Fibrinogen substitution improves whole blood clot firmness after dilution with hydroxyethyl starch in bleeding patients undergoing radical cystectomy: a randomized, placebo-controlled clinical trial

Goal-directed Coagulation Management in Major Trauma

Severe tissue trauma is frequently associated with hemorrhagic shock and subsequent pronounced coagulopathy [1]. Uncontrolled bleeding is the second most common cause of death, and hemorrhage is directly responsible for 40 % of all trauma-related deaths [2]. Coagulopathy can be detected with standard coagulation tests immediately after arrival in the emergency room (ER) in approximately 25–35 % of all trauma patients [1], [2]. Moreover, early trauma-induced coagulopathy is associated with a 4-fold increase in mortality [1]. Blood coagulation monitoring is essential in order to assess the underlying coagulation disorder and to tailor hemostatic treatment. Thromboelastometry (TEM) and thrombelastography (TEG) are promising point-of-care technologies providing rapid information on the initiation process of clot formation, clot quality, and stability of the clot [3].

Posttraumatic massive bleeding: a challenging multidisciplinary task

Massive bleeding is a key issue in the treatment of trauma and surgery. It does in fact account for more than 50% of all trauma-related deaths within the first 48 h following hospital admission, and it can significantly raise the mortality rate of any kind of surgery. Despite this great clinical relevance, evidence on the management of massive bleeding is surprisingly scarce, and its treatment is often based on empirical grounds. Successful treatment of massive haemorrhage depends on better understanding of the associated physiological changes as well as on good team work between the different specialists involved in the management of such a complex condition. The aim of this article is to provide an overview of the pathophysiology as well as of current treatment options of such a condition, including the new concept of "damage control resuscitation", which integrates permissive hypotension, haemostatic resuscitation and damage control surgery.

Role of fibrinogen in trauma-induced coagulopathy

Coagulation defects related to severe trauma, trauma-induced coagulopathy (TIC), have a number of causal factors including: major blood loss with consumption of clotting factors and platelets, and dilutional coagulopathy after administration of crystalloids and colloids to maintain blood pressure. In addition, activation of the fibrinolytic system or hyperfibrinolysis, hypothermia, acidosis, and metabolic changes can also affect the coagulation system. All of these directly affect fibrinogen polymerization and metabolism. Other bleeding-related deficiencies usually develop later in massive bleeding related to severe multiple trauma. In major blood loss, fibrinogen reaches a critical value earlier than other procoagulatory factors, or platelets. The question of the critical threshold value is presently the subject of heated debate. A threshold of 100 mg dl(-1) has been recommended, but recent clinical data have shown that at a fibrinogen level of <150-200 mg dl(-1), there is already an increased tendency to peri- and postoperative bleeding. A high fibrinogen count exerts a protective effect with regard to the amount of blood loss. In multiple trauma patients, priority must be given to early and effective correction of impaired fibrin polymerization by administering fibrinogen concentrate.

Prophylactic Fibrinogen Infusion in Cardiac Surgery Patients: Effects on Biomarkers of Coagulation, Fibrinolysis, and Platelet Function

Objective: We have recently reported that prophylactic fibrinogen infusion reduces bleeding after coronary artery bypass grafting (CABG) surgery. Because fibrinogen for the first time was administered to patients without hereditary fibrinogen deficiency or ongoing bleeding, a detailed analysis of the effects of fibrinogen concentrate on biomarkers of coagulation, fibrinolysis, and platelet function was performed. Methods: Twenty CABG patients with preoperative plasma fibrinogen levels <3.8 g/L were included in a prospective study. Patients were randomized to preoperative infusion of 2 g fibrinogen concentrate (fibrinogen group) or no infusion (control group). Activated partial thromboplastin time (aPTT), prothrombin time, activated clotting time, and plasma concentrations of fibrinogen, antithrombin, thrombin-antithrombin complex, prothrombin fragment 1.2, and D-dimer, thromboelastometry, platelet count, and platelet aggregometry were analyzed before and 15 minutes after infusion, and 2 and 24 hours after surgery. Results: Fifteen minutes after infusion of fibrinogen concentrate, fibrinogen plasma levels increased by 0.6 ± 0.2 g/L (P < .001 between groups), and induced minimal changes in aPTT and plasma levels of antithrombin, while remaining variables remained unchanged. After surgery, fibrinogen levels no longer differed between groups. D-dimer was significantly higher after surgery in the fibrinogen group (P = .03), while none of the other markers were statistically different between groups. Conclusions: Infusion of 2 g fibrinogen to cardiac surgery patients, without hereditary or acquired fibrinogen deficiency or ongoing bleeding, results in no or minimal changes in biomarkers reflecting coagulation and platelet function. An increased release of fibrin degradation products was detected after surgery in fibrinogen-treated patients.

Is fibrinogen the answer to coagulopathy after massive transfusions?

Coagulopathy is a major cause of morbidity and mortality in patients who have suffered severe hemorrhage and received massive transfusions. Administration of a fibrinogen concentrate along with red blood cells can quickly restore hemostasis in a clinically relevant animal model.

Effects of different fibrinogen concentrations on blood loss and coagulation parameters in a pig model of coagulopathy with blunt liver injury

INTRODUCTION

The early application of fibrinogen could potentially reverse haemodilution-induced coagulopathy, although the impact of varying concentrations of fibrinogen to reverse dilutional coagulopathy has not been studied in vivo. We postulated that fibrinogen concentration is correlated with blood loss in a pig model of coagulopathy with blunt liver injury.

METHODS

Coagulopathy was induced in 18 anaesthetized pigs (32 +/- 1.6 kg body weight) by replacing 80% of blood volume with hydroxyethylstarch 130/0.4 and Ringer's lactated solution, and re-transfusion of erythrocytes. Animals were randomly assigned to receive either 70 mg kg-1 (F-70) or 200 mg kg-1 (F-200) fibrinogen or placebo before inducing blunt liver injury using a force of 225 +/- 26 Newton. Haemodynamics, coagulation parameters and blood loss were monitored for 2 hours. After death, histological examination of internal organs was performed to assess the presence of emboli and the equality of liver injury.

RESULTS

Plasma dilution caused severe coagulopathy. Measured by thromboelastography fibrinogen restored coagulation dose-dependently. Total blood loss was significantly lower and survival better in both fibrinogen groups as compared to controls (P < 0.05). Between the F-70 (1317 +/- 113 ml) and the F-200 group (1155 +/- 232 ml) no significant difference in total blood loss could be observed, despite improved coagulation parameters in the F-200 group (P < 0.05). Microscopy revealed even injury pattern and no (micro) thrombi for either group.

CONCLUSIONS

Restoring fibrinogen with 70 or 200 mg kg-1 after severe dilutional coagulopathy safely improved coagulation and attenuated blood loss after experimental blunt liver trauma. The higher dosage of fibrinogen was not associated with a further reduction in blood loss.

Goal-directed coagulation management of major trauma patients using thromboelastometry (ROTEM)-guided administration of fibrinogen concentrate and prothrombin complex concentrate

Introduction

The appropriate strategy for trauma-induced coagulopathy management is under debate. We report the treatment of major trauma using mainly coagulation factor concentrates.

Methods

This retrospective analysis included trauma patients who received ≥ 5 units of red blood cell concentrate within 24 hours. Coagulation management was guided by thromboelastometry (ROTEM^®). Fibrinogen concentrate was given as first-line haemostatic therapy when maximum clot firmness (MCF) measured by FibTEM (fibrin-based test) was <10 mm. Prothrombin complex concentrate (PCC) was given in case of recent coumarin intake or clotting time measured by extrinsic activation test (EXTEM) >1.5 times normal. Lack of improvement in EXTEM MCF after fibrinogen concentrate administration was an indication for platelet concentrate. The observed mortality was compared with the mortality predicted by the trauma injury severity score (TRISS) and by the revised injury severity classification (RISC) score.

Results

Of 131 patients included, 128 received fibrinogen concentrate as first-line therapy, 98 additionally received PCC, while 3 patients with recent coumarin intake received only PCC. Twelve patients received FFP and 29 received platelet concentrate. The observed mortality was 24.4%, lower than the TRISS mortality of 33.7% (P = 0.032) and the RISC mortality of 28.7% (P > 0.05). After excluding 17 patients with traumatic brain injury, the difference in mortality was 14% observed versus 27.8% predicted by TRISS (P = 0.0018) and 24.3% predicted by RISC (P = 0.014).

Conclusions

ROTEM^®-guided haemostatic therapy, with fibrinogen concentrate as first-line haemostatic therapy and additional PCC, was goal-directed and fast. A favourable survival rate was observed. Prospective, randomized trials to investigate this therapeutic alternative further appear warranted.

Management of bleeding following major trauma: an updated European guideline

INTRODUCTION

Evidence-based recommendations are needed to guide the acute management of the bleeding trauma patient, which when implemented may improve patient outcomes.

METHODS

The multidisciplinary Task Force for Advanced Bleeding Care in Trauma was formed in 2005 with the aim of developing a guideline for the management of bleeding following severe injury. This document presents an updated version of the guideline published by the group in 2007. Recommendations were formulated using a nominal group process, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) hierarchy of evidence and based on a systematic review of published literature.

RESULTS

Key changes encompassed in this version of the guideline include new recommendations on coagulation support and monitoring and the appropriate use of local haemostatic measures, tourniquets, calcium and desmopressin in the bleeding trauma patient. The remaining recommendations have been reevaluated and graded based on literature published since the last edition of the guideline. Consideration was also given to changes in clinical practice that have taken place during this time period as a result of both new evidence and changes in the general availability of relevant agents and technologies.

CONCLUSIONS

This guideline provides an evidence-based multidisciplinary approach to the management of critically injured bleeding trauma patients.

Correction of coagulation in dilutional coagulopathy: use of kinetic and capacitive coagulation assays to improve hemostasis

The management of dilutional coagulopathy due to fluid infusion and massive blood loss is a topic that deserves a biochemical approach. In this review article, we provide an overview of current guidelines and recommendations on diagnosis and on management of transfusion in acquired coagulopathy. We discuss the biochemical differences between kinetic clotting assays (clotting times) and new capacitive coagulation measurements that provide time-dependent information on thrombin generation and fibrin clot formation. The available evidence suggests that a combination of assay types is required for evaluating new transfusion protocols aimed to optimize hemostasis and stop bleeding. Although there is current consensus on the application of fresh frozen plasma to revert coagulopathy, factor concentrates may appear to be useful in the future.

Recovery of fibrinogen after administration of fibrinogen concentrate to patients with severe bleeding after cardiopulmonary bypass surgery

BACKGROUND

Normalization of plasma fibrinogen levels may be associated with satisfactory haemostasis and reduced bleeding. The aim of this retrospective study was to assess fibrinogen recovery parameters after administration of fibrinogen concentrate (Haemocomplettan P) to patients with diffuse bleeding in cardiovascular surgery. Data on transfusion and patient outcomes were also collected.

METHODS

Patient characteristic and clinical data were obtained from patient records.

RESULTS

of the thromboelastometry (FIBTEM)and of the standard coagulation tests, including plasma fibrinogen level, measured before surgery, before and after haemostatic therapy, and on the following day, were retrieved from laboratory records. Results Thirty-nine patients receiving fibrinogen concentrate for diffuse bleeding requiring haemostatic therapy after cardiopulmonary bypass were identified. The mean fibrinogen concentrate dose administered was 6.5 g. The mean fibrinogen level increased from 1.9 to 3.6 g litre(-1) (mean increment of 0.28 g litre(-1) per gram of concentrate administered); maximum clot firmness increased from 10 to 21 mm. The mean fibrinogen increase was 2.29 (sd 0.7) mg dl(-1) per mg kg(-1) bodyweight of concentrate administered. Thirty-five patients received no transfusion of fresh-frozen plasma (FFP) or platelet concentrate after receiving fibrinogen concentrate; the remaining four patients received platelet concentrate intraoperatively. Eleven patients received platelets, FFP, or both during the first postoperative day. No venous thromboses, arterial ischaemic events, or deaths were registered during hospitalization.

CONCLUSIONS

In this retrospective study, fibrinogen concentrate was effective in increasing plasma fibrinogen level, and contributed to the correction of bleeding after cardiovascular surgery.

New insights into acute coagulopathy in trauma patients

Abnormal coagulation parameters can be found in 25% of trauma patients with major injuries. Furthermore, trauma patients presenting with coagulopathy on admission have worse clinical outcome. Tissue trauma and systemic hypoperfusion appear to be the primary factors responsible for the development of acute traumatic coagulopathy immediately after injury. As a result of overt activation of the protein C pathway, the acute traumatic coagulopathy is characterised by coagulopathy in conjunction with hyperfibrinolysis. This coagulopathy can then be exacerbated by subsequent physiologic and physical derangements such as consumption of coagulation factors, haemodilution, hypothermia, acidemia and inflammation, all factors being associated with ongoing haemorrhage and inadequate resuscitation or transfusion therapies. Knowledge of the different mechanisms involved in the pathogenesis of acute traumatic coagulopathy is essential for successful management of bleeding trauma patients. Therefore, early evidence suggests that treatment directed at aggressive and targeted haemostatic resuscitation can lead to reductions in mortality of severely injured patients.

Successful rotational thromboelastometry-guided treatment of traumatic haemorrhage, hyperfibrinolysis and coagulopathy

Transfusion of allogeneic blood products is associated with increased morbidity and mortality. Therefore, strategies for reducing transfusion of these products during trauma management are valuable. We report a case of severe blunt abdominal trauma, successfully treated with antifibrinolytic medication and fibrinogen concentrate. Rotational thromboelastometry (ROTEM) was used to identify hyperfibrinolysis and afibrinogenaemia. In order to achieve haemostasis, over a 3-h period, the patient received a total of 1 g of tranexamic acid, 7 U of packed red blood cells, 16 g of fibrinogen concentrate (Haemocomplettan P), 3500 ml of colloids and 5500 ml of lactated Ringer's solution. Together with surgical measures, this treatment stopped the bleeding and stabilised the patient. There was no transfusion of either fresh-frozen plasma or platelets. The limited need for allogeneic blood products is of particular interest, and clinical studies of the approach used here appear to be warranted.

HES 130/0.4 impairs haemostasis and stimulates pro-inflammatory blood platelet function

Introduction

Hydroxyethyl starch (HES) solutions are widely used for volume replacement therapy but are also known to compromise coagulation, impair renal function and increase long-term mortality. To test the hypotheses that HES 130/0.4 has fewer adverse effects than HES 200/0.5 and exerts anti-inflammatory properties, we compared the effects of HES 130/0.4, HES 200/0.5 and saline on in vitro haemostasis and pro-inflammatory platelet function.

Methods

Whole blood samples from healthy volunteers were mixed with 6% HES 130/0.4, 10% HES 200/0.5, or normal saline to achieve a final haemodilution rate of 10% or 40%. Haemostatic capacity was characterised by thromboelastography (ROTEM) and measurement for FXIIIa activity. Platelet activation and pro-inflammatory platelet functions were characterised by flow cytometry measuring the platelet activation marker CD62P and binding of fibrinogen to platelets as well as the formation of heterotypic platelet-leukocyte conjugates.

Results

Compared with saline, HES 130/0.4 dose-dependently impaired formation and firmness of the fibrin clot but did not affect the fibrin crosslinking activity of FXIIIa. At 40% but not at 10% haemodilution rate, HES 200/0.5 also increased platelet fibrinogen binding and both HES solutions increased expression of CD62P, the main receptor for platelet-leukocyte adhesion. HES 130/0.4 but not HES 200/0.5 increased formation of platelet-neutrophil conjugates and, to a lesser degree, platelet-monocyte conjugates.

Conclusions

Our data demonstrate that HES 130/0.4 has similar adverse effects as HES 200/0.5. In particular, both types of HES impair coagulation capacity and stimulate, rather than attenuate, pro-inflammatory platelet function.

Mechanisms of hydroxyethyl starch-induced dilutional coagulopathy

BACKGROUND

The biochemical mechanisms causing dilutional coagulopathy following infusion of hydroxyethyl starch 130/0.4 (HES) are not known in detail.

OBJECTIVES

To give a detailed biochemical description of the mechanism of coagulopathy following 30%in vivo dilution with HES, to present a systematic ex vivo test of various hemostatic agents, and to investigate the hypothesis that acquired fibrinogen deficiency constitutes the most important determinant of the coagulopathy.

METHODS

Dynamic whole blood clot formation assessed by thromboelastometry, platelet count, thrombin generation, and the activities of von Willebrand factor, coagulation factor II, FVII, FVIII, FIX, FX and FXIII were measured in 20 bleeding patients enrolled in a prospective clinical study investigating in vivo substitution of blood loss with HES up to a target level of 30%. Thromboelastometry parameters were further evaluated after ex vivo spiking experiments with fibrinogen, prothrombin complex concentrate (PCC), FXIII, activated recombinant FVIIa (rFVIIa), fresh frozen plasma, and platelets.

RESULTS

Hemodilution reduced maximum clot firmness (MCF), whereas whole blood clotting time (CT) and maximum velocity remained unaffected. All coagulation factor activities were reduced. Fibrinogen, FII, FXIII and FX activities decreased significantly below the levels expected from dilution. The endogenous thrombin potential was unchanged. Ex vivo addition of fibrinogen normalized the reduced MCF and increased the maximum velocity, whereas PCC, rFVIIa and platelets shortened the CT but showed no effect on the reduced MCF.

CONCLUSIONS

Acquired fibrinogen deficiency seems to be the leading determinant in dilutional coagulopathy, and ex vivo addition corrected the coagulopathy completely.