Impact of hyper- and hypothermia on cellular and whole-body physiology.

The incidence of heat-related illnesses and heatstroke continues to rise amidst global warming. Hyperthermia triggers inflammation, coagulation, and progressive multiorgan dysfunction, and, at levels above 40 °C, can even lead to cell death. Blood cells, particularly granulocytes and platelets, are highly sensitive to heat, which promotes proinflammatory and procoagulant changes.

Mitochondrial dysfunction is a major cause of thromboinflammation and inflammatory cell death in critical illnesses.

Background: Mitochondria generate the adenosine triphosphate (ATP) necessary for eukaryotic cells, serving as their primary energy suppliers, and contribute to host defense by producing reactive oxygen species. In many critical illnesses, including sepsis, major trauma, and heatstroke, the vicious cycle between activated coagulation and inflammation results in tissue hypoxia-induced mitochondrial dysfunction, and impaired mitochondrial function contributes to thromboinflammation and cell death.

Methods: A computer-based online search was performed using the PubMed and Web of Science databases for published articles concerning sepsis, trauma, critical illnesses, cell death, mitochondria, inflammation, coagulopathy, and organ dysfunction.

Therapeutic Plasma Exchange for Fibrinogen-Associated Hyperviscosity: Results of the COPLEX Randomized Controlled Trial.

Background: Therapeutic plasma exchange (TPE) is the primary intervention for treating symptomatic hyperviscosity from hypergammaglobulinemia, yet its efficacy for treating hyperviscosity related to hyperfibrinogenemia is unclear.

Objective: Define the safety and efficacy of TPE for critically ill COVID-19 patients with elevated blood viscosity from hyperfibrinogenemia.

Method: A prospective, randomized controlled trial in critically ill COVID-19 patients at a single US healthcare system.

Troubleshooting heparin resistance.

The term heparin resistance is likely best defined as the failure of an appropriate dose of unfractionated heparin (UFH) to achieve a predetermined level of anticoagulation. Unfortunately, and despite many prior reports, there is no established consensus as to what either the appropriate dose or the predetermined level should be. Traditionally, assays used to monitor anticoagulation with UFH have been clot based, including the activated partial thromboplastin time, used for patients on the ward or intensive care unit, and the activated clotting time, used for patients undergoing vascular interventions and cardiopulmonary bypass.

Autophagy and autophagic cell death in sepsis: friend or foe?

In sepsis, inflammation, and nutrient deficiencies endanger cellular homeostasis and survival. Autophagy is primarily a mechanism of cellular survival under fasting conditions. However, autophagy-dependent cell death, known as autophagic cell death, is proinflammatory and can exacerbate sepsis.

Designing Future Clinical Trials for Sepsis-associated Disseminated Intravascular Coagulation.

Defining success in a clinical trial is not necessarily a straightforward task, especially when the target population is critically ill patients where few agents have demonstrated effectiveness. This has been the case for trials of anticoagulation in patients with sepsis-associated disseminated intravascular coagulation (DIC), which have generally examined patients with severe sepsis but not specifically DIC. Limitations of existing studies include inadequate anticoagulant doses and delayed initiation of treatment.

Use of coagulation factor concentrates and blood transfusion in cardiac surgery: a retrospective cohort study of adults with hereditary and acquired bleeding disorders.

Background: Cardiac surgery poses a significant risk of perioperative bleeding and allogeneic blood transfusions, particularly in patients with bleeding disorders. Increasingly frequent use of coagulation factor concentrates could impact haemorrhagic risks, thromboembolic events, and costs. We describe the use of coagulation factor concentrates and allogeneic blood products in cardiac surgical patients with hereditary and acquired bleeding disorders to assess pertinent outcomes, including perioperative haemorrhage, thromboembolism, and hospital costs.

Acquired von Willebrand syndrome during extracorporeal membrane oxygenation support: a comprehensive review of current evidence: communication from the ISTH SSC on perioperative and critical care thrombosis and hemostasis.

During extracorporeal membrane oxygenation (ECMO) support, the high shear stress in the ECMO circuit results in increased proteolysis of von Willebrand factor (VWF), loss of VWF high-molecular-weight multimers, and impaired ability to bind to platelets and collagen. These structural changes in VWF are consistent with acquired von Willebrand syndrome (AVWS) type 2A and may contribute to the bleeding diathesis frequently observed in ECMO patients. We performed a systematic review of all clinical studies evaluating the prevalence and associated outcomes of AVWS in ECMO patients.

Nanobody activator improves sensitivity of the von Willebrand factor activity assay to multimer size.

Background: The activity of von Willebrand factor (VWF) in facilitating platelet adhesion and aggregation correlates with its multimer size. Traditional ristocetin-dependent functional assays lack sensitivity to multimer sizes. Recently, nanobodies targeting the autoinhibitory module and activating VWF were identified.

Managing sepsis and septic shock in an endothelial glycocalyx-friendly way: from the viewpoint of surviving sepsis campaign guidelines.

Maintaining tissue perfusion in sepsis depends on vascular integrity provided by the endothelial glycocalyx, the critical layer covering the luminal surface of blood vessels. The glycocalyx is composed of proteoglycans, glycosaminoglycans, and functional plasma proteins that are critical for antithrombogenicity, regulating tone, controlling permeability, and reducing endothelial interactions with leukocytes and platelets. Degradation of the glycocalyx in sepsis is substantial due to thromboinflammation, and treatments for sepsis and septic shock may exacerbate endotheliopathy via additional glycocalyx injury.

Four years into the pandemic, managing COVID-19 patients with acute coagulopathy: what have we learned?

Coagulopathy alongside micro- and macrovascular thrombotic events were frequent characteristics of patients presenting with acute COVID-19 during the initial stages of the pandemic. However, over the past 4 years, the incidence and manifestations of COVID-19-associated coagulopathy have changed due to immunity from natural infection and vaccination and the appearance of new SARS-CoV-2 variants. Diagnostic criteria and management strategies based on early experience and studies for COVID-19-associated coagulopathy thus require reevaluation.

The role of thromboinflammation in acute kidney injury among patients with septic coagulopathy.

Inflammation and coagulation are critical self-defense mechanisms for mitigating infection that can nonetheless induce tissue injury and organ dysfunction. In severe cases, like sepsis, a dysregulated thromboinflammatory response may result in multiorgan dysfunction. Sepsis-associated acute kidney injury (AKI) is a significant contributor to patient morbidity and mortality.

Thromboinflammation and microcirculation damage in heatstroke.

Rising temperatures associated with climate change have significantly increased the risk of heatstroke. Unfortunately, the trend is anticipated to persist and increasingly threaten vulnerable populations, particularly older adults. According to Japan's environment ministry, over 1000 people died from heatstroke in 2021, and 86% of deaths occurred in those above 65.

Finding a common definition of heparin resistance in adult cardiac surgery: communication from the ISTH SSC subcommittee on perioperative and critical care thrombosis and hemostasis.

Ensuring adequate anticoagulation for patients requiring cardiac surgery and cardiopulmonary bypass (CPB) is important due to the adverse consequences of inadequate anticoagulation with respect to bleeding and thrombosis. When target anticoagulation is not achieved with typical doses, the term heparin resistance is routinely used despite the lack of uniform diagnostic criteria. Prior reports and guidance documents that define heparin resistance in patients requiring CPB and guidance documents remain variable based on the lack of standardized criteria.

Contemporary management of major haemorrhage in critical care.

Haemorrhagic shock is frequent in critical care settings and responsible for a high mortality rate due to multiple organ dysfunction and coagulopathy. The management of critically ill patients with bleeding and shock is complex, and treatment of these patients must be rapid and definitive. The administration of large volumes of blood components leads to major physiological alterations which must be mitigated during and after bleeding.

Risk stratification utilizing sequential organ failure assessment (SOFA) score, antithrombin activity, and demographic data in sepsis-associated disseminated intravascular coagulation (DIC).

Disseminated intravascular coagulation (DIC) is a frequent complication in patients with sepsis and is associated with increased mortality. Anticoagulant therapy may be appropriate for certain patients with DIC, particularly those with increased disease severity and deficiency in the physiologic anticoagulant antithrombin. We retrospectively analyzed post-marketing survey data from 1562 patients with sepsis-associated DIC and antithrombin activity of 70% or less.

Optimizing RBC Transfusion Outcomes in Patients with Acute Illness and in the Chronic Transfusion Setting.

Red blood cell (RBC) transfusion is a common clinical intervention used to treat patients with acute and chronic anemia. The decision to transfuse RBCs in the acute setting is based on several factors but current clinical studies informing optimal RBC transfusion decision making (TDM) are largely based upon hemoglobin (Hb) level. In contrast to transfusion in acute settings, chronic RBC transfusion therapy has several different purposes and is associated with distinct transfusion risks such as iron overload and RBC alloimmunization.

Defining heparin resistance: communication from the ISTH SSC Subcommittee of Perioperative and Critical Care Thrombosis and Hemostasis.

The term heparin resistance (HR) is used by clinicians without specific criteria. We performed a literature search and surveyed our SSC membership to better define the term when applied to medical and intensive care unit patients. The most common heparin dosing strategy reported in the literature (53%) and by survey respondents (80.

Prophylactic Platelet Transfusion: Is There Evidence of Benefit, Harm, or No Effect?

The optimal use of prophylactic platelet transfusion remains uncertain in a number of clinical scenarios. Platelet count thresholds have been established in patients with hematologic malignancies, yet thresholds backed by scientific data are limited or do not exist for many patient populations. Clinical scenarios involving transfusion thresholds for thrombocytopenic patients with critical illness, need for surgery or invasive procedures, or those involving specials populations like children and neonates, lack clear evidence for discerning favorable outcomes without undue risk related to platelet transfusion.

Antibody-mediated antigen loss switches augmented immunity to antibody-mediated immunosuppression.

Antibodies against fetal red blood cell (RBC) antigens can cause hemolytic disease of the fetus and newborn (HDFN). Reductions in HDFN due to anti-RhD antibodies have been achieved through use of Rh immune globulin (RhIg), a polyclonal antibody preparation that causes antibody-mediated immunosuppression (AMIS), thereby preventing maternal immune responses against fetal RBCs. Despite the success of RhIg, it is only effective against 1 alloantigen.

Multiplatform analyses reveal distinct drivers of systemic pathogenesis in adult versus pediatric severe acute COVID-19.

The pathogenesis of multi-organ dysfunction associated with severe acute SARS-CoV-2 infection remains poorly understood. Endothelial damage and microvascular thrombosis have been identified as drivers of COVID-19 severity, yet the mechanisms underlying these processes remain elusive. Here we show alterations in fluid shear stress-responsive pathways in critically ill COVID-19 adults as compared to non-COVID critically ill adults using a multiomics approach.