lipolysis as a result of decreased fetal insulin responsiveness.

Antibiotic pretreatment of heart valve prostheses to prevent early prosthetic valve endocarditis

BACKGROUND AND AIM OF THE STUDY

Prosthetic valve endocarditis (PVE), a rare but major complication after heart valve replacement surgery, has potentially catastrophic consequences despite maximal treatment. Thus, preventive measures are essential. The study aim was to investigate the effect of pretreating heart valve prostheses with the antibiotics baneomycin and daptomycin, with and without surgical sealant fibrin glue as a drug-releasing substance. The biocompatibility of baneocin and daptomycin was also investigated.

METHODS

Samples of polyethylene terephthalate (PTE), as used for the sewing cuffs of prosthetic heart valves, were tested; untreated samples served as controls. All samples were contaminated with Staphylococcus epidermidis, and colony-forming units (CFUs) then counted. Cytotoxicity tests were performed using the MTT-assay to evaluate the effects of baneomycin and daptomycin on cell proliferation and wound healing.

RESULTS

Untreated and fibrin glue-coated samples were directly infected with a bacterial count of 2.82 +/- 0.63 x 10(5) CFU/ml and 2.80 +/- 1.07 x 10(5) CFU/ml, on average. Baneocin-impregnated samples were sterile for 1.9 +/- 0.38 days, with a subsequent bacterial count of 2.26 +/- 0.6 x 10(5) CFU/ml, while daptomycin-impregnated samples were sterile for 2.9 +/- 0.38 days, with a subsequent bacterial count of 1.81 +/- 0.53 x 10(5) CFU/ml. Samples coated with a fibrin glue-baneocin mixture were sterile for 3.14 +/- 0.38 days, after which the bacterial count was 0.74 +/- 0.47 x 10(5) CFU/ml. After coating with a fibrin glue-daptomycin mixture, samples were sterile for 7.0 +/- 0.58 days, and the bacterial count was 0.70 +/- 0.56 x 10(5) CFU/ml.

CONCLUSION

In this in-vitro study, the pretreatment of prosthetic heart valves with antibiotics reduced the risk of bacterial adhesion and consequent infection. The combination of antibiotics with fibrin glue prolonged this preventive effect, with baneocin demonstrating a better biocompatibility than daptomycin. On the basis of its antibacterial efficacy, daptomycin appears to be a more suitable antibiotic to prevent early PVE with Gram-positive bacteria. The soaking of prosthetic heart valves in antibiotic solutions prior to implantation, in combination with fibrin glue in cases of suspected endocarditis, can prevent the development of early PVE. This preventive strategy should be investigated for use as a standard procedure in clinical practice.

Five-years surveillance of invasive aspergillosis in a university hospital

Background

As the most common invasive fungal infection, invasive aspergillosis (IA) remains a serious complication in immunocompromised patients, leading to increased mortality. Antifungal therapy is expensive and may result in severe adverse effects.

The aim of this study was to determine the incidence of invasive aspergillosis (IA) cases in a tertiary care university hospital using a standardized surveillance method.

Methods

All inpatients at our facility were screened for presence of the following parameters: positive microbiological culture, pathologist's diagnosis and antifungal treatment as reported by the hospital pharmacy. Patients fulfilling one or more of these indicators were further reviewed and, if appropriate, classified according to international consensus criteria (EORTC).

Results

704 patients were positive for at least one of the indicators mentioned above. Applying the EORTC criteria, 214 IA cases were detected, of which 56 were proven, 25 probable and 133 possible. 44 of the 81 (54%) proven and probable cases were considered health-care associated. 37 of the proven/probable IA cases had received solid organ transplantation, an additional 8 had undergone stem cell transplantation, and 10 patients were suffering from some type of malignancy. All the other patients in this group were also suffering from severe organic diseases, required long treatment and experienced several clinical complications. 7 of the 56 proven cases would have been missed without autopsy. After the antimycotic prophylaxis regimen was altered, we noticed a significant decrease (p = 0.0004) of IA during the investigation period (2003-2007).

Conclusion

Solid organ and stem cell transplantation remain important risk factors for IA, but several other types of immunosuppression should also be kept in mind. Clinical diagnosis of IA may be difficult (in this study 13% of all proven cases were diagnosed by autopsy only). Thus, we confirm the importance of IA surveillance in all high-risk patients.

Surgical site infections--economic consequences for the health care system

PURPOSES

Unfortunately, surgical site infections (SSIs) are a quite common complication and represent one of the major causes of postoperative morbidity and mortality, and may furthermore lead to enormous additional costs for hospitals and health care systems.

METHODS

In order to determine the estimated costs due to SSIs, a MEDLINE search was performed to identify articles that provide data on economic aspects of SSIs and compared to findings from a matched case-control study on costs of SSIs after coronary bypass grafting (CABG) in a German tertiary care university hospital.

RESULTS

A total of 14 studies on costs were found. The additional costs of SSI vary between $3,859 (mean) and $40,559 (median). Median costs of a single CABG case in the recently published study were $49,449 (€36,261) vs. $18,218 (€13,356) in controls lacking infection (p < 0.0001). The median reimbursement from health care insurance companies was $36,962 (€27,107) leading to a financial loss of $12,482 (€9,154) each.

CONCLUSION

Costs of SSIs may almost triple the individual overall health care costs and those additional charges may not be sufficiently covered. Appropriate measures to reduce SSI rates must be taken to improve the patient's safety. This should also diminish costs for health care systems which benefits the entire community.

Sternal surgical site infection prevention - is there any room for improvement?

OBJECTIVE

The objectives of this multicenter study are to evaluate current clinical practices in cardiac surgery concerning the prevention and management of sternal wound infections, to identify room for improvement, and to support implementation of systematic measures.

METHODS

As a part of a campaign for infection prevention in cardiac surgery in Germany, a multiple-choice questionnaire with two main sections was developed and submitted to all cardiac surgery units in Germany (79). The project was realized in cooperation with the German Society for Thoracic and Cardiovascular Surgery, the BQS Institute for Quality and Patient Safety, and the National Reference Center for Nosocomial Infection Surveillance.

RESULTS

A representative number (54 of 79 or 68%) of German cardiac surgery centers participated in the survey, in which heterogeneous procedures and various standards for prevention were observed. Surveillance, standards, and advanced training regarding hygiene measures are present in almost all participating hospitals. Methicillin-resistant Streptococcus aureus (MRSA) screening is performed in 81.5% (44/54) of all participating departments. A little less than one-tenth (7.4%) perform decolonization measures on all patients, while 85.2% perform decolonization measures only on MRSA-positive patients. Application of perioperative antibiotic prophylaxis ranges from single-shot application to 3 days of treatment. Longer treatment is expensive and time-intensive, and also increases the risk of Clostridium difficile-associated diarrhea. Nearly three-quarters (70.4%) of all participating hospitals perform preoperative hair removal 1 day before surgery. Common techniques are clipping machines (53.7%), razors (40.7%), clipping machines and depilatory cream (1.9%), or depilatory cream only (1.9%). Remanent (37.0%) and non-remanent disinfectants (55.6%) are used for preoperative skin disinfection. The time of the first wound-dressing change varies from the day of surgery (1.9%) over the first (42.6%) or second (46.3%) day after surgery to up to 3 or more days after surgery (9.3%).

CONCLUSIONS

The results of the evaluation show that basic measures for infection prevention in cardiac surgery in Germany are well implemented. Nevertheless, a relevant heterogeneity in the use of special measures was observed, although research-based guidelines for infection prevention in surgery do exist and many studies have demonstrated the usefulness and feasibility of these measures.

Prevention of early vascular graft infection using regional antibiotic release

BACKGROUND

Infections after prosthetic replacement of the aorta remain a serious and life-threatening complication. The only appropriate treatment is the surgical removal of the infected prosthesis. Accordingly, there is a need for new procedures to prevent the infection of vascular prostheses. This in vitro experiment investigated the effect of the pretreatment of vascular prostheses with antibiotics (daptomycin or baneocin) and the effect of antibiotics combined with fibrin sealant as possible prophylaxis of perioperative graft infection.

METHODS

Untreated prostheses served as controls. Pretreated prostheses of double woven velour vascular grafts were contaminated with Staphylococcus epidermidis, and colony-forming units were counted each day (CFU/mL).

RESULTS

The period of sterility differed significantly as a function of the pretreatment. Uncoated prostheses were immediately non-sterile and exhibited 2.63 ± 0.61 × 10(5) CFU/mL. Baneocin pretreatment resulted in sterility for 1.7 ± 0.6 (95% confidence interval (CI) 1.0-2.4) d before we detected 2.14 ± 0.57 × 10(5) CFU/mL on the prostheses. Pretreatment with daptomycin yielded 2.9 ± 0.4 (CI 2.6-3.2) and fibrin sealant/baneocin compound yielded 3.1 ± 0.3 (CI 2.9-3.3) d of sterility, after which 1.81 ± 0.86 × 10(5) CFU/mL and 1.04 ± 0.77 × 10(5) CFU/mL were recorded. Finally, pretreatment with fibrin sealant/daptomycin led to sterility for 7.1 ± 0.3 (CI 6.9-7.3) d, after which 0.77 ± 0.60 × 10(5) CFU/mL were observed on the prostheses.

CONCLUSIONS

The risk of vascular graft infection is reduced by pretreating the prostheses with antibiotics. The antibiotic/fibrin compound exhibited an effect of delayed antibiotic release. Vascular prostheses should therefore be pretreated with antibiotic solution to reduce bacterial adhesion. This procedure might be an effective prophylaxis for perioperative vascular graft infection and provides suitable protection for the prosthetic material.

Economic aspects of deep sternal wound infections

OBJECTIVES

Surgical-site infections are a very expensive complication in cardiac surgery. Thus, the total costs for coronary artery bypass grafting (CABG) surgery may substantially increase when a deep sternal wound infection (DSWI) occurs. This may be due to an extended length of stay (LOS), the need for additional surgical procedures, vacuum-assisted wound dressing and antibiotic therapy. This study compares the LOS in the hospital and on an intensive care unit (ICU) as well as the total costs for patients undergoing CABG depending upon the occurrence of a subsequent DSWI.

METHODS

A case-control study was performed. Total costs of DSWI cases were analysed and compared to patients undergoing CABG without DSWI. Inclusion criterion for cases was the development of a DSWI according to the CDC criteria during hospital stay after CABG. Two control patients without any signs or symptoms of an infection during hospital stay were matched to each case by (1) type of surgery according to their diagnosis-related group (DRG), (2) age +/-5 years, (3) gender and (4) duration of preoperative hospital stay +/-2 days, but at least as long as the time at risk of cases before infection.

RESULTS

Between January 2006 and March 2008, 17 CABG patients with DSWI (cases) and 34 matched controls were included. The median overall costs of a CABG case were 36,261 Euro compared with 13,356 Euro per control patient without infection (p<0.0001). The median overall LOS was 34.4 days versus 16.5 days, respectively (p=0.0006). The median LOS on ICU was 6.3 days versus 5.3 days (no significant difference).

CONCLUSION

DSWI represents an important economic factor for the hospital as they may almost triple the costs for patients undergoing CABG. Thus, appropriate infection control measures for the prevention of DSWI should be enforced.

[Hand hygiene and campaigns]

BACKGROUND

Hand disinfection is a well-known and appropriate practise for infection prevention. Hence, it is logical to encourage its compliance and to provide its sustainability in the daily routine of a hospital. Several campaigns address an improvement of this important prevention measure.

METHODS

In the Hannover Medical School the health staffs on the intensive care units and bone marrow transplantation wards were examined for this topic by a standardised questionnaire. The aim was to detect deficiencies and the level of knowledge.

RESULTS

The forms were handed out to 838 health-care workers on 12 wards. 346 (41.2 %) were analysed. Inadequate hand disinfection due to a lack of time was the most common answer (43.1 %), followed by "there is no reason" (37.3 %). The alcoholic hand rub should be better available (50.3 %) and a continuing education programme should be provided (42.8 %) for improving hand hygiene practise.

CONCLUSION

The survey revealed the known risk factors for non-compliance. At this point, the national hand campaign "Aktion Saubere Hände" supports training courses by providing instruction materials for all participants. These materials are used for training health-care workers individually.

Role of endotoxin in the pathogenesis of critical illness polyneuropathy

Critical illness polyneuropathy (CIP) occurs in association with sepsis and multiple organ failure; however, little is known about the pathomechanisms of CIP and its therapy. In order to determine the parameters which interfere with development of CIP, electrophysiological investigations of peripheral nerves and biochemical measures were correlated to each other. The present study includes 20 consecutive patients in an intensive care unit developing severe sepsis or septic shock. Nerve conduction studies and electromyography were performed with occurring sepsis (day 1, 7, 14) and neurophysiological parameters were correlated with biochemical measures, especially indicators of infection and inflammation. It was found that all patients developed neurophysiological signs of axonal motor polyneuropathy. There was a significant correlation between serum concentrations of endotoxin and interleukin-2 receptors (IL2-R) and reduction of the amplitude of the compound motor action potentials. Other clinical and biochemical parameters showed no significant correlations with neurophysiological data. This finding apparently indicates that endotoxin damages nerve axons directly or indirectly, e.g. by activation of inflammatory cascades (IL2-R). Endotoxin appears to be an essential factor in the pathogenesis of CIP in sepsis, and therapeutic options neutralizing endotoxin may prevent development of CIP.

Local Mechanical Properties of Plasma Treated Polystyrene Surfaces

We study how a local air plasma treatment affects the mechanical properties of polystyrene by performing indentation measurements on the polymer in the elastic and plastic regime. The local exposure to plasma was obtained by placing a shadow-mask with quadratic holes of 45 x 45 microm(2) on top of the polymer substrate, providing uncovered (exposed to the plasma) and covered (protected from the plasma) areas. We have analyzed quantitatively the topography and the elastic-plastic properties of such a sample with atomic force microscopy (AFM) measurements, both before and after plasma treatment. To enhance the differences between covered and uncovered areas, the sample has been exposed to solvent vapor. This generates regions which are differently swollen. The quantitative investigation of the mechanical properties of the swollen sample for different solvent exposure times gives further insight into the changes of polystyrene mechanical properties caused by the plasma.

The influence of dental alloys on three-body wear of human enamel and dentin in an inlay-like situation

This in vitro study evaluated the effect of metal alloys on three-body wear resistance of enamel and dentin, and vice versa. Three-body wear of human enamel, dentin, a soft gold alloy (BiOcclus Inlay), a CoCr alloy (Remanium 2000), a resin cement (Variolink II) and a zinc oxide phosphate cement (Harvard) was investigated using the ACTA-machine. Sample chambers of eight sample wheels were prepared with pure materials or combinations of human tooth substance, alloys and cement, simulating an inlay-like situation. After 100,000 and 200,000 cycles in a millet suspension with a spring force of 20 N, the amount of abraded material was profilometrically measured and evaluated by 3D surface data analysis. After 200,000 cycles, the materials demonstrated a mean loss of 0.41 microm for CoCr, 51 microm for gold, 57 microm for enamel, 164 microm for dentin, 79 microm for Variolink and 369 microm for Harvard. Using ANOVA and the Games-Howell-test, resin cement, enamel and gold were a subset not shown to differ, as was zinc phosphate cement and dentin. CoCr demonstrated the least wear and differed significantly from all materials. Enamel wear was significantly reduced in mixed chambers with CoCr, and gold after 200,000 cycles compared to enamel in pure chambers. In summary, a soft gold alloy can be recommended for inlays when considering three-body abrasion since the wear rate of the "soft" gold alloy corresponded to that of human enamel.

TNFalpha inhibits insulin's antiapoptotic signaling in vascular smooth muscle cells

Tumor necrosis factor alpha (TNFalpha) interferes with insulin signaling in adipose tissue and may promote insulin resistance. Insulin resistance is associated with vascular injury, but little is known about the interaction of TNFalpha and insulin in the vasculature. By activating the Insulin receptor (IR) --> IRS-1 --> phosphatidylinositol-3-kinase (PI3K) --> Akt-pathway, insulin protects vascular smooth muscle cells (VSMC) from undergoing apoptosis. We therefore investigated the effect of TNFalpha on insulin's antiapoptotic signaling in rat aortic VSMC. Insulin induced rapid tyrosine-phosphorylation of the IR and IRS-1 and caused a 2.8-fold increase of IRS-1-bound PI3K. TNFalpha had no effect on insulin-induced tyrosine-phosphorylation of IR or IRS-1, but inhibited insulin-stimulated IRS-1/PI3K-association by 84%. Insulin-induced phosphorylation of Akt downstream of PI3K was inhibited by TNFalpha in a similar pattern. We next examined the effect of TNFalpha on insulin's protective actions on H(2)O(2)-induced apoptosis. Insulin alone prevented 72.8% of H(2)O(2)-induced apoptosis, which was significantly inhibited by TNFalpha. TNFalpha alone did not induce apoptosis. In contrast, TNFalpha had no effect on PDGF-induced antiapoptotic signal transduction via Akt. Thus, TNFalpha selectively interferes with insulin's antiapoptotic signaling in VSMC by inhibiting the association of IRS-1/PI3K and the downstream activation of Akt.

Doxazosin inhibits monocyte chemotactic protein 1-directed migration of human monocytes

Monocyte chemotactic protein 1 (MCP-1)-directed transendothelial migration of monocytes plays a key role in the early development of atherosclerosis. Migration of monocytes requires degradation of extracellular matrices, a process that involves matrix metalloproteinases (MMP) and tissue inhibitors of MMPs (TIMP). Recent studies suggest that the alpha1-adrenergic receptor antagonist doxazosin (Dox) might have antiatherosclerotic effects, although the underlying mechanisms are poorly understood. The purpose of the present study was to determine the effects of Dox on MCP-1-directed monocyte migration, MMP-9 activity, and TIMP-1 expression. MCP-1 (50 ng/ml) stimulated migration of human peripheral blood monocytes (HPBM) 2.7+/-0.42-fold and THP-1 human monocytes 5.9+/-0.83-fold compared with unstimulated control. Dox inhibited MCP-1-induced migration in a dose-dependent manner, with a maximal reduction at 10 microM of 69.5+/-5.9% in HPBM and 72.2+/-3.2% in THP-1 cells. Dox blocked migration even after pretreatment with phenoxybenzamine, an irreversible alpha1-adrenergic receptor antagonist (HPBM: phenoxybenzamine 1 microM + Dox 10 microM, 71.9+/-2.2% inhibition; THP-1 cells: phenoxybenzamine 1 microM + Dox 10 microM: 78+/-7.7% inhibition), suggesting that the antimigratory activity of Dox is mediated through a novel mechanism unrelated to its blocking of the alpha1-adrenergic receptor. Dox (10 microM) inhibited MMP-9 activity by 67.6+/-10.5%, whereas MMP-9 protein levels were not affected. Also, Dox increased PMA-induced-tissue inhibitor of MMPs-1 (TIMP-1) expression by 134.4+/-6.6%. Dox 10 microM. The present study demonstrates a potential novel antiatherosclerotic action of Dox by blocking MCP-1-directed monocyte migration, which might be partly mediated by inhibition of MMP-9 activity.

Selective expression of the proprotein convertases furin, pc5, and pc7 in proliferating vascular smooth muscle cells of the rat aorta in vitro

The aim of this study was to investigate whether transformation of quiescent vascular smooth muscle cells (VSMCs) into proliferating secretory cells is accompanied by an expression of processing enzymes that activate de novo-synthesized growth factors. Three enzymes belonging to the family of the kexin/subtilisin-like mammalian proprotein convertases (PCs), furin, PC5, and PC7, were found to be upregulated after balloon denudation in vivo. To determine their importance in these cell processes, we investigated their gene regulation using a short-term organ culture system. After incubation of rat aorta for 4 and 24 hr in serum-free medium, we demonstrated a significant induction of VSMC proliferation. The affected subset of VSMCs, positive for alpha-smooth muscle actin, also expressed proliferating cell nuclear antigen (PCNA). Our results revealed a parallel upregulation of furin, PC5, and PC7 in PCNA-immunolabeled cells. As a substrate model for comparison with PCs we used nerve growth factor (NGF). NGF is known to be activated by PCs. As shown by Northern blotting analysis, NGF mRNA concentration was significantly increased in cultured explants. NGF was released into the culture medium. In conclusion, both PCs and NGF are coordinately modulated on induction of VSMC proliferation.

Integrins alphavbeta3 and alphavbeta5 mediate VSMC migration and are elevated during neointima formation in the rat aorta

Neointima formation involves tissue expression of matrix proteins and growth factors. The role of alphavbeta3, but not alphavbeta5 integrin in vascular cells has been sufficiently investigated. The aim of the present study was to determine and compare the function of alphavbeta3 and alphavbeta5 integrins in rat aortic (RASMC) and human coronary vascular smooth muscle cells (HCSMC) and to characterize their expression accompanying neointima formation in vivo. RASMC and HCSMC express alphavbeta3 and alphavbeta5 integrin subunits. The alphavbeta5 integrin predominantly mediated adhesion of RASMCs to vitronectin and spreading on vitronectin via RGD-binding sequences. In contrast, the alphavbeta3 integrin did not contribute to the adhesion and spreading on fibronectin, vitronectin, gelatin or collagen I coated layers. PDGF-directed migration through gelatin coated membranes involved both alphavbeta3 and alphavbeta5 integrins. Selective blocking antibodies for alphavbeta3 and alphavbeta5 inhibited migration of RASMC and HCSMC by more than 60 % (p < 0.01). Integrin expression was studied in vivo in thoracic aorta of Sprague Dawley rats before and after balloon injury. In situ hybridization demonstrated low signals for alphav, beta3 and beta5 mRNA in uninjured aorta, which increased significantly at 14 days, localized predominantly in the neointima. Northern analysis of aorta after 14 days of injury also demonstrated an upregulation of alphav, beta3 and beta5 mRNA compared to uninjured aorta. Consistent with the increase in message levels, increased integrin protein expression was seen in the neointima after 7 and 14 days. This study provides evidence that alphavbeta3 and alphavbeta5 are elevated during neointima formation in the rat and indicates a novel role for alphavbeta5 participating in mechanisms regulating smooth muscle cell migration.

Expression of CD40 in vascular smooth muscle cells and macrophages is associated with early development of human atherosclerotic lesions

CD40-CD154-mediated signaling has recently been described as playing a role in cellular functions involved in atherosclerotic processes. CD40 is expressed in macrophages, lymphocytes, endothelial cells, and vascular smooth muscle cells. However, cross-sectional studies investigating the expression of CD40 in atherosclerotic lesions are lacking. In the present study the expression of CD40 was studied in atherosclerotic lesions from 43 patients classified according to the World Health Organization criteria. Serial immunohistologic stainings of human iliac arteries from 43 patients were performed using monoclonal antibodies. Lesions were classified according to World Health Organization criteria, and CD40 expression was analyzed with regard to cell morphology and cellular markers by 2 independent observers. Human atherosclerotic lesions revealed a significant increase in intimal thickness, number of inflammatory infiltrates, and CD40-positive macrophages and vascular smooth muscle cells with progression of the lesions. This increase was most prominent from stage 0 to stage I. A significant correlation between intimal thickness and CD40-positive macrophages (r = 0.75, p <0.0005) and CD40-positive vascular smooth muscle cells (r = 0.81, p <0.0005) was observed. Ligation of the cellular CD40 receptor contributes to inflammatory cellular events in human vascular smooth muscle cells. These data suggest a direct association of CD40 expression in atherosclerotic lesions with early plaque development.

Peroxisome proliferator-activated receptor and retinoid X receptor ligands inhibit monocyte chemotactic protein-1-directed migration of monocytes

Monocyte chemotactic protein-1 (MCP-1)-directed transendothelial migration of monocytes plays a key role in the development of inflammatory diseases. Infiltration of tissues by monocytes requires degradation of extracellular matrices, a process that involves matrix metalloproteinases. We studied the effects of peroxisome proliferator-activated receptor (PPAR) gamma, alpha, and retinoid X receptor alpha (RXRalpha) ligands on MCP-1-directed migration and matrix metalloproteinase expression of a human acute monocytic leukemia cell line (THP-1). PPARgamma ligands attenuated MCP-1-induced migration, with 50% inhibition (IC(50)) at 2.8 microM for troglitazone and 4.8 microM for rosiglitazone. PPARalpha ligands WY-14643 (IC(50): 0.9 microM) and 5,8,11,14-eicosatetranoic acid (IC(50): 9.9 microM), and the potent RXRalpha ligand AGN 4204 (IC(50): 3.6 nM) also blocked monocyte migration. Troglitazone, rosiglitazone, or AGN 4204 inhibited phorbol 12-myristate 13-acetate (PMA)-induced matrix metalloproteinase-9 expression. PPARalpha activators WY-14643 and 5,8,11,14-eicosatetraynoic acid, however, had no inhibitory effect. AGN 4204 increased PMA-induced tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) expression, whereas all PPAR ligands showed no effect. All PPAR and RXRalpha ligands blocked chemotaxis of THP-1 monocytes in the absence of a matrix barrier. This study demonstrates that activated PPARs and RXRalpha, block MCP-1-directed monocyte migration, mediated, at least in part, through their effects on matrix metalloproteinase-9 or TIMP-1 production, or chemotaxis.