The Value of Next-Generation Sequencing in Diagnosis and Therapy of Critically Ill Patients with Suspected Bloodstream Infections: A Retrospective Cohort Study.

Bloodstream infection (BSI), a frequent cause of severe sepsis, is a life-threatening complication in critically ill patients and still associated with a high mortality rate. Rapid pathogen identification from blood is crucial for an early diagnosis and the treatment of patients with suspected BSI. For this purpose, novel diagnostic tools on the base of genetic analysis have emerged for clinical application. The aim of this study was to assess the diagnostic value of additional next-generation sequencing (NGS) pathogen test for patients with suspected BSI in a surgical ICU and its potential impact on antimicrobial therapy. In this retrospective single-centre study, clinical data and results from blood culture (BC) and NGS pathogen diagnostics were analysed for ICU patients with suspected BSI. Consecutive changes in antimicrobial therapy and diagnostic procedures were evaluated. Results: 41 cases with simultaneous NGS and BC sampling were assessed. NGS showed a statistically non-significant higher positivity rate than BC (NGS: 58.5% (24/41 samples) vs. BC: 21.9% (9/41); p = 0.056). NGS detected eight different potentially relevant bacterial species, one fungus and six different viruses, whereas BC detected four different bacterial species and one fungus. NGS results affected antimicrobial treatment in 7.3% of cases. Conclusions: NGS-based diagnostics have the potential to offer a higher positivity rate than conventional culture-based methods in patients with suspected BSI. Regarding the high cost, their impact on anti-infective therapy is currently limited. Larger randomized prospective clinical multicentre studies are required to assess the clinical benefit of this novel diagnostic technology.

Sex-related differences in functional capacity and its implications in risk stratification before major non-cardiac surgery: a post hoc analysis of the international METS study.

Background: Poor functional capacity has been identified as an important modifiable risk factor for postoperative complications. Cardiopulmonary exercise testing (CPET) provides objective parameters of functional capacity (e.g., oxygen consumption at peak exercise, peak VO2), with significant prognostication for postoperative complications. However, sex-specific thresholds for functional capacity to predict surgical risk are yet to be established. Therefore, we performed a post hoc analysis of the international, multicentre, prospective observational METS (Measurement of Exercise Tolerance before Surgery) study to evaluate if sex-specific thresholds of peak VO2 improve risk prediction of postoperative complications. Methods: We undertook a post hoc analysis (HREC/71824/PMCC) of the METS study, which was performed between March 2013 and March 2016. We investigated whether sex-specific differences exist for CPET-derived parameters and associated thresholds for predicting postoperative complications in this large cohort of patients that had major non-cardiac surgery (n = 1266). Logistic regression models were analyzed for the association of low peak VO2 with moderate-to-severe in-hospital postoperative complications. Optimal sex-specific peak VO2 thresholds were obtained by maximizing the Youden index of receiver operating characteristic (ROC) curves. Finally, multivariable logistic regression models tested the resulting sex-specific thresholds against the established non-sex-specific peak VO2 threshold (14 mL kg-1 min-1) adjusted for clinically relevant features such as comorbidities and surgical complexity. Models were evaluated by bootstrapping optimism-corrected area under the ROC curve and the net reclassification improvement index (NRI). Findings: Female patients (n = 480) had a lower mean (SD) peak VO2 than males (16.7 (4.9) mL kg-1 min-1 versus 21.2 (6.5) mL kg-1 min-1, p < 0.001) and a lower postoperative complication rate (10.4% versus 15.3%; p = 0.018) than males (n = 786). The optimal peak VO2 threshold for predicting postoperative complications was 12.4 mL kg-1 min-1 for females and 22.3 mL kg-1 min-1 for males, respectively. In the multivariable regression model, low non-sex-specific peak VO2 did not independently predict postoperative complications. In contrast, low sex-specific peak VO2 was an independent predictor of postoperative complications (OR 2.29; 95% CI: 1.60, 3.30; p < 0.001). The optimism-corrected AUC-ROC of the sex-specific model was higher compared with the non-sex-specific model (0.73 versus 0.7; DeLong's test: p = 0.021). The sex-specific model classified 39% of the patients more correctly than the baseline model (NRI = 0.39; 95% CI: 0.24, 0.55). In contrast, the non-sex-specific model only classified 9% of the patients more correctly when compared against the baseline model (NRI = 0.09; 95% CI: -0.04, 0.22). Interpretation: Our data report sex-specific differences in preoperative CPET-derived functional capacity parameters. Sex-specific peak VO2 thresholds identify patients at increased risk for postoperative complications with a higher discriminatory ability than a sex-unspecific threshold. As such, sex-specific threshold values should be considered in preoperative CPET to potentially improve risk stratification and to guide surgical decision-making, including eligibility for surgery, preoperative optimization strategies (prehabilitation) or seeking non-surgical options. Funding: There was no funding for the present study. The original METS study was funded by Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, Ontario Ministry of Health and Long-Term Care, Ontario Ministry of Research, Innovation and Science, UK National Institute of Academic Anaesthesia, UK Clinical Research Collaboration, Australian and New Zealand College of Anaesthetists, and Monash University.

Association of reintubation and hospital costs and its modification by postoperative surveillance: A multicenter retrospective cohort study.

OBJECTIVE: We estimated hospital costs associated with postoperative reintubation and tested the hypothesis that prolonged surveillance in the post-anesthesia care unit (PACU) modifies the hospital costs of reintubation. DESIGN: Retrospective observational research study. SETTING: Two tertiary care academic healthcare networks in the Bronx, New York and Boston, Massachusetts, USA. PATIENTS: 68,125 adult non-cardiac surgical patients undergoing general anesthesia between 2016 and 2021. INTERVENTIONS: The exposure variable was unplanned reintubation within 7 days of surgery. MEASUREMENTS: The primary outcome was direct hospital costs associated with patient care related activities. We used a multivariable generalized linear model based on log-transformed costs data, adjusting for pre- and intraoperative confounders. We matched our data with data from the Healthcare Cost and Utilization Project-National Inpatient Sample (HCUP-NIS). In the key secondary analysis, we examined if prolonged postoperative surveillance, defined as PACU utilization (≥4 h) modifies the association between reintubation and costs of care. MAIN RESULTS: 1759 (2.6%) of patients were re-intubated within 7 days after surgery. Reintubation was associated with higher direct hospital costs (adjusted model estimate 2.05; 95% CI: 2.00-2.10) relative to no reintubation. In the HCUP-NIS matched cohort, the adjusted absolute difference (ADadj) in costs amounted to US$ 18,837 (95% CI: 17,921-19,777). The association was modified by the duration of PACU surveillance (p-for-interaction <0.001). In patients with a shorter PACU length of stay, reintubation occurred later (median of 2 days; IQR 1, 5) versus 1 days (IQR 0, 2; p < .001), and was associated with magnified effects on hospital costs compared to patients who stayed in the PACU longer (ADadj of US$ 23,444, 95% CI: 21,217-25,799 versus ADadj of US$ 17,615, 95% CI: 16,350-18,926; p < .001). CONCLUSION: Postoperative reintubation is associated with 2-fold higher hospital costs. Prolonged surveillance in the recovery room mitigated this effect. The cost-saving effect of longer PACU length of stay was likely driven by earlier reintubation in patients who needed this intervention.

Effects of Hypobaric Hypoxia on Coagulation in Healthy Subjects Exposed to 3,500 m Altitude.

Kammerer, Tobias, Anna Walzl, Thomas Müller, Philipp Groene, Giulia Roveri, Rachel Turner, Johanna Roche, Hannes Gatterer, Christoph Siebenmann, and Simon T. Schäfer. Effects of hypobaric hypoxia on coagulation in healthy subjects exposed to 3,500 m altitude. High Alt Med Biol. 24:94-103, 2023. Background: Hypoxia is discussed as a trigger for prothrombotic changes both in intensive care and high altitude medicine. This research study aimed to evaluate the effect of isolated hypobaric hypoxia (HH) on coagulation in females in a highly standardized setting. Methods: Twelve healthy female subjects were studied under HH (equivalent to 3,500 m) and normoxia (NX) during two 4-day sojourns, in a strictly controlled crossover design. Nutrition, fluid intake, hormonal status (i.e., menstrual cycle variation), and physical stress were standardized. Functional coagulation and blood lysis were measured by viscoelastometry and compared between HH and NX. In addition, plasma-based coagulation tests (PBCTs), namely prothrombin time, activated partial thromboplastin time, fibrinogen, factor VIII coagulation activity (FVIII:C), von Willebrand factor antigen (vWF:Ag), and von Willebrand factor ristocetin cofactor activity (vWF:RCo) were measured. Results: Neither for Viscoelastic Haemostatic Assays nor for PBCTs significant changes were found for HH compared with NX (all p > 0.05). Specifically, the lysis ability, as well as clotting time, clot formation, clot amplitude, and maximum clot firmness unchanged were similar between HH and NX. This also applied to all other variables. Conclusion: We demonstrate that moderate HH per se has no influence on blood coagulation in healthy females.

Predictive value of coagulation variables and glycocalyx shedding in hospitalized COVID-19 patients - a prospective observational study.

OBJECTIVES: Covid-19 disease causes an immense burden on the healthcare system. It has not yet been finally clarified which patients will suffer from a severe course and which will not. Coagulation disorders can be detected in many of these patients. The aim of the present study was therefore to identify variables of the coagulation system including standard and viscoelastometric tests as well as components of glycocalyx damage that predict admission to the intensive care unit. METHODS: Adult patients were included within 24 h of admission. Blood samples were analyzed at hospital admission and at ICU admission if applicable. We analyzed group differences and furthermore performed receiver operator characteristics (ROC). RESULTS: This study included 60 adult COVID-19 patients. During their hospital stay, 14 patients required ICU treatment. Comparing ICU and non-ICU patients at time of hospital admission, D-dimer (1450 µg/ml (675/2850) vs. 600 µg/ml (500/900); p = 0.0022; cut-off 1050 µg/ml, sensitivity 71%, specificity 89%) and IL-6 (47.6 pg/ml (24.9/85.4 l) vs. 16.1 pg/ml (5.5/34.4); p = 0.0003; cut-off 21.25 pg/ml, sensitivity 86%, specificity 65%) as well as c-reactive protein (92 mg/dl (66.8/131.5) vs. 43.5 mg/dl (26.8/83.3); p = 0.0029; cutoff 54.5 mg/dl, sensitivity 86%, specificity 65%) were higher in patients who required ICU admission. Thromboelastometric variables and markers of glycocalyx damage (heparan sulfate, hyaluronic acid, syndecan-1) at the time of hospital admission did not differ between groups. CONCLUSION: General inflammatory variables continue to be the most robust predictors of a severe course of a COVID-19 infection. Viscoelastometric variables and markers of glycocalyx damage are significantly increased upon admission to the ICU without being predictors of ICU admission.

Next-Generation Sequencing in Critically Ill COVID-19 Patients with Suspected Bloodstream Infections: A Retrospective Cohort Study.

BACKGROUND: Rapid pathogen identification and appropriate antimicrobial therapy are crucial in critically ill COVID-19 patients with bloodstream infections (BSIs). This study aimed to evaluate the diagnostic performance and potential therapeutic benefit of additional next-generation sequencing (NGS) of microbial DNA from plasma in these patients. METHODS: This monocentric descriptive retrospective study reviewed clinical data and pathogen diagnostics in COVID-19 ICU patients. NGS (DISQVER®) and blood culture (BC) samples were obtained on suspicion of BSIs. Data were reviewed regarding the adjustment of antimicrobial therapy and diagnostic procedures seven days after sampling and analyzed using the Chi²-test. RESULTS: Twenty-five cases with simultaneous NGS and BC sampling were assessed. The NGS positivity rate was 52% (13/25) with the detection of 23 pathogens (14 bacteria, 1 fungus, 8 viruses), and the BC positivity rate was 28% (7/25, 8 bacteria; p = 0.083). The NGS-positive patients were older (75 vs. 59.5 years; p = 0.03) with a higher prevalence of cardiovascular disease (77% vs. 33%; p = 0.03). These NGS results led to diagnostic procedures in four cases and to the commencement of four antimicrobial therapies in three cases. Empirical treatment was considered appropriate and continued in three cases. CONCLUSIONS: In COVID-19 patients with suspected BSIs, NGS may provide a higher positivity rate than BC and enable new therapeutic approaches.

End-tidal carbon dioxide in the early phase of cardiopulmonary exercise testing prior to major colorectal cancer surgery associates with postoperative outcome.

BACKGROUND: Cardiopulmonary exercise testing (CPET) objectively informs preoperative risk stratification prior to major surgery. CPET facilities are resource intensive and therefore more cost-effective triage methods are desirable for scalability. We tested two dynamic CPET parameters (end-tidal CO2 (PetCO2) and heart rate (HR)) to early phase exercise and resting diffusion capacity (DLCO) as potential point of care assessments that could be used outside of formal CPET testing facilities. METHODS: We conducted a retrospective cohort study including 84 patients who underwent CPET prior to elective major abdominal cancer surgery. Data were analyzed for PetCO2 and HR in response to early phase (2 minutes) exercise as well as resting DLCO against postoperative complications and two-year survival. Complications were classified according to Clavien-Dindo classification into less severe and severe (CD>IIIb) grades. Optimal cut points for predicting outcomes were determined using the Youden Index of receiver operating characteristic (ROC) curves. Multivariate regression modeling including both logistic and Cox proportional-hazards model adjusted to age and comorbidity burden was used to analyse the association between the selected parameters and postoperative outcomes. RESULTS: PetCO2, in response to two minutes of loaded exercise was higher in survivors than in non-survivors (median (IQR) 40.0 (4.2) mmHg vs. 34.5 (5.2) mmHg, P<0.001). There was no association between chronotropic response and postoperative outcome. The optimal cut point for predicting postoperative complications and survival was 38 mmHg and 37.1 mmHg for PetCO2, respectively. Low PetCO2 was associated with considerably lower odds of survival (OR 0.12; 95% CI 0.03, 0.47; P=0.003) and additionally increased odds of severe postoperative complications (OR 6.77; 95% CI 1.45, 38.4; P=0.019). Reduced age-predicted DLCO% <80% was associated with increased mortality (HR 5.27; 95% CI 1.09, 25.5; P=0.039). CONCLUSIONS: Assessment of DLCO at rest and dynamic assessment of PetCO2 during the early phase of exercise may potentially be developed as inexpensive point-of-care triage tools to scale objective preoperative risk assessment.

Omission of tranexamic acid does not increase the amount of perioperative blood transfusions in patients undergoing one-level spinal fusion surgery: a retrospective propensity score-matched noninferiority study.

INTRODUCTION: Application of tranexamic acid (TXA) in spine surgery is very frequent even without signs of hyperfibrinolysis, although its beneficial blood-saving effects are offset by harmful adverse events such as thromboembolic incidents. Thus, we investigated whether in relatively less invasive spinal procedures such as one-level posterior spinal fusion, omission of TXA affects the requirement for blood transfusions. METHODS: We conducted a retrospective propensity score-matched noninferiority study with 212 patients who underwent one-level posterior spine fusion and who were stratified according to whether they received TXA intraoperatively at our tertiary care center. The primary endpoint was the volume of transfused packed red cells. Testing for noninferiority or equivalence was performed by two one-sided testing procedure (TOST) with a priori defined noninferiority margins ([Formula: see text]). RESULTS: After propensity score matching a total of five patients (11.6%) treated with TXA were transfused compared with five patients (11.6%) who did not receive TXA. The majority of patients (51.2%) had a risk-increasing condition. The risk difference (no TXA-TXA) of intraoperative transfusion was - 4.7% (CI 90% - 13.62 to 4.32%), and omitting TXA was noninferior ([Formula: see text] = [Formula: see text]  10%). The mean intergroup difference in transfused volume (no TXA-TXA) was - 23.26 ml intraoperatively (CI 90% - 69.34 to 22.83 ml) and - 46.51 ml overall (CI 90% - 181.12 to 88.1 ml), respectively, suggesting equivalence of TXA omission ([Formula: see text] = [Formula: see text] 300 ml). The hemoglobin decline between both groups was also equivalent (with [Formula: see text] = [Formula: see text] 1 g/dl) both on the first postoperative day ([Formula: see text] Hb = 0.02 g/dl, CI 90% - 0.53 to 0.56 g/dl) and at discharge ([Formula: see text] Hb = - 0.29 g/dl, CI 90% - 0.89 to 0.31 g/dl). CONCLUSION: We demonstrated that requirement of transfusion is rare among one-level fusion surgery and the omission of TXA is noninferior with regard to blood transfusion in high-risk patients undergoing this procedure. Therefore, the prophylactic use of TXA cannot be recommended here, suggesting to focus on alternative blood conservation strategies, if necessary.

Hypoxia briefly increases diuresis but reduces plasma volume by fluid redistribution in women.

We have recently reported that hypobaric hypoxia (HH) reduces plasma volume (PV) in men by decreasing total circulating plasma protein (TCPP). Here, we investigated whether this applies to women and whether an inflammatory response and/or endothelial glycocalyx shedding could facilitate the TCCP reduction. We further investigated whether acute HH induces a short-lived diuretic response that was overlooked in our recent study, where only 24-h urine volumes were evaluated. In a strictly controlled crossover protocol, 12 women underwent two 4-day sojourns in a hypobaric chamber: one in normoxia (NX) and one in HH equivalent to 3,500-m altitude. PV, urine output, TCPP, and markers for inflammation and glycocalyx shedding were repeatedly measured. Total body water (TBW) was determined pre- and postsojourns by deuterium dilution. PV was reduced after 12 h of HH and thereafter remained 230-330 mL lower than in NX (P < 0.0001). Urine flow was 45% higher in HH than in NX throughout the first 6 h (P = 0.01) but lower during the second half of the first day (P < 0.001). Twenty-four-hour urine volumes (P ≥ 0.37) and TBW (P ≥ 0.14) were not different between the sojourns. TCPP was lower in HH than in NX at the same time points as PV (P < 0.001), but inflammatory or glycocalyx shedding markers were not consistently increased. As in men, and despite initially increased diuresis, HH-induced PV contraction in women is driven by a loss of TCPP and ensuing fluid redistribution, rather than by fluid loss. The mechanism underlying the TCPP reduction remains unclear but does not seem to involve inflammation or glycocalyx shedding.NEW & NOTEWORTHY This study is the first to investigate the mechanisms underlying plasma volume (PV) contraction in response to hypoxia in women while strictly controlling for confounders. PV contraction in women has a similar time course and magnitude as in men and is driven by the same mechanism, namely, oncotically driven redistribution rather than loss of fluid. We further report that hypoxia facilitates an increase in diuresis, that is, however, short-lived and of little relevance for PV regulation.

Cannulation of the popliteal vein as an intraoperative emergency access in prone position: A case report.

Many surgeries have to be performed in the prone position. Access to central vessels is very limited in this position. This requires forward planning with regard to the placement of a central venous catheter. Emergency situations or unexpected intraoperative events in prone position are challenging, as a conventional central venous access is not possible. We describe the cannulation of the popliteal vein in such a case. We report the case of a patient with severe intracerebral hemorrhage who was transferred to our emergency department where his clinical condition rapidly deteriorated. Due to the surgical approach, a prone position was necessary and preoperative central venous cannulation was not possible. We therefore performed an alternative vascular access in prone position using a ultrasound-guided cannulation of the popliteal vein. The cannulation of the popliteal vein described here can be carried out as a quick and easy feasible alternative in emergency situations in prone position. The ultrasound-guided catheter insertion succeeded without any problems and there was no evidence of a deep vein thrombosis after the intervention.

Point-of-care detection and differentiation of anticoagulant therapy - development of thromboelastometry-guided decision-making support algorithms.

BACKGROUND: DOAC detection is challenging in emergency situations. Here, we demonstrated recently, that modified thromboelastometric tests can reliably detect and differentiate dabigatran and rivaroxaban. However, whether all DOACs can be detected and differentiated to other coagulopathies is unclear. Therefore, we now tested the hypothesis that a decision tree-based thromboelastometry algorithm enables detection and differentiation of all direct Xa-inhibitors (DXaIs), the direct thrombin inhibitor (DTI) dabigatran, as well as vitamin K antagonists (VKA) and dilutional coagulopathy (DIL) with high accuracy. METHODS: Following ethics committee approval (No 17-525-4), and registration by the German clinical trials database we conducted a prospective observational trial including 50 anticoagulated patients (n = 10 of either DOAC/VKA) and 20 healthy volunteers. Blood was drawn independent of last intake of coagulation inhibitor. Healthy volunteers served as controls and their blood was diluted to simulate a 50% dilution in vitro. Standard (extrinsic coagulation assay, fibrinogen assay, etc.) and modified thromboelastometric tests (ecarin assay and extrinsic coagulation assay with low tissue factor) were performed. Statistical analyzes included a decision tree analyzes, with depiction of accuracy, sensitivity and specificity, as well as receiver-operating-characteristics (ROC) curve analysis including optimal cut-off values (Youden-Index). RESULTS: First, standard thromboelastometric tests allow a good differentiation between DOACs and VKA, DIL and controls, however they fail to differentiate DXaIs, DTIs and VKAs reliably resulting in an overall accuracy of 78%. Second, adding modified thromboelastometric tests, 9/10 DTI and 28/30 DXaI patients were detected, resulting in an overall accuracy of 94%. Complex decision trees even increased overall accuracy to 98%. ROC curve analyses confirm the decision-tree-based results showing high sensitivity and specificity for detection and differentiation of DTI, DXaIs, VKA, DIL, and controls. CONCLUSIONS: Decision tree-based machine-learning algorithms using standard and modified thromboelastometric tests allow reliable detection of DTI and DXaIs, and differentiation to VKA, DIL and controls. TRIAL REGISTRATION: Clinical trial number: German clinical trials database ID: DRKS00015704 .

Coagulation under Mild Hypothermia Assessed by Thromboelastometry.

INTRODUCTION: While previous studies have shown a significant impact of extreme hypo- and hyperthermia on coagulation, effects of much more frequently occurring perioperative mild hypothermia are largely unknown. This study therefore aimed to analyze the effects of mild hypothermia using rotational thromboelastometry in vitro. MATERIALS AND METHODS: Twelve healthy volunteers were included in this study. Standard thromboelastometric tests (EXTEM, INTEM, FIBTEM) were used to evaluate coagulation in vitro at 39, 37, 35.5, 35, and 33°C. Beyond standard thromboelastometric tests, we also evaluated the effects of mild hypothermia on the TPA-test (ClotPro, Enicor GmbH, Munich, Germany), a new test which aims to detect fibrinolytic capacity by adding tissue plasminogen activator to the sample. Data are presented as the median with 25/75th percentiles. RESULTS: Extrinsically activated coagulation (measured by EXTEM) showed a significant increase in clot formation time (CFT; 37°C: 90 s [81/105] vs. 35°C: 109 s [99/126]; p = 0.0002), while maximum clot firmness (MCF) was not significantly reduced. Intrinsically activated coagulation (measured by INTEM) also showed a significant increase in CFT (37°C: 80 s [72/88] vs. 35°C: 94 s [86/109]; p = 0.0002) without significant effects on MCF. Mild hypothermia significantly increased both the lysis onset time (136 s [132/151; 37°C] vs. 162 s [141/228; 35°C], p = 0.0223) and lysis time (208 s [184/297; 37°C] vs. 249 s [215/358; 35°C]; p = 0.0259). CONCLUSION: This demonstrates that even under mild hypothermia coagulation is significantly altered in vitro. Perioperative temperature monitoring and management are greatly important and can help to prevent mild hypothermia and its adverse effects. Further investigation and in vivo testing of coagulation under mild hypothermia is needed.

Functional Testing for Tranexamic Acid Duration of Action Using Modified Viscoelastometry.

INTRODUCTION: Tranexamic acid (TXA) is the standard medication to prevent or treat hyperfibrinolysis. However, prolonged inhibition of lysis (so-called "fibrinolytic shutdown") correlates with increased mortality. A new viscoelastometric test enables bedside quantification of the antifibrinolytic activity of TXA using tissue plasminogen activator (TPA). MATERIALS AND METHODS: Twenty-five cardiac surgery patients were included in this prospective observational study. In vivo, the viscoelastometric TPA test was used to determine lysis time (LT) and maximum lysis (ML) over 96 h after TXA bolus. Additionally, plasma concentrations of TXA and plasminogen activator inhibitor 1 (PAI-1) were measured. Moreover, dose effect curves from the blood of healthy volunteers were performed in vitro. Data are presented as median (25-75th percentile). RESULTS: In vivo TXA plasma concentration correlated with LT (r = 0.55; p < 0.0001) and ML (r = 0.62; p < 0.0001) at all time points. Lysis was inhibited up to 96 h (LTTPA-test: baseline: 398 s [229-421 s] vs. at 96 h: 886 s [626-2,175 s]; p = 0.0013). After 24 h, some patients (n = 8) had normalized lysis, but others (n = 17) had strong lysis inhibition (ML <30%; p < 0.001). The high- and low-lysis groups differed regarding kidney function (cystatin C: 1.64 [1.42-2.02] vs. 1.28 [1.01-1.52] mg/L; p = 0.002) in a post hoc analysis. Of note, TXA plasma concentration after 24 h was significantly higher in patients with impaired renal function (9.70 [2.89-13.45] vs.1.41 [1.30-2.34] µg/mL; p < 0.0001). In vitro, TXA concentrations of 10 µg/mL effectively inhibited fibrinolysis in all blood samples. CONCLUSIONS: Determination of antifibrinolytic activity using the TPA test is feasible, and individual fibrinolytic capacity, e.g., in critically ill patients, can potentially be measured. This is of interest since TXA-induced lysis inhibition varies depending on kidney function.

Viscoelastometry for detecting oral anticoagulants.

BACKGROUND: Determination of anticoagulant therapy is of pronounced interest in emergency situations. However, routine tests do not provide sufficient insight. This study was performed to investigate the impact of anticoagulants on the results of viscoelastometric assays using the ClotPro device. METHODS: This prospective, observational study was conducted in patients receiving dabigatran, factor Xa (FXa)-inhibitors, phenprocoumon, low molecular weight heparin (LMWH) or unfractionated heparin (UFH) (local ethics committee approval number: 17-525-4). Healthy volunteers served as controls. Viscoelastometric assays were performed, including the extrinsic test (EX-test), intrinsic test (IN-test) Russel's viper venom test (RVV-test), ecarin test (ECA-test), and the tissue plasminogen activator test (TPA-test). RESULTS: 70 patients and 10 healthy volunteers were recruited. Clotting time in the EX-test (CTEX-test) was significantly prolonged versus controls by dabigatran, FXa inhibitors and phenprocoumon. CTIN-test was prolonged by dabigatran, FXa inhibitors and UFH. Dabigatran, FXa inhibitors and UFH significantly prolonged CTRVV-test in comparison with controls (median 200, 207 and 289 vs 63 s, respectively; all p < 0.0005). Only dabigatran elicited a significant increase in CTECA-test compared to controls (median 307 vs 73 s; p < 0.0001). CTECA-test correlated strongly with dabigatran plasma concentration (measured by anti-IIa activity; r = 0.9970; p < 0.0001) and provided 100% sensitivity and 100% specificity for detecting dabigatran. Plasma concentrations (anti-XA activity) of FXa inhibitors correlated with CTRVV-test (r = 0.7998; p < 0.0001), and CTRVV-test provided 83% sensitivity and 64% specificity for detecting FXa inhibitors. CONCLUSIONS: In emergency situations, ClotPro viscoelastometric assessment of whole-blood samples may help towards determining the presence and type of anticoagulant class that a patient is taking. TRIAL REGISTRATION: German clinical trials database ID: DRKS00015302 .

Comparison of Two Different Fibrinogen Concentrates in an in vitro Model of Dilutional Coagulopathy.

INTRODUCTION: Fibrinogen concentrates are widely used to restore clot stability in situations of bleeding. Fibrinogen preparations are produced using different production methods, resulting in different compounds. Thus, different preparations might have a distinct impact on blood coagulation. We tested the effect of fibrinogen concentrates Haemocomplettan® (CSL Behring, Marburg, Germany) and fibryga® (Octapharma GmbH, Langenfeld, Germany) on the impairments induced by 60% dilutional coagulopathy in vitro. MATERIALS AND METHODS: The influence of the fibrinogen concentrates fibryga® and Haemocomplettan® on colloid (gelatine, hydroxyethyl starch [HES], albumin)-induced or crystalloid (Ringer's acetate)-induced dilutional coagulopathy was analysed using rotational thromboelastometry (ROTEM®) and standard laboratory tests. The following experimental conditions were analysed in vitro: whole blood, 60% dilution (40% blood and 60% diluent) ± 50 or 100 mg/kg-1 fibryga® or Haemocomplettan®, respectively. RESULTS: Dilution with either diluent resulted in prolonged clotting time (CT) in an extrinsic activated test (CTEXTEM) and decreased maximum clot firmness (MCFFIBTEM) as expressed, e.g., by gelatine: (59.5 s [62/54.8] vs. 95 s [102.8/86.8]; p < 0.001 and 14 mm [16/10.5] vs. 3 mm [4-3]; p < 0.001). Substitution after 60% dilution with HES resulted in no difference between the preparations, except for shorter thrombin time with fibryga® (14 s [15/14] vs. 18 s [18.8/17]; p = 0.0093; low dose). CTEXTEM was higher with Haemocomplettan® in a gelatine-induced dilution (51 s [54.5/47.5] vs. 63 s [71/60.3]; p = 0.0202; low dose) whereas thrombin time was lower with fibryga® (19.5 s [20.8/19] vs. 27 s [29/25.3]; p = 0.0017). In dilution with albumin, differences in CTEXTEM (69 s [76.5/66] vs. 56 s [57/53.3]; p = 0.0114; low dose) and thrombin time (18 s [18/17] vs. 24.5 s [25.8/24]; p = 0.0202; low dose) were seen. In dilution with crystalloid solution, again differences in CTEXTEM (53.5 s [57.8/53] vs. 45 s [47/43]; p = 0.035; low dose) and thrombin time (17 s [17/16] vs. 23.5 s [24/23]; p = 0.0014; low dose) were seen. Fibrinogen levels were more increased by high-dose substitution of both preparations. CONCLUSION: Based on this data it can be stated that both fibryga® and Haemocomplettan® had the same performance in our in vitro model except for CTEXTEM and thrombin time.

Real-time detection and differentiation of direct oral anticoagulants (rivaroxaban and dabigatran) using modified thromboelastometric reagents.

INTRODUCTION: Timely measurement of direct oral anticoagulants (DOACs) is challenging, though clinically important. We tested the hypotheses, that thromboelastometry is able to detect dabigatran and rivaroxaban and discriminates between dabigatran and rivaroxaban as representatives of the two groups of DOACs. METHODS AND MATERIALS: We conducted a prospective-observational study: In-vitro dose-effect-curves for rivaroxaban and dabigatran were performed (n = 10). Ex-vivo: Patients with indication of DOAC treatment (stroke; dabigatran/rivaroxaban) were included (n = 21). Blood samples were analyzed before first intake, at first estimated peak level and at 24 h after first but before following intake and 3 h after 24 h-intake. Standard and modified thromboelastometric-assays, using low tissue factor concentrations (TFTEM) or ecarin (ECATEM) were used. Receiver-operating-characteristics-curve-analysis (ROC), regression-analysis and two-way-ANOVA were performed. RESULTS: In-vitro: TFTEM detected dabigatran and rivaroxaban (ROC_AUC: 0.99; sensitivity/specificity: 100%/98%) but could not discriminate. Dabigatran prolongs CTECATEM whereas rivaroxaban did not. Clotting Time (CT)-ratio TFTEM/ECATEM discriminated highly sensitive (100%) and specific (100%) between dabigatran and rivaroxaban even at very low concentrations (ROC_AUC:1.0). CTECATEM correlated with dabigatran spiked concentrations (r = 0.9985; p < 0.001) and CTTFTEM (r = 0.9363; p = 0.006) with rivaroxaban. Similarly results could be demonstrated with patient data: We confirmed the performance for the differentiation of CT-ratio TFTEM/ECATEM (sensitivity 100%/specificity 100%) at any time after first intake of either DOAC. CONCLUSION: The thromboelastometric tests TFTEM and ECATEM detect and differentiate rivaroxaban and dabigatran. Further investigations evaluate the other DOACs and the differentiation to phenprocoumon. However, results need to be confirmed in a larger study, and especially cut off values for differentiation need to be calculated from a larger sample size.

Hypoxic-inflammatory responses under acute hypoxia: In Vitro experiments and prospective observational expedition trial.

Induction of hypoxia-inducible-factor-1α (HIF-1α) pathway and HIF-target genes allow adaptation to hypoxia and are associated with reduced incidence of acute mountain sickness (AMS). Little is known about HIF-pathways in conjunction with inflammation or exercise stimuli under acute hypobaric hypoxia in non-acclimatized individuals. We therefore tested the hypotheses that 1) both hypoxic and inflammatory stimuli induce hypoxic-inflammatory signaling pathways in vitro, 2) similar results are seen in vivo under hypobaric hypoxia, and 3) induction of HIF-dependent genes is associated with AMS in 11 volunteers. In vitro, peripheral blood mononuclear cells (PBMCs) were incubated under hypoxic (10%/5% O2) or inflammatory (CD3/CD28) conditions. In vivo, Interleukin 1ß (IL-1ß), C-X-C Chemokine receptor type 4 (CXCR-4), and C-C Chemokine receptor type 2 (CCR-2) mRNA expression, cytokines and receptors were analyzed under normoxia (520 m above sea level (a.s.l.)), hypobaric hypoxia (3883 m a.s.l.) before/after exercise, and after 24 h under hypobaric hypoxia. In vitro, isolated hypoxic (p = 0.004) or inflammatory (p = 0.006) stimuli induced IL-1ß mRNA expression. CCR-2 mRNA expression increased under hypoxia (p = 0.005); CXCR-4 mRNA expression remained unchanged. In vivo, cytokines, receptors, and IL-1ß, CCR-2 and CXCR-4 mRNA expression increased under hypobaric hypoxia after 24 h (all p ≤ 0.05). Of note, proinflammatory IL-1ß and CXCR-4 mRNA expression changes were associated with symptoms of AMS. Thus, hypoxic-inflammatory pathways are differentially regulated, as combined hypoxic and exercise stimulus was stronger in vivo than isolated hypoxic or inflammatory stimulation in vitro.