Christoph Lichtenstern

Cell death serum biomarkers are early predictors for survival in severe septic patients with hepatic dysfunction

IntroductionSevere sepsis, septic shock, and resulting organ failure represent the most common cause of death in intensive care medicine, with mortality ranging from 40% to 70%. It is still unclear whether necrosis or apoptosis plays the predominant role in severe sepsis. Determining the prevalent mode of cell death would be valuable, as new therapeutic agents (eg, antiapoptotic drugs such as caspase inhibitors) may improve unsatisfactory outcomes in patients with severe sepsis. Furthermore, the prognostic value of newly developed cell death serum biomarkers is of great interest.MethodsIn total, 147 patients (101 patients with severe sepsis, 28 postoperative patients after major abdominal surgery, 18 healthy volunteers) were enrolled. Baseline and clinical data were evaluated. Blood samples from patients with severe sepsis were collected at the time of sepsis diagnosis, and 48 and 120 hours later; samples from healthy volunteers were collected once, and from postoperative patients, once immediately after surgery. We measured caspase-cleaved and uncleaved cytokeratin-18 (CK-18, intermediate filament protein) as a marker of cell death, isolated CK-18 fragments as a marker of apoptosis, as well as IL-6, soluble vascular cell adhesion molecule, and soluble intercellular adhesion molecule.ResultsAge and sex of patients with severe sepsis and postoperative patients were comparable, whereas healthy volunteers were significantly younger. In healthy volunteers, the mode of cellular turnover was primarily apoptotic cell death. Postoperative patients showed comparable levels of apoptotic activity, but necrotic cell death was markedly increased, probably due to surgical tissue injury. In contrast, patients with severe sepsis, and especially non-survivors of the septic group showed increased levels of markers for both apoptotic and necrotic cell death. In severe septic patients with liver dysfunction, necrosis is increased relative to severe septic patients with intact hepatic function. For severe septic patients with liver dysfunction, a cut-off value for caspase-cleaved and uncleaved cytokeratin-18 could be calculated, in order to identify patients at high risk for death due to severe sepsis.ConclusionsThe measurement of caspase-cleaved and uncleaved cytokeratin-18 appears to be an early predictor for survival in severe septic patients with hepatic dysfunction. Furthermore, the loss of parenchymal cells due to necrosis may be the primary mode of cell death in these patients. This may limit possible therapeutic options.

Tigecycline for the treatment of patients with severe sepsis or septic shock: a drug use evaluation in a surgical intensive care unit

OBJECTIVES Adequate antimicrobial therapy is crucial for the survival of critically ill patients with severe nosocomial infections. Tigecycline, the first available agent in the new class of glycylcyclines, is active against multiresistant gram-positive and gram-negative bacteria. The aim of this observational, retrospective evaluation was to assess tigecycline use patterns in a surgical intensive care unit (SICU) of a tertiary care centre. METHODS Data from 70 patients receiving tigecycline in the SICU were analysed. We reviewed tigecycline use in terms of demographic data and co-morbidities, disease severity, clinical indication, microbiology, therapy regimens and mortality. A logistic regression analysis was performed to identify prognostic factors for mortality. RESULTS The majority of patients had co-morbidities such as cancer (51%) or renal replacement therapy (57%). The mean Acute Physiology and Chronic Health Evaluation (APACHE) II score of patients at admission was 27. Intra-abdominal infection was most frequently diagnosed (50% of patients); intra-abdominal infection and pneumonia were diagnosed in 14%. Methicillin-resistant Staphylococcus aureus was found in 16% of patients (colonization; infection: 6%) and vancomycin-resistant enterococci in 27% (colonization; infection: 21%). The mean duration of tigecycline therapy was 9 +/- 4 days; 76% of patients received tigecycline in combination, with 64% being treated second line. APACHE score and renal replacement were identified as predictive factors for mortality. SICU mortality was 30%. CONCLUSIONS Tigecycline treatment of critically ill SICU patients with severe sepsis or septic shock appeared to result in remarkably low mortality. Tigecycline may be an important treatment option for septic patients with infections resistant to other available agents.

Viscoelastic and aggregometric point-of-care testing in patients with septic shock – cross-links between inflammation and haemostasis

In the pathogenesis of sepsis, inflammation‐induced changes in coagulation play a pivotal role.

Implementation of Practice Guidelines for Antifungal Therapy in a Surgical Intensive Care Unit and Its Impact on Use and Costs

Background: Considering the complexity of diagnosis, high costs of therapy and high morbidity and mortality of systemic fungal infections, antifungal therapy of intensive care patients should follow clearly defined guidelines. We outline the impact of a standardised practice of antifungal treatment in an interdisciplinary surgical intensive care unit of a university hospital. Methods: Therapy was intended to be optimised by implementation of standardised practice guidelines supported by the clinical pharmacist. Costs for antifungal agents during a period of 18 months before and after implementation of the practice guidelines were compared, respectively. Results: The intervention was associated with a significant decrease in use of antifungal agents. Analysis of data revealed a reduction in costs by 50%. This could substantially be attributed to the implementation of the practice guidelines. Conclusion: The implementation of standardised practice guidelines for antifungal therapy in intensive care units decreased the use of selected antifungal agents and resulted in substantial reduction in expenditure on antifungal agents.

Left ventricular end-diastolic area is a measure of cardiac preload in patients with early septic shock.

Background and objective Central venous pressure, intrathoracic blood volume, and left ventricular end-diastolic area are reliable measures of cardiac preload under stable clinical conditions. The purpose of this study was to compare different preload parameters over 24 h under conditions of multiple, frequently changing treatments in early septic shock. Methods In 28 mechanically ventilated patients within 6 h of the onset of septic shock, left ventricular end-diastolic area was measured using transoesophageal echocardiography. Intrathoracic blood volume, stroke volume variation, and central venous pressure were analysed as preload parameters. The relation between parameter changes and changes in therapy was examined with respect to cardiac index and stroke volume index. Results Regarding preload variables, linear regression analyses revealed a significant correlation between left ventricular end-diastolic area and stroke volume index (r2 = 0.59, P < 0.001) and cardiac index (r2 = 0.41, P < 0.001), respectively. Changes in left ventricular end-diastolic index and intrathoracic blood volume index reflected changes in the stroke volume index, whereas central venous pressure did not. Myocardial responsiveness also failed to predict changes in the stroke volume index. Conclusion Only the left ventricular end-diastolic area index may help predict preload in ventilated patients with early septic shock.

Sepsis Induces Specific Changes in Histone Modification Patterns in Human Monocytes

Background Sepsis is a global burden and the primary cause of death in intensive care units worldwide. The pathophysiological changes induced by the host’s systemic inflammatory response to infection are not yet fully understood. During sepsis, the immune system is confronted with a variety of factors, which are integrated within the individual cells and result in changes of their basal state of responsiveness. Epigenetic mechanisms like histone modifications are known to participate in the control of immune reactions, but so far the situation during sepsis is unknown. Methods and Findings In a pilot approach, we performed combined chromatin immunoprecipitation followed by high-throughput sequencing to assess the genome-wide distribution of the chromatin modifications histone 3 lysine 4 and 27 trimethylation and lysine 9 acetylation in monocytes isolated from healthy donors (n = 4) and patients with sepsis (n = 2). Despite different underlying causes for sepsis, a comparison over promoter regions shows a high correlation between the patients for all chromatin marks. These findings hold true also when comparing patients to healthy controls. Despite the global similarity, differential analysis reveals a set of distinct promoters with significant enrichment or depletion of histone marks. Further analysis of overrepresented GO terms show an enrichment of genes involved in immune function. To the most prominent ones belong different members of the HLA family located within the MHC cluster together with the gene coding for the major regulator of this locus—CIITA. Conclusions We are able to show for the first time that sepsis in humans induces selective and precise changes of chromatin modifications in distinct promoter regions of immunologically relevant genes, shedding light on basal regulatory mechanisms that might be contributing to the functional changes occurring in monocytes.

Development and validation of a high-performance liquid chromatography assay for posaconazole utilizing solid-phase extraction

Abstract Background: Posaconazole is a new broad-spectrum triazole antifungal drug that is used in prophylaxis and therapy of opportunistic fungal infections in immunocompromised patients. Up to now, it is available as an oral suspension only. Due to variable systemic availability known from other azoles, such as itraconazole, it is important to measure blood levels, especially in patients undergoing abdominal surgery which may influence the intestinal resorption. Methods: A sensitive and selective high-performance liquid chromatography method for the precise determination of posaconazole and the internal standard clotrimazole in human plasma was developed and validated. Samples were extracted using solid-phase extraction and separated on a reversed-phase C8 column (150×4.6 mm, 5 μm) using phosphate buffer (pH 6.7, 0.04 M):acetonitrile:methanol (43:49:8, v/v/v) as mobile phase. UV detection was performed at 260 nm. Results: This method showed that a lower limit of quantification was 50 ng/mL and the limit of detection 3 ng/mL. Linearity was tested in the range from 50 to 5000 ng/mL (r2=0.9998). Mean recovery was 86%. Conclusions: The method proved to be a useful tool for therapeutic drug monitoring. It is specific, precise and showed excellent reproducibility as well as a favourable accuracy. Clin Chem Lab Med 2008;46:1747–51.

Concurrent Left Ventricular Assist Device (LVAD) Implantation and Percutaneous Temporary RVAD Support via CardiacAssist Protek-Duo TandemHeart to Preempt Right Heart Failure

Right ventricular failure (RVF) is an unfortunate complication that continues to limit outcomes following durable left ventricular assist device (LVAD) implantation. Despite several ‘RVF risk scores’ having been proposed, preoperative prediction of post-LVAD RVF remains a guesstimate at best. Current strategies for institution of temporary RVAD support are invasive, necessitate additional re-thoracotomy, restrict postoperative mobilization, and/or entail prolonged retention of prosthetic material in-situ. The authors propose a novel surgical strategy comprising simultaneous implantation of a permanent LVAD and percutaneous TandemHeart® plus ProtekDuo® to provide temporary RVAD support and preempt RVF in patients with impaired RV function.

Are there new approaches for diagnosis, therapy guidance and outcome prediction of sepsis?

Beside many efforts to improve outcome, sepsis is still one of the most frequent causes of death in critically ill patients. It is the most common condition with high mortality in intensive care units. The complexity of the septic syndrome comprises immunological aspects - i.e., sepsis induced immunosuppression - but is not restricted to this fact in modern concepts. So far, exact mechanisms and variables determining outcome and mortality stay unclear. Since there is no typical risk profile, early diagnosis and risk stratification remain difficult, which hinders rapid and effective treatment initiation. Due to the heterogeneous nature of sepsis, potential therapy options should be adapted to the individual. Biomarkers like C-reactive protein and procalcitonin are routinely used as complementary tools in clinical decision-making. Beyond the acute phase proteins, a wide bunch of promising substances and non-laboratory tools with potential diagnostic and prognostic value is under intensive investigation. So far, clinical decision just based on biomarker assessment is not yet feasible. However, biomarkers should be considered as a complementary approach.

Viral Infections in Septic Shock (VISS-Trial)-Crosslinks Between Inflammation and Immunosuppression

BACKGROUND Recent investigations provided evidence that herpes simplex virus (HSV-1) and cytomegalovirus (CMV) are reactivated in critically ill individuals. However, at this time, it remains unclear whether these viral infections are of real pathogenetic relevance or represent innocent bystanders. MATERIALS AND METHODS In total, 60 patients with septic shock were enrolled. Blood samples and tracheal secretion were collected at the time of sepsis diagnosis (T0) as well as 7 d (T1), 14 d (T2), 21 d (T3), and 28 d (T4) later. The following virologic diagnostics were performed: (1) Viral load of herpes simplex virus type1 (HSV-1) and cytomegalovirus (CMV) in blood samples as well as tracheal secretion using polymerase chain reaction (PCR). (2) Detection of CMV-antigen (pp65) in blood samples using immunofluorescence microscopy. Furthermore plasma levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) were evaluated using ELISA-kits. RESULTS Thirty-one patients (51.7%) were found to be positive for HSV-1, whereas in 16 patients (26.7%) CMV could be identified. Patients with a positive PCR for HSV-1 and/or CMV showed a significantly prolonged length of hospital stay and absolute time of respirator-dependant ventilation. Furthermore, survival curves of patients with a high HSV-1-load (>10E8) in tracheal secretion in comparison with those with a lower HSV-1-load (<10E8) revealed a significantly impaired survival. CONCLUSIONS Viral superinfections with HSV-1 or CMV can frequently be observed in patients with septic shock, especially in those with increased disease severity and a prolonged need for respirator-dependant ventilation. In patients with a viral superinfection morbidity is increased, whereas differences in mortality seem to be dosage-dependant.