Impairment of coagulation by commonly used resuscitation fluids in human volunteers

Internal fibrinolysis of fibrin clots is driven by pore expansion

Blood clots, which are composed of blood cells and a stabilizing mesh of fibrin fibers, are critical in cessation of bleeding following injury. However, their action is transient and after performing their physiological function they must be resolved through a process known as fibrinolysis. Internal fibrinolysis is the degradation of fibrin by the endogenous or innate presence of lytic enzymes in the bloodstream; under healthy conditions, this process regulates hemostasis and prevents bleeding or clotting. Fibrin-bound tissue plasminogen activator (tPA) converts nearby plasminogen into active plasmin, which is bound to the fibrin network, breaking it down into fibrin degradation products and releasing the entrapped blood cells. It is poorly understood how changes in the fibrin structure and lytic protein ratios influence the biochemical regulation and behavior of internal fibrinolysis. We used turbidity kinetic tracking and microscopy paired with mathematical modeling to study fibrin structure and lytic protein ratios that restrict internal fibrinolysis. Analysis of simulations and experiments indicate that fibrinolysis is driven by pore expansion of the fibrin network. We show that this effect is strongly influenced by the ratio of fibrin:tPAwhen compared to absolute tPA concentration. Thus, it is essential to consider relative protein concentrations when studying internal fibrinolysis both experimentally and in the clinic. An improved understanding of effective internal lysis can aid in development of better therapeutics for the treatment of bleeding and thrombosis.

CAPILLARY LEAK AND EDEMA AFTER RESUSCITATION: THE POTENTIAL CONTRIBUTION OF REDUCED ENDOTHELIAL SHEAR STRESS CAUSED BY HEMODILUTION

ABSTRACT

Normal shear stress is essential for the normal structure and functions of the microcirculation. Hemorrhagic shock leads to reduced shear stress due to reduced tissue perfusion. Although essential for the urgent restoration of cardiac output and systemic blood pressure, large volume resuscitation with currently available solutions causes hemodilution, further reducing endothelial shear stress. In this narrative review, we consider how the use of currently available resuscitation solutions results in persistent reduction in endothelial shear stress, despite successfully increasing cardiac output and systemic blood pressure. We consider how this reduced shear stress causes (1) a failure to restore normal vasomotor function and normal tissue perfusion thus leading to persistent tissue hypoxia and (2) increased microvascular endothelial permeability resulting in edema formation and impaired organ function. We discuss the need for clinical research into resuscitation strategies and solutions that aim to quickly restore endothelial shear stress in the microcirculation to normal.

Characterization of 2 Different Prothrombin Complex Concentrates by Different Hemostatic Assays in an In Vitro Hemodilution Model

BACKGROUND

Viscoelastically guided coagulation factor concentrate-based algorithms for the treatment of trauma-induced coagulopathy include the administration of prothrombin complex concentrates (PCCs). However, the exact role of PCC preparations in this context is a matter of debate. Particularly, the ideal diagnostic trigger for their administration and potential differences between heparin-containing and heparin-free preparations remain unclear. We investigated the hypothesis that 2 different PCCs might have distinct influences on in vitro blood coagulation.

METHODS

We conducted a direct comparison of 2 commercially available PCC preparations (the heparin-containing Beriplex P/N and the heparin-free Cofact) in an in vitro hemodilution model. Sole fibrinogen substitution served as the control group. To characterize the hemostatic changes, we utilized conventional coagulation tests, a thrombin generation assay (TGA), and 2 different viscoelastic hemostatic assays (VHAs; ROTEM delta and ClotPro).

RESULTS

Irrespective of the diagnostic assay used, no significant differences between the 2 PCC groups were observed. Fibrinogen levels remained stable from the baseline throughout every dilution level. The control group already showed an increased endogenous thrombin potential (ETP; nM·L -1 ·min -1 ) at all dilution levels compared to baseline (baseline, 2829.4 (432.8); 40% dilution, 4211.7 (391.6); 60% dilution, 4290.9 (300.8); 80% dilution, 3861.4 (303.5); all P < .001). Spiking with both PCC preparations led to a further-pronounced thrombin elevation in comparison to the control group (ETP at 40% dilution, PCC1: 4913.3 [370.2], PCC2: 4988.1 [265.7]; 60% dilution, PCC1: 5174.5 [234.7], PCC2: 5390.4 [334.9]; 80% dilution, PCC1: 5253.8 [357.9], PCC2: 5392.6 [313.4]; all P < .001). Conventional coagulation tests did not mirror the TGA results. Despite increased thrombin generation, prothrombin time was significantly prolonged at all dilution levels for the control group, and both PCC groups exhibited significant prolongations at the 60% and 80% dilution levels (all P < .001) compared to baseline. Similarly, VHA did not depict the thrombin elevation. Furthermore, descriptive analyses revealed relevant differences between the 2 VHA devices, particularly at baseline.

CONCLUSIONS

Both PCC preparations (ie, irrespective of heparin content) induced significant elevation of thrombin generation, which was not depicted by conventional coagulation tests or VHA. Our in vitro results suggest that diagnostic assays routinely used to guide PCC administration might not adequately reflect thrombin generation in bleeding patients.

Association between Functional Parameters of Coagulation and Conventional Coagulation Tests in the Setting of Fluid Resuscitation with Balanced Crystalloid or Gelatine: A Secondary Analysis of an In Vivo Prospective Randomized Crossover Study

Functional point-of-care tests (POCTs) have evolved into useful tools for diagnosing disorders of blood coagulation and fibrinolysis. We aimed to describe the in vivo association between standard and functional parameters of coagulation and fibrinolysis in the setting of acute hemodilution induced by an infusion of balanced crystalloid or synthetic gelatine solutions. This prospective randomized crossover in vivo study included healthy male volunteers aged 18–30 years. Enrolled participants were randomly assigned to receive either the Optilyte^® or Geloplasma^® infusion. Laboratory analysis included conventional coagulation parameters and rotational thromboelastometry (ROTEM) assays. A total of 25 healthy Caucasian males were included. ROTEM viscoelastic assays presented moderate to strong correlations with conventional coagulation tests, regardless of the fluid type utilized. Irrespectively of the extent of hemodilution, significant correlations remained unaffected. The strongest associations were found between the ROTEM clot formation and clot strength and the fibrinogen concentration and platelet count, and between the ROTEM clotting time and the APTT and PT. This in vivo experimental study in healthy male volunteers demonstrated that ROTEM may be used as a credible alternative to standard laboratory tests to assess blood coagulation and fibrinolysis in the setting of fluid resuscitation with both crystalloid and colloid solutions. The study was registered online in the ClinicalTrials.gov database (NCT05148650).

Chinese expert consensus on diagnosis and treatment of coagulation dysfunction in COVID-19

Since December 2019, a novel type of coronavirus disease (COVID-19) in Wuhan led to an outbreak throughout China and the rest of the world. To date, there have been more than 1,260,000 COVID-19 patients, with a mortality rate of approximately 5.44%. Studies have shown that coagulation dysfunction is a major cause of death in patients with severe COVID-19. Therefore, the People's Liberation Army Professional Committee of Critical Care Medicine and Chinese Society on Thrombosis and Hemostasis grouped experts from the frontline of the Wuhan epidemic to come together and develop an expert consensus on diagnosis and treatment of coagulation dysfunction associated with a severe COVID-19 infection. This consensus includes an overview of COVID-19-related coagulation dysfunction, tests for coagulation, anticoagulation therapy, replacement therapy, supportive therapy and prevention. The consensus produced 18 recommendations which are being used to guide clinical work.

Introduction of a standardised protocol, including systematic use of tranexamic acid, for management of severe adult trauma patients in a low-resource setting: the MSF experience from Port-au-Prince, Haiti

BACKGROUND

Bleeding is an important cause of death in trauma victims. In 2010, the CRASH-2 study, a multicentre randomized control trial on the effect of tranexamic acid (TXA) administration to trauma patients with suspected significant bleeding, reported a decreased mortality in randomized patients compared to placebo. Currently, no evidence on the use of TXA in humanitarian, low-resource settings is available. We aimed to measure the hospital outcomes of adult patients with severe traumatic bleeding in the Médecins Sans Frontières Tabarre Trauma Centre in Port-au-Prince, Haiti, before and after the implementation of a Massive Haemorrhage protocol including systematic early administration of TXA.

METHODS

Patients admitted over comparable periods of four months (December2015- March2016 and December2016 - March2017) before and after the implementation of the Massive Haemorrhage protocol were investigated. Included patients had blunt or penetrating trauma, a South Africa Triage Score ≥ 7, were aged 18-65 years and were admitted within 3 h from the traumatic event. Measured outcomes were hospital mortality and early mortality rates, in-hospital time to discharge and time to discharge from intensive care unit.

RESULTS

One-hundred and sixteen patients met inclusion criteria. Patients treated after the introduction of the Massive Haemorrhage protocol had about 70% less chance of death during hospitalization compared to the group "before" (adjusted odds ratio 0.3, 95%confidence interval 0.1-0.8). They also had a significantly shorter hospital length of stay (p = 0.02).

CONCLUSIONS

Implementing a Massive Haemorrhage protocol including early administration of TXA was associated with the reduced mortality and hospital stay of severe adult blunt and penetrating trauma patients in a context with poor resources and limited availability of blood products.

Early diuretic use and mortality in critically ill patients with vasopressor support: a propensity score-matching analysis

Background

The effect of loop diuretic use in critically ill patients on vasopressor support or in shock is unclear. This study aimed to explore the relationship between loop diuretic use and hospital mortality in critically ill patients with vasopressor support.

Methods

Data were extracted from the Medical Information Mart for Intensive Care III database. Adult patients with records of vasopressor use within 48 h after intensive care unit admission were screened. Multivariable logistic regression and propensity score matching was used to investigate any association.

Results

Data on 7828 patients were included. The crude hospital mortality was significantly lower in patients with diuretic use (166/1469 vs. 1171/6359, p <  0.001). In the extended multivariable logistic models, the odds ratio (OR) of diuretic use was consistently significant in all six models (OR range 0.56–0.75, p < 0.05 for all). In the subgroup analysis, an interaction effect was detected between diuretic use and fluid balance (FB). In the positive FB subgroup, diuretic use was significantly associated with decreased mortality (OR 0.64, 95% confidence interval (CI) 0.51–0.78) but was insignificant in the negative FB subgroup. In the other subgroups of mean arterial pressure, maximum sequential organ failure assessment score, and lactate level, the association between diuretic use and mortality remained significant and no interaction was detected. After propensity score matching, 1463 cases from each group were well matched. The mortality remained significantly lower in the diuretic use group (165/1463 vs. 231/1463, p < 0.001).

Conclusions

Although residual confounding cannot be excluded, loop diuretic use is associated with lower mortality.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2309-9) contains supplementary material, which is available to authorized users.

Time-related association between fluid balance and mortality in sepsis patients: interaction between fluid balance and haemodynamics

This study aimed to investigate the time-related association between cumulative fluid balance (FB) and mortality. Data were extracted from the Medical Information Mart for Intensive Care (MIMIC) III. FB data on 8584 patients at the first (FB-fir24hr) and second (FB-sec24hr) 24 hours after intensive care unit admission were analysed. Compared to the combination of FB-fir24hr ≤ 0 and FB-sec24 hr ≤ 0, the combination of FB-fir24hr > 0 and FB-sec24hr ≤ 0 had significantly higher FB, with an insignificant odds ratio (OR) for mortality. However, the mortality ORs of two other combinations (FB-fir24hr ≤ 0 and FB-sec24hr > 0; FB-fir24hr > 0 and FB-sec24hr > 0) were significantly high. Furthermore, multivariable logistic analysis showed a significant stepwise increase ORs for mortality with increasing FB-sec24hr quartiles, with no significant increase in FB-fir24hr quartiles aside from quartile 4. In patients with negative FB, a stepwise decrease in mortality ORs with increasing FB-sec24hr quartiles was found with no significant difference in FB-fir24hr quartiles. In conclusion, the positive FB during the second but not the first 24 hours was associated with increased mortality in sepsis. Achieving more negative FB was associated with decreased mortality only in the second 24 hours.

[Trauma-induced coagulopathy]

The main cause of death in the patient group less than 45 years is trauma. Beside severe traumatic brain injury, bleeding remains a leading cause of death in this group. For a causal therapy, it is necessary to understand the pathophysiology of trauma-induced coagulopathy (TIC). Beside the well-known lethal triad of trauma (hypothermia, acidosis, and coagulopathy), dilution and hypoperfusion with activation of the protein C pathway play a crucial role. TIC is a complex independent syndrome which may be present without initial hypercoagulopathy. A rapid and differentiated diagnosis and goal-directed therapy is crucial for causal therapy.

Conservative fluid therapy in septic shock: an example of targeted therapeutic minimization

Intravenous fluids (IVFs) represent a basic therapeutic intervention utilized in septic shock. Unfortunately, the optimal method for administering IVFs to maximize patient outcomes is unknown. A meta-analysis of four randomized trials of goal-directed therapy did not demonstrate a significant reduction in mortality (odds ratio 0.609; 95% confidence interval 0.363 to 1.020; P = 0.059), whereas 18 trials with historical controls showed a significant increase in survival (odds ratio 0.580; 95% confidence interval 0.501 to 0.672; P < 0.0001). Based on these data, clinicians should be aware of the potential for harm due to the excessive administration of IVFs to patients with septic shock.

Fluid balance and cardiac function in septic shock as predictors of hospital mortality

INTRODUCTION

Septic shock is a major cause of morbidity and mortality throughout the world. Unfortunately, the optimal fluid management of septic shock is unknown and currently is empirical.

METHODS

A retrospective analysis was performed at Barnes-Jewish Hospital (St. Louis, Missouri). Consecutive patients (n = 325) hospitalized with septic shock who had echocardiographic examinations performed within 24 hours of shock onset were enrolled.

RESULTS

A total of 163 (50.2%) patients with septic shock died during hospitalization. Non-survivors had a significantly larger positive net fluid balance within the 24 hour window of septic shock onset (median (IQR): 4,374 ml (1,637 ml, 7,260 ml) vs. 2,959 ml (1,639.5 ml, 4,769.5 ml), P = 0.004). The greatest quartile of positive net fluid balance at 24 hours and eight days post-shock onset respectively were found to predict hospital mortality, and the greatest quartile of positive net fluid balance at eight days post-shock onset was an independent predictor of hospital mortality (adjusted odds ratio (AOR), 1.66; 95% CI, 1.39 to 1.98; P = 0.004). Survivors were significantly more likely to have mild left ventricular dysfunction as evaluated by bedside echocardiography and non-survivors had slightly elevated left ventricular ejection fraction, which was also found to be an independent predictor of outcome.

CONCLUSIONS

Our data confirms the importance of fluid balance and cardiac function as outcome predictors in patients with septic shock. A clinical trial to determine the optimal administration of intravenous fluids to patients with septic shock is needed.

Cardiovascular management of septic shock in 2012

Septic shock is a major cause of morbidity and mortality throughout the world. Source control, antimicrobial therapy, early goal-directed fluid resuscitation, and infusion of vasoactive pharmaceuticals remain the cornerstones of treatment. However, the cardiovascular management of septic shock is evolving. Basic science and clinical researchers have identified novel drug targets and are testing the efficacy of new therapeutic agents. For example, prevention of microvascular leak during septic shock is the focus of active investigations and may soon provide considerable benefit to patients. Among the important topics that will be discussed in this review are the following: the role of vascular endothelial dysfunction in microvascular leak, the impact of cytokines upon structural and functional proteins within the endothelial barrier and within the heart, and the ability of selective vasopressin 1a receptor agonists to minimize tissue edema and improve hemodynamic status.

The treatment of traumatic shock: recent advances and unresolved questions

Uncontrolled bleeding remains a leading cause of potentially preventable death after trauma. Timely, adequate resuscitation in traumatic shock is an essential, lifesaving aspect of polytrauma care. Whilst basic principles in the treatment of traumatic shock remain the same-achieving hemorrhage control and replacing lost volume, the way this is achieved has changed significantly in the last five years. The abandonment of blood pressure driven uncontrolled fluid resuscitation, the introduction of the concept of hemostatic resuscitation, and the increasing use of massive transfusion protocols have all contributed to an improvement in timely access to various blood products. The increase in knowledge regarding the pathophysiology of trauma, the availability of adjuncts, and the array of resuscitation monitoring options available have all contributed to a potentially improved approach to resuscitation. The purpose of this report is to review the most important advances in traumatic shock therapy in the last five years.

The coagulopathy of trauma: a review of mechanisms

BACKGROUND

Bleeding is the most frequent cause of preventable death after severe injury. Coagulopathy associated with severe injury complicates the control of bleeding and is associated with increased morbidity and mortality in trauma patients. The causes and mechanisms are multiple and yet to be clearly defined.

METHODS

Articles addressing the causes and consequences of trauma-associated coagulopathy were identified and reviewed. Clinical situations in which the various mechanistic causes are important were sought along with quantitative estimates of their importance.

RESULTS

Coagulopathy associated with traumatic injury is the result of multiple independent but interacting mechanisms. Early coagulopathy is driven by shock and requires thrombin generation from tissue injury as an initiator. Initiation of coagulation occurs with activation of anticoagulant and fibrinolytic pathways. This Acute Coagulopathy of Trauma-Shock is altered by subsequent events and medical therapies, in particular acidemia, hypothermia, and dilution. There is significant interplay between all mechanisms.

CONCLUSIONS

There is limited understanding of the mechanisms by which tissue trauma, shock, and inflammation initiate trauma coagulopathy. Acute Coagulopathy of Trauma-Shock should be considered distinct from disseminated intravascular coagulation as described in other conditions. Rapid diagnosis and directed interventions are important areas for future research.

Acute coagulopathy of trauma: mechanism, identification and effect

PURPOSE OF REVIEW

Acute coagulopathy of trauma has only been described relatively recently. Developing early in the postinjury phase, it is associated with increased transfusion requirements and poor outcomes. This review examines the possible initiators, mechanism and clinical importance of acute coagulopathy.

RECENT FINDINGS

Acute coagulopathy of trauma occurs in patients with shock and is characterized by a systemic anticoagulation and hyperfibrinolysis. Dilution, acidemia and consumption of coagulation proteases do not appear to be significant factors at this stage. There is evidence to implicate activation of the protein C pathway in this process. Diagnosis of acute coagulopathy currently relies on laboratory assessment of clotting times. These tests do not fully characterize the coagulopathy and have significant limitations, which reduce their clinical utility.

SUMMARY

Acute coagulopathy results in increased transfusion requirements, incidence of organ dysfunction, critical care stay and mortality. Recognition of an early coagulopathic state has implications for the care of shocked patients and the management of massive transfusion. Identification of novel mechanisms for traumatic coagulopathy may lead to new avenues for drug discovery and therapeutic intervention.

Effects of albumin 5% and artificial colloids on clot formation in small infants

Albumin is often cited in textbooks as the gold standard for fluid replacement in paediatrics, but in practice artificial colloids are more frequently used. Although one concern with the use of artificial colloids is their intrinsic action on haemostasis, the available data in children are inconclusive for 6% hydroxyethyl starch 130/0.4 (HES) and no data exist for gelatine solution with respect to coagulation. A total of 42 children (3-15 kg) undergoing surgery and needing colloid replacement were randomly assigned to receive 15 mlxkg(-1) of either albumin 5%, 4% modified gelatine solution or 6% hydroxyethyl starch 130/0.4 solution. Standard coagulation tests and modified thrombelastography (ROTEM) were performed. After colloid administration, routine coagulation test results changed significantly and comparably in all groups, although activated partial thromboplastin time values increased more with gelatine and HES. Coagulation time was unchanged in the children who received albumin or gelatine but other activated modified thrombelastography values were significantly impaired in all groups. After gelatine and after albumin the median clot firmness decreased significantly but remained within the normal range. Following HES, coagulation time increased significantly, and clot formation time, alpha angle, clot firmness, and fibrinogen/fibrin polymerisation were significantly more impaired than for albumin or gelatine, reaching median values below the normal range. From a haemostatic point of view it might be preferable to use gelatine solution as an alternative to albumin; HES showed the greatest effects on the overall coagulation process.