Stefan Hofer

Central sympatholytics prolong survival in experimental sepsis.

IntroductionOne of the main causes of death in European and US intensive care units is sepsis. It involves a network of pro-inflammatory cytokines such as TNF-α, IL-1β and IL-6. Furthermore, there is an up regulation of transcription factors such as nuclear factor (NF) κB. It has previously been shown that clonidine is able to significantly reduce pro-inflammatory cytokines in surgical patients. We therefore hypothesise that the clinically used central alpha-2 agonist clonidine has the ability to improve survival in experimental sepsis by inhibiting the sympathetic tone and consequently inhibiting the pro-inflammatory cytokine release.MethodsTo investigate this therapeutic potential of clonidine in a prospective randomised laboratory investigation we used a murine model of caecal ligation and puncture (CLP) induced sepsis. Animals receiving pre-emptive injections were treated with either clonidine (5 μg/kg) or dexmedetomidine (40 μg/kg) 12 and 1 hours before the operation, as well as 1, 6 and 12 hours afterwards. Another group of animals only received clonidine (5 μg/kg) 1, 6 and 12 hours after the operation, while the pre-emptive injections were normal saline. The control groups received solvent injections at the respective time points.ResultsPre-emptive administration of a central sympatholytic significantly reduced mortality (clonidine: p = 0.015; dexmedetomidine: p = 0.029), although postoperative administration of clonidine failed to significantly prolong survival. Furthermore pre-emptive administration of clonidine significantly attenuated the cytokine response after CLP-induced sepsis (mIL-1beta: p = 0.017; mIL-6: p < 0.0001; mTNF-α: p < 0.0001), preserved blood pressure control (p = 0.024) and down-regulated the binding activity of NF-κB. There were no changes in the pro-inflammatory cytokine response when peripheral blood was incubated with lipopolysaccharide alone compared with incubation with clonidine (10-4 M) plus LPS (p > 0.05).ConclusionsOur results demonstrate that the pre-emptive administration of either clonidine or dexmedetomidine have the ability to successfully improve survival in experimental sepsis. Furthermore, there seems to be a connection between the central muscarinic network and the vagal cholinergic response. By down-regulating pro-inflammatory mediators sympatholytics may be a useful adjunct sedative in patients with a high risk for developing sepsis.

First Evaluation of Automated Specimen Inoculation for Wound Swab Samples by Use of the Previ Isola System Compared to Manual Inoculation in a Routine Laboratory: Finding a Cost-Effective and Accurate Approach

ABSTRACT Automation of plate streaking is ongoing in clinical microbiological laboratories, but evaluation for routine use is mostly open. In the present study, the recovery of microorganisms from the Previ Isola system plated polyurethane (PU) swab samples is compared to manually plated control viscose swab samples from wounds according to the CLSI procedure M40-A (quality control of microbiological transport systems). One hundred twelve paired samples (224 swabs) were analyzed. In 80/112 samples (71%), concordant culture results were obtained with the two methods. In 32/112 samples (29%), CFU recovery of microorganisms from the two methods was discordant. In 24 (75%) of the 32 paired samples with a discordant result, Previ Isola plated PU swabs were superior. In 8 (25%) of the 32 paired samples with a discordant result, control viscose swabs were superior. The quality of colony growth on culture media for further investigations was superior with Previ Isola inoculated plates compared to manual plating techniques. Gram stain results were concordant between the two methods in 62/112 samples (55%). In 50/112 samples (45%), the results of Gram staining were discordant between the two methods. In 34 (68%) of the 50 paired samples with discordant results, Gram staining of PU swabs was superior to that of control viscose swabs. In 16 (32%) of the 50 paired samples, Gram staining of control viscose swabs was superior to that of PU swabs. We report the first clinical evaluation of Previ Isola automated specimen inoculation for wound swab samples. This study suggests that use of an automated specimen inoculation system has good results with regard to CFU recovery, quality of Gram staining, and accuracy of diagnosis.

Next-generation sequencing diagnostics of bacteremia in septic patients

BackgroundBloodstream infections remain one of the major challenges in intensive care units, leading to sepsis or even septic shock in many cases. Due to the lack of timely diagnostic approaches with sufficient sensitivity, mortality rates of sepsis are still unacceptably high. However a prompt diagnosis of the causative microorganism is critical to significantly improve outcome of bloodstream infections. Although various targeted molecular tests for blood samples are available, time-consuming blood culture-based approaches still represent the standard of care for the identification of bacteria.MethodsHere we describe the establishment of a complete diagnostic workflow for the identification of infectious microorganisms from seven septic patients based on unbiased sequence analyses of free circulating DNA from plasma by next-generation sequencing.ResultsWe found significant levels of DNA fragments derived from pathogenic bacteria in samples from septic patients. Quantitative evaluation of normalized read counts and introduction of a sepsis indicating quantifier (SIQ) score allowed for an unambiguous identification of Gram-positive as well as Gram-negative bacteria that exactly matched with blood cultures from corresponding patient samples. In addition, we also identified species from samples where blood cultures were negative. Reads of non-human origin also comprised fragments derived from antimicrobial resistance genes, showing that, in principle, prediction of specific types of resistance might be possible.ConclusionsThe complete workflow from sample preparation to species identification report could be accomplished in roughly 30xa0h, thus making this approach a promising diagnostic platform for critically ill patients suffering from bloodstream infections.

Sleep-disordered breathing is a risk factor for delirium after cardiac surgery: a prospective cohort study

IntroductionDelirium is a frequent complication after cardiac surgery. Although various risk factors for postoperative delirium have been identified, the relationship between nocturnal breathing disorders and delirium has not yet been elucidated. This study evaluated the relationship between sleep-disordered breathing (SDB) and postoperative delirium in cardiac surgery patients without a previous diagnosis of obstructive sleep apnea.MethodsIn this prospective cohort study, 92 patients undergoing elective cardiac surgery with extracorporeal circulation were evaluated for both SDB and postoperative delirium. Polygraphic recordings were used to calculate the apnea-hypopnea index (AHI; mean number of apneas and hypopneas per hour recorded) of all patients preoperatively. Delirium was assessed during the first four postoperative days using the Confusion Assessment Method. Clinical differences between individuals with and without postoperative delirium were determined with univariate analysis. The relationship between postoperative delirium and those covariates that were associated with delirium in univariate analysis was determined by a multivariate logistic regression model.ResultsThe median overall preoperative AHI was 18.3 (interquartile range, 8.7 to 32.8). Delirium was diagnosed in 44 patients. The median AHI differed significantly between patients with and without postoperative delirium (28 versus 13; P = 0.001). A preoperative AHI of 19 or higher was associated with an almost sixfold increased risk of postoperative delirium (odds ratio, 6.4; 95% confidence interval, 2.6 to 15.4; P <0.001). Multivariate logistic regression analysis showed that preoperative AHI, age, smoking, and blood transfusion were independently associated with postoperative delirium.ConclusionsPreoperative SDB (for example, undiagnosed obstructive sleep apnea) were strongly associated with postoperative delirium, and may be a risk factor for postoperative delirium.

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.

Relevance of Candida and other mycoses for morbidity and mortality in severe sepsis and septic shock due to peritonitis.

This single‐centre retrospective cohort study evaluated the incidence and outcome of mycoses in critical ill patients (n = 283) with sepsis due to peritonitis. Overall mortality was 41.3%, and the 28‐day mortality was 29.3%. Fungal pathogens were found in 51.9%. The common first location was the respiratory tract (66.6%), followed by the abdominal site (19.7%). Candida colonisation was found in 64.6%, and invasive Candida infection in 34.0%. Identified fungi were Candida spp. in 98.6% and Aspergillus spp. in 6.1%. Patients with fungal pathogens showed a higher rate of postoperative peritonitis, APACHE II and tracheotomy. In comparison to patients without fungal pathogens, these patients showed a longer duration on mechanical ventilation, and a higher overall mortality. Patients with Candida‐positive swabs from abdominal sites had more fascia dehiscence and anastomosis leakage. Seventy‐two patients (48.9%) received antifungal therapy, 26 patients were treated empirically. Antifungal therapy was not associated with a decrease in mortality. Age and renal replacement therapy were associated with mortality. In conclusion, fungi are common pathogens in critically ill patients with peritonitis, and detection of fungi is associated with an increase in overall mortality. Particularly, Candida‐positive abdominal swabs are associated with an increase in morbidity. However, we were not able to demonstrate a survival benefit for antifungal therapy in peritonitis patients.

Soluble TREM-1 as a diagnostic and prognostic biomarker in patients with septic shock: an observational clinical study

Abstract Objectives: The impact of TREM-1-mediated inflammation was investigated in different inflammatory settings. Methods: Secondary analyses of an observational clinical pilot study, including 60 patients with septic shock, 30 postoperative controls and 30 healthy volunteers. Results: Plasma levels of sTREM-1 were found to identify patients with septic shock more effectively than procalcitonin and C-reactive protein. Moreover, sTREM-1 was identified to be an early predictor for survival in patients with septic shock. Conclusion: Due to its diagnostic as well as prognostic value in sepsis syndrome, implementation of sTREM-1 measurements in routine diagnostics should be taken into account.

Acute respiratory distress syndrome induction by pulmonary ischemia–reperfusion injury in large animal models

Acute respiratory distress syndrome (ARDS) is a common critical pulmonary complication after esophagectomy and other thoracic surgeries (e.g., lung transplantation, pulmonary thromboendarterectomy). Direct pulmonary ischemia-reperfusion injury (PIRI) is known to play the main role in induction of ARDS in these cases. Large animal models are an appropriate choice for ARDS as well as PIRI study because of their physiological and anatomic similarities to the human body. With regard to large animal models, we reviewed different methods of inducing in situ direct PIRI and the commonly applied methods for diagnosing and monitoring ARDS or PIRI in an experimental research setting.

RAGE-mediated inflammation in patients with septic shock

BACKGROUNDnThe receptor for advanced glycation end-products (RAGE)-pathway is described to be a crucial component of the innate immune response in sepsis. The aims of the present study were, therefore, to delineate the kinetics of membrane-bound RAGE expression, to quantify its soluble isoforms, and to determine the extent of metabolic (e.g., AGE-CML) as well as immunologic (e.g., S100A8/A9) ligands in different inflammatory settings in humans.nnnMATERIALS AND METHODSnThe presented data result from secondary analyses of an observational clinical pilot study, including patients with septic shock (nxa0=xa060), postoperative controls (nxa0=xa030), and healthy volunteers (nxa0=xa030). Surface-bound expression of RAGE by peripheral blood leukocytes was determined by flow cytometry. In addition, plasma levels of sRAGE, esRAGE, AGE-CML, S100A8/A9, S100A8/A9-CML, RBP, RBP-CML, HSA-CML, HMBG-1, and ß-Amyloid were measured using ELISA.nnnRESULTSnIn patients with septic shock, RAGE expression was significantly increased in comparison to both control groups, which was paralleled by a significant increase in sRAGE plasma levels. Formation of AGE-CML was shown to be dependent on the availability of the unmodified protein. However, the total amount of AGE-CML did not differ significantly between septic patients and healthy volunteers at early stages or was even lower in patients with sepsis at later stages. In contrast, immunologic ligands (e.g., S100A8/A9) were shown to be significantly elevated in septic patients within the entire study period.nnnCONCLUSIONSnActivation of the RAGE-pathway was shown to be of relevance in patients with septic shock, mainly driven by an increase in immunologic (e.g., S100A8/A9) rather than metabolic ligands (e.g., CML-derived AGE-formation).

Reversal of Anticoagulation With Dabigatran in an 82-Year-Old Patient With Traumatic Retroperitoneal Arterial Bleeding Using the New Antidote Idarucizumab: A Case Report.

Dabigatran etexilate is a direct oral anticoagulant used for the prevention of stroke in atrial fibrillation. Idarucizumab is a recently approved specific antidote that reverses the effect of dabigatran within minutes. We report the case of an 82-year-old patient with traumatic retroperitoneal arterial bleeding under anticoagulation with dabigatran etexilate. By administration of idarucizumab, we successfully normalized coagulation and saved the patient from an operation. In the course of the disease, a slight reincrease in dabigatran etexilate plasma levels was observed 2 days after the reversal, which could lead to a new onset of bleeding.