Four-day antithrombin therapy does not seem to attenuate hypercoagulability in patients suffering from sepsis

The role of inflammation and antithrombin supplementation on thromboelastographic parameters during veno-venous ECMO for respiratory failure

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) may act as a driver or propagator of systemic inflammation. In turn, cytokine release can modify thromboelastographic (TEG) tests which are commonly used for anticoagulation monitoring. In this context, antithrombin (AT) supplementation might further modify TEG.

METHODS

This is a pre-specified sub-study of the "Randomized Controlled Trial of Antithrombin Supplementation During Extracorporeal Membrane Oxygenation" study (investigator-initiated, randomized, single-blind, two-arm trial) conducted in two Italian ECMO referral ICUs. Adult patients requiring vv-ECMO for respiratory failure and undergoing unfractioned heparin (UFH) administration were enrolled and randomized whether to receive AT supplementation. Plasma samples for cytokine assay (IL-8, IL-10, IL-6, IL-1β, TNF-α and Pro-ADM) and heparinase TEG were collected from every patient before ECMO start, 24 h and 72 h after ECMO start, before ECMO removal, and 7 days after ECMO removal or upon ICU discharge whichever happened first. AT concentration, coagulation and clinical data were collected before ECMO start and at pre-fixed time points.

RESULTS

Thirty-nine patients were enrolled (21 treatments, 18 controls). TEG-R had a weak-to-moderate positive correlation with IL-8, IL-6, IL-10 and TNF-α and a moderate positive correlation with Pro-ADM. TEG-ANG showed a weak negative correlation with IL-8, IL-6 and TNF-α, while TEG-MA negatively correlated with IL-8, TNF-α and Pro-ADM. AT supplementation seemed to modify the association between TEG-MA and IL-8, IL-10 and Pro-ADM; conversely, AT did not affect the relationship among TEG-R or TEG-ANG and the studied cytokines.

CONCLUSIONS

High concentrations of systemic cytokines correlated with longer reaction times and decreased angle and amplitude at TEG, suggesting that an increase in inflammation is related with hypocoagulability as revealed by thromboelastography.

Coagulation profiles in patients with sepsis/septic shock identify mixed hypo-hypercoagulation patterns based on rotational thromboelastometry: A prospective observational study

INTRODUCTION

Sepsis-induced hemostatic disturbances are common and are associated with poor outcomes. Additionally, conventional coagulation tests (CCTs) overdiagnose hypocoagulation and cannot detect hypercoagulation and hyperfibrinolysis. The aim of this study was to describe the coagulation profiles of patients with sepsis/septic shock using rotational thromboelastometry (ROTEM) and to compare coagulation states between sepsis and septic shock groups and between surviving and non-surviving groups.

MATERIALS AND METHODS

This prospective, observational, single-center study was conducted in the intensive care unit (ICU) of the University Medical Center Ho Chi Minh City, from 6/2020-12/2021. Patients aged ≥18 years with sepsis or septic shock according to the Sepsis-3 criteria were included. ROTEM and CCTs were concurrently performed within the first 24 h of ICU admission.

RESULTS

In total, 161 patients were enrolled. Based on ROTEM, 72.7 % of patients with sepsis/septic shock had coagulation disorders, including 25.5 % hypercoagulation, 54.7 % hypocoagulation, 13.6 % mixed hypo-hypercoagulation patterns, and 18.6 % hyperfibrinolysis. A common mixed disorder subtype was characterized by prolonged initial clotting time (CT) with subsequently increased clot firmness. Fibrinogen levels and maximum clot formation (MCF)-fibtem were strongly correlated (rho = 0.73, p < 0.05). Hypocoagulation was observed more in the septic shock group than in the sepsis group. Compared to survivors, non-survivors had more prolonged CT-extem.

CONCLUSIONS

ROTEM could identify hypocoagulability, hypercoagulability, mixed hypo-hypercoagulability patterns, and hyperfibrinolysis in patients with sepsis/septic shock. Elevated MCF-fibtem and elevated fibrinogen levels were notably common and strongly correlated. The septic shock group had more hypocoagulation than the sepsis group. Lastly, non-survivors had more prolonged CT-extem than survivors.

Endothelial dysfunction and immunothrombosis in sepsis

Sepsis is a life-threatening clinical syndrome characterized by multiorgan dysfunction caused by a dysregulated or over-reactive host response to infection. During sepsis, the coagulation cascade is triggered by activated cells of the innate immune system, such as neutrophils and monocytes, resulting in clot formation mainly in the microcirculation, a process known as immunothrombosis. Although this process aims to protect the host through inhibition of the pathogen’s dissemination and survival, endothelial dysfunction and microthrombotic complications can rapidly lead to multiple organ dysfunction. The development of treatments targeting endothelial innate immune responses and immunothrombosis could be of great significance for reducing morbidity and mortality in patients with sepsis. Medications modifying cell-specific immune responses or inhibiting platelet–endothelial interaction or platelet activation have been proposed. Herein, we discuss the underlying mechanisms of organ-specific endothelial dysfunction and immunothrombosis in sepsis and its complications, while highlighting the recent advances in the development of new therapeutic approaches aiming at improving the short- or long-term prognosis in sepsis.

Pharmacological methods for blood stabilization in the extracorporeal circuit (review of literature)

We summarize the possible benefits and risks of using various anticoagulants during hemoperfusion. Clotting in the extracorporeal circuit can lead to a decrease in the effectiveness of therapy,  additional workload,  risk to the patient and economic losses. At the same time, relatively excessive anticoagulation against the background of existing hemostasis  disorders  can lead to severe hemorrhagic complications, which in turn  worsen the prognosis of patients. The article describes the causes of heparin resistance, the main techniques for overcoming it, and provides practical guidelines for anticoagulant therapy during hemoperfusion. It is well known that routine methods of monitoring hemostasis (such as platelet count, activated partial thromboplastin time) are unable to assess the balance of pro/anticoagulants. The authors have proposed a reasonable personalized approach to anticoagulant therapy  of extracorporeal blood purification depending  on the pathology  in patient and thromboelastography (TEG) data, and antithrombin III levels.

Anticoagulant therapies against sepsis-induced disseminated intravascular coagulation

Disseminated intravascular coagulation (DIC) is a frequent but lethal complication in sepsis. Anticoagulant therapies, such as heparin, antithrombin, activated protein C, and recombinant human-soluble thrombomodulin, were expected to regulate the progression of coagulopathy in sepsis. Although a number of randomized controlled trials (RCTs) have evaluated the survival effects of these therapies over the past few decades, there remains no consistent evidence showing a significant survival benefit of anticoagulant therapies. Currently, anticoagulant therapies are not conducted as a standard treatment against sepsis in many countries and regions. However, most of these RCTs were performed overall in patients with sepsis but not in those with sepsis-induced DIC, who were theoretically the optimal target population of anticoagulants. Actually, multiple lines of evidence from observational studies and meta-analyses of the RCTs have suggested that anticoagulant therapies might reduce mortality only when used in septic DIC. In addition, the severity of illness is another essential factor that maximally affects the efficacy of the therapy. Therefore, to provide evidence on the true effect of anticoagulant therapies, the next RCTs must be designed to enroll only patients with sepsis-induced overt DIC and a high severity of illness. To prepare these future RCTs, a novel scientific infrastructure for accurate detection of patients who can receive maximal benefit from anticoagulant therapies also needs to be established.

Which Septic Shock Patients With Non-Overt DIC Progress to DIC After Admission? Point-of-Care Thromboelastography Testing

BACKGROUND

Disseminated intravascular coagulation (DIC) is a life-threatening complication of septic shock; however, risk factors for its development after admission are unknown. Thromboelastography (TEG) can reflect coagulation disturbances in early non-overt DIC that are not detected by standard coagulation tests. This study investigated the risk factors including TEG findings as early predictors for DIC development after admission in septic shock patients with non-overt DIC.

METHODS

This retrospective observation study included 295 consecutive septic shock patients with non-overt DIC at admission between January 2016 and December 2019. DIC was defined as an International Society on Thrombosis and Hemostasis (ISTH) score ≥ 5. The primary outcome was non-overt DIC at admission that met the ISTH DIC criteria within 3 days after admission.

RESULTS

Of the 295 patients with non-overt DIC, 89 (30.2%) developed DIC after admission. The DIC group showed a higher ISTH score and 28-day mortality rate than the non-DIC group (2 vs. 3, P < 0.001; 13.6% vs. 27.0%, P = 0.008, respectively). The DIC rate increased with the ISTH score (7.7%, 13.3%, 15.8%, 36.5%, and 61.4% for scores of 0, 1, 2, 3, and 4, respectively). Among TEG values, the maximum amplitude (MA) was higher in the non-DIC group (P < 0.001). On multivariate analysis, an MA < 64 mm was independently associated with DIC development (odds ratio, 2.311; 95% confidence interval, 1.298-4.115).

CONCLUSIONS

DIC more often developed among those with admission ISTH scores ≥ 3 and was associated with higher mortality rates. An MA < 64 mm was independently associated with DIC development in septic shock patients.

Role of thromboelastography in the evaluation of septic shock patients with normal prothrombin time and activated partial thromboplastin time

Coagulopathy is frequent in septic shock and plays a key role in multiple organ dysfunction. The aim of this study is to investigate application values of thromboelastography (TEG) for outcome in septic shock patients with a normal value of prothrombin time (PT) and active partial thromboplastin time (aPTT). Prospective observational study using 1298 consecutive septic shock patients with TEG at admission was conducted at the emergency department (ED) of a tertiary care hospital in South Korea between 2016 and 2019. After excluding overt-disseminated intravascular coagulation (DIC) defined by scoring system, we included patients with a normal value of international normalized ratio ≤ 1.3 and aPTT ≤ 34 s. The primary outcome was 28-day mortality. 893 patients were included and 129 patients with overt DIC were excluded. Of the 764 remaining patients, 414 (54.2%) patients showed normal PT and aPTT (28-day mortality rate, 11.4%). TEG values such as reaction time, kinetic time (K), alpha angle (α), maximum amplitude (MA) and lysis index (LY 30) showed no significant mean difference between the survivor and non-survivor groups. However, hypocoagulable TEG values such as α < 53° (12.0% vs. 23.4%; p = 0.039), and MA < 50 mm (6.3% vs. 21.3%; p = 0.002) were significantly higher in the non-survived group. In multivariate analysis, hypocoagulable state (defined as K > 3 and α < 53 and MA < 50) was independent factors associated with increased risk of death (OR 4.882 [95% CI, 1.698–14.035]; p = 0.003). In conclusion, septic shock patients with normal PT and aPTT can be associated with impaired TEG profile, such as hypocoagulability, associated with increased mortality.

Viscoelastic hemostasis assays in septic, critically ill coronavirus disease 2019 patients: a practical guide for clinicians

Coronavirus disease 2019 (COVID-19)-associated coagulopathy is unusual, poorly defined and is linked with significant hypercoagulability and microthrombotic and macrothrombotic complications leading to worse outcomes and higher mortality. Conventional coagulation assays do not always actively reflect these derangements and might fail to detect this coagulopathy. Viscoelastic hemostatic assays (VHA) provide a possible tool that adds to conventional coagulation assays in identifying this hypercoagulable state. VHA has been mostly used in surgery and trauma but it's still not well defined in sepsis patients with lack of large randomized trials. Few studies described VHA findings in patients with COVID-19 showing significant hypercoagulability and fibrinolysis shutdown. Clinicians taking care of these patients might have little experience interpreting VHA results. By reviewing the available literature on the use of VHA in sepsis, and the current knowledge on COVID-19-associated coagulopathy we provide clinicians with a practical guide on VHA utilization in patients with COVID-19.

Role of Thromboelastography as an Early Predictor of Disseminated Intravascular Coagulation in Patients with Septic Shock

(1) Background: The currently proposed criteria for diagnosing overt disseminated intravascular coagulation (DIC) are not suitable for early detection of DIC. Thromboelastography (TEG) rapidly provides a comprehensive assessment of the entire coagulation process and is helpful as a guide for correcting consumptive coagulopathy in sepsis-induced DIC. This study aimed to investigate the role of TEG in the prediction of DIC in patients with septic shock. (2) Methods: TEG was conducted prospectively in 1294 patients with septic shock at the emergency department (ED) between January 2016 and December 2019. After exclusion of 405 patients with “do not attempt resuscitation” orders, those refusing enrollment, and those developing septic shock after ED presentation, 889 patients were included. DIC was defined as an International Society on Thrombosis and Hemostasis score ≥ 5 points within 24 h. (3) Results: Of the 889 patients with septic shock (mean age 65.6 ± 12.7 years, 58.6% male), 158 (17.8%) developed DIC. TEG values, except lysis after 30 min, were significantly different between the DIC and non-DIC groups. Among the TEG values, the maximal amplitude (MA) had the highest discriminating power for DIC, with an area under the curve of 0.814. An MA < 60 indicated DIC with 79% sensitivity, 73% specificity, and 94% negative predictive value. Based on multivariable analysis, MA < 60 was an independent predictor of DIC (odds ratio 5.616 (95% confidence interval: 3.213–9.818)). (4) Conclusions: In patients with septic shock, the MA value in TEG could be a valuable tool for early prediction of DIC.

Are thromboelastometric and thromboelastographic parameters associated with mortality in septic patients? A systematic review and meta-analysis

BACKGROUND

Thromboelastometry/elastography (ROTEM/TEG) showed promising results for diagnosis of sepsis-induced coagulopathy, but their association with the outcome is unclear. Our aim was to assess any difference in ROTEM/TEG measurements between septic survivors and non-survivors.

METHODS

Pubmed, Web of Science, Embase and Cochrane Library databases were investigated. The research aimed to include any randomized or observational study: i) on septic adult patients admitted to Intensive Care Unit (ICU) or Emergency Department (ED); ii) including ROTEM/TEG; iii) assessing mortality.

RESULTS

Seven prospective and four retrospective observational studies (952 patients) were included. According to the INTEM/kaolin-assay, clotting time (CT)/R (standardized mean difference(SMD) -0.29, 95% CI -0.49 to -0.09, p = 0.004) and clot formation time (CFT)/K (SMD -0.42, 95% CI -0.78 to -0.06, p = 0.02) were shorter in survivors. According to the EXTEM-assay, CT was shorter (MD -11.66 s, 95% CI -22.59 to -0.73, p = 0.04), while MCF was higher (MD 3.49 mm, 95% CI 0.43 to 6.55, p = 0.03) in survivors. A hypocoagulable profile was more frequent in non-survivors (OR 0.31, 95%CI 0.18 to 0.55, p < 0.0001). Overall, the risk of bias of the included studies was moderate and the quality of evidence low.

CONCLUSIONS

Hypocoagulability and lower MCF in EXTEM may be associated with higher mortality in sepsis.

Thromboelastography as a tool for monitoring blood coagulation dysfunction after adequate fluid resuscitation can predict poor outcomes in patients with septic shock

BACKGROUND

Coagulation abnormalities are universal in patients with septic shock and likely play a key role in multiple organ dysfunction syndrome. Early diagnosis and management of sepsis-induced coagulopathy can influence the outcome. Thromboelastography (TEG) can effectively distinguish hypercoagulability and hypocoagulability in patients with septic shock. TEG may be a useful tool to objectively evaluate the degree and risk of sepsis.

METHODS

A total of 76 adult patients with septic shock were enrolled and divided into four groups: patients with hypotension requiring vasopressor and serum lactate level >2 mmol/L (group A), patients with hypotension requiring vasopressor and serum lactate level ≤2 mmol/L (group B), patients with mean arterial pressure ≥65 mmHg and serum lactate level >2 mmol/L (group C), and patients with mean arterial pressure ≥65 mmHg and serum lactate level ≤2 mmol/L (group D) after adequate fluid resuscitation. TEG values were obtained at the emergency room and after 6 hours of adequate fluid resuscitation. Data on fibrinogen (FIB) levels, international normalized ratio (INR), activated partial thromboplastin time (aPTT), blood gas, platelet count, and D-dimers were also collected.

RESULTS

The length of stay in the intensive care unit was 9.11 ± 5.36 days. Mortality rate was 6.58%. The values of reaction time, kinetics time, maximum amplitude, alpha angle, aPTT, INR, serum creatinine, FIB, and sepsis-related organ failure assessment (SOFA) score showed a significant differences. The results of the routine coagulation tests, blood gas volume, platelet count, procalcitonin level, D-dimer level, white blood cell count, creatinine level, disseminated intravascular coagulation score, SOFA score, and TEG values after adequate fluid resuscitation were significantly different between groups A and B, groups A and C, groups A and D, groups B and D, and groups C and D.

CONCLUSION

TEG is helpful in predicting the severity of sepsis and outcome of patients.

Optimal Antithrombin Activity Threshold for Initiating Antithrombin Supplementation in Patients With Sepsis-Induced Disseminated Intravascular Coagulation: A Multicenter Retrospective Observational Study

Low-dose antithrombin supplementation therapy (1500 IU/d for 3 days) improves outcomes in patients with sepsis-induced disseminated intravascular coagulation (DIC). This retrospective study evaluated the optimal antithrombin activity threshold to initiate supplementation, and the effects of supplementation therapy in 1033 patients with sepsis-induced DIC whose antithrombin activity levels were measured upon admission to 42 intensive care units across Japan. Of the 509 patients who had received antithrombin supplementation therapy, in-hospital mortality was significantly reduced only in patients with very low antithrombin activity (≤43%; bottom quartile; adjusted hazard ratio: 0.603; 95% confidence interval: 0.368-0.988; P = .045). Similar associations were not observed in patients with low, moderate, or normal antithrombin activity levels. Supplementation therapy did not correlate with the incidence of bleeding requiring transfusion. The adjusted hazard ratios for in-hospital mortality increased gradually with antithrombin activity only when initial activity levels were very low to normal but plateaued thereafter. We conclude that antithrombin supplementation therapy in patients with sepsis-induced DIC and very low antithrombin activity may improve survival without increasing the risk of bleeding.

A summary of the Japan septic disseminated intravascular coagulation study

Over the past few decades, the large, international, randomized controlled trials of anticoagulant therapies for patients with sepsis have not yielded any improvement in mortality rates. However, in Japan, anticoagulant therapies are administered for sepsis patients with disseminated intravascular coagulation (DIC), but not for sepsis patients without DIC. Furthermore, epidemiological data regarding sepsis in Japan are scarce. Therefore, a nationwide multicenter retrospective observational study, the Japan Septic Disseminated Intravascular Coagulation (JSEPTIC DIC) study, was undertaken. The JSEPTIC DIC study enrolled 42 intensive care units and included 3,195 patients with sepsis. The results of the JSEPTIC DIC study indicated the following: (i) anticoagulant therapy may be effective in sepsis-induced DIC patients at high risk for death, (ii) recombinant human soluble thrombomodulin administration and antithrombin supplementation are associated with survival benefits in patients with sepsis-induced DIC.

The effect of sepsis and septic shock on the viscoelastic properties of clot quality and mass using rotational thromboelastometry: A prospective observational study

PURPOSE

The study purpose was to define changes in coagulation across the sepsis spectrum using rotational thromboelastometry (ROTEM).

METHODS

Sepsis patients were recruited on admission to the Emergency Department and Intensive Care Units of a large teaching hospital in Wales. ROTEM markers of clot development and fibrinolysis were determined, as well as standard coagulation markers. A healthy control group matched for age and gender was also recruited (n=44).

RESULTS

100 patients were recruited (50 sepsis, 20 severe sepsis and 30 septic shock). Maximum clot firmness was significantly higher in the sepsis (p<0.001) and severe sepsis (p=0.012) groups than the healthy control (71.6±4.5 and 70.4±4.1 vs 64.4 respectively). In septic shock there was prolonged clot development; however, maximum clot firmness remained normal. Fibrinolytic function was significantly impaired in septic shock, which was also significantly associated with 28-day mortality (p<0.001).

CONCLUSIONS

ROTEM indicated significantly enhanced clot structural development in sepsis and severe sepsis, which could be indicative of a hypercoagulable phase. In septic shock, despite there being a prolongation of clotting pathways and impaired fibrinolysis, clot mass was comparably normal, suggestive of the development of a clot with healthy characteristics.

Similar but not the same: Differential diagnosis of HLH and sepsis

Differential diagnosis of hemophagocytic lymphohistiocytosis (HLH; hemophagocytic syndrome) and sepsis is critically important because the life-saving aggressive immunosuppressive treatment, required in the effective HLH therapy, is absent in sepsis guidelines. Moreover, HLH may be complicated by sepsis. Hyperinflammation, present in both states, gives an overlapping clinical picture including fever and performance status deterioration. The aim of this review is to provide aid in this challenging diagnostic process. Analysis of clinical features and laboratory results in multiple groups of patients (both adult and pediatric) with either HLH or sepsis allows to propose criteria differentiating these two conditions. The diagnosis of HLH is supported by hyperferritinemia, splenomegaly, marked cytopenias, hypofibrinogenemia, low CRP, characteristic cytokine profile and, only in adults, hypertriglyceridemia. In the presence of these parameters (especially the most characteristic hyperferritinemia), the other HLH criteria should be assessed. Genetic analyses can reveal familial HLH. Hemophagocytosis is neither specific nor sensitive for HLH.

Efficacy and safety of anticoagulant therapy in three specific populations with sepsis: a meta-analysis of randomized controlled trials

ESSENTIALS: Most anticoagulant therapy has failed to demonstrate a survival benefit in the overall sepsis population. We conducted separate meta-analyses of anticoagulant therapy in three different populations. Survival benefit was observed only in the septic disseminated intravascular coagulation (DIC) population. Further randomized controlled trials should focus on specific populations with septic DIC.

SUMMARY

BACKGROUND

Although many preclinical trials have indicated the effectiveness and safety of anticoagulant therapy as an adjuvant therapy against sepsis, there is little evidence to support its effectiveness to reduce mortality in the overall population with sepsis in clinical situations. However, several studies suggested that specific anticoagulant therapy may potentially reduce mortality in patients with sepsis-induced disseminated intravascular coagulation (DIC).

OBJECTIVE

We investigated whether the survival benefit of anticoagulant therapy might pertain to the coagulopathic population with sepsis.

METHODS

We conducted separate meta-analyses of randomized controlled trials for anticoagulant therapy in three different populations: (i) overall population with sepsis, (ii) population with sepsis-induced coagulopathy, and (iii) population with sepsis-induced DIC. We searched MEDLINE, Scopus, and the Cochrane Central Register of Controlled Trials comparing anticoagulant therapy with placebo or no intervention in sepsis patients. We measured all-cause mortality as the primary outcome and bleeding complications as the secondary outcome.

RESULTS

We analyzed 24 trials enrolling 14 767 patients. There were no significant reductions in mortality in the overall sepsis population and the population with sepsis-induced coagulopathy. Otherwise, we observed significant reductions in mortality (risk ratio 0.72, 95% confidence interval 0.62-0.85) in the population with sepsis-induced DIC. As adverse events, bleeding complications tended to increase similarly with anticoagulant therapy in all three populations.

CONCLUSION

Although associated with an increased risk of bleeding, anticoagulant therapy resulted in no survival benefits in the overall sepsis population and even the population with sepsis-induced coagulopathy; beneficial effects on mortality were observed only in the population with sepsis-induced DIC.

Antithrombin III for critically ill patients

BACKGROUND

Critical illness is associated with uncontrolled inflammation and vascular damage which can result in multiple organ failure and death. Antithrombin III (AT III) is an anticoagulant with anti-inflammatory properties but the efficacy and any harmful effects of AT III supplementation in critically ill patients are unknown. This review was published in 2008 and updated in 2015.

OBJECTIVES

To examine:1. The effect of AT III on mortality in critically ill participants.2. The benefits and harms of AT III.We investigated complications specific and not specific to the trial intervention, bleeding events, the effect on sepsis and disseminated intravascular coagulation (DIC) and the length of stay in the intensive care unit (ICU) and in hospital in general.

SEARCH METHODS

We searched the following databases from inception to 27 August 2015: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid SP), EMBASE (Ovid SP,), CAB, BIOSIS and CINAHL. We contacted the main authors of trials to ask for any missed, unreported or ongoing trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) irrespective of publication status, date of publication, blinding status, outcomes published, or language. We contacted the investigators and the trial authors in order to retrieve missing data. In this updated review we include trials only published as abstracts.

DATA COLLECTION AND ANALYSIS

Our primary outcome measure was mortality. Two authors each independently abstracted data and resolved any disagreements by discussion. We presented pooled estimates of the intervention effects on dichotomous outcomes as risk ratios (RR) with 95% confidence intervals (CI). We performed subgroup analyses to assess risk of bias, the effect of AT III in different populations (sepsis, trauma, obstetrics, and paediatrics), and the effect of AT III in patients with or without the use of concomitant heparin. We assessed the adequacy of the available number of participants and performed trial sequential analysis (TSA) to establish the implications for further research.

MAIN RESULTS

We included 30 RCTs with a total of 3933 participants (3882 in the primary outcome analyses).Combining all trials, regardless of bias, showed no statistically significant effect of AT III on mortality with a RR of 0.95 (95% CI 0.88 to 1.03), I² statistic = 0%, fixed-effect model, 29 trials, 3882 participants, moderate quality of evidence). For trials with low risk of bias the RR was 0.96 (95% Cl 0.88 to 1.04, I² statistic = 0%, fixed-effect model, 9 trials, 2915 participants) and for high risk of bias RR 0.94 (95% Cl 0.77 to 1.14, I² statistic = 0%, fixed-effect model, 20 trials, 967 participants).For participants with severe sepsis and DIC the RR for mortality was non-significant, 0.95 (95% Cl 0.88 to 1.03, I² statistic = 0%, fixed-effect model, 12 trials, 2858 participants, moderate quality of evidence).We conducted 14 subgroup and sensitivity analyses with respect to the different domains of risk of bias, but detected no statistically significant benefit in any subgroup analyses.Our secondary objective was to assess the benefits and harms of AT III. For complications specific to the trial intervention the RR was 1.26 (95% Cl 0.83 to 1.92, I² statistic = 0%, random-effect model, 3 trials, 2454 participants, very low quality of evidence). For complications not specific to the trial intervention, the RR was 0.71 (95% Cl 0.08 to 6.11, I² statistic = 28%, random-effects model, 2 trials, 65 participants, very low quality of evidence). For complications other than bleeding, the RR was 0.72 ( 95% Cl 0.42 to 1.25, I² statistic = 0%, fixed-effect model, 3 trials, 187 participants, very low quality of evidence). Eleven trials investigated bleeding events and we found a statistically significant increase, RR 1.58 (95% CI 1.35 to 1.84, I² statistic = 0%, fixed-effect model, 11 trials, 3019 participants, moderate quality of evidence) in the AT III group. The amount of red blood cells administered had a mean difference (MD) of 138.49 (95% Cl -391.35 to 668.34, I² statistic = 84%, random-effect model, 4 trials, 137 participants, very low quality of evidence). The effect of AT III in patients with multiple organ failure (MOF) was a MD of -1.24 (95% Cl -2.18 to -0.29, I² statistic = 48%, random-effects model, 3 trials, 156 participants, very low quality of evidence) and for patients with an Acute Physiology and Chronic Health Evaluation score (APACHE) at II and III the MD was -2.18 (95% Cl -4.36 to -0.00, I² statistic = 0%, fixed-effect model, 3 trials, 102 participants, very low quality of evidence). The incidence of respiratory failure had a RR of 0.93 (95% Cl 0.76 to 1.14, I² statistic = 32%, random-effects model, 6 trials, 2591 participants, moderate quality of evidence). AT III had no statistically significant impact on the duration of mechanical ventilation (MD 2.20 days, 95% Cl -1.21 to 5.60, I² statistic = 0%, fixed-effect model, 3 trials, 190 participants, very low quality of evidence); on the length of stay in the ICU (MD 0.24, 95% Cl -1.34 to 1.83, I² statistic = 0%, fixed-effect model, 7 trials, 376 participants, very low quality of evidence) or on the length of stay in hospital in general (MD 1.10, 95% Cl -7.16 to 9.36), I² statistic = 74%, 4 trials, 202 participants, very low quality of evidence).

AUTHORS' CONCLUSIONS

There is insufficient evidence to support AT III substitution in any category of critically ill participants including the subset of patients with sepsis and DIC. We did not find a statistically significant effect of AT III on mortality, but AT III increased the risk of bleeding events. Subgroup analyses performed according to duration of intervention, length of follow-up, different patient groups, and use of adjuvant heparin did not show differences in the estimates of intervention effects. The majority of included trials were at high risk of bias (GRADE; very low quality of evidence for most of the analyses). Hence a large RCT of AT III is needed, without adjuvant heparin among critically ill patients such as those with severe sepsis and DIC, with prespecified inclusion criteria and good bias protection.

Tracheostomy in intensive care unit patients can be performed without bleeding complications in case of normal thromboelastometry results (EXTEM CT) despite increased PT-INR: a prospective pilot study

Background

Coagulopathy is often accompanied by prolongation of prothrombin time (PT) in septic and nonseptic patients in intensive care unit (ICU). The conventional way to correct the coagulopathy is to administer fresh frozen plasma (FFP) before invasive procedures to minimise the risk of bleeding. However, prolonged PT can be present even in hypercoagulation status, resulting in unnecessary administration of FFP. In the present study, we have assessed the reliability of thromboelastometry in case of prolonged PT and the relationship to bleeding complications during surgical tracheostomy.

Methods

The study was conducted during the period between April 2013 and April 2014 in patients undergoing surgical tracheostomy. Coagulation status was assessed using PT, and the status was reassessed by thromboelastometry for prolonged PT. Tracheostomy was performed in patients with normal thromboelastometry results without administering FFP.

Results

Tracheostomy was performed in total 119 patients. Normal value of PT as measured by international normalized ratio (INR) ≤ 1.2 was found in 64 (54 %) patients, while prolonged INR > 1.2 was found in 55 (46 %) patients. Patients with INR ≥ 1.3 (with INR min- 1.3, max- 1.84, and median- 1.48) were further analysed by thromboelastometry. Despite prolonged INR, thromboelastometry results were in normal ranges in all cases except one. With normal thromboelastometry, tracheostomy was performed safely without any bleeding complication.

Conclusions

Surgical tracheostomy in septic and nonseptic patients can be performed without bleeding complications in case of normal thromboelastometry results (EXTEM CT) despite increased PT-INR. This method can help physicians to reduce unnecessary administration of FFP in patients.

Association between biomarkers of endothelial injury and hypocoagulability in patients with severe sepsis: a prospective study

Introduction

Patients with severe sepsis often present with concurrent coagulopathy, microcirculatory failure and evidence of vascular endothelial activation and damage. Given the critical role of the endothelium in balancing hemostasis, we investigated single-point associations between whole blood coagulopathy by thrombelastography (TEG) and plasma/serum markers of endothelial activation and damage in patients with severe sepsis.

Methods

A post-hoc multicenter prospective observational study in a subgroup of 184 patients from the Scandinavian Starch for Severe Sepsis/Septic Shock (6S) Trial. Study patients were admitted to two Danish intensive care units. Inclusion criteria were severe sepsis, pre-intervention whole blood TEG measurement and a plasma/serum research sample available from baseline (pre-intervention) for analysis of endothelial-derived biomarkers. Endothelial-derived biomarkers were measured in plasma/serum by enzyme-linked immunosorbent assay (syndecan-1, thrombomodulin, protein C (PC), tissue-type plasminogen activator and plasminogen activator inhibitor-1). Pre-intervention TEG, functional fibrinogen (FF) and laboratory and clinical data, including mortality, were retrieved from the trial database.

Results

Most patients presented with septic shock (86%) and pulmonary (60%) or abdominal (30%) focus of infection. The median (IQR) age was 67 years (59 to 75), and 55% were males. The median SOFA and SAPS II scores were 8 (6 to 10) and 56 (41 to 68), respectively, with 7-, 28- and 90-day mortality rates being 21%, 39% and 53%, respectively. Pre-intervention (before treatment with different fluids), TEG reaction (R)-time, angle and maximum amplitude (MA) and FF MA all correlated with syndecan-1, thrombomodulin and PC levels. By multivariate linear regression analyses, higher syndecan-1 and lower PC were independently associated with TEG and FF hypocoagulability at the same time-point: 100 ng/ml higher syndecan-1 predicted 0.64 minutes higher R-time (SE 0.25), 1.78 mm lower TEG MA (SE 0.87) and 0.84 mm lower FF MA (SE 0.42; all P <0.05), and 10% lower protein C predicted 1.24 mm lower TEG MA (SE 0.31).

Conclusions

In our cohort of patients with severe sepsis, higher circulating levels of biomarkers of mainly endothelial damage were independently associated with hypocoagulability assessed by TEG and FF. Endothelial damage is intimately linked to coagulopathy in severe sepsis.

Trial registration

Clinicaltrials.gov number: NCT00962156. Registered 13 July 2009.

Thromboelastography in patients with severe sepsis: a prospective cohort study

PURPOSE

To investigate the association between consecutively measured thromboelastographic (TEG) tracings and outcome in patients with severe sepsis.

METHODS

Multicentre prospective observational study in a subgroup of the Scandinavian Starch for Severe Sepsis/Septic Shock (6S) Trial (NCT00962156) comparing hydroxyethyl starch (HES) 130/0.42 vs. Ringer's acetate for fluid resuscitation in severe sepsis. TEG (standard and functional fibrinogen) was measured consecutively for 5 days, and clinical data including bleeding and death was retrieved from the trial database. Statistical analyses included Cox regression with time-dependent covariates and joint modelling techniques.

RESULTS

Of 267 eligible patients, we analysed 260 patients with TEG data. At 90 days, 68 (26 %) had bled and 139 (53 %) had died. For all TEG variables, hypocoagulability according to the reference range was significantly associated with increased risk of death. In a linear model, hazard ratios for death were 6.03 (95 % confidence interval, 1.64-22.17) for increased clot formation speed, 1.10 (1.04-1.16) for decreased angle, 1.09 (1.05-1.14) for decreased clot strength and 1.12 (1.06-1.18) for decreased fibrinogen contribution to clot strength (functional fibrinogen MA), showing that deterioration towards hypocoagulability in any TEG variable significantly increased the risk of death. Patients treated with HES had lower functional fibrinogen MA than those treated Ringer's acetate, which significantly increased the risk of subsequent bleeding [HR 2.43 (1.16-5.07)] and possibly explained the excess bleeding with HES in the 6S trial.

CONCLUSIONS

In our cohort of patients with severe sepsis, progressive hypocoagulability defined by TEG variables was associated with increased risk of death and increased risk of bleeding.

Thromboelastometry as a supplementary tool for evaluation of hemostasis in severe sepsis and septic shock

BACKGROUND

Sepsis leads to disruption of hemostasis, making early evaluation of coagulation essential. The aim of this study was to provide a detailed investigation of coagulation and the use of blood products in patients with severe sepsis or septic shock, admitted to a multidisciplinary intensive care unit.

METHODS

Thirty-six patients with severe sepsis or septic shock were included in this prospective observational study. Blood samples and information on transfusion of blood products were obtained for up to 3 consecutive days, and day 7 if the patient was still in the intensive care unit. Thromboelastometry (ROTEM(®)), analyses of thrombin generation, and conventional coagulation tests were performed.

RESULTS

ROTEM(®) revealed an overall normo-coagulable state among patients with severe sepsis or septic shock. Conventional coagulation analyses showed divergent results with hypercoagulable trends in terms of reduced antithrombin and acute phase response with increased fibrinogen and fibrin d-dimer, and on the other hand, coagulation disturbances with a decreased prothrombin time and prolonged activated partial thromboplastin time. This hypocoagulabe state was supported by a delayed and reduced thrombin generation. Twelve patients experienced 21 independent transfusion episodes with fresh frozen plasma. Of these, only five (22%) transfusions were performed because of active bleeding.

CONCLUSION

ROTEM(®) demonstrated an overall normo-coagulation, whereas the conventional coagulation tests and thrombin generation analyses mainly reflected hypocoagulation. Given the dynamic and global features of ROTEM(®), this analysis may be a relevant supplementary tool for the assessment of hemostasis in patients with severe sepsis or septic shock.

Utility of thromboelastography and/or thromboelastometry in adults with sepsis: a systematic review

Introduction

Coagulation abnormalities are frequent in sepsis. Conventional coagulation assays, however, have several limitations. A surge of interest exists in the use of point-of-care tests to diagnose hypo- and hypercoagulability in sepsis.

We performed a systematic review of available literature to establish the value of rotational thromboelastography (TEG) and thromboelastometry (ROTEM) compared with standard coagulation tests to detect hyper- or hypocoagulability in sepsis patients. Furthermore, we assessed the value of TEG/ROTEM to identify sepsis patients likely to benefit from therapies that interfere with the coagulation system.

Methods

MEDLINE, EMBASE, and the Cochrane Library were searched from 1 January 1980 to 31 December 2012. The search was limited to adults, and language was limited to English. Reference lists of retrieved articles were hand-searched for additional studies. Ongoing trials were searched on http://www.controlled-trials.com and http://www.clinicaltrials.gov. Studies addressing TEG/ROTEM measurements in adult patients with sepsis admitted to the ICU were considered eligible.

Results

Of 680 screened articles, 18 studies were included, of which two were randomized controlled trials, and 16 were observational cohort studies. In patients with sepsis, results show both hyper- and hypocoagulability, as well as TEG/ROTEM values that fell within reference values. Both hyper- and hypocoagulability were to some extent associated with diffuse intravascular coagulation. Compared with conventional coagulation tests, TEG/ROTEM can detect impaired fibrinolysis, which can possibly help to discriminate between sepsis and systemic inflammatory response syndrome (SIRS). A hypocoagulable profile is associated with increased mortality. The value of TEG/ROTEM to identify patients with sepsis who could possibly benefit from therapies interfering with the coagulation system could not be assessed, because studies addressing this topic were limited.

Conclusion

TEG/ROTEM could be a promising tool in diagnosing alterations in coagulation in sepsis. Further research on the value of TEG/ROTEM in these patients is warranted. Given that coagulopathy is a dynamic process, sequential measurements are needed to understand the coagulation patterns in sepsis, as can be detected by TEG/ROTEM.

A randomized, controlled, multicenter trial of the effects of antithrombin on disseminated intravascular coagulation in patients with sepsis

INTRODUCTION

To test the hypothesis that the administration of antithrombin concentrate improves disseminated intravascular coagulation (DIC), resulting in recovery from DIC and better outcomes in patients with sepsis, we conducted a prospective, randomized controlled multicenter trial at 13 critical care centers in tertiary care hospitals.

METHODS

We enrolled 60 DIC patients with sepsis and antithrombin levels of 50 to 80% in this study. The participating patients were randomly assigned to an antithrombin arm receiving antithrombin at a dose of 30 IU/kg per day for three days or a control arm treated with no intervention. The primary efficacy end point was recovery from DIC on day 3. The analysis was conducted with an intention-to-treat approach. DIC was diagnosed according to the Japanese Association for Acute Medicine (JAAM) scoring system. The systemic inflammatory response syndrome (SIRS) score, platelet count and global markers of coagulation and fibrinolysis were measured on day 0 and day 3.

RESULTS

Antithrombin treatment resulted in significantly decreased DIC scores and better recovery rates from DIC compared with those observed in the control group on day 3. The incidence of minor bleeding complications did not increase, and no major bleeding related to antithrombin treatment was observed. The platelet count significantly increased; however, antithrombin did not influence the sequential organ failure assessment (SOFA) score or markers of coagulation and fibrinolysis on day 3.

CONCLUSIONS

Moderate doses of antithrombin improve DIC scores, thereby increasing the recovery rate from DIC without any risk of bleeding in DIC patients with sepsis.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (UMIN-CTR) UMIN000000882.

Hypercoagulability in response to elevated body temperature and central hypovolemia

BACKGROUND

Coagulation abnormalities contribute to poor outcomes in critically ill patients. In trauma patients exposed to a hot environment, a systemic inflammatory response syndrome, elevated body temperature, and reduced central blood volume occur in parallel with changes in hemostasis and endothelial damage. The objective of this study was to evaluate whether experimentally elevated body temperature and reduced central blood volume (CBV) per se affects hemostasis and endothelial activation.

METHODS

Eleven healthy volunteers were subjected to heat stress, sufficient to elevate core temperature, and progressive reductions in CBV by lower body negative pressure (LBNP). Changes in hemostasis were evaluated by whole blood haemostatic assays, standard hematologic tests and by plasma biomarkers of coagulation and endothelial activation/disruption.

RESULTS

Elevated body temperature and decreased CBV resulted in coagulation activation evidenced by shortened activated partial tromboplastin time (-9% [IQR -7; -4]), thrombelastography: reduced reaction time (-15% [-24; -4]) and increased maximum amplitude (+4% (2; 6)), all P < 0.05. Increased fibrinolysis was documented by elevation of D-dimer (+53% (12; 59), P = 0.016). Plasma adrenaline and noradrenaline increased 198% (83; 346) and 234% (174; 363) respectively (P = 0.006 and P = 0.003).

CONCLUSIONS

This experiment revealed emerging hypercoagulability in response to elevated body temperature and decreased CBV, whereas no effect on the endothelium was observed. We hypothesize that elevated body temperature and reduced CBV contributes to hypercoagulability, possibly due to moderate sympathetic activation, in critically ill patients and speculate that normalization of body temperature and CBV may attenuate this hypercoagulable response.

Discrepant fibrinolytic response in plasma and whole blood during experimental endotoxemia in healthy volunteers

Background

Sepsis induces early activation of coagulation and fibrinolysis followed by late fibrinolytic shutdown and progressive endothelial damage. The aim of the present study was to investigate and compare the functional hemostatic response in whole blood and plasma during experimental human endotoxemia by the platelet function analyzer, Multiplate and by standard and modified thrombelastography (TEG).

Methods

Prospective physiologic study of nine healthy male volunteers undergoing endotoxemia by means of a 4-hour infusion of E. coli lipopolysaccharide (LPS, 0.5 ng/kg/hour), with blood sampled at baseline and at 4 h and 6 h. Physiological and standard biochemical data and coagulation tests, TEG (whole blood: TEG, heparinase-TEG, Functional Fibrinogen; plasma: TEG±tissue-type plasminogen activator (tPA)) and Multiplate (TRAPtest, ADPtest, ASPItest, COLtest) were recorded. Mixed models with Tukey post hoc tests and correlations were applied.

Results

Endotoxemia induced acute SIRS with increased HR, temperature, WBC, CRP and procalcitonin and decreased blood pressure. It also induced a hemostatic response with platelet consumption and reduced APTT while INR increased (all p<0.05). Platelet aggregation decreased (all tests, p<0.05), whereas TEG whole blood clot firmness increased (G, p = 0.05). Furthermore, during endotoxemia (4 h), whole blood fibrinolysis increased (clot lysis time (CLT), p<0.001) and Functional Fibrinogen clot strength decreased (p = 0.049). After endotoxemia (6 h), whole blood fibrinolysis was reduced (CLT, p<0.05). In contrast to findings in whole blood, the plasma fibrin clot became progressively more resistant towards tPA-induced fibrinolysis at both 4 h and 6 h (p<0.001).

Conclusions

Endotoxemia induced a hemostatic response with reduced primary but enhanced secondary hemostasis, enhanced early fibrinolysis and fibrinogen consumption followed by downregulation of fibrinolysis, with a discrepant fibrinolytic response in plasma and whole blood. The finding that blood cells are critically involved in the vasculo-fibrinolytic response to acute inflammation is important given that disturbances in the vascular system contribute significantly to morbidity and mortality in critically ill patients.

Coagulation assessment in children with diabetic ketoacidosis

OBJECTIVES

To assess potential hypercoagulability during diabetic ketoacidosis in children.

DESIGN

A prospective, controlled pilot study.

SETTING

University-affiliated pediatric critical care unit and emergency department in a tertiary care children's hospital.

PATIENTS

Children (1-18 years) admitted with an episode of diabetic ketoacidosis and healthy children as controls. All patients with diabetic ketoacidosis managed according to a preestablished protocol.

INTERVENTIONS

Thromboelastography was performed using citrated whole-blood samples drawn at the time of admission and upon biochemical and clinical resolution of diabetic ketoacidosis. Citrated whole-blood samples drawn from healthy nondiabetic children acted as control samples.

MEASUREMENTS AND MAIN RESULTS

Fifteen patients (11.7 ± 4.1 years) in the diabetic ketoacidosis group and 20 patients (8.9 ± 4.5 years; p = 0.06) in the control group completed the study. Values for standard thromboelastography parameters (R and K time, α angle, maximum amplitude, coagulation index, and Ly30) in the diabetic ketoacidosis group, both on admission and resolution, were within the control range; thromboelastography profiles of diabetic ketoacidosis patients on admission were not significantly different from profiles obtained upon diabetic ketoacidosis resolution. The mean α-angle was significantly higher in known diabetic patients compared with newly diagnosed diabetics on admission; however, it still remained within the control normal range.

CONCLUSIONS

Thromboelastographic assay results do not reflect a hypercoagulable state in this group of children with diabetic ketoacidosis. Further investigation is required to examine the potential role of injured endothelium in the suspected hypercoagulability during diabetic ketoacidosis.

Consecutive thrombelastography clot strength profiles in patients with severe sepsis and their association with 28-day mortality: a prospective study

PURPOSE

The aim of this study was to assess associations between consecutive thrombelastography (TEG) profiles and standard coagulation tests and disease severity and mortality in patients with severe sepsis.

MATERIALS AND METHODS

This was a prospective observational study of adults with severe sepsis admitted to the intensive care unit (ICU). Clinical scores/variables, infection, TEG, biochemistry, therapy, and overall mortality were recorded.

RESULTS

Fifty patients (60% men, median age 62 years, 28-day mortality 24%) were included. At admission, 22%, 48%, and 30% had a hypocoagulable, normocoagulable, and hypercoagulable TEG clot strength (maximum amplitude [MA]), respectively. Hypocoagulable patients had higher Sequential Organ Failure Assessment and disseminated intravascular coagulation scores compared with hypercoagulable patients and higher 28-day mortality compared with normocoagulable patients (all P < .05). Most patients (73%-91%) displayed a TEG MA comparable with the admission profile during the initial 4 ICU days or until death/discharge. Patients progressing to hypocoagulable MA had a high early mortality (80%) and hypocoagulable MA independently predicted 28-day mortality (adjusted odds ratio, 4.29 [95% confidence interval, 1.35-13.65], P = .014). In hypocoagulable and hypercoagulable patients, only fibrinogen (P = .041 and P < .001, respectively) contributed independently to clot strength, whereas both platelets (P < .001) and fibrinogen (P < .001) contributed independently to clot strength in normocoagulable patients.

CONCLUSIONS

The ICU admission TEG MA remained constant for several days in patients with severe sepsis and hypocoagulable MA independently predicted 28-day mortality.

Persistent hypocoagulability in patients with septic shock predicts greater hospital mortality: impact of impaired thrombin generation

PURPOSE

Sepsis induces hypercoagulability, hypofibrinolysis, microthrombosis, and endothelial dysfunction leading to multiple organ failure. However, not all studies reported benefit from anticoagulation for patients with severe sepsis, and time courses of coagulation abnormalities in septic shock are poorly documented. Therefore, the aim of this prospective observational cohort study was to describe the coagulation profile of patients with septic shock and to determine whether alterations of the profile are associated with hospital mortality.

METHODS

Thirty-nine patients with septic shock on ICU admission were prospectively included in the study. From admission to day 7, analytical coagulation tests, thrombin generation (TG) assays, and thromboelastometric analyses were performed and tested for association with survival.

RESULTS

Patients with septic shock presented on admission prolongation of prothrombin time, activated partial thromboplastin time (aPTT), increased consumption of most procoagulant factors as well as both delay and deficit in TG, all compatible with a hypocoagulable state compared with reference values (P < 0.001). Time courses revealed a persistent hypocoagulability profile in non-survivors as compared with survivors. From multiple logistic regression, prolonged aPTT (P = 0.007) and persistence of TG deficit (P = 0.024) on day 3 were strong predictors of mortality, independently from disease severity scores, disseminated intravascular coagulation score, and standard coagulation tests on admission.

CONCLUSIONS

Patients with septic shock present with hypocoagulability at the time of ICU admission. Persistence of hypocoagulability assessed by prolonged aPTT and unresolving deficit in TG on day 3 after onset of septic shock is associated with greater hospital mortality.

Arteriovenous differences of hematological and coagulation parameters in patients with sepsis

In critically ill patients, either arterial or venous blood is usually available for sampling and measurement of basic coagulation parameters. The aim of this study was to examine whether in these patients the values of coagulation parameters differ significantly with respect to the source of the blood samples. In a group of 44 patients with severe sepsis, we compared the values of coagulation, thromboelastography and selected hematological parameters between the arterial and venous blood. In most of the investigated parameters (international normalized ratio, activated partial thromboplastin time, fibrinogen concentration, erythrocyte count, leukocyte and platelet count, hemoglobin level and thromboelastography parameters), we did not find significant differences (P > 0.1). However, we found a significantly lower antithrombin activity and a significantly higher D-dimer concentration in venous blood compared to arterial blood (P < 0.05). This could be associated with increased consumption of antithrombin and generation of D-dimer as a consequence of microthrombi formation in the capillaries. We therefore conclude that for the purpose of assessment of coagulation status in septic patients, arterial and venous blood cannot be treated as equivalent.

Immunomodulation in sepsis: state of the art and future perspective

Despite advances in supportive care of critically ill patients, sepsis remains an important cause of death worldwide. More than 750,000 individuals develop severe sepsis in North America annually, with a mortality rate varying between 35 and 50%. Over recent years, numerous efforts have been committed to understanding the pathophysiology of septic syndrome, as well as attempts to intervene in the inflammatory cascade with the aim of altering the outcome of the syndrome and to improve survival. Not all of these attempts have been successful. Issued guidelines by the International Sepsis Forum have incorporated only the use of corticosteroids, tight glycemic control and the use of recombinant activated protein C as recommendations for the management of the septic patient along with the initial resuscitation and infection-site control measures. These strategies along, with novel attempts of immunomodulation, are thoroughly reviewed in this article.

Comparison of thromboelastometry with procalcitonin, interleukin 6, and C-reactive protein as diagnostic tests for severe sepsis in critically ill adults

Introduction

Established biomarkers for the diagnosis of sepsis are procalcitonin, interleukin 6, and C-reactive protein. Although sepsis evokes changes of coagulation and fibrinolysis, it is unknown whether thromboelastometry can detect these alterations. We investigated whether thromboelastometry variables are suitable as biomarkers for severe sepsis in critically ill adults.

Methods

In the observational cohort study, blood samples were obtained from patients on the day of diagnosis of severe sepsis (n = 56) and from postoperative patients (n = 52), and clotting time, clot formation time, maximum clot firmness, alpha angle, and lysis index were measured with thromboelastometry. In addition, procalcitonin, interleukin 6, and C-reactive protein levels were determined. For comparison of biomarkers, receiver operating characteristic (ROC) curves were used, and the optimal cut-offs and odds ratios were calculated.

Results

In comparison with postoperative controls, patients with sepsis showed an increase in lysis index (97% ± 0.3 versus 92 ± 0.5; P < 0.001; mean and SEM) and procalcitonin (2.5 ng/ml ± 0.5 versus 30.6 ± 8.7; P < 0.001). Clot-formation time, alpha angle, maximum clot firmness, as well as interleukin 6 and C-reactive protein concentrations were not different between groups; clotting time was slightly prolonged. ROC analysis demonstrated an area under the curve (AUC) of 0.901 (CI 0.838 - 0.964) for the lysis index, and 0.756 (CI 0.666 - 0.846) for procalcitonin. The calculated cut-off for the lysis index was > 96.5%, resulting in a sensitivity of 84.2%, and a specificity of 94.2%, with an odds ratio of 85.3 (CI 21.7 - 334.5).

Conclusions

The thromboelastometry lysis index proved to be a more reliable biomarker of severe sepsis in critically ill adults than were procalcitonin, interleukin 6, and C-reactive protein. The results also demonstrate that early involvement of the hemostatic system is a common event in severe sepsis.

Fibrinogen and antithrombin in hematological patients with neutropenic fever

The value of plasma fibrinogen and antithrombin as predictors of severe sepsis was investigated in 69 adult hematological patients, who had altogether 93 periods of neutropenic fever. Patients had either acute myeloid leukemia or had received a high dose of chemotherapy supported by autologous stem cell transplantation. In febrile periods with severe sepsis, the median fibrinogen concentration at the start of the fever was significantly higher (5.0 g/L) than that without severe sepsis (4.5 g/L) (p=0.009). Normal plasma fibrinogen could rule out a group of patients with severe sepsis at the beginning of the fever. The antithrombin activity decreased, both in fever periods with severe sepsis and in those without. The decrease in antithrombin activity was found to be greater in fever periods characterized by severe sepsis. In conclusion, elevated plasma fibrinogen and constantly decreasing antithrombin were shown to be linked to the development of severe sepsis.

Hypocoagulability, as evaluated by thrombelastography, at admission to the ICU is associated with increased 30-day mortality

Thrombelastography (TEG), a cell-based whole blood assay, may better reflect haemostatic competence than conventional coagulation assays and this was therefore evaluated including the clot forming parameters: R, angle and maximal amplitude in patients at ICU admission. This was a prospective, observational study of patients admitted to a general ICU at a tertiary care university hospital with an expected stay of more than 24 h. Blood samples for TEG and standard coagulation analysis were obtained at admission. The APACHE II and sequential organ failure assessment (SOFA) scores and 30-day mortality were recorded. At ICU admission, 106 patients (42%) showed hypocoagulability as evaluated by TEG and these patients had higher first day SOFA score (P < 0.0001) and higher 30-days (42 vs. 13%, P < 0.0001) mortality than patients presenting with a normal TEG. In 30-day survivors, admission platelet count (P = 0.05), angle (P < 0.001) and maximal amplitude (P = 0.001) were higher and R decreased (P = 0.0013) compared with nonsurvivors. Hypocoagulability at admission as evaluated by TEG was an independent risk factor for 30-day mortality [adjusted odds ratio (OR) 3.5; 95% confidence interval (CI) 1.7-7.1]. Hypocoagulability as evaluated by TEG was frequent at admission in general ICU patients and associated with a higher rate of ventilator treatment, higher rate of renal replacement therapy and a higher use of blood products. Hypocoagulability is an independent risk factor for 30-day mortality.

Discard volume necessary for elimination of heparin flush effect on thromboelastography

Heparin is commonly used to prevent obstruction of indwelling arterial catheters with blood clots. It is known to affect the outcomes of analysis of coagulation parameters with thromboelastography (TEG); therefore, it has been recommended to neutralize its effect with heparinase. However, heparinase may also neutralize the effect of low molecular weight heparin and endogenous heparinoids present in critically ill patients and thus yields unreliable results. The aim of this study was to evaluate the minimal discard blood volume needed to eliminate the effect of heparin flush on TEG parameters without the use of heparinase. Ten patients with indwelling arterial catheter were included in the study. Coagulation parameters were evaluated with kaolin-activated TEG. Blood samples were obtained after discarding 1, 2, 3, 4, 5 or 10 ml of blood to eliminate the effect of heparin. We investigated the influence of the discard volume on time until the first detectable clot (R), speed of clot development (alpha angle), maximal amplitude of the measured clot and time to maximal amplitude of the measured clot. We found an increase in coagulation (reflecting the heparin elimination) with the increasing discard volume between 1 and 4 ml. This was obvious from an increase in alpha angle and maximal amplitude of the measured clot and a decrease in R and time to maximal amplitude of the measured clot (P < 0.001). However, values obtained after discarding 4, 5 and 10 ml of blood did not differ markedly. To obtain valid information about TEG parameters, it is necessary to discard volume of at least 4 ml of blood (i.e., five times the volume of catheter dead space).

Elevated cardiac troponin I in sepsis and septic shock: no evidence for thrombus associated myocardial necrosis

Background

Elevated cardiac troponin I (cTnI) is frequently observed in patients with severe sepsis and septic shock. However, the mechanisms underlying cTnI release in these patients are still unknown. To date no data regarding coagulation disturbances as a possible mechanism for cTnI release during sepsis are available.

Methodology/Principal Findings

Consecutive patients with systemic inflammatory response syndrome (SIRS), sepsis or septic shock without evidence of an acute coronary syndrome were analyzed. Coagulation parameters (clotting time (CT), clot formation time (CFT), maximum clot firmness (MCF), α-angle) were assessed in native whole blood samples, and using specific activators to evaluate the extrinsic and intrinsic as well as the fibrin component of the coagulation pathway with the use of rotational thrombelastometry (ROTEM).

Thirty-eight patients were included and 22 (58%) were cTnI-positive. Baseline characteristics between TnI-positive and -negative patients were similar. The CT, CFT, MCF and the α-angle were similar between the groups with trends towards shorter CT in the extrinsic and fibrin activation.

Conclusions/Significance

We found no differences in coagulation parameters analyzed with rotational thrombelastometry between cTnI-positive and -negative patients with SIRS, severe sepsis, and septic shock. These findings suggest that pathophysiological mechanisms other than thrombus-associated myocardial damage might play a major role, including reversible myocardial membrane leakage and/or cytokine mediated apoptosis in these patients.

Thromboelastometry for the assessment of coagulation abnormalities in early and established adult sepsis: a prospective cohort study

INTRODUCTION

The inflammatory response to an invading pathogen in sepsis leads to complex alterations in hemostasis by dysregulation of procoagulant and anticoagulant factors. Recent treatment options to correct these abnormalities in patients with sepsis and organ dysfunction have yielded conflicting results. Using thromboelastometry (ROTEM(R)), we assessed the course of hemostatic alterations in patients with sepsis and related these alterations to the severity of organ dysfunction.

METHODS

This prospective cohort study included 30 consecutive critically ill patients with sepsis admitted to a 30-bed multidisciplinary intensive care unit (ICU). Hemostasis was analyzed with routine clotting tests as well as thromboelastometry every 12 hours for the first 48 hours, and at discharge from the ICU. Organ dysfunction was quantified using the Sequential Organ Failure Assessment (SOFA) score.

RESULTS

Simplified Acute Physiology Score II and SOFA scores at ICU admission were 52 +/- 15 and 9 +/- 4, respectively. During the ICU stay the clotting time decreased from 65 +/- 8 seconds to 57 +/- 5 seconds (P = 0.021) and clot formation time (CFT) from 97 +/- 63 seconds to 63 +/- 31 seconds (P = 0.017), whereas maximal clot firmness (MCF) increased from 62 +/- 11 mm to 67 +/- 9 mm (P = 0.035). Classification by SOFA score revealed that CFT was slower (P = 0.017) and MCF weaker (P = 0.005) in patients with more severe organ failure (SOFA >or= 10, CFT 125 +/- 76 seconds, and MCF 57 +/- 11 mm) as compared with patients who had lower SOFA scores (SOFA <10, CFT 69 +/- 27, and MCF 68 +/- 8). Along with increasing coagulation factor activity, the initially increased International Normalized Ratio (INR) and prolonged activated partial thromboplastin time (aPTT) corrected over time.

CONCLUSIONS

Key variables of ROTEM(R) remained within the reference ranges during the phase of critical illness in this cohort of patients with severe sepsis and septic shock without bleeding complications. Improved organ dysfunction upon discharge from the ICU was associated with shortened coagulation time, accelerated clot formation, and increased firmness of the formed blood clot when compared with values on admission. With increased severity of illness, changes of ROTEM(R) variables were more pronounced.

Effects of anticoagulant strategies on activation of inflammation and coagulation

Acute inflammatory events, such as those that occur in sepsis, lead to dysregulation of the coagulation cascade. The hemostatic imbalance in sepsis, characterized by the excessive activation of procoagulant pathways and the impairment of anticoagulant activity, leads to disseminated intravascular coagulation and results in microvascular thrombosis, tissue hypoperfusion and, ultimately, multiple organ failure and death. Furthermore, natural anti-inflammatory mechanisms of the endogenous anticoagulants are diminished by the impaired coagulation. Supportive strategies aiming at inhibiting activation of coagulation and inflammation by treatment with exogenous anticoagulants have been found to be beneficial in experimental and initial clinical studies. This review summarizes the available experimental and clinical data regarding the interaction between coagulation and inflammation, focusing on the two anticoagulants which are in clinical use, antithrombin and activated protein C. Identification of the different biological mechanisms of the two endogenous anticoagulants might help to determine target patient populations as well as to develop new anticoagulant analogs that differ in there respective effects in coagulation and inflammation.

Antithrombin and hypercoagulability in sepsis: insights from thrombelastography?

Antithrombin (AT) has been used for over 25 years to successfully treat disseminated intravascular coagulation (DIC). A four-day AT therapy in patients with DIC in the KyberSept trial has been related to a clear survival benefit in patients not receiving concomitant heparin. Gonano and coworkers performed thrombelastography (TEG) measurements in patients with severe sepsis and clearly showed hypercoagulability, as defined by five TEG parameters, compared to healthy controls. In the AT group they found a trend towards normalization of TEG parameters after treatment, although this did not reach statistical significance. This first clinical evaluation of hypercoagulability during AT treatment could not provide evidence for an attenuation of coagulopathy, an effect that might be due to high inter-individual variability.