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

Fibrinogen (FI)

Das Hauptsubstrat der Gerinnung ist Fibrinogen (FI). Bei akuter Blutung ist es zumeist der erste Gerinnungsfaktor, der kritische Grenzwerte erreicht (150–200 mg/dl). FI kann hervorragend mittels point-of-care-tauglicher viskoelastischer Methoden (Thrombelstographie oder Thrombelastometrie) monitiert werden. Die Substitution kann mittels Frischplasma, Cryopräzipitat oder Fibrinogenkonzentrat erfolgen. Frischplasma ist nicht besonders effektiv, mit einer erhöhten Morbidität, insbesondere bei kritisch Kranken, sowie mit Volumenbelastung assoziiert. Cryopräzipitat wird in einigen europäischen Ländern nicht angeboten. Die Gabe von Fibrinogenkonzentrat wird in verschiedenen Leitlinien empfohlen. Als Akut-Phase-Protein kann FI physiologischerweise bei Entzündungsprozessen, schweren Verletzungen sowie nach großen Operationen in kurzer Zeit auf über 1000 mg/dl ansteigen; wobei hier Fibrinogenspaltprodukte anti-inflammatorische und sogar antibakterielle Eigenschaften haben.

Blood Products

Perioperative hemorrhage, anemia, thrombocytopenia, and coagulopathy are common in the surgical intensive care unit. As a result, blood product transfusion occurs frequently. While red blood cell, plasma, and platelet transfusions have a lifesaving role in the resuscitation of patients with trauma and hemorrhagic shock, their application in other settings is under scrutiny. Current data would suggest a conservative approach be taken, thus avoiding unnecessary transfusion and associated potential adverse events. New and developmental products such as prothrombin complex concentrates offer appealing alternatives to traditional transfusion practice—potentially with fewer risks—however, further investigation into their safety and efficacy is required before practice change can take place.

Reducing transfusion requirements in liver transplantation

Liver transplantation (LT) was historically associated with massive blood loss and transfusion. Over the past two decades transfusion requirements have reduced dramatically and increasingly transfusion-free transplantation is a reality. Both bleeding and transfusion are associated with adverse outcomes in LT. Minimising bleeding and reducing unnecessary transfusions are therefore key goals in the perioperative period. As the understanding of the causes of bleeding has evolved so too have techniques to minimize or reduce the impact of blood loss. Surgical “piggyback” techniques, anaesthetic low central venous pressure and haemodilution strategies and the use of autologous cell salvage, point of care monitoring and targeted correction of coagulopathy, particularly through use of factor concentrates, have all contributed to declining reliance on allogenic blood products. Pre-emptive management of preoperative anaemia and adoption of more restrictive transfusion thresholds is increasingly common as patient blood management (PBM) gains momentum. Despite progress, increasing use of marginal grafts and transplantation of sicker recipients will continue to present new challenges in bleeding and transfusion management. Variation in practice across different centres and within the literature demonstrates the current lack of clear transfusion guidance. In this article we summarise the causes and predictors of bleeding and present the evidence for a variety of PBM strategies in LT.

[Multidisciplinary consensus document on the management of massive haemorrhage (HEMOMAS document)]

Massive haemorrhage is common and often associated with high morbidity and mortality. We perform a systematic review of the literature, with extraction of the recommendations from the existing evidences because of the need for its improvement and the management standardization. From the results we found, we wrote a multidisciplinary consensus document. We begin with the agreement in the definitions of massive haemorrhage and massive transfusion, and we do structured recommendations on their general management (clinical assessment of bleeding, hypothermia management, fluid therapy, hypotensive resuscitation and damage control surgery), blood volume monitoring, blood products transfusion (red blood cells, fresh frozen plasma, platelets and their best transfusion ratio), and administration of hemostatic components (prothrombin complex, fibrinogen, factor VIIa, antifibrinolytic agents).

Fibrinogen concentrate administration inhibits endogenous fibrinogen synthesis in pigs after traumatic hemorrhage

BACKGROUND

Fibrinogen plays a central role in coagulation and falls to critical levels early after trauma. Administration of fibrinogen concentrate (FC) to improve hemostasis after severe bleeding seems beneficial, but it is unclear whether its use introduces excessive fibrinogen with a potential risk of thrombosis. This study investigated changes of endogenous fibrinogen metabolism from FC administration following traumatic hemorrhage in pigs.

METHODS

Anesthetized, instrumented pigs were randomized into lactated Ringer's (LR) solution only and LR plus FC groups (n = 7 each). Femur fracture of each pig's left leg was followed by hemorrhage of 60% total blood volume and resuscitation with LR (3× bled volume, LR group) or LR plus FC at 250 mg/kg (LR-FC group). Afterward, a constant infusion of stable isotopes 1-C-phenylalanine (phe, 6 hours) and d5-phe (3 hours) was performed with hourly blood sampling and subsequent gas chromatography-mass spectrometry analysis to quantify fibrinogen synthesis and breakdown rates, respectively. Blood gas and coagulation indices (thromboelastography) were measured on intermittent blood samples, and hemodynamics was continuously monitored. Animals were euthanized after the 6-hour isotope period.

RESULTS

Mean arterial pressure decreased by 50% after hemorrhage but improved after LR resuscitation in both groups. Hemorrhage and LR resuscitation reduced total protein, hematocrit, fibrinogen, and platelets to 50% of baseline values. Moreover, hemorrhage and resuscitation decreased fibrinogen concentration (207 ± 6 vs. 132 ± 7 mg/dL) and clot strength (72 ± 2 vs. 63 ± 2 mm) in both groups (p < 0.05). FC administration restored plasma fibrinogen concentrations and clot strength within 15 minutes, while no changes occurred in the LR group. Fibrinogen synthesis rates in the LR-FC group (1.3 ± 0.2 mg/kg/h) decreased versus the LR group (3.1 ± 0.5; p < 0.05), whereas fibrinogen breakdown rates were similar.

CONCLUSION

Our data suggest an effective feedback mechanism that regulates host fibrinogen availability and thereby suggests that acute thrombosis from FC administration is an unlikely risk.

Multidisciplinary consensus document on the management of massive haemorrhage (HEMOMAS document)

Massive haemorrhage is common and often associated with high morbidity and mortality. We perform a systematic review of the literature, with extraction of the recommendations from the existing evidences because of the need for its improvement and the management standardization. From the results we found, we wrote a multidisciplinary consensus document. We begin with the agreement in the definitions of massive haemorrhage and massive transfusion, and we do structured recommendations on their general management (clinical assessment of bleeding, hypothermia management, fluid therapy, hypotensive resuscitation and damage control surgery), blood volume monitoring, blood products transfusion (red blood cells, fresh frozen plasma, platelets and their best transfusion ratio), and administration of hemostatic components (prothrombin complex, fibrinogen, factor VIIa, antifibrinolytic agents).

The effects of in vitro hemodilution and fibrinogen concentrate substitution on thromboelastometry analysis in patients qualified for liver transplantation - preliminary results

BACKGROUND

Dilutional coagulopathy might cause life-threatening hemorrhages in liver transplantation. Liver insufficiency is usually accompanied by alteration in fibrinogen (Fib) synthesis, which is one of the main clotting factors providing appropriate hemostasis. Intraoperative hemodilution results in further Fib concentration reduction enhancing coagulopathy and blood loss. Exogenous Fib substitution might prevent this.

METHODS

A prospective study with a control group was designed. The study group consists of patients with cirrhosis who qualified for liver transplantation. Inclusion and exclusion criteria were strictly established. The blood collected from participants was diluted up to 30% and 60% with crystalloid (saline) or colloid (hydroxyethyl starch) in 2 parallel series. The first series consisted of diluted blood, the second of diluted blood with Fib concentrate. Thromboelastometry tests were performed on every blood sample. After collecting data from the first 12 participants, we performed a preliminary analysis.

RESULTS

The maximum clot formation (MCF) in the EXTEM test decreased with progressive blood dilution in both study arms. The MCF values were lower than 35 mm in every diluted blood sample of the study group. The recovery of decreased MCF after Fib concentrate substitution was observed in both groups. The improvement in clot formation was also expressed as amplitude of clot firmness in the 10th minute (A10) in the FIBTEM test.

CONCLUSIONS

Clot formation is disturbed more profoundly by hemodilution in cirrhotic patients. Fib concentrate substitution might be effective in the management of dilutional coagulopathy.

Rotational thromboelastometry–guided blood product management in major spine surgery

OBJECT

Major spinal surgery in adult patients is often associated with significant intraoperative blood loss. Rotational thromboelastometry (ROTEM) is a functional viscoelastometric method for real-time hemostasis testing. In this study, the authors sought to characterize the coagulation abnormalities encountered in spine surgery and determine whether a ROTEM-guided, protocol-based approach to transfusion reduced blood loss and blood product use and cost.

METHODS

A hospital database was used to identify patients who had undergone adult deformity correction spine surgery with ROTEM-guided therapy. All patients who received ROTEM-guided therapy (ROTEM group) were matched with historical cohorts whose coagulation status had not been evaluated with ROTEM but who were treated using a conventional clinical and point-of-care laboratory approach to transfusion (Conventional group). Both groups were subdivided into 2 groups based on whether they had received intraoperative tranexamic acid (TXA), the only coagulation-modifying medication administered intraoperatively during the study period. In the ROTEM group, 26 patients received TXA (ROTEM-TXA group) and 24 did not (ROTEM-nonTXA group). Demographic, surgical, laboratory, and perioperative transfusion data were recorded. Data were analyzed by rank permutation test, adapted for the 1:2 ROTEM-to-Conventional matching structure, with p < 0.05 considered significant.

RESULTS

Comparison of the 2 groups in which TXA was used showed significantly less fresh-frozen plasma (FFP) use in the ROTEM-TXA group than in the Conventional-TXA group (median 0 units [range 0–4 units] vs 2.5 units [range 0–13 units], p < 0.0002) but significantly more cryoprecipitate use (median 1 unit [range 0–4 units] in the ROTEM-TXA group vs 0 units [range 0–2 units] in the Conventional-TXA group, p < 0.05), with a nonsignificant reduction in blood loss (median 2.6 L [range 0.9–5.4 L] in the ROTEM-TXA group vs 2.9 L [0.7–7.0 L] in the Conventional-TXA group, p = 0.21). In the 2 groups in which TXA was not used, the ROTEM-nonTXA group showed significantly less blood loss than the Conventional-nonTXA group (median 1 L [range 0.2–6.0 L] vs 1.5 L [range 1.0–4.5 L], p = 0.0005), with a trend toward less transfusion of packed red blood cells (pRBC) (median 0 units [range 0–4 units] vs 1 unit [range 0–9 units], p = 0.09]. Cryoprecipitate use was increased and FFP use decreased in response to ROTEM analysis identifying hypofibrinogenemia as a major contributor to ongoing coagulopathy.

CONCLUSIONS

In major spine surgery, ROTEM-guided transfusion allows for standardization of transfusion practices and early identification and treatment of hypofibrinogenemia. Hypofibrinogenemia is an important cause of the coagulopathy encountered during these procedures and aggressive management of this complication is associated with less intraoperative blood loss, reduced transfusion requirements, and decreased transfusion-related cost.

Effects of Fibrinogen Concentrate on Thrombin Generation, Thromboelastometry Parameters, and Laboratory Coagulation Testing in a 24-Hour Porcine Trauma Model

Introduction:

In a 24-hour porcine model of liver injury, we showed that fibrinogen supplementation does not downregulate endogenous fibrinogen synthesis. Here we report data from the same study showing the impact of fibrinogen on coagulation variables.

Materials and Methods:

Coagulopathy was induced in 20 German land race pigs by hemodilution and blunt liver injury. Animals randomly received fibrinogen concentrate (100 mg/kg) or saline. Coagulation parameters were assessed and thromboelastometry (ROTEM) was performed.

Results:

Fibrinogen concentrate significantly reduced the prolongations of EXTEM clotting time, EXTEM clot formation time, and prothrombin time induced by hemodilution and liver injury. A decrease in clot strength was also ameliorated. Endogenous thrombin potential was significantly higher in the fibrinogen group than in the control group, 20 minutes (353 ± 24 vs 289 ± 22 nmol/L·min; P < .05) and 100 minutes (315 ± 40 vs 263 ± 38 nmol/L·min; P < .05) after the start of infusion. However, no significant between-group differences were seen in other thrombin generation parameters or in d-dimer or thrombin–antithrombin levels. Fibrinogen–platelet binding was reduced following liver injury, with no significant differences between groups. No significant between-group differences were observed in any parameter at ∼12 and ∼24 hours.

Conclusion:

This study suggests that, in trauma, fibrinogen supplementation may shorten some measurements of the speed of coagulation initiation and produce a short-lived increase in endogenous thrombin potential, potentially through increased clotting substrate availability. Approximately 12 and 24 hours after starting fibrinogen concentrate/saline infusion, all parameters measured in this study were comparable in the 2 study groups.

Practice guidelines for perioperative blood management: an updated report by the American Society of Anesthesiologists Task Force on Perioperative Blood Management*

The American Society of Anesthesiologists Committee on Standards and Practice Parameters and the Task Force on Perioperative Blood Management presents an updated report of the Practice Guidelines for Perioperative Blood Management.

Supplemental Digital Content is available in the text.

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.

Thromboelastography in patients with severe sepsis: a prospective cohort study

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Anesthetic management of severe or worsening postpartum hemorrhage]

INTRODUCTION

Risk factors of maternal morbidity and mortality during postpartum hemorrhage (PPH) include non-optimal anesthetic management. As the anesthetic management of the initial phase is addressed elsewhere, the current chapter is dedicated to the management of severe PPH.

METHODS

A literature search was performed using PubMed and Medline databases, and the Cochrane Library, for articles published from 2003 up to and including 2013. Several keywords related to anesthetic and critical care practice, and obstetrical management were used, in various combinations. Guidelines from several societies and organisations were also read.

RESULTS

When PPH worsens, one should ask for additional team personnel (professional consensus). Patients should be monitored for heart rate, blood pressure, skin and mucosal pallor, bleeding at skin puncture sites, diuresis and the volume of genital bleeding (grade B). Because of the possible rapid worsening of coagulapathy, patients should undergo regular evaluation of coagulation status (professional consensus). Prevention and management of hypothermia should be considered (professional consensus), by warming intravenous fluids and blood products, and by active body warming (grade C). Antibiotics should be given, if not already administered at the initial phase (professional consensus). Vascular fluids must be given (grade B), the choice being left at the physician discretion. Blood products transfusion should be decided based on the clinical severity of PPH (professional consensus). Priority is given to red blood cells (RBC) transfusion, with the aim to maintain Hb concentration>8g/dL. The first round of products could include 3 units of RBC (professional consensus), and the following round 3 units of RBC, and 3 units of fresh frozen plasma (FFP). The FFP:RBC ratio should be kept between 1:2 and 1:1 (professional consensus). Depending on the etiology of PPH, the early administration of FFP is left at the discretion of the physician (professional consensus). Platelet count should be maintained at>50 G/L (professional consensus). During massive PPH, fibrinogen concentration should be maintained at>2g/L (professional consensus). Fibrinogen can be given without prior fibrinogen measurement in case of massive bleeding (professional consensus). General anesthesia should be considered in case of hemodynamic instability, even when an epidural catheter is in place (professional consensus).

CONCLUSION

The anesthetic management aims to restore and maintain optimal respiratory state and circulation, to treat coagulation disorders, and to allow invasive obstetrical and radiologic procedures. Clinical and instrumental monitoring are needed to evaluate the severity of PPH, to guide the choice of therapeutic options, and to assess treatments efficacy.

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.

Fibrinogen Concentrate Does Not Suppress Endogenous Fibrinogen Synthesis in a 24-hour Porcine Trauma Model

Background:

Fibrinogen concentrate may reduce blood loss after trauma. However, its effect on endogenous fibrinogen synthesis is unknown. The authors investigated the effect of exogenous human fibrinogen on endogenous fibrinogen metabolism in a 24-h porcine trauma model.

Methods:

Coagulopathy was induced in 20 German Landrace pigs by hemodilution and blunt liver injury. Animals were randomized to receive fibrinogen concentrate (100 mg/kg; infusion beginning 20 min postinjury and lasting approximately 10 min) or saline. Fibrinogen concentration, thromboelastometry, and quantitative reverse transcriptase polymerase chain reaction of fibrinogen genes in liver tissue samples were recorded. Internal organs were examined histologically for emboli.

Results:

Coagulation parameters were impaired and plasma fibrinogen concentrations were reduced before starting infusion of fibrinogen concentrate/saline. Twenty minutes after starting infusion, exogenous fibrinogen supplementation had increased plasma fibrinogen concentration versus controls (171 ± 19 vs. 63 ± 10 mg/dl [mean ± SD for Multifibren U]; 185 ± 30 vs. 41 ± 4 mg/dl [Thrombin reagent]; P &lt; 0.05 for both comparisons). The between-group difference in plasma fibrinogen concentration diminished thereafter, with maximum concentrations in both groups observed at approximately 24 h, that is, during the acute-phase reaction after trauma. Fibrinogen supplementation did not down-regulate endogenous fibrinogen synthesis (no between-group differences in fibrinogen messenger RNA). Total postinjury blood loss was significantly lower in the fibrinogen group (1,062 ± 216 vs. 1,643 ± 244 ml; P &lt; 0.001). No signs of thromboembolism were observed.

Conclusions:

Administration of human fibrinogen concentrate did not down-regulate endogenous porcine fibrinogen synthesis. The effect on plasma fibrinogen concentration was most pronounced at 20 min but nonsignificant at approximately 24 h.

Novel approaches in management of perioperative coagulopathy

PURPOSE OF REVIEW

The recent advances in hemostatic monitoring, and discussion of the clinical implications of hemostatic therapies based on different blood components and factor concentrates.

RECENT FINDINGS

Implementing suitable laboratory tests and transfusion protocols is highly recommended because the laboratory test guided, protocol-driven transfusion approach reduces blood component utilization, and possibly leads to improved outcomes. Timely assessment of coagulation has been difficult using conventional coagulation tests, but thrombocytopenia, fibrin polymerization defects, and fibrinolysis can be quickly assessed on thromboelastometry. The latter testing can be applied to guide the dosing of fibrinogen and prothrombin complex concentrate, which are selectively used to correct fibrinogen deficiency, and improve thrombin generation in acquired coagulopathy. These therapeutic approaches are novel, and potentially effective in reducing the exposure to allogeneic components (e.g., plasma and platelets) and side-effects of transfusion. Although the accessibility of different therapies among different countries, tranexamic acid is widely available, and is an effective blood conservation measure with a good safety profile in various surgical settings.

SUMMARY

Our understanding of perioperative coagulopathy, diagnostic tools, and therapeutic approaches has evolved in recent years. Additional multidisciplinary efforts are required to understand the optimal combinations, cost-effectiveness, and safety profiles of allogeneic components, and available factor concentrates.

Analysis of the safety and pharmacodynamics of human fibrinogen concentrate in animals

Fibrinogen, a soluble 340kDa plasma glycoprotein, is critical in achieving and maintaining hemostasis. Reduced fibrinogen levels are associated with an increased risk of bleeding and recent research has investigated the efficacy of fibrinogen concentrate for controlling perioperative bleeding. European guidelines on the management of perioperative bleeding recommend the use of fibrinogen concentrate if significant bleeding is accompanied by plasma fibrinogen levels less than 1.5-2.0g/l. Plasma-derived human fibrinogen concentrate has been available for therapeutic use since 1956. The overall aim of the comprehensive series of non-clinical investigations presented was to evaluate i) the pharmacodynamic and pharmacokinetic characteristics and ii) the safety and tolerability profile of human fibrinogen concentrate Haemocomplettan P® (RiaSTAP®). Pharmacodynamic characteristics were assessed in rabbits, pharmacokinetic parameters were determined in rabbits and rats and a safety pharmacology study was performed in beagle dogs. Additional toxicology tests included: single-dose toxicity tests in mice and rats; local tolerance tests in rabbits; and neoantigenicity tests in rabbits and guinea pigs following the introduction of pasteurization in the manufacturing process. Human fibrinogen concentrate was shown to be pharmacodynamically active in rabbits and dogs and well tolerated, with no adverse events and no influence on circulation, respiration or hematological parameters in rabbits, mice, rats and dogs. In these non-clinical investigations, human fibrinogen concentrate showed a good safety profile. This data adds to the safety information available to date, strengthening the current body of knowledge regarding this hemostatic agent.

Endogenous thrombin potential following hemostatic therapy with 4-factor prothrombin complex concentrate: a 7-day observational study of trauma patients

Introduction

Purified prothrombin complex concentrate (PCC) is increasingly used as hemostatic therapy for trauma-induced coagulopathy (TIC). However, the impact of PCC administration on coagulation status among patients with TIC has not been adequately investigated.

Methods

In this observational, descriptive study, data relating to thrombin generation were obtained from plasma samples gathered prospectively from trauma patients upon emergency room (ER) admission and over the following 7 days. Standard coagulation tests, including measurement of antithrombin (AT) and fibrinogen, were performed. Three groups were investigated: patients receiving no coagulation therapy (NCT group), patients receiving fibrinogen concentrate only (FC group), and patients treated with PCC and fibrinogen concentrate (FC-PCC group).

Results

The study population (77 patients) was predominantly male (84.4%); mean age was 40 ± 15 years and mean injury severity score was 25.6 ± 12.7. There were no significant differences between the three study groups in thrombin-related parameters upon ER admission. Endogenous thrombin potential (ETP) was significantly higher in the FC-PCC group compared with the NCT group on days 1 to 4 and the FC group on days 1 to 3. AT levels were significantly lower in the FC-PCC group from admission until day 3 (versus FC group) or day 4 (versus NCT group). Fibrinogen increased over time, with no significant between-group differences after ER admission. Despite ETP being higher, prothrombin time and activated partial thromboplastin time were significantly prolonged in the FC-PCC group from admission until day 3 to 4.

Conclusions

Treatment with PCC increased ETP for several days, and patients receiving PCC therapy had low AT concentrations. These findings imply a potential pro-thrombotic state not reflected by standard coagulation tests. This is probably important given the postoperative acute phase increase in fibrinogen levels, although studies with clinical endpoints are needed to ascertain the implications for patient outcomes. We recommend careful use of PCC among trauma patients, with monitoring and potentially supplementation of AT.

Pros and cons of tetrastarch solution for critically ill patients

Proper fluid management is crucial for the management of critically ill patients. However, there is a continuing debate about the choice of the fluid, i.e., crystalloid vs. colloid. Colloid solution is theoretically advantageous to the crystalloid because of larger volume effect and less interstitial fluid accumulation, and hydroxyethyl starch (HES) is most frequently used for perioperative setting. Nevertheless, application of HES solution is relatively limited due to its side effects including renal toxicity and coagulopathy. Since prolonged presence of large HES molecule is responsible for these side effects, rapidly degradable HES solution with low degree of substitution (tetrastarch) supposedly has less potential for negative effects. Thus, tetrastarch may be more frequently used in the ICU setting. However, several large-scale randomized trials reported that administration of tetrastarch solution to the patients with severe sepsis has negative effects on mortality and renal function. These results triggered further debate and regulatory responses around the world. This narrative review intended to describe the currently available evidence about the advantages and disadvantages of tetrastarch in the ICU setting.

Management of hemorrhage in trauma

Hemorrhage remains one of the leading causes of trauma-related deaths. Uncontrolled diffuse microvascular bleeding in the course of initial care is common, potentially resulting in exsanguination. Early and aggressive hemostatic intervention increases survival and reduces the incidence of massive transfusion. Thus, timely diagnosis of the underlying coagulation disorders is mandatory. It has been shown that standard coagulation tests do not sufficiently characterize trauma-induced coagulopathy (TIC). This has led to increasing interest in alternatives, such as the viscoelastic test, to diagnose TIC and to provide the basis for a goal-directed hemostatic therapy. The concept of damage control resuscitation (DCR) has been introduced widely in trauma patients with severe bleeding. This strategy addresses important confounders of the coagulation process such as hemodilution, hypothermia, and acidosis; DCR is based on a damage control surgical approach, permissive hypotension, and improvement of hemostatic competence. Many studies have shown benefit in mortality when using high ratios of fresh frozen plasma (FFP) to red blood cells (RBC) as early treatment. However, there is increased awareness that coagulation factor concentrate could be beneficial in the treatment of trauma-induced coagulopathy.

In vitro efficacy of RiaSTAP after rapid reconstitution

BACKGROUND

Fibrinogen is the first coagulation factor to reach critical levels during hemorrhage. Consequently, reestablishing normal fibrinogen levels is necessary to achieve adequate hemostasis. Fibrinogen is supplemented through administration of fresh frozen plasma, cryoprecipitate, or human fibrinogen concentrate, RiaSTAP. RiaSTAP is potentially the most advantageous fibrinogen replacement product because it offers the highest fibrinogen concentration, lowest volume, and most consistent dose. Unfortunately, RiaSTAP is limited by a protocol reconstitution time of 15 min. Conversely, physicians in emergency settings frequently resort to a forceful and rapid reconstitution, which causes foaming and possible protein loss and/or damage. This study aims to address the in vitro effectiveness of protocol-reconstituted RiaSTAP versus rapidly reconstituted RiaSTAP versus cryoprecipitate.

METHODS

Three fibrinogen treatments were prepared: protocol-reconstituted RiaSTAP, rapidly reconstituted RiaSTAP, and thawed cryoprecipitate. Each treatment was added in theoretical doses of 0-600 mg/dL to fibrinogen-depleted plasma (normal fibrinogen level is 150-450 mg/dL). Samples were generated in triplicate, and each sample was subjected to rapid thrombelastography and Clauss assays. The rapid thrombelastography assay measures the hemostatic potential of a blood and/or plasma sample. The maximum amplitude (MA) parameter indicates overall clot strength and is a reflection of fibrinogen efficacy. The Clauss assay measures the time to clot formation in response to a known concentration of thrombin, and the amount of functional fibrinogen is then determined from a standard curve.

RESULTS

For all fibrinogen treatments, increasing fibrinogen dose resulted in an increase in MA. There was no significant difference in MA between both RiaSTAP reconstitutions (slope of RiaSTAP [protocol], 10.85 mm/[100 mg/dL] and slope of RiaSTAP [rapid], 10.54 mm/[100 mg/dL]). However, both protocol-reconstituted RiaSTAP and rapidly reconstituted RiaSTAP have higher MA values than cryoprecipitate in doses of ≥100 mg/dL. Moreover, each replicate of cryoprecipitate showed a higher variance in fibrinogen efficacy (coefficient of variance [CV] = 44.7%) at a fibrinogen dose of 300 mg/dL. RiaSTAP, however, showed a lower variance in fibrinogen efficacy for both reconstitutions (RiaSTAP [protocol], CV = 3.3% and RiaSTAP [rapid], CV = 2.7%), indicating a consistent fibrinogen dose.

CONCLUSIONS

RiaSTAP (either reconstitution method) has greater hemostatic potential and less variability in fibrinogen concentration compared with cryoprecipitate. Rapidly reconstituted RiaSTAP does not compromise hemostatic potential and can be used to potentially facilitate hemostasis in rapidly bleeding patients.

Venous thromboembolism in patients undergoing operations for lung cancer: a systematic review

BACKGROUND

The risk of venous thromboembolism is perceived to be high in patients with lung cancer. However, existing studies in patients undergoing operations for lung cancer draw inconsistent conclusions and recommendations in terms of thromboprophylaxis. The aim of this study was to perform a systematic review of the risk of perioperative and postoperative venous thromboembolism for patients undergoing potential curative surgical procedures for primary lung cancer

METHODS

This was a systematic review including studies of patients with primary lung cancer undergoing operations with curative intent.

RESULTS

We included 19 studies with a total of 10,660 patients. All studies, except 1, were observational in design. Marked heterogeneity was found between the studies in terms of methodologic aspects, patient characteristics, and findings. The mean risk of venous thromboembolism (VTE) was estimated at 2.0% (range, 0.2%-19%), with a mean observation period of 16 months (range, 0.1-22), and the risk was nearly identical in studies with 1 month of follow-up and studies with a longer follow-up.

CONCLUSIONS

The evidence for using thromboprophylaxis after lung cancer operations is relatively sparse, and the use is based predominantly on clinical consensus. However, the risk of VTE seems to occur predominantly within the initial postoperative period, and subsequently the risk falls. Future research should focus on identifying patients and surgical procedures that increase the risk of VTE. This could be accomplished by large observational studies in addition to randomized controlled trials evaluating different thromboprophylaxis strategies.

Consistency of thromboelastometry analysis under scrutiny: results of a systematic evaluation within and between analysers

While the use of thromboelastometry analysis (ROTEM®) in evaluation of haemostasis is rapidly increasing, important validity parameters of testing remain inadequately examined. We aimed to study systematically the consistency of thromboelastometry parameters within individual tests regarding measurements between different analysers, between different channels of the same analyser, between morning and afternoon measurements (circadian variation), and if measured four weeks apart. Citrated whole blood samples from 40 healthy volunteers were analysed with two analysers in parallel. EXTEM, INTEM, FIBTEM, HEPTEM and APTEM tests were conducted. A Bland-Altman comparison was performed and homogeneity of variances was tested using the pitman test. P-value ranges were used to classify the level of homogeneity (p<0.15 - low homogeneity, p = 0.15 to 0.5 - intermediate homogeneity, p>0.5 high homogeneity). Less than half of all comparisons made showed high homogeneity of variances (p>0.5) and in about a fifth of comparisons data distributions were heterogeneous (p<0.15). There was no clear pattern for homogeneity. On average, comparisons of MCF, ML and LI30 measurements tended to be better, but none of the tests assessed outperformed another. In conclusion, systematic investigation reveals large differences in the results of some thromboelastometry parameters and lack of consistency. Clinicians and scientists should take these inconsistencies into account and focus on parameters with a higher homogeneity such as MCF.

Coagulation and the surgical neonate

Both coagulopathy and abnormal thrombosis can complicate the anesthetic and surgical management of neonatal patients; however, the patterns of bleeding and thrombosis in neonates differ from those in adults or older children. Severe coagulopathic bleeding most commonly occurs during heart surgery and almost certainly contributes to morbidity and mortality in this population. Such severe bleeding is rare during other surgery; the exception is babies presenting to the operating room with established coagulopathy secondary to severe sepsis. Alternatively, pathological thrombosis will mainly occur in association with indwelling vascular access devices or surgically created vascular shunts. There are important differences between the coagulation system in neonates and older patients. The implication of this is that therapies established in other patient groups will not be optimal for neonates without adaptation. While evidence from high-quality clinical trials is rarely available, an understanding of how coagulation in neonates differs can help to guide practice. This review will discuss important differences between the coagulation system of neonates and older patients and how these relate to newer models of coagulation. The emphasis will be on issues likely to impact on perioperative care. In particular, the management of severe bleeding, the manipulation of coagulation during heart surgery, and the management of coagulopathy in septic neonates will be discussed in detail.

Efficacy and safety of fibrinogen concentrate in trauma patients--a systematic review

PURPOSE

Uncontrolled bleeding is the main preventable cause of death in severe trauma patients. Fibrinogen is the first coagulation factor to decrease during trauma-induced coagulopathy, suggesting that pharmacological replacement might assist early hemorrhage control. Several sources of fibrinogen are available; however, fibrinogen concentrate (FC) is not routinely used in trauma settings in most countries. The aim of this review is to summarize the available literature evaluating the use of FC in the management of severe trauma.

METHODS

Studies reporting the administration of FC in trauma patients published between January 2000 and April 2013 were identified from MEDLINE and from the Cochrane Library.

RESULTS

The systematic review identified 12 articles reporting FC usage in trauma patients: 4 case reports, 7 retrospective studies, and 1 prospective observational study. Three of these were not restricted to trauma patients.

CONCLUSIONS

Despite methodological flaws, some of the available studies suggested that FC administration may be associated with a reduced blood product requirement. Randomized trials are warranted to determine whether FC improves outcomes in prehospital management of trauma patients or whether FC is superior to another source of fibrinogen in early hospital management of trauma patients.

Effects of fibrinogen concentrate after shock/resuscitation: a comparison between in vivo microvascular clot formation and thromboelastometry*

OBJECTIVES

Dilutional coagulopathy after resuscitation with crystalloids/colloids clinically often appears as diffuse microvascular bleeding. Administration of fibrinogen reduces bleeding and increases maximum clot firmness, measured by thromboelastometry. Study objective was to implement a model where microvascular bleeding can be directly assessed by visualizing clot formation in microvessels, and correlations can be made to thromboelastometry.

DESIGN

Randomized animal study.

SETTING

University research laboratory.

SUBJECTS

Male Syrian Golden hamsters.

INTERVENTIONS

Microvessels of Syrian Golden hamsters fitted with a dorsal window chamber were studied using videomicroscopy. After 50% hemorrhage followed by 1 hour of hypovolemia resuscitation with 35% of blood volume using a high-molecular-weight hydroxyethyl starch solution (Hextend, Hospira, MW 670 kD) occurred. Animals were then treated with 250 mg/kg fibrinogen IV (Laboratoire français du Fractionnement et des Biotechnologies, Paris, France) or an equal volume of saline before venular vessel wall injuries was made by directed laser irradiation, and the ability of microthrombus formation was assessed.

MEASUREMENTS AND MAIN RESULTS

Thromboelastometric measurements of maximum clot firmness were performed at the beginning and at the end of the experiment. Resuscitation with hydroxyethyl starch and sham treatment significantly decreased FIBTEM maximum clot firmness from 32 ± 9 mm at baseline versus 13 ± 5 mm after sham treatment (p < 0.001). Infusion of fibrinogen concentrate significantly increased maximum clot firmness, restoring baseline levels (baseline 32 ± 9 mm; after fibrinogen administration 29 ± 2 mm). In vivo microthrombus formation in laser-injured vessels significantly increased in fibrinogen-treated animals compared with sham (77% vs 18%).

CONCLUSIONS

Fibrinogen treatment leads to increased clot firmness in dilutional coagulopathy as measured with thromboelastometry. At the microvascular level, this increased clot strength corresponds to an increased prevalence of thrombus formation in vessels injured by focused laser irradiation.

Restoring hemostasis: fibrinogen concentrate versus cryoprecipitate

Fibrinogen plays a key role in the coagulation process, and therefore maintaining adequate quantities of fibrinogen is an essential step in achieving satisfactory hemostasis in patients with acquired hypofibrinogenemia. Potential options for treating acquired hypofibrinogenemia in patients with uncontrolled bleeding include the use of cryoprecipitate or fibrinogen replacement therapy. This review provides a brief overview of the hemostatic process and the methods for assessing coagulopathy and discusses the efficacy and safety of cryoprecipitate and fibrinogen concentrate in restoring fibrinogen levels, achieving hemostasis and reducing transfusion requirements in different patient populations requiring rapid hemostasis. Other issues relevant to the clinical use of these agents in restoring hemostasis, including variations in product composition, preparation time and cost, are also examined.

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.

Impact of fibrinogen concentrate alone or with prothrombin complex concentrate (+/- fresh frozen plasma) on plasma fibrinogen level and fibrin-based clot strength (FIBTEM) in major trauma: a retrospective study

Background

Low plasma fibrinogen concentration is a predictor of poor outcome in major trauma patients. The role of fibrinogen concentrate for rapidly increasing fibrinogen plasma levels in severe trauma is not well defined.

Methods

In this retrospective study we included severe trauma patients treated with fibrinogen concentrate alone (FC group), fibrinogen concentrate with prothrombin complex concentrate (FC–PCC group) or fibrinogen concentrate with PCC and fresh frozen plasma (FC–PCC–FFP group). PCC was generally administered as the second step of intraoperative therapy, while FFP was only administered as a third step. All patients received ≥1 g fibrinogen concentrate within 24 hours. Plasma fibrinogen concentration and ROTEM parameters upon emergency room (ER) admission, intensive care unit (ICU) admission, and after 24 hours were analysed.

Results

Among 157 patients fulfilling the inclusion criteria, 83% were male; mean age was 44 years and median injury severity score (ISS) was 29. Standard coagulation tests reflected increasing severity of coagulopathy with increasing complexity of haemostatic therapy (highest severity in the FC–PCC–FFP group; p < 0.0001). Total 24-hour fibrinogen concentrate dose also increased with complexity of haemostatic therapy. Plasma fibrinogen concentration was maintained, with no significant difference between ER admission and ICU admission in all patient groups. FIBTEM clot firmness at 10 minutes (CA₁₀) was similarly maintained, albeit with a small increase in the FC–PCC group. Fibrinogen concentration and FIBTEM CA₁₀ were within the normal range in all groups at 24 hours. The ratio of fibrinogen concentrate to red blood cells (g:U) ranged between 0.7:1.0 and 1.0:1.0.

Conclusion

Fibrinogen concentrate therapy maintained fibrinogen concentration and FIBTEM CA₁₀ during the initial phase of trauma care until ICU admission. After 24 hours, these parameters were comparable between the three groups and within the normal range for each of them. Further studies are warranted to investigate the effect of fibrinogen concentrate on clinical outcomes.

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.

Cryoprecipitate use in the PROMMTT study

BACKGROUND

There are few clinical data to guide the use of cryoprecipitate in severely injured trauma patients. Cryoprecipitate is a rich source of fibrinogen and has been associated with improved survival in animal as well as limited human studies. Our objectives were to identify patterns and predictors of cryoprecipitate use and determine whether transfusing cryoprecipitate was associated with improved survival.

METHODS

This secondary analysis of 1,238 of 1,245 PRospective Observational Multicenter Major Trauma Transfusion (PROMMTT) study patients who had timed transfusion data included 359 (29%) who received cryoprecipitate. For this analysis, one dose of cryoprecipitate was defined as 10 U. Unadjusted predictors of cryoprecipitate use were identified using logistic regression. Multivariable time-dependent Cox models were performed to examine the association of cryoprecipitate on time to in-hospital death.

RESULTS

Cryoprecipitate use varied significantly by center, ranging from 7% to 82%. Among patients who received cryoprecipitate, the median number of units infused by 24 hours was 10 (interquartile range, 10-20). The median time from admission to first cryoprecipitate unit was 2.7 hours (interquartile range, 1.7-4.4 hours). Of those who died of a hemorrhagic death within 6 hours of admission, 72% received no cryoprecipitate. Other unadjusted predictors of cryoprecipitate use included Injury Severity Score (ISS), initial fibrinogen levels, base deficit, international normalized ratio, prothrombin time/partial thromboplastin time, hemoglobin, damage-control surgery, and surgical intervention of the chest and abdomen. Cryoprecipitate use was not associated with in-hospital mortality after adjusting for initial pH, initial hemoglobin, emergency department systolic blood pressure, emergency department Glasgow Coma Scale (GCS) score, blood product use, ISS, and center.

CONCLUSION

Ten US Level 1 trauma centers vary greatly in their timing and use of cryoprecipitate in severely injured trauma patients. We could not identify any association of cryoprecipitate use with in-hospital mortality, although most patients did not receive this product. Randomized controlled studies are needed to determine if cryoprecipitate (or fibrinogen concentrates) have a beneficial effect.

Severe bleeding in surgical and trauma patients: the role of fibrinogen replacement therapy

Fibrinogen is in a central position in the coagulation system, playing an important role in platelet aggregation and establishing the fibrin network. Fibrinogen is also the first coagulation factor to become critically low during surgery and after major trauma. Hemostatic support has traditionally involved using transfusion of allogeneic blood products, including fresh frozen plasma; however, there is a lack of conclusive evidence supporting the clinical effectiveness of fresh frozen plasma in these situations. Early, targeted fibrinogen substitution may be preferable in terms of speed of administration and clinical effectiveness, with recent studies adding to the weight of evidence demonstrating the potential to significantly reduce blood loss and transfusion requirements in surgical and severe trauma patients with this approach. The availability of point-of-care testing using viscoelastic techniques to guide fibrinogen substitution has enabled the development of transfusion algorithms that lead to individualized, goal-directed, and targeted use of fibrinogen concentrates to improve clinical outcomes. Fibrinogen replacement has become the standard-of-care in several major surgical centers in Europe and is recommended in current European trauma treatment guidelines. Future prospective studies will help to establish the critical threshold and target levels for fibrinogen substitution in different acute-care situations and should encourage more widespread use of this rational and effective approach to the treatment of bleeding-induced coagulopathies.

Postoperative fibrinogen level is associated with postoperative bleeding following cardiothoracic surgery and the effect of fibrinogen replacement therapy remains uncertain

BACKGROUND

Traditionally, a fibrinogen level > 1 g L(-1) has been viewed as the critical plasma concentration required for hemostasis. No definitive trial has investigated the plasma fibrinogen hemostatic threshold and fibrinogen replacement in complex surgical patients with acquired bleeding.

OBJECTIVES

To explore the plasma fibrinogen level required for hemostasis in cardiothoracic surgery patients and assess the association of fibrinogen replacement therapy (using cryoprecipitate or fibrinogen concentrate) with reducing postoperative bleeding rate.

PATIENTS/METHODS

Data from a prospectively collated database were used to examine the relationship between postoperative plasma fibrinogen level and the postoperative rate of bleeding within the hour of plasma fibrinogen measurement (n = 430) and to explore the effect of cryoprecipitate infusion (n = 76) or fibrinogen concentrate administration (n = 8) on postoperative bleeding rate.

RESULTS

A low plasma fibrinogen level was significantly associated with bleeding, with an odds ratio of 3.06 for every 1 g L(-1) decrease in fibrinogen (95% confidence interval 1.05-8.90) with adjustment for confounders. A fibrinogen threshold associated with excess bleeding was not identified, but this relationship was a continuum. There was no reduction in bleeding following administration of cryoprecipitate or fibrinogen concentrate to raise the post-infusion fibrinogen level to a median of 2.00 and 1.70 g L(-1) , respectively.

CONCLUSIONS

There is a continuum of bleeding severity with reducing fibrinogen concentration. Fibrinogen concentrate or cryoprecipitate infusion did not significantly reduce bleeding rate; however, confirmation by a randomized controlled trial is required. It remains uncertain whether low postoperative fibrinogen levels are causally associated with postoperative bleeding.

Haemorrhagic shock, therapeutic management

The management of a patient in post-traumatic haemorrhagic shock will meet different logics that will apply from the prehospital setting. This implies that the patient has beneficiated from a "Play and Run" prehospital strategy and was sent to a centre adapted to his clinical condition capable of treating all haemorrhagic lesions. The therapeutic goals will be to control the bleeding by early use of tourniquet, pelvic girdle, haemostatic dressing, and after admission to the hospital, the implementation of surgical and/or radiological techniques, but also to address all the factors that will exacerbate bleeding. These factors include hypothermia, acidosis and coagulopathy. The treatment of these contributing factors will be associated to concepts of low-volume resuscitation and permissive hypotension into a strategy called "Damage Control Resuscitation". Thus, the objective in situation of haemorrhagic shock will be to not exceed a systolic blood pressure of 90 mmHg (in the absence of severe head trauma) until haemostasis is achieved.