Thromboelastography as an early prediction method for hypofibrinogenemia in emergency department patients with primary postpartum hemorrhage

BACKGROUND

Timely and accurate assessment of coagulopathy is crucial for the management of primary postpartum hemorrhage (PPH). Thromboelastography (TEG) provides a comprehensive assessment of coagulation status and is useful for guiding the treatment of hemorrhagic events in various diseases. This study aimed to evaluate the role of TEG in predicting hypofibrinogenemia in emergency department (ED) patients with primary PPH.

METHODS

We conducted a retrospective observational study in the ED of a university-affiliated tertiary hospital between November 2015 and August 2023. TEG was performed upon admission. The cutoff value for hypofibrinogenemia was 200 mg/dL. The primary outcome was the presence of hypofibrinogenemia.

RESULTS

Among the 174 patients, 73 (42.0%) had hypofibrinogenemia. The need for massive transfusion was higher in the hypofibrinogenemia group (37.0% vs. 5.0%, p < 0.001). Among the TEG parameters, all values were significantly different between the groups, except for lysis after 30 min, suggesting a tendency toward hypocoagulability. Multivariable analysis revealed that the alpha angle (odds ratio (OR) 0.924, 95% confidence interval (CI) 0.876-0.978) and maximum amplitude (MA) (OR 0.867, 95% CI 0.801-0.938) were independently associated with hypofibrinogenemia. The optimal cutoff values for the alpha angle and maximum amplitude (MA) for hypofibrinogenemia were 63.8 degrees and 56.1 mm, respectively.

CONCLUSION

Point-of-care TEG could be a valuable tool for the early identification of hypofibrinogenemia in ED patients with primary PPH.

Early viscoelastometric guided fibrinogen replacement combined with escalation of clinical care reduces progression in postpartum haemorrhage: a comparison of outcomes from two prospective observational studies

BACKGROUND

Viscoelastometric haemostatic assays (VHA) give rapid information on coagulation status, allowing individualised resuscitation.

METHODS

This paper compares outcomes from two observational studies of postpartum haemorrhage (PPH) in the same institution, before and after practice changed from fixed ratio empirical transfusion of coagulation products with laboratory coagulation testing to VHA-guided fibrinogen replacement incorporated into an enhanced PPH care bundle. In both studies, all blood samples were taken near 1000 mL qualitative blood loss (QBL). In Study One, QBL started once PPH was identified, and resuscitation with coagulation blood products was empirical or based on laboratory tests of coagulation. In Study Two, QBL started at delivery and VHA was used to guide fibrinogen replacement if FIBTEM A5 was <12 mm (Claus fibrinogen ≤2 g/L) or to withhold coagulation products if FIBTEM A5 was >12 mm.

RESULTS

Improved PPH outcomes were observed in Study Two, with rates of measured blood loss ≥2500 mL, ≥4 units red blood cell (RBC) transfusion, fresh frozen plasma transfusion and ≥8 units of any blood product transfusion all reduced (P < 0.01). Clinically significant improvements occurred in women with fibrinogen ≤2 g/L at study entry, where the proportion of women who received ≥4 units RBC transfusion fell from 67% in Study One to 0% in Study Two (P = 0.0007).

CONCLUSIONS

These results suggest that use of VHA as part of an early bundle of PPH care targeting fibrinogen ≤2 g/L with fibrinogen concentrate reduces PPH progression. The greatest benefit was seen when fibrinogen levels were ≤2 g/L at first testing.

Predelivery Haemostatic Biomarkers in Women with Non-Severe Postpartum Haemorrhage

Background: Postpartum haemorrhage (PPH) is a frequent complication of childbirth that is difficult to predict. Predelivery coagulation biomarkers may help to guide preventive strategies. Our objective was to evaluate the association of predelivery haemostatic biomarkers with non-severe PPH. Methods: A nested case-control study was conducted within the « Study of Biological Determinants of Bleeding Postpartum » in order to compare different haemostatic biomarkers in plasma from pregnant women with non-severe PPH (cases) and controls without PPH matched for age, body mass index, term, and mode of delivery. Blood was collected at entry in the delivery room. Global haemostatic assays (thrombin generation assay (TGA) and plasmin generation assay (PGA)) were then performed on freshly thawed aliquots of platelet-poor plasma. Results: A total of 370 pregnant women (185 cases and 185 controls) were included. Median [interquartile range] predelivery platelet count was lower in PPH cases than in controls (217 [181-259] versus 242 [196-280] G/L). TGA and PGA parameters were similar between cases and controls. In a subset analysis of vaginal deliveries (n = 144), median predelivery TGA thrombin peak was lower, and median predelivery PGA lag phase was longer in cases compared to controls. In multivariable analysis, only predelivery platelet count was independently associated with non-severe PPH. Conclusions: Predelivery platelet count is associated with non-severe PPH. Differences in other haemostatic parameters are tenuous, questioning their usefulness in predicting non-severe PPH.

Strategies to prevent blood loss and reduce transfusion in emergency general surgery, WSES-AAST consensus paper

Emergency general surgeons often provide care to severely ill patients requiring surgical interventions and intensive support. One of the primary drivers of morbidity and mortality is perioperative bleeding. In general, when addressing life threatening haemorrhage, blood transfusion can become an essential part of overall resuscitation. However, under all circumstances, indications for blood transfusion must be accurately evaluated. When patients decline blood transfusions, regardless of the reason, surgeons should aim to provide optimal care and respect and accommodate each patient's values and target the best outcome possible given the patient's desires and his/her clinical condition. The aim of this position paper was to perform a review of the existing literature and to provide comprehensive recommendations on organizational, surgical, anaesthetic, and haemostatic strategies that can be used to provide optimal peri-operative blood management, reduce, or avoid blood transfusions and ultimately improve patient outcomes.

Thromboembolic events in severe postpartum hemorrhage treated with recombinant activated factor VII: a systematic literature review and meta-analysis

Postpartum hemorrhage (PPH) is an obstetric complication with high associated morbidity. Recombinant activated factor VII (rFVIIa) is used to treat severe PPH when uterotonics fail to stop bleeding. However, data on the safety of rFVIIa treatment of severe PPH from adequately powered trials are lacking. We systematically reviewed published data on the incidence of thromboembolic events (TEs) in women with PPH treated or not treated with rFVIIa (PROSPERO CRD42022360736). Databases (Embase, MEDLINE, BIOSIS, Current Contents, and the Cochrane Library) were searched for peer-reviewed publications published between January 1996 and August 2022 and conference abstracts published between January 2017 and August 2022 using search terms related to thromboembolism or infarction and PPH. Data were extracted from all publications reporting on a general population of women with PPH with information on TEs. Descriptive summary statistics and the estimated proportion of TEs were analyzed using a generalized linear mixed model based on the binomial distribution. Quality assessments were based on the checklist by Downs and Black. From 1637 potentially eligible studies, 55 publications were included reporting on 611 women treated and 32,488 women not treated with rFVIIa. The global estimated proportion of TEs was 1.82% (prediction interval [PI], 0.30-10.23) and 0.72% (PI, 0.03-16.47) in women with severe PPH treated and those not treated with rFVIIa, respectively. The estimated proportions of TEs were similarly small, with wide and largely overlapping PIs. Additional well-designed trials are needed to improve understanding of TE incidence in PPH.

Management and outcomes of women with low fibrinogen concentration during pregnancy or immediately postpartum: A UK national population-based cohort study

INTRODUCTION

Pregnant women with a fibrinogen level <2 g/L represent a high-risk group that is associated with severe postpartum hemorrhage and other complications. Women who would qualify for fibrinogen therapy are not yet identified.

MATERIAL AND METHODS

A population-based cross-sectional study was conducted using the UK Obstetric Surveillance System between November 2017 and October 2018 in any UK hospital with a consultant-led maternity unit. Any woman pregnant or immediately postpartum with a fibrinogen <2 g/L was included. Our aims were to determine the incidence of fibrinogen <2 g/L in pregnancy, and to describe its causes, management and outcomes.

RESULTS

Over the study period 124 women with fibrinogen <2 g/L were identified (1.7 per 10 000 maternities; 95% confidence interval 1.4-2.0 per 10 000 maternities). Less than 5% of cases of low fibrinogen were due to preexisting inherited dysfibrinogenemia or hypofibrinogenemia. Sixty percent of cases were due to postpartum hemorrhage caused by placental abruption, atony, or trauma. Amniotic fluid embolism and placental causes other than abruption (previa, accreta, retention) were associated with the highest estimated blood loss (median 4400 mL) and lowest levels of fibrinogen. Mortality was high with two maternal deaths due to massive postpartum hemorrhage, 27 stillbirths, and two neonatal deaths.

CONCLUSIONS

Fibrinogen <2 g/L often, but not exclusively, affected women with postpartum hemorrhage due to placental abruption, atony, or trauma. Other more rare and catastrophic obstetrical events such as amniotic fluid embolism and placenta accreta also led to low levels of fibrinogen. Maternal and perinatal mortality was extremely high in our cohort.

Deranged Balance of Hemostasis and Fibrinolysis in Disseminated Intravascular Coagulation: Assessment and Relevance in Different Clinical Settings

The disruption of hemostasis/fibrinolysis balance leads to disseminated intravascular coagulation, manifested clinically by bleeding or thrombosis, and multiorgan failure. This study reviews hemostatic assessment and therapeutic strategies that restore this balance in critically ill patients.

Rationale for the Potential Use of Recombinant Activated Factor VII in Severe Post-Partum Hemorrhage

Severe post-partum hemorrhage (PPH) is a major cause of maternal mortality worldwide. Recombinant activated factor VII (rFVIIa) has recently been approved by the European Medicines Agency for the treatment of severe PPH if uterotonics fail to achieve hemostasis. Although large randomized controlled trials are lacking, accumulated evidence from smaller studies and international registries supports the efficacy of rFVIIa alongside extended standard treatment to control severe PPH. Because rFVIIa neither substitutes the activity of a missing coagulation factor nor bypasses a coagulation defect in this population, it is not immediately evident how it exerts its beneficial effect. Here, we discuss possible mechanistic explanations for the efficacy of rFVIIa and the published evidence in patients with severe PPH. Recombinant FVIIa may not primarily increase systemic thrombin generation, but may promote local thrombin generation through binding to activated platelets at the site of vascular wall injury. This explanation may also address safety concerns that have been raised over the administration of a procoagulant molecule in a background of increased thromboembolic risk due to both pregnancy-related hemostatic changes and the hemorrhagic state. However, the available safety data for this and other indications are reassuring and the rates of thromboembolic events do not appear to be increased in women with severe PPH treated with rFVIIa. We recommend that the administration of rFVIIa be considered before dilutional coagulopathy develops and used to support the current standard treatment in certain patients with severe PPH.

Agnostic identification of plasma biomarkers for postpartum hemorrhage risk

BACKGROUND

Postpartum hemorrhage is difficult to predict, is associated with significant maternal morbidity, and is the leading cause of maternal mortality worldwide. The identification of maternal biomarkers that can predict increased postpartum hemorrhage risk would enhance clinical care and may uncover mechanisms that lead to postpartum hemorrhage.

OBJECTIVE

This retrospective case-control study employed agnostic proteomic profiling of maternal plasma samples to identify differentially abundant proteins in controls and postpartum hemorrhage cases.

STUDY DESIGN

Maternal plasma samples were procured from a cohort of >60,000 participants in a single institution's perinatal repository. Postpartum hemorrhage was defined as a decrease in hematocrit of ≥10% or receipt of transfusion within 24 hours after delivery. Postpartum hemorrhage cases (n=30) were matched by maternal age and delivery mode (vaginal or cesarean) with controls (n=56). Mass spectrometry was used to identify differentially abundant proteins using integrated peptide peak areas. Statistically significant differences between groups were defined as P<.05 after controlling for multiple comparisons.

RESULTS

By study design, cases and controls did not differ in race, ethnicity, gestational age at delivery, blood type, or predelivery platelet count. Cases had slightly but significantly lower predelivery and postdelivery hematocrit and hemoglobin. Mass spectrometry detected 1140 proteins, including 77 proteins for which relative abundance differed significantly between cases and controls (fold change >1.15, P<.05). Of these differentially abundant plasma proteins, most had likely liver or placental origins. Gene ontology term analysis mapped to protein clusters involved in responses to wound healing, stress response, and host immune defense. Significantly differentially abundant proteins with the highest fold change (prostaglandin D2 synthase, periostin, and several serine protease inhibitors) did not correlate with predelivery hematocrit or hemoglobin but identified postpartum hemorrhage cases with logistic regression modeling revealing good-to-excellent area under the operator receiver characteristic curves (0.802-0.874). Incorporating predelivery hemoglobin with these candidate proteins further improved the identification of postpartum hemorrhage cases.

CONCLUSION

Agnostic analysis of maternal plasma samples identified differentially abundant proteins in controls and postpartum hemorrhage cases. Several of these proteins are known to participate in biologically plausible pathways for postpartum hemorrhage risk and have potential value for predicting postpartum hemorrhage. These findings identify candidate protein biomarkers for future validation and mechanistic studies.

Prognostic Role of Initial Thromboelastography in Emergency Department Patients with Primary Postpartum Hemorrhage: Association with Massive Transfusion

BACKGROUND

The early prediction of the need for massive transfusions (MTs) and the preparation of blood products are essential for managing patients with primary postpartum hemorrhage (PPH). Thromboelastography (TEG) enables a thorough evaluation of coagulation status and is useful for guiding the treatment of hemorrhagic events in various diseases. We investigated the role of TEG in predicting the need for MT in patients with primary PPH.

METHODS

A retrospective observational study was conducted in the emergency department (ED) of a university-affiliated, tertiary referral center between November 2015 and August 2023. TEG was performed upon admission. We defined MT as the requirement for transfusion of more than 10 units of packed red blood cells within the first 24 h. The primary outcome was the need for MT.

RESULTS

Among the 184 patients with initial TEG, 34 (18.5%) required MT. Except for lysis after 30 min, the MT and non-MT groups had significantly different TEG values. Based on multivariate analysis, an angle < 60 was an independent predictor of MT (odds ratio (OR) 7.769; 95% confidence interval (CI), 2.736-22.062), along with lactate (OR, 1.674; 95% CI, 1.218-2.300) and shock index > 0.9 (OR, 4.638; 95% CI, 1.784-12.056). Alpha angle < 60 degrees indicated the need for MT with 73.5% sensitivity, 72.0% specificity, and 92.3% negative predictive value.

CONCLUSIONS

Point-of-care testing of TEG has the potential to be a useful tool in accurately predicting the necessity for MT in ED patients with primary PPH at an early stage.

Massive transfusion in trauma

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of currently recommended treatment approaches for traumatic hemorrhage shock, with a special focus on massive transfusion.

RECENT FINDINGS

Severe trauma patients require massive transfusion, but consensual international definitions for traumatic hemorrhage shock and massive transfusion are missing. Current literature defines a massive transfusion as transfusion of a minimum of 3-4 packed red blood cells within 1 h. Using standard laboratory and/or viscoelastic tests, earliest diagnosis and treatment should focus on trauma-induced coagulopathy and substitution of substantiated deficiencies.

SUMMARY

To initiate therapy immediately massive transfusion protocols are helpful focusing on early hemorrhage control using hemostatic dressing and tourniquets, correction of metabolic derangements to decrease coagulopathy and substitution according to viscoelastic assays and blood gases analysis with tranexamic acid, fibrinogen concentrate, red blood cells, plasma and platelets are recommended. Alternatively, the use of whole blood is possible. If needed, further support using prothrombin complex, factor XIII or desmopressin is suggested.

Changing hemostatic management in post-partum hemorrhage

Early and fast assessment of hemostasis during postpartum hemorrhage (PPH) is essential to allow early characterization of coagulopathy, estimate bleeding severity and improve outcome. During PPH, fibrinogen decrease occurs earlier than other coagulation factors deficiency and hypofibrinogenemia is an early marker of PPH severity of progression. With good evidence in the context of PPH, point-of-care viscoelastic (VET) hemostatic assays have been shown to provide rapid assessment of hemostatic disorders, low fibrinogen levels, and allow VET-guided fibrinogen replacement. Further studies are needed to define the thresholds for the other coagulation parameters.

Contemporary management of major haemorrhage in critical care

Haemorrhagic shock is frequent in critical care settings and responsible for a high mortality rate due to multiple organ dysfunction and coagulopathy. The management of critically ill patients with bleeding and shock is complex, and treatment of these patients must be rapid and definitive. The administration of large volumes of blood components leads to major physiological alterations which must be mitigated during and after bleeding. Early recognition of bleeding and coagulopathy, understanding the underlying pathophysiology related to specific disease states, and the development of individualised management protocols are important for optimal outcomes. This review describes the contemporary understanding of the pathophysiology of various types of coagulopathic bleeding; the diagnosis and management of critically ill bleeding patients, including major haemorrhage protocols and post-transfusion management; and finally highlights recent areas of opportunity to better understand optimal management strategies for managing bleeding in the intensive care unit (ICU).

The role of viscoelastic hemostatic assays for postpartum hemorrhage management and bedside intrapartum care

Viscoelastic hemostatic assays are point-of-care devices that assess coagulation and fibrinolysis in whole blood samples. These technologies provide numeric and visual information of clot initiation, clot strength, and clot lysis under low-shear conditions, and have been used in a variety of clinical settings and subpopulations, including trauma, cardiac surgery, and obstetrics. Emerging data indicate that these devices are useful for detecting important coagulation defects during major postpartum hemorrhage (especially low plasma fibrinogen concentration [hypofibrinogenemia]) and informing clinical decision-making for blood product use. Data from observational studies suggest that, compared with traditional formulaic approaches to transfusion management, targeted or goal-directed transfusion approaches using data from viscoelastic hemostatic assays are associated with reduced hemorrhage-related morbidity and lower blood product requirement. Viscoelastic hemostatic assays can also be used to identify and treat coagulation defects in patients with inherited or acquired coagulation disorders, such as factor XI deficiency or immune-mediated thrombocytopenia, and to assess hemostatic profiles of patients prescribed anticoagulant medications to mitigate the risk of epidural hematoma after neuraxial anesthesia and postpartum hemorrhage after delivery.

What do we know about why women bleed and what do we not know?

Women or people with a uterus are vulnerable to both normal and abnormal bleeding. During the reproductive years, the uterus is prepared physiologically to accept an embryo and support its growth and development during pregnancy, or in the absence of implantation of an embryo, recycle through the process of menstruation and accept an embryo a month or so later. If fertilization takes place and an embryo or embryos implant in the uterus, the fetal trophoblast, or outer cell layer of the embryo, invades and dilates the maternal spiral arteries and forms the placenta. No matter when in gestation a pregnancy ends, at the conclusion of pregnancy, the placenta should separate from the wall of the uterus and be expelled. Abnormal bleeding occurs during pregnancy or after delivery when the normal uteroplacental interface has not been established or is interrupted; during miscarriage; during ectopic pregnancy; during premature separation of the placenta; or during postpartum hemorrhage. Heavy menstrual bleeding, a subset of abnormal menstrual bleeding, can be quantitatively defined as >80 mL of blood loss per cycle. Unlike postpartum hemorrhage, heavy menstrual bleeding is significantly associated with an underlying bleeding disorder. While there is other reproductive tract bleeding in women, notably bleeding at the time of ovulation or with a life-threatening ruptured ectopic pregnancy, the unique bleeding that women experience is predominantly uterine in origin. Many of the unique aspects of uterine hemostasis, however, remain unknown.

CT-001, a novel fast-clearing factor VIIa, enhanced the hemostatic activity in postpartum samples

ABSTRACT

The hemostatic system is upregulated to protect pregnant mothers from hemorrhage during childbirth. Studies of the details just before and after delivery, however, are lacking. Recombinant factor VIIa (rFVIIa) has recently been granted approval by the European Medicines Agency for the treatment of postpartum hemorrhage (PPH). A next-generation molecule, CT-001, is being developed as a potentially safer and more efficacious rFVIIa-based therapy. We sought to evaluate the peripartum hemostatic status of pregnant women and assess the ex vivo hemostatic activity of rFVIIa and CT-001 in peripartum blood samples. Pregnant women from 2 study sites were enrolled in this prospective observational study. Baseline blood samples were collected up to 3 days before delivery. Postdelivery samples were collected 45 (±15) minutes after delivery. Between the 2 time points, soluble fibrin monomer and D-dimer increased whereas tissue factor, FVIII, FV, and fibrinogen decreased. Interestingly, the postdelivery lag time and time to peak in the thrombin generation assay were shortened, and the peak thrombin generation capacity was maintained despite the reduced levels of coagulation proteins after delivery. Furthermore, both rFVIIa and CT-001 were effective in enhancing clotting activity of postdelivery samples in activated partial thromboplastin time, prothrombin time, thrombin generation, and viscoelastic hemostatic assays, with CT-001 demonstrating greater activity. In conclusion, despite apparent ongoing consumption of coagulation factors at the time of delivery, thrombin output was maintained. Both rFVIIa and CT-001 enhanced the upregulated hemostatic activity in postdelivery samples, and consistent with previous studies comparing CT-001 and rFVIIa in vitro and in in vivo, CT-001 demonstrated greater activity than rFVIIa.

Long-Term Safety Analysis of a Fibrinogen Concentrate (RiaSTAP®/Haemocomplettan® P)

Fibrinogen concentrate treatment is recommended for acute bleeding episodes in adult and pediatric patients with congenital and acquired fibrinogen deficiency. Previous studies have reported a low risk of thromboembolic events (TEEs) with fibrinogen concentrate use; however, the post-treatment TEE risk remains a concern. A retrospective evaluation of RiaSTAP®/Haemocomplettan® P (CSL Behring, Marburg, Germany) post-marketing data was performed (January 1986-June 2022), complemented by a literature review of published studies. Approximately 7.45 million grams of fibrinogen concentrate was administered during the review period. Adverse drug reactions (ADRs) were reported in 337 patients, and 81 (24.0%) of these patients experienced possible TEEs, including 14/81 (17.3%) who experienced fatal outcomes. Risk factors and the administration of other coagulation products existed in most cases, providing alternative explanations. The literature review identified 52 high-ranking studies with fibrinogen concentrate across various clinical areas, including 26 randomized controlled trials. Overall, a higher number of comparative studies showed lower rates of ADRs and/or TEEs in the fibrinogen group versus the comparison group(s) compared with those that reported higher rates or no differences between groups. Post-marketing data and clinical studies demonstrate a low rate of ADRs, including TEEs, with fibrinogen concentrate treatment. These findings suggest a favorable safety profile of fibrinogen concentrate, placing it among the first-line treatments effective for managing intraoperative hemostatic bleeding.

Viscoelastic testing: Critical appraisal of new methodologies and current literature

United States Food and Drug Administration (FDA)-approved viscoelastic testing (VET) methodologies have significantly changed in the last 10 years, with the availability of cartridge-based VET. Some of these cartridge-based methodologies use harmonic resonance-based clot detection. While VET has always allowed for the evaluation of real-time clot formation, cartridge-based VET provides increased ease of use as well as greater portability and robustness of results in out-of-laboratory environments. Here we review the use of VET in a variety of clinical contexts, including cardiac surgery, trauma, liver transplant, obstetrics, and hypercoagulable states such as COVID-19. As of now, high quality randomized trial evidence for new generation VET (TEG 6s, HemoSonics Quantra, ROTEM sigma) is limited. Nevertheless, the use of VET-guided transfusion algorithms appears to result in reduced blood usage without worsening of patient outcomes. Future work comparing the new generation VET instruments and continuing to validate clinically important cut-offs will help move the field of point-of-care coagulation monitoring forward and increase the quality of transfusion management in bleeding patients.

[Postpartum Hemorrhage]

Postpartum hemorrhage (PPH) affects about 4% of all deliveries in high-income countries and continues to rise, a trend attributable to the increase in caesarean section rates and maternal morbidity. Preventive measures such as the precautionary administration of uterotonics effectively reduce the risk of severe bleeding irrespective of birth mode. As a time-critical condition and a significant contributor to adverse maternal outcomes, PPH needs to be diagnosed early by measuring, not estimating, blood losses. Institutional treatment algorithms should be available to guide stage-based interdisciplinary management without delay. The main therapy goals are to identify the etiology and stop the bleeding by using uterotonics and mechanical and surgical interventions, to restore hemodynamic stability by volume and transfusion therapy and to optimize hemostasis by laboratory- and viscoelastic assay-guided factor replacement. This review highlights current recommendations for prevention, diagnosis and treatment of PPH.

Acute obstetric coagulopathy during postpartum hemorrhage is caused by hyperfibrinolysis and dysfibrinogenemia: an observational cohort study

BACKGROUND

Postpartum hemorrhage (PPH) may be exacerbated by hemostatic impairment. Information about PPH-associated coagulopathy is limited, often resulting in treatment strategies based on data derived from trauma studies.

OBJECTIVES

To investigate hemostatic changes associated with PPH.

PATIENTS/METHODS

From a population of 11 279 maternities, 518 (4.6%) women were recruited with PPH ≥ 1000 mL or placental abruption, amniotic fluid embolism, or concealed bleeding. Routine coagulation and viscoelastometric results were collated. Stored plasma samples were used to investigate women with bleeds > 2000 mL or those at increased risk of coagulopathy defined as placenta abruption, amniotic fluid embolism, or need for blood components. Procoagulant factors were assayed and global hemostasis was assessed using thrombin generation. Fibrinolysis was investigated with D-dimer and plasmin/antiplasmin complexes. Dysfibrinogenemia was assessed using the Clauss/antigen ratio.

RESULTS

At 1000 mL blood loss, Clauss fibrinogen was ≤2 g/L in 2.4% of women and 6/27 (22.2%) cases of abruption. Women with very large bleeds (>3000 mL) had evidence of a dilutional coagulopathy, although hemostatic impairment was uncommon. A subgroup of 12 women (1.06/1000 maternities) had a distinct coagulopathy characterized by massive fibrinolysis (plasmin/antiplasmin > 40 000 ng/mL), increased D-dimer, hypofibrinogenemia, dysfibrinogenemia, reduced factor V and factor VIII, and increased activated protein C, termed acute obstetric coagulopathy. It was associated with fetal or neonatal death in 50% of cases and increased maternal morbidity.

CONCLUSIONS

Clinically significant hemostatic impairment is uncommon during PPH, but a subgroup of women have a distinct and severe coagulopathy characterized by hyperfibrinolysis, low fibrinogen, and dysfibrinogenemia associated with poor fetal outcomes.

Management of severe peri-operative bleeding: Guidelines from the European Society of Anaesthesiology and Intensive Care: Second update 2022

BACKGROUND

Management of peri-operative bleeding is complex and involves multiple assessment tools and strategies to ensure optimal patient care with the goal of reducing morbidity and mortality. These updated guidelines from the European Society of Anaesthesiology and Intensive Care (ESAIC) aim to provide an evidence-based set of recommendations for healthcare professionals to help ensure improved clinical management.

DESIGN

A systematic literature search from 2015 to 2021 of several electronic databases was performed without language restrictions. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to assess the methodological quality of the included studies and to formulate recommendations. A Delphi methodology was used to prepare a clinical practice guideline.

RESULTS

These searches identified 137 999 articles. All articles were assessed, and the existing 2017 guidelines were revised to incorporate new evidence. Sixteen recommendations derived from the systematic literature search, and four clinical guidances retained from previous ESAIC guidelines were formulated. Using the Delphi process on 253 sentences of guidance, strong consensus (>90% agreement) was achieved in 97% and consensus (75 to 90% agreement) in 3%.

DISCUSSION

Peri-operative bleeding management encompasses the patient's journey from the pre-operative state through the postoperative period. Along this journey, many features of the patient's pre-operative coagulation status, underlying comorbidities, general health and the procedures that they are undergoing need to be taken into account. Due to the many important aspects in peri-operative nontrauma bleeding management, guidance as to how best approach and treat each individual patient are key. Understanding which therapeutic approaches are most valuable at each timepoint can only enhance patient care, ensuring the best outcomes by reducing blood loss and, therefore, overall morbidity and mortality.

CONCLUSION

All healthcare professionals involved in the management of patients at risk for surgical bleeding should be aware of the current therapeutic options and approaches that are available to them. These guidelines aim to provide specific guidance for bleeding management in a variety of clinical situations.

Emergency administration of fibrinogen concentrate for haemorrhage: systematic review and meta-analysis

INTRODUCTION

The occurrence of massive haemorrhages in various emergency situations increases the need for blood transfusions and increases the risk of mortality. Fibrinogen concentrate (FC) use may increase plasma fibrinogen levels more rapidly than fresh-frozen product or cryoprecipitate use. Previous several systematic reviews and meta-analyses have not effectively demonstrated FC efficacy in significantly improving the risk of mortality and reducing transfusion requirements. In this study, we investigated the use of FC for haemorrhages in emergency situations.

METHODS AND ANALYSIS

In this systematic review and meta-analysis, we included controlled trials, but excluded randomized controlled trials (RCTs) in elective surgeries. The study population consisted of patients with haemorrhages in emergency situations, and the intervention was emergency supplementation of FC. The control group was administered with ordinal transfusion or placebo. The primary and secondary outcomes were in-hospital mortality and the amount of transfusion and thrombotic events, respectively. The electronic databases searched included MEDLINE (PubMed), Web of Science, and the Cochrane Central Register of Controlled Trials.

RESULTS

Nine RCTs in the qualitative synthesis with a total of 701 patients were included. Results showed a slight increase in in-hospital mortality with FC treatment (RR 1.24, 95% CI 0.64-2.39, p = 0.52) with very low certainty of the evidence. There was no reduction in the use of red blood cells (RBC) transfusion in the first 24 h after admission with FC treatment (mean difference [MD] 0.0 Unit in the FC group, 95% CI - 0.99-0.98, p = 0.99) with very low certainty of the evidence. However, the use of fresh-frozen plasma (FFP) transfusion significantly increased in the first 24 h after admission with FC treatment (MD 2.61 Unit higher in the FC group, 95% CI 0.07-5.16, p = 0.04). The occurrence of thrombotic events did not significantly differ with FC treatment.

CONCLUSIONS

The present study indicates that the use of FC may result in a slight increase in in-hospital mortality. While FC did not appear to reduce the use of RBC transfusion, it likely increased the use of FFP transfusion and may result in a large increase in platelet concentrate transfusion. However, the results should be interpreted cautiously due to the unbalanced severity in the patient population, high heterogeneity, and risk of bias.

The Role of Thromboelastography during the Management of Postpartum Hemorrhage: Background, Evidence, and Practical Application

Postpartum hemorrhage (PPH) is a common cause of significant maternal morbidity and mortality that can be associated with coagulopathy, especially hypofibrinogenemia. There is interest in point-of-care viscoelastic hemostatic assays (POC-VHA) in PPH because prompt knowledge of coagulation status can aid diagnosis, identify cases of severe coagulopathy, and allow ongoing monitoring during rapid bleeding. The incidence of coagulopathy in most cases of PPH is low because of the procoagulant state of pregnancy, including raised fibrinogen levels of around 4 to 6 g/L. A Clauss fibrinogen of >2 g/L or POC-VHA equivalent has been found to be adequate for hemostasis during PPH. POC-VHA has been used successfully to diagnose hypofibrinogenemia (Clauss fibrinogen of ≤2 g/L) and guide fibrinogen treatment which has reduced bleed size and complications of massive transfusion. There are uncertainties about the use of POC-VHA to direct fresh frozen plasma and platelet administration during PPH. Several POC-VHA algorithms have been used successfully incorporated in the management of many thousands of PPHs and clinicians report that they are easy to use, interpret, and aid decision making. Due to the relative cost of POC-VHA and lack of definitive data on improving outcomes, these devices have not been universally adopted during PPH.

Comparison between the Rotational Thromboelastometry (ROTEM) Delta device against the Cartridge-based Thromboelastography 6s and Quantra in a healthy third trimester pregnant cohort

Rotational Thromboelastometry (ROTEM) Delta has been described in several postpartum hemorrhage algorithms, but this device requires pipetting and careful mixing of reagents to initiate the clotting reaction. In contrast, thromboelastography (TEG 6s) and the Quantra devices operate utilizing an automated pre-mixed cartridge that only requires a blood sample to start the clot strength analysis. We compared the correlation between 3 point of care viscoelastic testing (POCVT) devices to laboratory Clauss fibrinogen and platelets, their inter-device correlation, and the total running time difference between Quantra and ROTEM. A high correlation was noted between the Clauss fibrinogen and the fibrinogen parameters from ROTEM (r = 0.76-0.84, P < 0.0001), TEG6s (r = 0.71, P < 0.0001) and Quantra (r = 0.72, P = 0.0001). A moderate correlation between laboratory platelets and the ROTEM (r = 0.54;0.45, P < 0.0001; P = 0.0013) and Quantra (r = 0.66, P = 0.0001) parameters was noted. The inter-device correlation showed to be high when comparing the fibrinogen parameters of TEG6s and Quantra to that of ROTEM (r = 0.88 and 0.74, P < 0.0001, respectively). In contrast, a moderate correlation was noted between the platelet parameters of Quantra and ROTEM (r = 0.51, p = 0.0036). The Quantra device resulted 20.9 min (95% CI -0.2 to 4.7, P = 0.07) faster than the ROTEM if the warming and pipetting of reagents of the latter were considered. All the POCVT devices demonstrated a high correlation to laboratory Clauss fibrinogen, making each beneficial for the early recognition and management of hypofibrinogenemia.

Emerging technology for early detection and management of postpartum hemorrhage to prevent morbidity

Despite advances in hemorrhage detection and management, postpartum hemorrhage remains the single leading cause of maternal death worldwide. Within the United States, hemorrhage is the leading cause of maternal death on the day of delivery and within the first week after delivery. Blood transfusion after hemorrhage represents a large proportion of severe maternal morbidity during and after delivery. Blood loss during delivery has historically been assessed visually by inspecting soiled pads, linens, and laparotomy sponges. These methods underestimate the volume of blood loss by as much as 40%, becoming increasingly inaccurate as blood loss increases. Young, healthy obstetrical patients compensate for blood loss via peripheral vasoconstriction, maintaining heart rate and blood pressure in a normal range until over 1 L of blood has been lost. A significant decrease in blood pressure along with marked tachycardia (>120 bpm) may not be seen until 30% to 40% of blood volume has been lost, or 2.0 to 2.6 L in a healthy term pregnant patient, after which the patient may rapidly decompensate. In resource-poor settings especially, the narrow window between the emergence of significant vital sign abnormalities and clinical decompensation may prove catastrophic. Once hemorrhage is detected, decisions regarding blood product transfusion are routinely made on the basis of inaccurate estimates of blood loss, placing patients at risk of underresuscitation (increasing the risk of hemorrhagic shock and end-organ damage) or overresuscitation (increasing the risk of transfusion reaction, fluid overload, and alloimmunization). We will review novel technologies that have emerged to assist both in the early and accurate detection of postpartum hemorrhage and in decisions regarding blood product transfusion.

How should we measure platelet count before central neuraxial blockade in parturients with thrombocytopenia?

Patients with low platelet counts are a concern to the obstetric anaesthetist as, although rare, there is a risk of a spinal epidural haematoma following central neuraxial blockade. Although conventional plasma-based tests are frequently used to guide central neuraxial blockade in patients with thrombocytopenia, interest in the use of viscoelastic haemostatic assays is increasing.

Evaluating the Association Between Fibrinogen and Rotational Thromboelastometry and the Progression to Severe Obstetric Hemorrhage

AIM

This study aims to investigate the ability of fibrinogen and rotational thromboelastometry (ROTEM) parameters measured at obstetric hemorrhage protocol initiation to predict severe hemorrhage.

METHODS

In this retrospective study we included patients whose hemorrhage was managed with an obstetric massive transfusion protocol. Fibrinogen and ROTEM parameters EXTEM clotting time (CT), clot formation time (CFT), alpha angle, A10, A20, lysis index 30 min after CT (LI30), FIBTEM A10, A20, were measured at initiation of the protocol with transfusion based on a predefined algorithm. Patients were grouped into either severe or nonsevere hemorrhage based on: peripartum fall in hemoglobin ≥4 g/dL, transfusion of ≥4 units of blood product, invasive procedures for hemorrhage control, intensive care unit admission, or death.

RESULTS

Of the 155 patients included, 108 (70%) progressed to severe hemorrhage. Fibrinogen, EXTEM alpha angle, A10, A20, FIBTEM A10, A20 were significantly lower in the severe hemorrhage group while the CFT was significantly prolonged in the severe hemorrhage group. In univariate analysis, predicted progression to severe hemorrhage yielded areas under the receiver operating characteristic curve (95% confidence interval [CI]) of: fibrinogen: 0.683 (0.591-0.776), CFT: 0.671 (0.553, 0.789), EXTEM alpha angle: 0.690 (0.577-0.803), A10: 0.693 (0.570-0.815), A20: 0.678 (0.563-0.793), FIBTEM A10: 0.726 (0.605-0.847), and A20: 0.709 (0.594-0.824). In a multivariable model, fibrinogen was independently associated with severe hemorrhage (odds ratio [95% CI] = 1.037 [1.009-1.066]) for every 50 mg/dL decrease in fibrinogen drawn at obstetric hemorrhage massive transfusion protocol initiation.

CONCLUSION

Both fibrinogen and ROTEM parameters measured at the initiation of an obstetric hemorrhage protocol are useful parameters for predicting severe hemorrhage.

Haemostatic support in postpartum haemorrhage: A review of the literature and expert opinion

Postpartum haemorrhage (PPH) remains the leading cause of pregnancy-related deaths worldwide. Typically, bleeding is controlled by timely obstetric measures in parallel with resuscitation and treatment of coagulopathy. Early recognition of abnormal coagulation is crucial and haemostatic support should be considered simultaneously with other strategies as coagulopathies contribute to the progression to massive haemorrhage. However, there is lack of agreement on important topics in the current guidelines for management of PPH. A clinical definition of PPH is paramount to understand the situation to which the treatment recommendations relate; however, reaching a consensus has previously proven difficult. Traditional definitions are based on volume of blood loss, which is difficult to monitor, can be misleading and leads to treatment delay. A multidisciplinary approach to define PPH considering vital signs, clinical symptoms, coagulation and haemodynamic changes is needed. Moreover, standardised algorithms or massive haemorrhage protocols should be developed to reduce the risk of morbidity and mortality and improve overall clinical outcomes in PPH. If available, point-of-care testing should be used to guide goal-directed haemostatic treatment. Tranexamic acid should be administered as soon as abnormal bleeding is recognised. Fibrinogen concentrate rather than fresh frozen plasma should be administered to restore haemostasis where there is elevated risk of fibrinogen deficiency (e.g., in catastrophic bleeding or in cases of abruption or amniotic fluid embolism) as it is a more concentrated source of fibrinogen. Lastly, organisational considerations are equally as important as clinical interventions in the management of PPH and have the potential to improve patient outcomes.

The role of point of care thromboelastography (TEG) and thromboelastometry (ROTEM) in management of Primary postpartum haemorrhage: A meta-analysis and systematic review

Background

The utility of instantaneous evaluation of coagulation during primary postpartum haemorrhage (PPH) is paramount in the context of empirical blood product transfusion-related risk of dilutional and consumptive coagulopathy and circulatory overload.

Methods

A profound screening of electronic databases till August 15, 2022 was carried out after being enlisted in PROSPERO (CRD42021275514). Randomized control studies, comparative cohort studies, and cross-sectional studies comparing point-of-care viscoelastic test guided blood product transfusion with empirical transfusion in patients with PPH were included.

Results

We retrieved five studies, with a total of 1914 parturient with PPH. Patients receiving transfusion based upon point of care viscoelastic tests had lesser risk of having emergency hysterectomy (Odds ratio (OR) = 0.55, 95% CI 0.32-0.95, I2 = 7%), transfusion-associated circulatory overload (TACO) (OR = 0.03, 95% CI 0.00-0.50), reduced transfusion of fresh frozen plasma (OR = 0.07, 95% CI 0.04-0.14, I2 = 89%), platelets (OR = 0.51, 95% CI 0.28-0.91, I2 = 89%), packed red blood cell transfusion (OR = 0.70, 95% CI 0.55-0.88, I2 = 89%), and had better cost-effective treatment [Mean difference (MD) = -357.5, 95% CI - 567.75 to -147.25, I2 = 93%] than patient received empirical transfusion. However, there was no significant difference in the requirement of ICU admissions (OR = 0.77, 95% CI = 0.46-1.29, I2 = 82%). No mortality was detected across the studies.

Conclusions

Point of care viscoelastic assessment guided transfusion in PPH confederates with reduced morbidity. Nevertheless, more studies on the triggering values for transfusion, long-term survival, and cost-benefit in patients with PPH are warranted to establish its utility.

Laboratory Testing of Hemostasis in Pregnancy: A Brief Overview

Normal pregnancy is associated with significant physiological changes in the coagulation and fibrinolytic systems with an inclination toward a hypercoagulable state. This includes an increase in plasma levels of most clotting factors, a decrease in endogenous anticoagulants, and inhibition of fibrinolysis. Although these changes are critical in maintaining placental function and reducing postpartum hemorrhage, they may contribute to an increased risk of thromboembolism, particularly toward the end of pregnancy and during puerperium. Hemostasis parameters and the non-pregnant population reference ranges cannot be used in the assessment of bleeding or thrombotic complication risk during pregnancy, and pregnancy-specific information and reference ranges are not always available to support the interpretation of laboratory tests. This review aims to summarize the use of relevant hemostasis tests to promote evidence-based interpretation of laboratory test results as well as discuss challenges associated with testing during pregnancy.

Viscoelastic testing: an illustrated review of technology and clinical applications

Viscoelastic testing (VET), including thromboelastography and thromboelastometry, provides a rapid and comprehensive picture of whole blood coagulation dynamics and hemostasis that can be reviewed and evaluated at the point-of-care. This technology is over 50 years old; however, over the past few years, there has been a significant increase in research examining the use of VET. Best practice guidelines for the use of VET exist in both the United States and Europe, particularly for elective cardiac surgery, although recommendations for implementation are somewhat limited in some clinical areas by the lack of studies constituting high-grade evidence. Other challenges to implementation surround validation of the technology in some care settings as well as lack of training. Nevertheless, there is a wide range of potential clinical applications, such as treating coagulopathies in liver disease and transplant surgery, critical care, as well as within obstetrical hemorrhage. In this illustrated review, we provide an overview of viscoelastic testing technology (also called viscoelastic hemostatic assays) and describe how the assays can be used to provide a broad overview of hemostasis from clot formation to clot lysis, while highlighting the contribution of coagulation factors and platelets. We then summarize the major clinical applications for viscoelastic testing, including more recent applications, such as in COVID-19. Each section describes the clinical context, and key publications, followed by a representative algorithm and key guidelines.

[Peripartum hemorrhage, diagnostics and treatment : Update of the S2k guidelines AWMF 015/063 from August 2022]

The current S2k guidelines on the diagnostics and treatment of peripartum hemorrhage are summarized in this article from the perspective of anesthesiology based on a fictitious case report. The update of the guidelines was written under the auspices of the German Society of Gynecology and Obstetrics with the participation of other professional societies and interest groups from Germany, Austria and Switzerland and published by the AWMF in 2022 under the register number 015/063.

Optimizing systems to manage postpartum hemorrhage

Systems to optimize the management of postpartum hemorrhage must ensure timely diagnosis, rapid hemodynamic and hemostatic resuscitation, and prompt interventions to control the source of bleeding. None of these objectives can be effectively completed by a single clinician, and the management of postpartum hemorrhage requires a carefully coordinated interprofessional team. This article reviews systems designed to standardize hemorrhage diagnosis and response.

Patient Blood Management in Vascular Surgery

Patient blood management (PBM) is an evidence-based, multidisciplinary approach aimed at appropriately allocating blood products to patients requiring transfusion while simultaneously minimizing inappropriate transfusions. The 3 pillars of patient blood management are optimizing erythropoiesis, minimizing blood loss, and optimizing physiological reserve of anemia. Benefits seen from PBM include limiting hospital costs and mitigating harm from numerous risks of transfusion.

The role of fibrinogen in postpartum hemorrhage

Postpartum hemorrhage (PPH) is the leading cause of maternal death worldwide (WHO), with almost 60000 deaths annually. Pregnancy is a prothrombotic state with increased levels of several coagulation factors to protect the parturient from bleeding problems during delivery. Fibrinogen has a significant role in coagulation and bleeding. Studies have pointed out that lower fibrinogen levels before delivery, but also at the initiation of PPH, are predictive of major hemorrhage. Early, the goal-directed fibrinogen concentrate therapy might be very useful in a subgroup of patients with serious PPH. This review aims to summarize the current literature on fibrinogen during PPH.

Point-of-care coagulation testing for postpartum haemorrhage

The use of viscoelastic haemostatic assays (VHAs) to guide blood product replacement during postpartum haemorrhage is expanding. Rotem and TEG devices can be used to detect and treat clinically significant hypofibrinogenaemia, although evidence to support the role of VHAs for guiding fresh frozen plasma and platelet transfusion is less clear. If Rotem/TEG traces are normal, clinicians should investigate for another cause of bleeding, and haemostatic support is not required. Guidelines support the use of VHAs during postpartum haemorrhage as part of locally agreed algorithms. There is a wide consensus that fibrinogen replacement is needed if the Fibtem A5 is <12 mm and if there is ongoing bleeding. Guidelines recommend against using VHAs to guide tranexamic acid infusion, and this drug should be given as soon as bleeding is recognised, irrespective of the Rotem/TEG traces. The cost-effectiveness of VHAs during postpartum haemorrhage needs to be addressed.

The Choice between Plasma-Based Common Coagulation Tests and Cell-Based Viscoelastic Tests in Monitoring Hemostatic Competence: Not an either-or Proposition

There has been a significant interest in the last decade in the use of viscoelastic tests (VETs) to determine the hemostatic competence of bleeding patients. Previously, common coagulation tests (CCTs) such as the prothrombin time (PT) and partial thromboplastin time (PTT) were used to assist in the guidance of blood component and hemostatic adjunctive therapy for these patients. However, the experience of decades of VET use in liver failure with transplantation, cardiac surgery, and trauma has now spread to obstetrical hemorrhage and congenital and acquired coagulopathies. Since CCTs measure only 5 to 10% of the lifespan of a clot, these assays have been found to be of limited use for acute surgical and medical conditions, whereby rapid results are required. However, there are medical indications for the PT/PTT that cannot be supplanted by VETs. Therefore, the choice of whether to use a CCT or a VET to guide blood component therapy or hemostatic adjunctive therapy may often require consideration of both methodologies. In this review, we provide examples of the relative indications for CCTs and VETs in monitoring hemostatic competence of bleeding patients.

Emergencies in obstetric anaesthesia: a narrative review

We conducted a narrative review in six areas of obstetric emergencies: category-1 caesarean section; difficult and failed airway; massive obstetric haemorrhage; hypertensive crisis; emergencies related to neuraxial anaesthesia; and maternal cardiac arrest. These areas represent significant research published within the last five years, with emphasis on large multicentre randomised trials, national or international practice guidelines and recommendations from major professional societies. Key topics discussed: prevention and management of failed neuraxial technique; role of high-flow nasal oxygenation and choice of neuromuscular drug in obstetric patients; prevention of accidental awareness during general anaesthesia; management of the difficult and failed obstetric airway; current perspectives on the use of tranexamic acid, fibrinogen concentrate and cell salvage; guidance on neuraxial placement in a thrombocytopenic obstetric patient; management of neuraxial drug errors, local anaesthetic systemic toxicity and unusually prolonged neuraxial block regression; and extracorporeal membrane oxygenation use in maternal cardiac arrest.

Hemostatic Effects of Tranexamic Acid in Cesarean Delivery: An Ancillary Study of the TRAAP2 Study

BACKGROUND

 Fibrinolysis activation during delivery contributes to postpartum hemorrhage (PPH). Clot lysis time studied with the global fibrinolytic capacity device (GFC/LT) is a functional test which rapidly assesses fibrinolytic profile. Tranexamic acid (TXA) is an efficient antifibrinolytic therapy.

METHODS

 We prospectively studied fibrinolysis and coagulation in 33 women included in the TRAAP2 trial, which aimed to assess the impact of TXA in preventing PPH following a cesarean delivery. TXA or placebo was randomly administered after childbirth as part of the TRAAP2 trial's protocol. Fibrinolytic (GFC/LT, plasma concentration of fibrinolysis activators and inhibitors) and hemostatic parameters were assayed at three sample times (TREF [T-reference] after anesthesia, T15 and T120minutes after TXA, or placebo administration).

RESULTS

 All cesarean deliveries were elective. In the placebo group, the clot lysis time assessed with GFC/LT significantly decreased between TREF and T120, indicating an activated fibrinolysis (44 [interquartile range, IQR: 40-48] vs. 34 [IQR: 30-36] minutes, p<0.001). In both TXA and placebo groups, significant fluctuations of the plasmatic concentrations of fibrinolytic mediators were noticed over time, suggesting fibrinolysis activation. Clot lysis time measured by GFC/LT was significantly increased in women of the TXA group as compared with those in the placebo group at T15 (120 [120-120] vs. 36 [34-41] minutes, p<0.001) and T120minutes (113 [99-120] vs. 34 [30-36] minutes, p<0.001) after drug administration, indicating a decreased in fibrinolysis in those women.

CONCLUSIONS

 GFC/LT evidenced fibrinolysis activation during cesarean delivery, linked to a decrease in fibrinolytic inhibitors. GFC/LT revealed a significant antifibrinolytic effect of TXA compared with placebo.

Fibrinogen concentrate and maternal outcomes in severe postpartum hemorrhage: A population-based cohort study with a propensity score-matched analysis

STUDY OBJECTIVE

Fibrinogen concentrate is used to treat severe postpartum hemorrhage despite limited evidence of its effectiveness in obstetric settings. We aimed to explore the association between its administration and maternal outcomes in women with severe postpartum hemorrhage.

DESIGN, SETTING AND PATIENTS

This secondary analysis of the EPIMOMS prospective population-based study, exploring severe maternal morbidity, as defined by national expert consensus (2012-2013, 182,309 deliveries, France), included all women with severe postpartum hemorrhage and transfused with red blood cells during active bleeding.

MEASUREMENTS

The primary endpoint was maternal near-miss or death, and the secondary endpoint the total number of red blood cells units transfused.

INTERVENTIONS

We studied fibrinogen concentrate administration as a binary variable and then by the timing of its administration. We used multivariable analysis and propensity score matching to account for potential indication bias.

MAIN RESULTS

Among the 730 women with severe postpartum hemorrhage and transfused, 313 (42.9%) received fibrinogen concentrate, and 142 (19.5%) met near-miss criteria or died. The risk of near-miss or death was not significantly lower among the women treated with fibrinogen concentrate than among those not treated, in either the multivariable analysis (adjusted RR = 1.03; 95% CI, 0.72-1.49; P = 0.855) or the propensity score analysis (RR = 0.85; 95% CI, 0.55-1.32; P = 0.477). Among women treated with fibrinogen concentrate, administration more than three hours after red blood cell transfusion started was associated with a higher risk of near-miss or death than administration before or within 30 min after the transfusion began (adjusted RR = 2.07; 95% CI, 1.10-3.89; P = 0.024). Results were similar for the secondary endpoint.

CONCLUSIONS

The use of fibrinogen concentrate in severe postpartum hemorrhage needing red blood cell transfusion during active bleeding is not associated with improved maternal outcomes.

Latest advances in postpartum hemorrhage management

Hemorrhage is the leading cause of maternal mortality worldwide. A maternal health priority is improving how healthcare providers prevent and manage postpartum hemorrhage (PPH). Because anesthesiologists can help facilitate how hospitals develop approaches for PPH prevention and anticipatory planning, we review the potential utility of PPH risk-assessment tools, bundles, and protocols. Anesthesiologists rely on clinical and diagnostic information for initiating and evaluating medical management. Therefore, we review modalities for measuring blood loss after delivery, which includes visual, volumetric, gravimetric, and colorimetric approaches. Point-of-care technologies for assessing changes in central hemodynamics (ultrasonography) and coagulation profiles (rotational thromboelastometry and thromboelastography) are also discussed. Anesthesiologists play a critical role in the medical and transfusion management of PPH. Therefore, we review blood ordering and massive transfusion protocols, fixed-ratio vs. goal-directed transfusion approaches, coagulation changes during PPH, and the potential clinical utility of the pharmacological adjuncts, tranexamic acid, and fibrinogen concentrate.

The relationship between INTEM/HEPTEM coagulation time ratio and heparin plasma concentration in obstetric patients: an exploratory in vitro investigation

PURPOSE

Unfractionated heparin continues to be one of the main agents used for thromboprophylaxis in obstetrics, which can complicate the placement of neuraxial anesthetics. In this study, we explored the relationship between a point-of-care coagulation test (thromboelastometry) and plasma heparin concentrations in vitro.

METHODS

We obtained blood from consenting obstetric patients with uncomplicated pregnancies in their third trimester who were not in labour and had a specific hematocrit range. Blood was processed and analyzed. We added increasing amounts of unfractionated heparin to samples from 0 to 0.3 U·mL^-1 in 0.05 U·mL^-1 increments to simulate increasing doses of unfractionated heparin. We performed INTEM and HEPTEM testing in parallel with activated partial thromboplastin time (aPTT) testing. We created a model of the relationship between heparin concentration and the INTEM/HEPTEM coagulation time (IH CT) ratio using nonlinear regression. A similar model for aPTT was also created.

RESULTS

Seventy-seven patients were included in the study. Only one concentration of heparin was added to blood samples of each patient. At a concentration of 0.05 U·mL^-1, the IH CT ratio was less than or equal to 1.1 in 9/11 (82%) samples. Activated partial thromboplastin time was not prolonged (> 35 sec) until a concentration of 0.1 U·mL^-1 heparin was added. In all samples, the IH CT ratio was prolonged at a concentration ≥ 0.2 U·mL^-1 as measured by thromboelastometry; however, at no concentration of heparin was aPTT prolonged in all samples.

CONCLUSION

The point-of-care IH CT ratio may be useful in identifying the presence of little to no heparin activity. Further research is needed to determine if this ratio can predict heparin activity in vivo.

[Postpartum hemorrhage : Interdisciplinary consideration in the context of patient blood management]

Postpartum hemorrhage (PPH) nowadays still represents a severe complication of both a vaginal delivery and a cesarean section. In German-speaking areas a new definition of the term has recently become established and the nomenclature with respect to the severe form of PPH was dropped. The handling of misoprostol as a uterotonic during treatment of PPH is also new, which is available in Germany only as a medical direct import. For adequate diagnostics and targeted treatment interdisciplinary and standardized algorithms should be established and the specialist disciplines involved should be sensitized to this problem. In addition to an adequate hemostasis, a developing coagulopathy must be recognized at an early stage and treated with targeted coagulation management. Through implementation concepts, particularly the second pillar (minimization of blood loss) and the third pillar (rational use of blood transfusions) of patient blood management, various aspects for improvement of treatment of a PPH can be identified.

Point-of-Care Viscoelastic Tests in the Management of Obstetric Hemorrhage

Obstetric hemorrhage remains the leading cause of maternal morbidity and mortality worldwide. Thromboelastography and rotational thromboelastometry are laboratory methods of assessing the kinetics of blood clot formation through real-time measurement of viscoelastic clot strength and may aid in management of severe hemorrhage. Although first described more than 70 years ago, viscoelastic testing devices are now available that allow for rapid point-of-care use of this technology to aid in real-time management of blood product replacement in cases of severe hemorrhage. These devices can be used to visually estimate multiple facets of hemostasis-coagulation, platelet function, and fibrinolysis-within 10-20 minutes. They have been used successfully in cardiac surgery, trauma, and liver transplantation and have potential for use in management of obstetric hemorrhage. Goals with their use include targeted transfusion of blood and its components for specific coagulation deficiencies. To date, however, published experiences with the use of these viscoelastic tests for obstetric hemorrhage have been limited. Because of the increasing use of the point-of-care tests by anesthesiologists, surgeons, and intensivists, the purpose of this report is to familiarize obstetricians with the technology involved and its use in severe hemorrhage complicating pregnancy.