Assessment and management of massive bleeding: coagulation assessment, pharmacologic strategies, and transfusion management

Clot dynamics and mortality: The MA-R ratio

INTRODUCTION

The coagulopathy of trauma, illustrated by a short R-time, is common and well understood. The physiology behind this may be early thrombin burst with rapid clot formation. Rapid consumption of fibrinogen, however, may result in weak clot and substrate depletion, resulting in low MA. While these characteristics are interesting, utilizing thromboelastography (TEG) to identify those at risk of subsequent bleeding diathesis, especially in those who do not demonstrate early signs of physiologic derangement, is challenging. We have developed a novel ratio utilizing TEG values to describe patients at specific risk of traumatic coagulopathy. The purpose of this study was to create a single TEG value, which would reflect both the hypercoagulability and hypocoagulability of TIC. We hypothesized that this ratio, at admission, would be indicative of TIC and predictive of both blood product transfusion volumes and subsequent mortality.

METHODS

Patients admitted via the highest activation criteria at one of two Level I trauma centers were included if they received at least 1 unit of packed red blood cells in the first 24 hours of admission. The admission TEG was collected, and a ratio was calculated by dividing the MA by the R-time (MA-R). MA-R quartiles were developed, and multivariable logistic regression was utilized to determine odds of mortality.

RESULTS

Three hundred thirty patients with admission TEG were included. In all patients, median age was 35 years (interquartile range, 25-54 years), Injury Severity Score (ISS) was 20 (interquartile range, 13-29), 76% were male, and 43% had penetrating trauma. The MA-R groups were based on quartiles. Multivariable analysis, controlling for mechanism of injury, ISS, and admission pH, showed that increasing ratios were associated with decreased odds of death. The lowest MA-R ratios were also significantly associated with higher ISS, higher rates of blunt injury, and higher plasma utilization without a significant difference in packed red blood cell administration.

CONCLUSIONS

Patients with the lowest MA-R ratios demonstrated the highest mortality rates. This novel ratio may prove highly useful to predict at-risk patients early, when other physiologic indicators are absent. The mechanism driving this finding may rest in fibrinogen depletion, resulting in weak clot. Patients with low MA-R ratios may benefit from earlier resuscitation with cryoprecipitate, rather than the traditional use of plasma found in current massive transfusion protocols.

LEVELS OF EVIDENCE

Prognostic study, Level I.

1: 1 Transfusion strategies are right for the wrong reasons

BACKGROUND

Early assessment of clot function identifies coagulopathies after injury. Abnormalities include a hypercoagulable state from excess thrombin generation, as well as an acquired coagulopathy. Efforts to address coagulopathy have resulted in earlier, aggressive use of plasma emphasizing 1:1 resuscitation. The purpose of this study was to describe coagulopathies in varying hemorrhagic profiles from a cohort of injured patients.

METHODS

All injured patients who received at least one unit of packed red blood cells (PRBC) in the first 24 hours of admission from September 2013 to May 2015 were eligible for inclusion. Group-Based Trajectory Modeling, using volume of transfusion over time, was used to identify specific hemorrhagic phenotypes. The thromboelastography profile of each subgroup was characterized and group features were compared.

RESULTS

Four hemorrhagic profiles were identified among 330 patients-minimal (MIN, group 1); patients with large PRBC requirements later in the hospital course (LH, group 2); massive PRBC usage (MH, group 3), and PRBC transfusion limited to shortly after injury (EH, group 4). All groups had an R-time shorter than the normal range (3.2-3.5, p = NS). Patients in group 3 had longer K-times (1.8 vs. 1.2-1.3, p < 0.05), significantly flatter α-angles (66.7 vs. 70.4-72.8, p < 0.05), and significantly weaker clot strength (MA 54.6 vs. 62.3-63.6, p < 0.05). Group 3 had greater physiologic derangements at admission and worse overall outcomes.

CONCLUSION

Hemorrhagic profiles suggest a rapid onset of clot formation in all subgroups but significantly suppressed thrombin burst and diminished clot strength in the most injured. Patients are both hypercoagulable, with early and precipitous clot formation, and also have a demonstrable hypocoagulability. The exact cause of traumatic hypocoagulability is likely multifactorial. Goal-directed resuscitation, as early as institution of the massive transfusion protocol, may be more effective in resuscitating the most coagulopathic patients.

LEVEL OF EVIDENCE

Prognostic study, level III.

Collaborative Strategies for Management of Obstetric Hemorrhage

Obstetric hemorrhage is a significant cause of perinatal morbidity and mortality that requires prompt recognition and collaborative intervention to prevent poor outcomes. Medical and surgical management goals include controlling bleeding, supporting tissue oxygenation and perfusion, and monitoring for coagulopathies and complications.

[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).

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).

Exploring ethical conflicts in emergency trauma research: the COMBAT (Control of Major Bleeding after Trauma) study experience

BACKGROUND

Up to 25% of severely injured patients develop trauma-induced coagulopathy. To study interventions for this vulnerable population for whom consent cannot be obtained easily, the Food and Drug Administration issued regulations for emergency research with an exception from informed consent (ER-EIC). We describe the community consultation and public disclosure (CC/PD) process in preparation for an ER-EIC study, namely the Control Of Major Bleeding After Trauma (COMBAT) study.

METHODS

The CC/PD was guided by the four bioethical principles. We used a multimedia approach, including one-way communications (newspaper ads, brochures, television, radio, and web) and two-way communications (interactive in-person presentations at community meetings, printed and online feedback forms) to reach the trials catchment area (Denver County's population: 643,000 and the Denver larger metro area where commuters reside: 2.9 million). Particular attention was given to special-interests groups (eg, Jehovah Witnesses, homeless) and to Spanish-speaking communities (brochures and presentations in Spanish). Opt-out materials were available during on-site presentations or via the COMBAT study website.

RESULTS

A total of 227 community organizations were contacted. Brochures were distributed to 11 medical clinics and 3 homeless shelters. The multimedia campaign had the potential to reach an estimated audience of 1.5 million individuals in large metro Denver area, the majority via one-way communication and 1900 in two-way communications. This resource intensive process cost more than $84,000.

CONCLUSION

The CC/PD process is resource-intensive, costly, and complex. Although the multimedia CC/PD reached a large audience, the effectiveness of this process remains elusive. The templates can be helpful to similar ER-EIC studies.

Dabigatran: patient management in specific clinical settings

Dabigatran, a direct thrombin inhibitor, is licensed for the prevention of venous thromboembolism after knee and hip replacement, the prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation and for the treatment of acute venous thromboembolism. As dabigatran has a favourable benefit–risk profile, it is being increasingly used. Dabigatran differs from vitamin K antagonists as regards its pharmacological characteristics and its impact on certain laboratory tests, and also in the lack of a direct antagonist that can reverse dabigatran-induced anticoagulation. In emergency settings such as acute bleeding, emergency surgery, acute coronary syndrome, thrombolysis for ischaemic stroke or overdosing, specific strategies are required. A working group of experts from various disciplines has developed strategies for the management of dabigatran-treated patients in emergency settings.

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.

How we manage AB plasma inventory in the blood center and transfusion service

The growing use of group AB plasma in the United States in recent years poses unique challenges to blood centers and transfusion services. Blood centers must collect sufficient plasma components from a limited pool of group AB donors while taking steps to improve transfusion safety that further restricts the available supply. Transfusion services, on the other hand, must use the finite resource in the most conscientious and medically appropriate manner. Recently, many investigations have challenged long-held beliefs about transfusion practice and appropriate indications for blood components across a variety of specialties. Balancing supply and demand of group AB plasma requires collaboration between blood suppliers and transfusion services, and opportunities for improvement exist on both sides of the equation.