Preoperative Fibrinogen Levels as a Predictor of Postoperative Bleeding after Open Heart Surgery

Preoperative anemia and anemia treatment in cardiac surgery: a systematic review and meta-analysis

PURPOSE

We aimed to conduct a systematic review and meta-analysis to assess the effects of anemia and anemia severity on patient outcomes in cardiac surgery and determine whether preoperative treatments confer postoperative benefit.

SOURCE

We searched four international databases for observational and randomized studies published until 1 October 2022. Study quality was assessed via Newcastle-Ottawa scores and the Cochrane Risk-of-Bias 2 tool and certainty of evidence was rated with the Grading of Recommendations, Assessment, Development and Evaluations approach. We conducted random-effects meta-analyses for our primary outcome of mortality, for secondary outcomes including length of stay (LOS) in the hospital and intensive care unit, and for postsurgical complications. As part of a secondary analysis, we analyzed short-term preoperative anemia treatments and conducted trial sequential analysis of randomized trials to assess the efficacy of these treatment programs.

PRINCIPAL FINDINGS

We included 35 studies (159,025 patients) in our primary meta-analysis. Preoperative anemia was associated with increased mortality (odds ratio [OR], 2.5; 95% confidence interval [CI], 2.2 to 2.9; P < 0.001, high certainty). Study-level meta-regression revealed lower hemoglobin levels and studies with lower proportions of male patients to be associated with increased risk of mortality. Preoperative anemia was also associated with an increase in LOS and postsurgical complications. Our secondary analysis (seven studies, 1,012 patients) revealed short-term preoperative anemia treatments did not significantly reduce mortality (OR, 1.1; 95% CI, 0.65 to 1.9; P = 0.69). Trial sequential analysis suggested that there was insufficient evidence to conclude if treatment programs yield any benefit or harm.

CONCLUSIONS

Preoperative anemia is associated with mortality and morbidity after cardiac surgery. More research is warranted to test the efficacy of current anemia treatment programs.

STUDY REGISTRATION

PROSPERO (CRD42022319431); first submitted 17 April 2023.

Potential for prolongation of fibrinogen concentrates post-reconstitution

BACKGROUND AND OBJECTIVES

Reconstituted fibrinogen concentrate is considered stable for 8-24 h based on product monographs. Given the long half-life of fibrinogen in vivo (3-4 days), we hypothesized that reconstituted sterile fibrinogen protein would remain stable longer than 8-24 h. Extending the expiry date for reconstituted fibrinogen concentrate could decrease wastage and facilitate reconstitution in advance to minimize turnaround times. We performed a pilot study to define the stability of reconstituted fibrinogen concentrates over time.

MATERIALS AND METHODS

Reconstituted Fibryga® (Octapharma AG) from 64 vials was stored in the temperature-controlled refrigerator (4 °C) for up to 7 days with functional fibrinogen concentration measured serially using the automated Clauss method. The samples were frozen, then thawed and diluted with pooled normal plasma in order for them to be batch tested.

RESULTS

Reconstituted fibrinogen samples stored in the refrigerator showed no significant reduction in functional fibrinogen concentration for the entire 7-day study period (p = 0.63). Duration of initial freezing had no detrimental effect on functional fibrinogen levels (p = 0.23).

CONCLUSION

Fibryga® can be stored at 2-8 °C post-reconstitution for up to one week with no loss in functional fibrinogen activity based on Clauss fibrinogen assay. Further studies with other fibrinogen concentrate formulations and clinical in vivo studies may be warranted.

Prevention and management of difficult hemostasis in acute type A aortic dissection repair

Postoperative bleeding after surgery for acute aortic dissection is one of the most common complications and has an important influence on mortality and morbidity. Therefore, various methods have been introduced to prevent or manage postoperative bleeding. In this article, we investigated the causes of bleeding after surgery for acute aortic dissection, and introduce appropriate transfusion or pharmacologic treatment, topical hemostatic agents, and local compressive maneuver to manage it.

The influence of circulating fibrinogen level on postoperative blood loss and blood transfusion in pediatric cardiac surgery: a retrospective observational study

BACKGROUND

Pediatric patients are at high risk of massive bleeding after cardiac surgery under cardiopulmonary bypass (CPB). Fibrinogen is essential for coagulation; however, pediatric patients with congenital heart disease (CHD) present abnormal fibrinogen function. The pre- and post-operative fibrinogen level may affect the bleeding and transfusion amount in patients undergoing cardiac surgery. However, the relationship between plasma fibrinogen levels and the bleeding and transfusion amount in pediatric cardiac surgery remains unclear. This study aimed to assess the association of pre-CPB fibrinogen levels (PreFib) and post-CPB fibrinogen levels (PostFib) with postoperative bleeding and transfusion volume in pediatric cardiac surgery.

METHODS

We reviewed the medical records of 375 newborns and infants who underwent cardiac surgery under CPB for CHD. The primary endpoint was the correlation of the PreFib and PostFib values, as well as their difference (FibGap), with the bleeding and transfusion amount within 24 postoperative hours.

RESULTS

There was no correlation of the PreFib, PostFib, and FibGap values with the bleeding and transfusion amounts at postoperative 24 hours. However, patients with PreFib and PostFib values of <150 and <100 mg/dL, respectively, showed a significantly higher frequency of postoperative platelet (PLT) transfusion. In patients with complex CHD, PreFib showed a weak negative correlation with the bleeding amount at postoperative 24 hours and the number of PLT-transfused patients.

CONCLUSIONS

Our findings suggest that in pediatric patients with CHD who cannot undergo point-of-care (POC) tests, those presenting PreFib and PostFib values of <150 and <100 mg/dL, respectively, have a significantly higher frequency of postoperative PLT transfusion.

Optimising bloodless cardiovascular surgery for Jehovah's Witnesses and beyond

Emerging evidence suggests surgical outcomes of patients undergoing cardiovascular surgery that refuse autologous transfusion is comparable to those who accept whole blood product transfusions. There are several methods that can be used to minimize blood loss during cardiovascular surgery. These methods can be categorised into pharmacological measures, including the use of erythropoietin, iron and tranexamic acid, surgical techniques, like the use of polysaccharide haemostat, and devices such as those used in acute normovolaemic haemodilution. More prospective studies with stricter protocols are required to assess surgical outcomes in bloodless cardiac surgery as well as further research into the long-term outcomes of bloodless cardiovascular surgery patients. This review summarizes current evidence on the use of pre-, intra-, and post-operative strategies aimed at the subset of patients who refuse blood transfusion, for example Jehovah's Witnesses.

Outcome of Major Hemorrhage at a Major Cardiothoracic Center in Patients with Activated Major Hemorrhage Protocol versus Nonactivated Protocol

This study aimed to determine the impact of major hemorrhage (MH) protocol (MHP) activation on blood administration and patient outcome at a UK major cardiothoracic center. MH was defined in patients (> 16 years) as those who received > 5 units of red blood cells (RBCs) in < 4 hours, or > 10 units in 24 hours. Data were collected retrospectively from patient electronic records and hospital transfusion databases recording issue of blood products from January 2016 to December 2018. Of 134 patients with MH, 24 had activated MHP and 110 did not have activated MHP. Groups were similar for age, sex, baseline hemoglobin, platelet count, coagulation screen, and renal function with no difference in the baseline clinical characteristics. The total number of red cell units (median and [IQR]) transfused was no different in the patients with activated (7.5 [5-11.75]) versus nonactivated (9 [6-12]) MHP (p = 0.35). Patients in the nonactivated MHP group received significantly higher number of platelet units (median: 3 vs. 2, p = 0.014), plasma (median: 4.5 vs. 1.5, p = 0.0007), and cryoprecipitate (median: 2 vs. 1, p = 0.008). However, activation of MHP was associated with higher mortality at 24 hours compared with patients with nonactivation of MHP (33.3 vs. 10.9%, p = 0.005) and 30 days (58.3 vs. 30.9%, p = 0.01). The total RBC and platelet (but not fresh frozen plasma [FFP]) units received were higher in deceased patients than in survivors. Increased mortality was associated with a higher RBC:FFP ratio. Only 26% of patients received tranexamic acid and these patients had higher mortality at 30 days but not at 24 hours. Deceased patients at 30 days had higher levels of fibrinogen than those who survived (median: 2.4 vs. 1.8, p = 0.01). Patients with activated MHP had significantly higher mortality at both 24 hours and 30 days despite lack of difference in the baseline characteristics of the patients with activated MHP versus nonactivated MHP groups. The increased mortality associated with a higher RBC:FFP ratio suggests dilutional coagulopathy may contribute to mortality, but higher fibrinogen at baseline was not protective.

Strategies to minimize intraoperative blood loss during major surgery

Background

Reducing operative blood loss improves patient outcomes and reduces healthcare costs. The aim of this article was to review current surgical, anaesthetic and haemostatic intraoperative blood conservation strategies.

Methods

This narrative review was based on a literature search of relevant databases up to 31 July 2019 for publications relevant to reducing blood loss in the surgical patient.

Results

Interventions can begin early in the preoperative phase through identification of patients at high risk of bleeding. Directly acting anticoagulants can be stopped 48 h before most surgery in the presence of normal renal function. Aspirin can be continued for most procedures. Intraoperative cell salvage is recommended when anticipated blood loss is greater than 500 ml and this can be continued after surgery in certain situations. Tranexamic acid is safe, cheap and effective, and routine administration is recommended when anticipated blood loss is high. However, the optimal dose, timing and route of administration remain unclear. The use of topical agents, tourniquet and drains remains at the discretion of the surgeon. Anaesthetic techniques include correct patient positioning, avoidance of hypothermia and regional anaesthesia. Permissive hypotension may be beneficial in selected patients. Promising haemostatic strategies include use of pharmacological agents such as desmopressin, prothrombin complex concentrate and fibrinogen concentrate, and use of viscoelastic haemostatic assays.

Conclusion

Reducing perioperative blood loss requires a multimodal and multidisciplinary approach. Although high-quality evidence exists in certain areas, the overall evidence base for reducing intraoperative blood loss remains limited.

Investigating the Effect of Fibrinogen Injection on Bleeding in Coronary Artery Bypass Surgery: A Clinical Trial

Background

Prevention and optimal treatment of postoperative bleeding are of great clinical importance in various types of surgeries including coronary artery bypass graft (CABG). Reducing the amount of bleeding will reduce the complications subsequent to blood transfusion. The positive effects of coagulation factors, especially fibrinogen, after cardiovascular bypass could have beneficial effects due to reduced bleeding and less need for blood transfusion. However, different studies have reported controversial findings.

Objectives

The present study aimed to evaluate the effect of prophylactic administration of fibrinogen on blood loss in patients undergoing CABG surgery to achieve more accurate clinical outcomes.

Methods

This was a double-blind randomized clinical trial conducted on 36 patients hospitalized in Ahvaz Imam Khomeini Hospital for coronary artery bypass graft. Patients were randomized to receive either fibrinogen concentrate (n = 18) or placebo (n = 18). Hemoglobin, hematocrit, international normalized ratio, prothrombin time, partial thromboplastin time, and fibrinogen were checked preoperatively. The transfusion of allogeneic blood components and the volume of blood loss were recorded and compared between the groups.

Results

Prophylactic fibrinogen injection reduced the need for blood transfusion, blood products, and postoperative hypotension in the fibrinogen group when compared to the control group (P ≤ 0.005). There was a significant difference between the two groups in terms of the amount of bleeding during operation (P ≤ 0.005).

Conclusions

Fibrinogen plays a key role in preventing and stopping the bleeding. Accordingly, fibrinogen decreases bleeding and the need for paced cell in patients in CABG. Given the adverse outcomes of bleeding and coagulopathy in patients undergoing surgery, we conclude that the use of fibrinogen could be beneficial as a prophylactic in hemorrhagic surgery.

The Effect of Fibrinogen on Blood Loss After Lumbar Surgery: A Double-Blind Randomized Clinical Trial

Background

Spinal surgeries often have a high risk of hemorrhage during and after surgery, thus most patients require blood transfusions and blood products. Fibrinogen is used in different forms to control hemorrhage.

Objectives

The present study aimed to evaluate the outcomes of prophylactic fibrinogen administration in reducing hemorrhage after lumbar surgery.

Methods

This was a randomized clinical trial conducted on 30 patients undergoing lumbar surgery. The levels of fibrinogen, as well as hemoglobin (HB), hematocrit (HCT), prothrombin time (PT), partial thromboplastin time (PTT), and INR, were assessed preoperatively as the baseline values. The patients were divided into two groups: intervention (N = 15) and control (N = 15) groups. The intervention group received 1 g fibrinogen dissolved in 50 cc distilled water with surgical incision and the control group received 50 cc distilled water with the surgical incision. At the end of the operation, the volume of hemorrhage transfused blood products (fresh frozen plasma, packed cell, and platelet) was measured. In addition, at 0, 6, and 24 hours after the end of surgery and transfer to recovery, serum levels of fibrinogen, HB, HCT, INR, PT, PTT, and hemovac drain volume were measured.

Results

The hemorrhage during and after the operation in the control group was significantly higher than that of the intervention group (P < 0.05). There were no significant differences between hemoglobin and serum level of fibrinogen before and after surgery between the two groups. The postoperative hypotension showed no significant difference between the two groups.

Conclusions

The findings showed the effectiveness of fibrinogen in reducing acute hemorrhage. Considering the adverse consequences of hemorrhage and coagulopathy in patients undergoing surgery, using fibrinogen as prophylaxis is recommended in surgeries with high risks of hemorrhage.

Short-term recovery pattern of plasma fibrinogen after cardiac surgery: A prospective observational study

Low plasma fibrinogen level is common after cardiopulmonary bypass (CPB). Current substitution practice with fibrinogen concentrate generally follows a single measurement and cut-off values from the literature, whereas early postoperative endogenous fibrinogen kinetics is incompletely described and widely disregarded. The aim of this study was to determine the short-term recovery pattern of plasma fibrinogen after CPB weaning. Our hypothesis was that in the absence of surgical bleeding, CPB-induced hypofibrinogenemia would resolve spontaneously and predictably within a few hours. In a prospective, observational study of 26 patients undergoing conventional CPB (cCPB) or minimally invasive extracorporeal circulation (MiECC), Clauss fibrinogen level (C-FIB) was determined at 10 closely spaced time points after protamine administration. Primary endpoint was the time to recovery of post-CPB fibrinogen levels to ≥1.5 g/L. C-FIB reached its nadir after protamine administration corresponding to 62 ± 5% (mean ± SD) of the baseline level after cCPB and 68 ± 7% after MiECC (p = 0.027 vs. cCPB). C-FIB recovered spontaneously at a nearly constant rate of approximately 0.08 g/L per hour. In all patients, C-FIB was ≥1.5 g/L at 4 hours and ≥2.0 g/L at 13 hours after CPB weaning. Following cardiac surgery with CPB and in the absence of surgical bleeding, spontaneous recovery of normal endogenous fibrinogen levels can be expected at a rate of 0.08 g/L per hour. Administration of fibrinogen concentrate triggered solely by a single-point measurement of low plasma fibrinogen some time after CPB is not justified.

Prophylactic Fibrinogen Decreases Postoperative Bleeding but Not Acute Kidney Injury in Patients Undergoing Heart Transplantation

The present study is the premier clinical attempt to scrutinize the practicability of prophylactic fibrinogen infusion in patients undergoing heart transplantation (HT). A total of 67 consecutive patients who had undergone HT between January 2012 and December 2014 were assessed. After exclusion of some patients, 23 patients were given preoperative 2 g fibrinogen concentrate over a period of 15 minutes after the termination of cardiopulmonary bypass pump and complete reversal of heparin, and 30 patients were not given. Some laboratories were measured before general anesthesia and at 6 and 24 hours after surgery. In addition, major adverse events were also evaluated during hospitalization. The mean age of the patients was 39.5 ± 11.4 years, with a predominance of male sex (77.4%). All laboratories at baseline were comparable between groups. The length of hospital stay was longer in the control group compared to the fibrinogen group (20 [16-22] vs 16 [12-19] days; P = .005). There was a trend for patients in the fibrinogen group to have more acute kidney injury (AKI) after surgery (10% vs 30.4%) and less reoperation for bleeding (20% vs 8.7%). The amount of postoperative bleeding was significantly higher in the control group compared to the fibrinogen group (P < .001). The number of packed red blood cell transfused during 24 hours after surgery was significantly lower in the fibrinogen group (P < .001). The transfusion of fibrinogen in patients undergoing HT may be associated with reductions in postoperative bleeding, the number of packed red blood cells, and hospital length of stay; however, it may enhance postoperative AKI.

Consensus Report by the Pediatric Acute Lung Injury and Sepsis Investigators and Pediatric Blood and Marrow Transplant Consortium Joint Working Committees on Supportive Care Guidelines for Management of Veno-Occlusive Disease in Children and Adolescents: Part 2-Focus on Ascites, Fluid and Electrolytes, Renal, and Transfusion Issues

Even though hepatic veno-occlusive disease (VOD) is a potentially fatal complication of hematopoietic cell transplantation (HCT), there is paucity of research on the management of associated multiorgan dysfunction. To help provide standardized care for the management of these patients, the HCT Subgroup of the Pediatric Acute Lung Injury and Sepsis Investigators and the Supportive Care Committee of the Pediatric Blood and Marrow Transplant Consortium, collaborated to develop evidence-based consensus guidelines. After conducting an extensive literature search, in part 2 of this series we discuss the management of fluids and electrolytes, renal dysfunction; ascites, pleural effusion, and transfusion and coagulopathy issues in patients with VOD. We consider the available evidence using the GRADE criteria.

A pilot study evaluating changes to haematological and biochemical tests after Flexible Ureterorenoscopy for the treatment of kidney stones

BACKGROUND

Currently there is limited research documenting the changes in blood parameters, following Flexible Ureterorenoscopy. This study aims to determine whether there are any changes in haematology and biochemistry parameters, following Flexible Ureterorenoscopy for the treatment of kidney stones.

METHODS

40 consecutive patients aged between 27-87 years (median 49 years) undergoing Flexible Ureterorenoscopy for the treatment of kidney stones were recruited (26 male, 14 female). Blood samples were collected from each patient at four time points: baseline (pre-operatively) followed by 30 minutes, 120 minutes and 240 minutes post-operatively. On these samples, routine haematological and biochemistry tests were carried out. In addition to the assessment of clinical parameters prospectively from the medical notes.

RESULTS

There was a significant decrease observed following Flexible Ureterorenoscopy in the following parameters: lymphocytes (p = 0.007), eosinophils (p = 0.001), basophils (p = 0.001), haemoglobin (p = 0.002), red blood cells (p = 0.001), platelet count (p = 0.001), fibrinogen concentration (p = 0.001), von Willebrand factor (p = 0.046), C reactive protein (p = 0.01), total protein (p = 0.001), albumin (p = 0.001), globulin (p = 0.001) and alkaline phosphatase (p = 0.001). In addition, there was a significant increase observed in the following parameters: white blood cells (p = 0.001), neutrophils (p = 0.001), activated partial thromboplastin time (p = 0.001), total bilirubin (p = 0.012), creatinine (p = 0.008), sodium (p = 0.002) and potassium (p = 0.001). Limiting factors for this study were the sample size, and restriction on the recruitment time points.

CONCLUSIONS

Significant changes were noted to occur in haematology and biochemistry parameters following Flexible Ureterorenoscopy. Some of the data presented in this study may represent the 'normal' post-operative response following FURS, as no major complications occurred, in the majority of our patients. This data on the 'normal response' will need to be validated but may ultimately aid clinicians in distinguishing patients at risk of complications, if reproduced in larger multi-centre studies.

Introduction of thromboelastometry-guided administration of fresh-frozen plasma is associated with decreased allogeneic blood transfusions and post-operative blood loss in cardiopulmonary-bypass surgery

BACKGROUND

Cardiac surgery is frequently associated with excessive blood loss requiring multiple blood transfusions which are, in turn, associated with increased morbidity and mortality. We evaluated the effectiveness of rotational thromboelastometry (ROTEM^®)-guided administration of fresh-frozen plasma (FFP) with regards to blood loss, transfusion requirements, and major post-operative complications.

MATERIALS AND METHODS

Coagulation management in 68 prospective patients undergoing cardiac surgery with cardiopulmonary bypass was based on a treatment algorithm guided by ROTEM^® measurements. The primary end-point was blood loss at 24 hours after surgery. Secondary end-points were: (i) need for allogeneic blood products after cardiopulmonary bypass and 24 hours post-operatively, and (ii) post-operative complications until discharge. The results were compared with those of a retrospective, control group of 69 patients who received empirical coagulation management before implementation of the ROTEM^®-guided algorithm.

RESULTS

Although patients with significantly lower haemoglobin levels received less packed red blood cells (PRBC) (840 vs 1,120 mL; p=0.031) and FFP (480 vs 720 mL; p=0.007) after introduction of the ROTEM^® algorithm, the intra-operative blood loss and post-operative haemoglobin levels were similar in the ROTEM^® and the retrospective control groups. In addition to significantly reduced blood loss and decreased requirements for PRBC (30.8 vs 62.3%; p<0.001) and FFP (25.0 vs 56.5%; p<0.001), the amounts of PRBC (315 vs 840 mL; p<0.001) and FFP (480 vs 840 mL; p=0.001) received during the first 24 hours after surgery were significantly reduced in the ROTEM^® group, as was the duration of post-operative hospitalisation.

DISCUSSION

Compared with empirical treatment, timely ROTEM^®-guided FFP administration during cardiac surgery can reduce not only overall blood product use and blood loss but also the duration of hospitalisation.

Crotalus atrox venom preconditioning increases plasma fibrinogen and reduces perioperative hemorrhage in a rat model of surgical brain injury

Perioperative bleeding is a potentially devastating complication in neurosurgical patients, and plasma fibrinogen concentration has been identified as a potential modifiable risk factor for perioperative bleeding. The aim of this study was to evaluate preconditioning with Crotalus atrox venom (Cv-PC) as potential preventive therapy for reducing perioperative hemorrhage in the rodent model of surgical brain injury (SBI). C. atrox venom contains snake venom metalloproteinases that cleave fibrinogen into fibrin split products without inducing clotting. Separately, fibrinogen split products induce fibrinogen production, thereby elevating plasma fibrinogen levels. Thus, the hypothesis was that preconditioning with C. atrox venom will produce fibrinogen spilt products, thereby upregulating fibrinogen levels, ultimately improving perioperative hemostasis during SBI. We observed that Cv-PC SBI animals had significantly reduced intraoperative hemorrhage and postoperative hematoma volumes compared to those of vehicle preconditioned SBI animals. Cv-PC animals were also found to have higher levels of plasma fibrinogen at the time of surgery, with unchanged prothrombin time. Cv-PC studies with fractions of C. atrox venom suggest that snake venom metalloproteinases are largely responsible for the improved hemostasis by Cv-PC. Our findings indicate that Cv-PC increases plasma fibrinogen levels and may provide a promising therapy for reducing perioperative hemorrhage in elective surgeries.

Preoperative hemoglobin level: the best predictor of transfusion of packed red cells

Blood transfusions could have serious consequences for patients. A reduction in the transfusion rate could be accomplished by an optimized blood management. Clear guidelines and awareness among all employees at a single institution have resulted in a reduction in transfusion rates in recent years. Identification of the group of patients who still received a blood transfusion in recent years could result in a further reduction. This study enrolled 4022 patients undergoing cardiothoracic surgery between 2008 and 2013. Patients were divided into three groups: “no blood transfusion”, “transfusion of packed red cells only” and “any other combinations of blood transfusion”. In total, 16 variables were tested for their association with the administration of homologous blood. The variables associated with blood transfusion were included in a stepwise multinomial logistic regression analysis to find the variables with the strongest association.

For the transfusion of packed red cells only and any other combinations of blood transfusion, the following predictors are found: gender, age, weight, type of surgery, reoperation, unstable angina pectoris, endocarditis, recent myocardial infarction, preoperative creatinine level, preoperative hemoglobin level and preoperative platelet count. The best predictor for the transfusion of packed red cells is preoperative hemoglobin level (4.1 to 7.8 mmol/l). For other blood products, the strongest association was found with type of surgery (aortic surgery, ventricular septal rupture and intracardiac tumour).

A Snapshot of Coagulopathy After Cardiopulmonary Bypass

Cardiac surgery involving cardiopulmonary bypass (CPB) is often associated with important blood loss, allogeneic blood product usage, morbidity, and mortality. Coagulopathy during CPB is complex, and the current lack of uniformity for triggers and hemostatic agents has led to a wide variability in bleeding treatment. The aim of this review is to provide a simplified picture of the data available on patients’ coagulation status at the end of CPB in order to provide relevant information for the development of tailored transfusion algorithms. A nonsystematic literature review was carried out to identify changes in coagulation parameters during CPB. Both prothrombin time and activated partial thromboplastin time increased during CPB, by a median of 33.3% and 17.9%, respectively. However, there was marked variability across the published studies, indicating these tests may be unreliable for guiding hemostatic therapy. Some thrombin generation (TG) parameters were affected, as indicated by a median increase in TG lag time of 55.0%, a decrease in TG peak of 17.5%, and only a slight decrease in endogenous thrombin potential of 7%. The most affected parameters were fibrinogen levels and platelet count/function. Both plasma fibrinogen concentration and FIBTEM maximum clot firmness decreased during CPB (median change of 36.4% and 33.3%, respectively) as did platelet count (44.5%) and platelet component (34.2%). This review provides initial information regarding changes in coagulation parameters during CPB but highlights the variability in the reported results. Further studies are warranted to guide physicians on the parameters most appropriate to guide hemostatic therapy.

Prediction of Post-Weaning Fibrinogen Status during Cardiopulmonary Bypass: An Observational Study in 110 Patients

Background

After cardiac surgery with cardiopulmonary bypass (CPB), acquired coagulopathy often leads to post-CPB bleeding. Though multifactorial in origin, this coagulopathy is often aggravated by deficient fibrinogen levels.

Objective

To assess whether laboratory and thrombelastometric testing on CPB can predict plasma fibrinogen immediately after CPB weaning.

Patients / Methods

This prospective study in 110 patients undergoing major cardiovascular surgery at risk of post-CPB bleeding compares fibrinogen level (Clauss method) and function (fibrin-specific thrombelastometry) in order to study the predictability of their course early after termination of CPB. Linear regression analysis and receiver operating characteristics were used to determine correlations and predictive accuracy.

Results

Quantitative estimation of post-CPB Clauss fibrinogen from on-CPB fibrinogen was feasible with small bias (+0.19 g/l), but with poor precision and a percentage of error >30%. A clinically useful alternative approach was developed by using on-CPB A10 to predict a Clauss fibrinogen range of interest instead of a discrete level. An on-CPB A10 ≤10 mm identified patients with a post-CPB Clauss fibrinogen of ≤1.5 g/l with a sensitivity of 0.99 and a positive predictive value of 0.60; it also identified those without a post-CPB Clauss fibrinogen <2.0 g/l with a specificity of 0.83.

Conclusions

When measured on CPB prior to weaning, a FIBTEM A10 ≤10 mm is an early alert for post-CPB fibrinogen levels below or within the substitution range (1.5–2.0 g/l) recommended in case of post-CPB coagulopathic bleeding. This helps to minimize the delay to data-based hemostatic management after weaning from CPB.

Pre-operative fibrinogen supplementation in cardiac surgery patients: an evaluation of different trigger values

BACKGROUND

Pre-operative fibrinogen levels are negatively associated with postoperative bleeding in cardiac surgery patients. The guidelines of the European Society of Anaesthesiology consider the possibility of a prophylactic pre-operative supplementation in patients with fibrinogen levels<`3.8 g/l. The present study is a reanalysis of published data aimed to define the diagnostic accuracy of different values of pre-operative fibrinogen levels in predicting severe post-operative bleeding.

METHODS

Data were retrieved for 2154 patients in four different studies. Severe bleeding (SB) was defined as a post-operative chest drain output>1 l/12 h. Diagnostic accuracy for prediction of SB was tested at three cutoff values of pre-operative fibrinogen (2.5 g/l, 3.0 g/l, and 3.8 g/l).

RESULTS

At all the three cutoff values, pre-operative fibrinogen levels had an excellent negative predictive value, ranging from 86% to 100%. Conversely, the positive predictive value was poor at all the cutoff levels: 12% (3.8 g/l), 14% (3.0 g/l), and 19% (2.5 g/l). Overall, the accuracy of pre-operative fibrinogen levels for the prediction of SB was poor. A strategy based on pre-operative fibrinogen supplementation would lead to inappropriate treatment in > 80% of the treated patients. Overall, a trigger value of 3.8 g/l would result in an inappropriate treatment in 52% of the patients, of 3.0 g/l in 20% of the patients, and of 2.5 g/l in 4% of the patients.

CONCLUSION

Correction of pre-operative fibrinogen levels below 3.8 g/l would lead to an excessive rate of inappropriate interventions. Values below 2.5 g/l could be considered.

How I use fibrinogen replacement therapy in acquired bleeding

Fibrinogen is a critical protein for hemostasis and clot formation. However, transfusion guidelines have variable recommendations for maintaining fibrinogen levels in bleeding patients. An increasing number of studies support the practice of fibrinogen replacement therapy for acquired coagulopathies, and additional studies are underway. Fibrinogen therapy can be administered with cryoprecipitate or fibrinogen concentrates, and clinical practice varies according to their availability and licensing status. Fibrinogen concentrate therapy has been studied in animal models and clinical trials and supports the critical role of fibrinogen repletion in bleeding patients. Point-of-care testing will have an important role in guiding fibrinogen replacement for hemostatic therapy in clinical settings such as cardiovascular surgery, postpartum hemorrhage, and trauma. Fibrinogen therapy is an important component of a multimodal strategy for the treatment of coagulopathic bleeding.

Safety of fibrinogen concentrate: analysis of more than 27 years of pharmacovigilance data

Fibrinogen concentrate use as a haemostatic agent has been increasingly explored. This study evaluates spontaneous reports of potential adverse drug reactions (ADRs) that occurred during postmarketing pharmacovigilance of Haemocomplettan P/RiaSTAP, and reviews published safety data. This descriptive study analysed postmarketing safety reports recorded in the CSL Behring pharmacovigilance database from January 1986 to December 2013. A literature review of clinical studies published during the same period was performed. Commercial data indicated that 2,611,294 g of fibrinogen concentrate were distributed over the pharmacovigilance period, corresponding to 652,824 standard doses of 4 g each, across a range of clinical settings and indications. A total of 383 ADRs in 106 cases were reported (approximately 1 per 24,600 g or 6,200 standard doses). Events of special interest included possible hypersensitivity reactions in 20 cases (1 per 130,600 g or 32,600 doses), possible thromboembolic events in 28 cases (1 per 93,300 g or 23,300 doses), and suspected virus transmission in 21 cases (1 per 124,300 g or 31,000 doses). One virus transmission case could not be analysed due to insufficient data; for all other cases, a causal relationship was assessed as unlikely due to negative polymerase chain reaction tests and/or alternative explanations. The published literature revealed a similar safety profile. In conclusion, underreporting of ADRs is a known limitation of pharmacovigilance. However, the present assessment indicates that fibrinogen concentrate is administered across a range of indications, with few ADRs and a low thromboembolic event rate. Overall, fibrinogen concentrate showed a promising safety profile.

Fibrinogen concentrate for bleeding--a systematic review

Fibrinogen concentrate as part of treatment protocols increasingly draws attention. Fibrinogen substitution in cases of hypofibrinogenaemia has the potential to reduce bleeding, transfusion requirement and subsequently reduce morbidity and mortality. A systematic search for randomised controlled trials (RCTs) and non-randomised studies investigating fibrinogen concentrate in bleeding patients was conducted up to November 2013. We included 30 studies of 3480 identified (7 RCTs and 23 non-randomised). Seven RCTs included a total of 268 patients (165 adults and 103 paediatric), and all were determined to be of high risk of bias and none reported a significant effect on mortality. Two RCTs found a significant reduction in bleeding and five RCTs found a significant reduction in transfusion requirements. The 23 non-randomised studies included a total of 2825 patients, but only 11 of 23 studies included a control group. Three out of 11 found a reduction in transfusion requirements while mortality was reduced in two and bleeding in one. In the available RCTs, which all have substantial shortcomings, we found a significant reduction in bleeding and transfusions requirements. However, data on mortality were lacking. Weak evidence from RCTs supports the use of fibrinogen concentrate in bleeding patients, primarily in elective cardiac surgery, but a general use of fibrinogen across all settings is only supported by non-randomised studies with serious methodological shortcomings. It seems pre-mature to conclude whether fibrinogen concentrate has a routine role in the management of bleeding and coagulopathic patients. More RCTs are urgently warranted.

Predictors of hypofibrinogenemia in blunt trauma patients on admission

PURPOSE

Massive bleeding usually leads to critically low levels of clotting factors, including fibrinogen. Although reduced fibrinogen levels correlate with increased mortality, predictors of hypofibrinogenemia have remained poorly understood. We investigated whether findings available on admission can be used as predictors of hypofibrinogenemia.

METHODS

We retrospectively reviewed serum fibrinogen levels tested on arrival in 290 blunt trauma patients transported to a level I trauma center during a 3-year period. The primary outcome was prehospital predictors for hypofibrinogenemia. Covariates included age, sex, prehospital fluid therapy, prehospital anatomical and physiological scores, time from injury, base excess, and lactate on arrival. All variables with values of p < 0.10 in univariate analysis were included in a multivariate logistic regression model. The relationships between the variables and the 7-day mortality rate were evaluated in a Cox proportional hazards model.

RESULTS

Patient's age [odds ratio (OR): 0.97, p < 0.001], Triage Revised Trauma Score (T-RTS) (OR: 0.81, p = 0.003), and prehospital fluid therapy (OR: 2.54, p = 0.01) were detected as independent predictors for hypofibrinogenemia in multivariate logistic regression analysis. Serum fibrinogen level [hazard ratio (HR): 0.99, p = 0.01] and T-RTS (HR: 0.77, p < 0.01) were associated with the 7-day mortality rate.

CONCLUSION

T-RTS is considered to play an important role in predicting hypofibrinogenemia and 7-day mortality in blunt trauma patients.

Can plasma fibrinogen levels predict bleeding after coronary artery bypass grafting?

BACKGROUND

Fibrinogen is the main biomarker for bleeding. To prevent excessive postoperative bleeding, it would be useful to identify high-risk patients before coronary artery bypass grafting (CABG).

OBJECTIVES

In order to predicating bleeding after CABG, we sought to determine whether preoperative fibrinogen concentration was associated with the amount of bleeding following CABG.

PATIENTS AND METHODS

A total of 144 patients (mean age = 61.50 ± 9.42 years; 65.7% men), undergoing elective and isolated CABG, were included in this case-series study. The same anesthesia technique and medicines were selected for all the patients. In the ICU, the patients were assessed in terms of bleeding at 12 and 24 hours post-operation, amount of contingent blood products received, and relevant tests. Statistical tests were subsequently conducted to analyze the correlation between preoperative fibrinogen concentration and the amount of post-CABG bleeding.

RESULTS

The mean ± standard deviation of bleeding at 12 and 24 hours post-operation was 285.37 ± 280.27 and 499.31 ± 355.57 mL, respectively. The results showed that postoperative bleeding was associated with different factors whereas pre-anesthesia fibrinogen was not correlated with bleeding at 12 (P = 0.856) and 24 hours (P = 0.936) post-operation. There were correlations between the extra-corporal circulation time and bleeding at 12 hours post-operation (ρ = 0.231, P = 0.007) and bleeding at 24 hours post-operation (ρ = 0.218, P = 0.013).

CONCLUSIONS

Preoperative assessment of plasma fibrinogen levels failed to predict post-CABG bleeding.

Theoretical modelling of fibrinogen supplementation with therapeutic plasma, cryoprecipitate, or fibrinogen concentrate

Background

We aimed to create a theoretical tool to model the effect of three haemostatic agents containing fibrinogen (therapeutic plasma, cryoprecipitate, and fibrinogen concentrate) on the patient's plasma fibrinogen level.

Methods

A mathematical model was developed step-wise. The relationship between the amount of haemostatic agent and plasma fibrinogen level was plotted for each agent. A fibrinogen concentration simulator (FCS_amount) was developed, where the amount of haemostatic agent was calculated from patient characteristics, agent characteristics, and target plasma fibrinogen level. Refinements were introduced so that (i) FCS_amount would account for in vivo fibrinogen recovery, (ii) circulatory volume would not increase ad infinitum with increasing amounts, and (iii) red blood cells would be included in the simulation if haematocrit decreased below a certain level. A second FCS (FCS_level) was created to calculate fibrinogen levels resulting from specified amounts of haemostatic agents.

Results

Fibrinogen concentration in haemostatic agents has a critical impact on their ability to increase patients' fibrinogen levels. If the target plasma fibrinogen level approaches the concentration of the fibrinogen source, the required amounts increase exponentially; it is impossible to achieve a target above the concentration of the fibrinogen source.

Conclusions

We successfully developed two theoretical tools answering the questions: ‘How much therapeutic plasma, cryoprecipitate, or fibrinogen concentrate would be needed to achieve a specified target fibrinogen level?’ and ‘What would be the resultant fibrinogen level for a specified amount of haemostatic agent?’ The current tools are not intended for clinical application, but they are potentially useful for educational purposes.

The effects of pre- and postoperative fibrinogen levels on blood loss after cardiac surgery: a systematic review and meta-analysis

OBJECTIVES

Fibrinogen concentrate is increasingly used in cardiac surgery when bleeding is anticipated or ongoing. Since randomized clinical studies to support this are lacking, it is relevant to know whether lower fibrinogen levels are associated with excessive bleeding. We performed a systematic review and meta-analysis to define the association between fibrinogen levels and blood loss after cardiac surgery.

METHODS

A database search (January 2013) was performed on publications assessing the association between pre- and postoperative fibrinogen levels and postoperative blood loss in adult patients undergoing cardiac surgery. Cohort studies and case-control studies were eligible for inclusion. The main outcome was the pooled correlation coefficient, calculated via Fisher's Z transformation scale, in a random-effects meta-analysis model stratified for the time point at which fibrinogen was measured.

RESULTS

A total of 20 studies were included. The pooled correlation coefficient of studies (n = 9) concerning preoperative fibrinogen levels and postoperative blood loss was -0.40 (95% confidence interval: -0.58, -0.18), pointing towards more blood loss in patients with lower preoperative fibrinogen levels. Among papers (n = 16) reporting on postoperative fibrinogen levels and postoperative blood loss, the pooled correlation coefficient was -0.23 (95% confidence interval: -0.29, -0.16).

CONCLUSIONS

Our meta-analysis indicated a significant but weak-to-moderate correlation between pre- and postoperative fibrinogen levels and postoperative blood loss in cardiac surgery. This moderate association calls for appropriate clinical studies on whether fibrinogen supplementation will decrease postoperative blood loss.

Fibrinogen concentrate in bleeding patients

BACKGROUND

Hypofibrinogenaemia is associated with increased morbidity and mortality, but the optimal treatment level, the use of preemptive treatment and the preferred source of fibrinogen remain disputed. Fibrinogen concentrate is increasingly used and recommended for bleeding with acquired haemostatic deficiencies in several countries, but evidence is lacking regarding indications, dosing, efficacy and safety.

OBJECTIVES

We assessed the benefits and harms of fibrinogen concentrate compared with placebo or usual treatment for bleeding patients.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 8); MEDLINE (1950 to 9 August 2013); EMBASE (1980 to 9 August 2013); International Web of Science (1964 to 9 August 2013); CINAHL (1980 to 9 August 2013); LILACS (1982 to 9 August 2013); and the Chinese Biomedical Literature Database (up to 10 November 2011), together with databases of ongoing trials. We contacted trial authors, authors of previous reviews and manufacturers in the field.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs), irrespective of blinding or language, that compared fibrinogen concentrate with placebo/other treatment or no treatment in bleeding patients, excluding neonates and patients with hereditary bleeding disorders.

DATA COLLECTION AND ANALYSIS

Three review authors independently abstracted data; we resolved any disagreements by discussion. Our primary outcome measure was all-cause mortality. We performed subgroup and sensitivity analyses to assess the effects of fibrinogen concentrate in adults and children in terms of various clinical and physiological outcomes. We presented pooled estimates of the effects of intervention on dichotomous outcomes as risk ratios (RRs) and on continuous outcomes as mean differences, with 95% confidence intervals (CIs). We assessed the risk of bias through assessment of trial methodological components and the risk of random error through trial sequential analysis.

MAIN RESULTS

We included six RCTs with a total of 248 participants; none of the trials were determined to have overall low risk of bias. We found 12 ongoing trials, from which we were unable to retrieve any data. Only two trials provided data on mortality, and one was a zero event study; thus the meta-analysis showed no statistically significant effect on overall mortality (2.6% vs 9.5%, RR 0.28, 95% CI 0.03 to 2.33). Our analyses on blood transfusion data suggest a beneficial effect of fibrinogen concentrate in reducing the incidence of allogenic transfusions (RR 0.47, 95% CI 0.31 to 0.72) but show no effect on other predefined outcomes, including adverse events such as thrombotic episodes.

AUTHORS' CONCLUSIONS

In the six available RCTs of elective surgery, fibrinogen concentrate appears to reduce transfusion requirements, but the included trials are of low quality with high risk of bias and are underpowered to detect mortality, benefit or harm. Furthermore, data on mortality are lacking, heterogeneity is high and acute or severe bleeding in a non-elective surgical setting remains unexplored. Currently, weak evidence supports the use of fibrinogen concentrate in bleeding patients, as tested here in primarily elective cardiac surgery. More research is urgently needed.

Fibrinogen concentrate reduces intraoperative bleeding when used as first-line hemostatic therapy during major aortic replacement surgery: results from a randomized, placebo-controlled trial

OBJECTIVES

We assessed whether fibrinogen concentrate as targeted first-line hemostatic therapy was more effective than placebo or a standardized transfusion algorithm in controlling coagulopathic bleeding in patients undergoing major aortic surgery.

METHODS

In this single-center, prospective, double-blind study, adults undergoing elective thoracic or thoracoabdominal aortic replacement surgery involving cardiopulmonary bypass were randomized to intraoperative fibrinogen concentrate (n = 29) or placebo (n = 32). Study medication was given if patients had clinically relevant coagulopathic bleeding, measured by 5-minute bleeding mass, after cardiopulmonary bypass removal, protamine administration, and surgical hemostasis. Fibrinogen concentrate dosing was individualized using the thromboelastometric FIBTEM test. If bleeding continued, a standardized transfusion algorithm was followed. In the placebo group, all 32 patients received 1 transfusion cycle of fresh-frozen plasma/platelets, and 30 patients required a second transfusion cycle; none of these patients received any other procoagulant therapy. Change in bleeding rate after treatment was compared using t tests.

RESULTS

Mean change in bleeding rate after fibrinogen concentrate was -48.3 g/5 min, compared with 0.4 g/5 min after placebo (P < .001), -16.1 g/5 min after 1 transfusion cycle (fresh-frozen plasma or platelets; P = .003), and -28.0 g/5 min after 2 transfusion cycles (fresh-frozen plasma and platelets; P = .11). Reductions in bleeding rate were greater for patients with higher bleeding rates before treatment, especially with fibrinogen concentrate.

CONCLUSIONS

FIBTEM-guided intraoperative hemostatic therapy with fibrinogen concentrate is more effective than placebo in controlling coagulopathic bleeding during major aortic replacement surgery. Fibrinogen concentrate is also more effective than 1 cycle of fresh-frozen plasma/platelets and is more rapid than--and at least as effective as--2 cycles of fresh-frozen plasma/platelets.

Coagulation management in patients undergoing mechanical circulatory support

The incidence of bleeding and thrombo-embolic complications in patients undergoing mechanical circulatory support therapy remains high and is associated with bad outcomes and increased costs. The need for anticoagulation and anti-platelet therapy varies widely between different pulsatile and non-pulsatile ventricular-assist devices (VADs) and extracorporeal membrane oxygenation (ECMO) systems. Therefore, a unique anticoagulation protocol cannot be recommended. Notably, most thrombo-embolic complications occur despite values of conventional coagulation tests being within the targeted range. This is due to the fact that conventional coagulation tests such as international normalised ratio (INR), activated partial thromboplastin time (aPTT) and platelet count cannot detect hyper- or hypofibrinolysis, hypercoagulability due to tissue factor expression on circulating cells or increased clot firmness, and platelet aggregation as well as response to anti-platelet drugs. By contrast, point-of-care (POC) whole blood viscoelastic tests (thromboelastometry/-graphy) and platelet function tests (impedance or turbidimetric aggregometry) reflect in detail the haemostatic status of patients undergoing mechanical circulatory support therapy and the efficacy of their anticoagulation and antiaggregation therapy. Therefore, monitoring of haemostasis using POC thromboelastometry/-graphy and platelet function analysis is recommended during mechanical circulatory support therapy to reduce the risk of bleeding and thrombo-embolic complications. Notably, these haemostatic tests should be performed repeatedly during mechanical circulatory support therapy since thrombin generation, clot firmness and platelet response may change significantly over time with a high inter- and intra-individual variability. Furthermore, coagulation management can be hampered in non-pulsatile VADs by acquired von Willebrand syndrome, and in general by acquired factor XIII deficiency as well as by heparin-induced thrombocytopenia. In addition, POC testing can be used in bleeding patients to guide calculated goal-directed therapy with allogeneic blood products, haemostatic drugs and coagulation factor concentrates to optimise the haemostasis and to minimise transfusion requirements, transfusion-associated adverse events and to avoid thrombo-embolic complications, as well. However, coagulation management in patients undergoing mechanical circulatory support therapy is somehow like navigating between Scylla and Charybdis, and development of protocols based on POC testing seems to be beneficial.

The FIB-PPH trial: fibrinogen concentrate as initial treatment for postpartum haemorrhage: study protocol for a randomised controlled trial

BACKGROUND

Postpartum haemorrhage (PPH) remains a leading cause of maternal mortality worldwide. In Denmark 2% of parturients receive blood transfusion. During the course of bleeding fibrinogen (coagulation factor I) may be depleted and fall to critically low levels, impairing haemostasis and thus worsening the ongoing bleeding. A plasma level of fibrinogen below 2 g/L in the early phase of postpartum haemorrhage is associated with subsequent development of severe haemorrhage. Use of fibrinogen concentrate allows high-dose substitution without the need for blood type crossmatch. So far no publications of randomised controlled trials involving acutely bleeding patients in the obstetrical setting have been published. This trial aims to investigate if early treatment with fibrinogen concentrate reduces the need for blood transfusion in women suffering severe PPH.

METHODS/DESIGN

In this randomised placebo-controlled double-blind multicentre trial, parturients with primary PPH are eligible following vaginal delivery in case of: manual removal of placenta (blood loss ≥ 500 ml) or manual exploration of the uterus after the birth of placenta (blood loss ≥ 1000 ml). Caesarean sections are also eligible in case of perioperative blood loss ≥ 1000 ml. The exclusion criteria are known inherited haemostatic deficiencies, prepartum treatment with antithrombotics, pre-pregnancy weight <45 kg or refusal to receive blood transfusion. Following informed consent, patients are randomly allocated to either early treatment with 2 g fibrinogen concentrate or 100 ml isotonic saline (placebo). Haemostatic monitoring with standard laboratory coagulation tests and thromboelastography (TEG, functional fibrinogen and Rapid TEG) is performed during the initial 24 hours.Primary outcome is the need for blood transfusion. To investigate a 33% reduction in the need for blood transfusion, a total of 245 patients will be included. Four university-affiliated public tertiary care hospitals will include patients during a two-year period. Adverse events including thrombosis are assessed in accordance with International Conference on Harmonisation (ICH) good clinical practice (GCP).

DISCUSSION

A widespread belief in the benefits of early fibrinogen substitution in cases of PPH has led to increased off-label use. The FIB-PPH trial is investigator-initiated and aims to provide an evidence-based platform for the recommendations of the early use of fibrinogen concentrate in PPH.

TRIAL REGISTRATION

ClincialTrials.gov NCT01359878.

Prothrombin complex concentrate and recombinant prothrombin alone or in combination with recombinant factor X and FVIIa in dilutional coagulopathy: a porcine model

BACKGROUND

This study was conducted to assess whether newly developed recombinant clotting factor concentrates enable the reversal of dilutional coagulopathy.

METHODS

In 50 anesthetized pigs, ~60% of the blood volume was withdrawn and replaced with hydroxyethyl starch. Pigs were randomized to receive either 200 mg kg(-1) fibrinogen (n = 10), fibrinogen and 35 IU kg(-1) prothrombin complex concentrate (PCC) (n = 10), fibrinogen and 4 mg kg(-1) recombinant human factor II (rhFII) concentrate (n = 10), fibrinogen and a three-factor combination (3F) of 4 mg kg(-1) rhFII, 0.006 mg kg(-1) recombinant human FVIIa and 0.32 mg kg(-1) recombinant human FX (n = 10), or saline (n = 10). Thereafter, a standardized liver laceration was performed to induce uncontrolled hemorrhage. Survival time and blood loss were determined, and standard coagulation tests and thrombelastometry were performed.

RESULTS

Fibrinogen combined with rhFII or PCC improved survival. Blood loss was significantly decreased in all groups as compared with the animals receiving saline. Clotting time was significantly shortened in the animals treated with fibrinogen and PCC, as well as in those treated with fibrinogen and 3F. One animal died after administration of fibrinogen and PCC.

CONCLUSION

Following hemodilution, a combination of fibrinogen and PCC, rhFII or 3F enhances coagulation and final clot strength. Mortality was reduced statistically significantly only in the animals treated with fibrinogen and rhFII or PCC, whereas administration of the combination of fibrinogen and PCC caused a fatal thromboembolic complication. The combination of fibrinogen and rhFII might be effective in reversing dilutional coagulopathy and may reduce blood loss in cases of dilutional coagulopathy.

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.