Emerging treatment strategies for trauma-induced coagulopathy

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.

Novel Insights into Heterozygous Factor XIII Deficiency

The prevalence and clinical significance of heterozygous factor XIII (FXIII) deficiency has long been debated, with controversial reports emerging since 1988. In the absence of large epidemiologic studies, but based on a few studies, a prevalence of 1 per 1,000 to 5,000 is estimated. In southeastern Iran, a hotspot area for the disorder, a study of more than 3,500 individuals found an incidence of 3.5%. Between 1988 and 2023, a total of 308 individuals were found with heterozygous FXIII deficiency, of which molecular, laboratory, and clinical presentations were available for 207 individuals. A total of 49 variants were found in the F13A gene, most of which were missense (61.2%), followed by nonsense (12.2%) and small deletions (12.2%), most occurring in the catalytic domain (52.1%) of the FXIII-A protein and most frequently in exon 4 (17%) of the F13A gene. This pattern is relatively similar to homozygous (severe) FXIII deficiency. In general, heterozygous FXIII deficiency is an asymptomatic condition without spontaneous bleeding tendency, but it can lead to hemorrhagic complications in hemostatic challenges such as trauma, surgery, childbirth, and pregnancy. Postoperative bleeding, postpartum hemorrhage, and miscarriage are the most common clinical manifestations, while impaired wound healing has been rarely reported. Although some of these clinical manifestations can also be observed in the general population, they are more common in heterozygous FXIII deficiency. While studies of heterozygous FXIII deficiency conducted over the past 35 years have shed light on some of the ambiguities of this condition, further studies on a large number of heterozygotes are needed to answer the major questions related to heterozygous FXIII deficiency.

Impact of restrictive versus liberal transfusion and clinical outcomes in critically ill children: A retrospective observational study

Background and Aims

Critically ill children with anemia often requires blood transfusion, which can cause several complications. It is important to decide when to start the red blood cell (RBC) transfusion; however, the guidelines is still lacking. The aim of this study was to compare restrictive and liberal transfusion strategy.

Methods

This is an observational retrospective study of critically‐ill children who receive RBC transfusion. Subjects categorized into two groups by initial hemoglobin (Hb), that is, restrictive (Hb ≤ 7 g/dl) and liberal (Hb ≤ 9.5 g/dl) strategy. In each group, subjects categorized based on: (1) Hb increment: high (increased ≥2.5 g/dl) and low (increase <2.5 g/dl) and (2) final Hb level: low (<7.0 mg/dl), moderate (7.0–10.0 mg/dl), and high (>10.0 mg/dl). Patient with hematologic or congenital disorder, severe malnutrition, chronic infection‐related anemia, and transfusion in Hb level ≥9.5 g/dl were exclude. Each patients were evaluated for the clinical outcome, which is: intensive care length of stay (IC‐LOS), length of mechanical ventilation (LoMV), and mortality rate.

Results

Clinical outcome and mortality rates of both transfusion strategies are similar. The mortality rates were lower in higher Hb increment and final Hb level (p = 0.04 and p = 0.01, respectively). Multivariate analysis in all groups revealed mortality rate had moderate correlation with Hb increment (odds ratio [OR] = 0.694, 95% confidence interval [CI] 0.549–0.878; p = 0.002) and moderate correlation (OR = 0.642, 95% CI 0.519–0.795; p = 0.000) with final Hb level. The similar results was found after categorization based on transfusion strategy.

Conclusion

We conclude the restrictive and liberal transfusion strategy have a similar effect to IC‐LOS, LoMV, and mortality rate. High Hb increment (≥2.5 g/dl) and moderate‐high final Hb (≥7.0 g/dl) after transfusion reduce the mortality rate.

Severe trauma patients requiring undelayable combined cranial and extracranial surgery: A scoping review of an emerging concept

Objectives

Although patients suffering from severe traumatic brain injury (sTBI) and severe trauma patients (STP) have been extensively studied separately, there is scarce evidence concerning STP with concomitant sTBI. In particular, there are no guidelines regarding the emergency surgical management of patients presenting a concomitant life-threatening intracranial hematoma (ICH) and a life-threatening non-compressible extra-cranial hemorrhage (NCEH).

Materials and Methods

A scoping review was conducted on Medline database from inception to September 2021.

Results

The review yielded 138 articles among which 10 were retained in the quantitative analysis for a total of 2086 patients. Seven hundrer and eighty-seven patients presented concomitant sTBI and extra-cranial severe injuries. The mean age was 38.2 years-old and the male to female sex ratio was 2.8/1. Regarding the patients with concomitant cranial and extra-cranial injuries, the mean ISS was 32.1, and the mean AIS per organ were 4.0 for the head, 3.3 for the thorax, 2.9 for the abdomen and 2.7 for extremity. This review highlighted the following concepts: emergency peripheric osteosynthesis can be safely performed in patients with concomitant sTBI (grade C). Invasive intracranial pressure monitoring is mandatory during extra-cranial surgery in patients with sTBI (grade C). The outcome of STP with concomitant sTBI mainly depends on the seriousness of sTBI, independently from the presence of extra-cranial injuries (grade C). After exclusion of early-hospital mortality, the impact of extra-cranial injuries on mortality in patients with concomitant sTBI is uncertain (grade C). There are no recommendations regarding the combined surgical management of patients with concomitant ICH and NCEH (grade D).

Conclusion

This review revealed the lack of evidence for the emergency surgical management of patients with concomitant ICH and NCEH. Hence, we introduce the concept of combined cranial and extra-cranial surgery. This damage-control surgical strategy aims to reduce the time spent with intracranial hypertension and to hasten the admission in the intensive care unit. Further studies are required to validate this concept in clinical practice.

Improved Hemodynamic Recovery and 72-Hour Survival Following Low-Volume Resuscitation with a PEGylated Carboxyhemoglobin in a Rat Model of Severe Hemorrhagic Shock

INTRODUCTION

Hemorrhage is a leading cause of death from potentially survivable civilian and military trauma. As projected conflicts move from settings of tactical and logistical supremacy to hyper-dynamic tactical zones against peer and near-peer adversaries, protracted medical evacuation times are expected. Treatment at the point-of-injury is critical. Although crystalloids like Lactated Ringer's (LR) are ubiquitous, whole blood (WB) is the preferred resuscitation fluid following hemorrhage; however, logistical constraints limit the availability of WB in prehospital settings. Hemoglobin-based oxygen carriers (HBOCs) offer both hemodynamic support and oxygen-carrying capacity while avoiding logistical constraints of WB. We hypothesized that low-volume resuscitation of severe hemorrhagic shock with an HBOC (PEGylated carboxyhemoglobin, [PC]) would improve hemodynamic recovery and 72-hour survival; comparable to WB and superior to LR.

MATERIALS AND METHODS

A total of 21 anesthetized male Sprague-Dawley rats underwent severe hemorrhagic shock followed by randomly assigned low-volume resuscitation with LR, WB, or PC, and then recovered from anesthesia for up to 72-hour observation. Mean arterial pressure (MAP) was recorded continuously under anesthesia, and arterial blood gases were measured at baseline (BL), 60 minutes post-hemorrhage (HS1h), and 24 hours post-resuscitation (PR24h). Survival was presented on a Kaplan-Meier plot and significance determined with a log-rank test. Cardiovascular and blood gas data were assessed with one-way analysis of variance and post hoc analysis where appropriate.

RESULTS

All measured cardiovascular and blood chemistry parameters were equivalent between groups at BL and HS1h. BL MAP values were 90 ± 3, 86 ± 1, and 89 ± 2 mmHg for LR, PC, and WB, respectively. Immediately following resuscitation, MAP values were 57 ± 4, 74 ± 5, and 62 ± 3 mmHg, with PC equivalent to WB and higher than LR (P < 0.05). WB and LR were both lower than BL (P < 0.0001), whereas PC was not (P = 0.13). The PC group's survival to 72 hours was 57%, which was not different from WB (43%) and higher than LR (14%; P < 0.05).

CONCLUSIONS

A single bolus infusion of PC produced superior survival and MAP response compared to LR, which is the standard fluid resuscitant carried by combat medics. PC was not different from WB in terms of survival and MAP, which is encouraging because its reduced logistical constraints make it viable for field deployment. These promising findings warrant further development and investigation of PC as a low-volume, early treatment for hemorrhagic shock in scenarios where blood products may not be available.

Anaesthetic considerations in polytrauma patients

Trauma remains a major public health concern due to the high cost, associated morbidity, and mortality both in developed and developing countries. Management of polytrauma patients has advanced and improved over the last few decades with a better understanding of the pathophysiology of shock, resuscitation, and hemodynamic changes. Anaesthesia and application of anaesthetic principles have consequently evolved and can be applied in polytrauma patients throughout their journey of treatment beginning from pre-hospital care, emergency department resuscitation, surgical procedures, and rehabilitation. Providing immediate pain relief is an important component in the management of these patients. Performing peripheral nerve blocks in the pre-hospital setting when feasible or on arrival in the emergency room provides rapid pain relief, better patient co-operation, decreases the risk of chronic pain syndromes. This narrative evaluates the role of anaesthesia and anaesthesiologists in the management of polytrauma patients. The authors performed a thorough review of the literature using various databased of Medline, PubMed, Embase, and Google Scholar. The relevant papers were also searched manually from the cross-referencing of retrieved papers. Full papers published in English till September 25, 2020 were included for this review. The keywords included 'trauma', 'difficult airway', 'anaesthesia', 'fluid and blood', 'monitoring', 'critical care', 'resuscitation' and 'surgery' in various combinations. The holistic management of trauma victims requires a multidisciplinary time-based approach for an optimal outcome. The management starts from assessment and simultaneous management for the optimization of the trauma victim from the first point of contact itself. The anaesthetic technique of choice in the perioperative management of trauma patients depends on different factors such as neurological status, cardiovascular stability, type and duration of surgery, coagulation status. Regional techniques are to be used whenever possible due to the beneficial effects observed with these techniques. Various important aspects are being discussed in subsequent sections.

Strategies to minimize intraoperative blood loss during major surgery

Background

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

Methods

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

Results

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

Conclusion

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

Fluid resuscitation with 0.9% saline alters haemostasis in an ovine model of endotoxemic shock

INTRODUCTION

Fluid resuscitation is a cornerstone of severe sepsis management, however there are many uncertainties surrounding the type and volume of fluid that is administered. The entire spectrum of coagulopathies can be seen in sepsis, from asymptomatic aberrations to fulminant disseminated intravascular coagulation (DIC). The aim of this study was to determine if fluid resuscitation with saline contributes to the haemostatic derangements in an ovine model of endotoxemic shock.

MATERIALS AND METHODS

Twenty-one adult female sheep were randomly divided into no endotoxemia (n = 5) or endotoxemia groups (n = 16) with an escalating dose of lipopolysaccharide (LPS) up to 4 μg/kg/h administered to achieve a mean arterial pressure below 60 mmHg. Endotoxemia sheep received either no bolus fluid resuscitation (n = 8) or a 0.9% saline bolus (40 mL/kg over 60 min) (n = 8). No endotoxemia, saline only animals (n = 5) underwent fluid resuscitation with a 0.9% bolus of saline as detailed above. Hemodynamic support with vasopressors was initiated if needed, to maintain a mean arterial pressure (MAP) of 60-65 mm Hg in all the groups.

RESULTS

Rotational thromboelastometry (ROTEM®) and conventional coagulation biomarker tests demonstrated sepsis induced derangements to secondary haemostasis. This effect was exacerbated by saline fluid resuscitation, with low pH (p = 0.036), delayed clot initiation and formation together with deficiencies in naturally occurring anti-coagulants antithrombin (p = 0.027) and Protein C (p = 0.001).

CONCLUSIONS

Endotoxemia impairs secondary haemostasis and induces changes in the intrinsic, extrinsic and anti-coagulant pathways. These changes to haemostasis are exacerbated following resuscitation with 0.9% saline, a commonly used crystalloid in clinical settings.

Rotation thromboelastometry (ROTEM) enables improved outcomes in the pediatric trauma population

Objective

We evaluated the role of rotation thromboelastometry (ROTEM) in managing acute traumatic coagulopathy in pediatric patients with trauma.

Methods

A retrospective cohort of pediatric patients with trauma from six institutes was studied during a 10-year period from 2007 to 2017. The associations between ROTEM-guided, goal-directed coagulation therapy and clinical outcomes were determined.

Results

Three hundred thirty-two pediatric patients (age < 15 years) who were treated with ROTEM-guided, goal-directed coagulation therapy were matched to 332 control pediatric patients with conventional plasmatic coagulation tests. The ROTEM protocol was associated with a significant reduction in the interval for admission to acute traumatic coagulopathy treatment, less plasma transfusions in the first 24 hours of admission, and a favorable coagulopathy recovery. Furthermore, the median number of total hospital days was significantly shorter for patients who had the ROTEM protocol than for control patients.

Conclusions

There are significant favorable outcomes, including rapid acute traumatic coagulopathy treatment and a lower 24-hour blood product requirement, following ROTEM-guided, goal-directed coagulation therapy among pediatric patients with blunt trauma.

Efficacy of Thromboelastography (TEG) in Predicting Acute Trauma-Induced Coagulopathy (ATIC) in Isolated Severe Traumatic Brain Injury (iSTBI)

To evaluate the efficacy of point-of-care thromboelastography (TEG) to predict acute trauma-induced coagulopathy (ATIC) in isolated severe TBI (iSTBI). We conducted an observational diagnostic cohort. Patients for whom TEG was performed before blood transfusion were stratified by conventional coagulation tests (CCTs) on admission and classified as "ATIC" (prothrombin time ≥ 16.70 s; international normalized ratio ≥ 1.27; activated partial thromboplastin time ≥ 28.80 s) (n = 24) or "no ATIC" (n = 34). Univariate analysis to compare groups, receiver operating characteristic analysis to establish cut-off and diagnostic validation was done. Fifty-eight patients were included [32(25-45) years; 97% male; GCS 6.3 ± 1.5]. 41% developed ATIC. Compared to no-ATIC, ATIC group had significantly prolonged κ-time (4.6 vs. 2.5 min; p = 0.01) and shortened α-angle (40.2° vs. 56.3°; p = 0.03). A cut-off for κ-time ≥ 3.7 (AUC 0.68 95% CI 0.54-0.82, specificity 70%, sensitivity 63%) and α angle ≤ 48.0 (AUC 0.66, 95% CI 0.51-0.81, specificity 67%, sensitivity 67%) was established. The diagnostic accuracy of this cut-off for identifying ATIC, was 55.6% with sensitivity (81.8%) and specificity (14.3%). TEG may be a clinically sensitive test for identifying the underlying coagulopathy following TBI. However confirmation with CCTs is recommended.

Hypotensive Resuscitation with Hypertonic Saline Dextran Improves Survival in a Rat Model of Hemorrhagic Shock at High Altitude

OBJECTIVE

To compare the efficacy of hypotensive resuscitation with hypertonic saline dextran 70 (HSD) and lactated Ringer (LR) solutions in a rat model of hemorrhagic shock at a simulated altitude of 4,000 m.

METHODS

Anesthetized rats were bled to maintain their mean arterial pressure (MAP) at 45 mm Hg for 1 h. The distal quarter of the tail was then amputated to allow free blood loss; rats were simultaneously resuscitated with 4 mL kg HSD (HSD group, n = 10) or 4 mL kg LR (LR group, n = 10), followed by hypotensive resuscitation with LR to maintain MAP at 55 to 60 mm Hg for 1 h. A control group received no resuscitation (n = 10). Afterward, the cut end of the tail was ligated. The MAP, acid-base balance, blood loss, volume of fluid infused, and survival were recorded.

RESULTS

Compared with controls, HSD resuscitation improved MAP (without increasing uncontrolled blood loss), increased arterial pH and oxygen saturation (SaO2), decreased arterial lactate concentration at the end of resuscitation, and resulted in higher survival rate (P < 0.05). Hypotensive resuscitation with LR also maintained higher MAP, pH, and SaO2 than the control group, but was associated with increased blood loss and inferior survival (P > 0.05).

CONCLUSIONS

For hemorrhagic shock at simulated high altitude, resuscitation of rats with a bolus of HSD was associated with reduced blood loss and serum lactate concentration, and superior SaO2, hemoglobin concentration and survival rate, compared with LR solution.

Hemostatic Therapy Using Tranexamic Acid and Coagulation Factor Concentrates in a Model of Traumatic Liver Injury

BACKGROUND

The potential clinical benefits of targeted therapy with coagulation factor concentrates (e.g., fibrinogen) and antifibrinolytic agents (e.g., tranexamic acid [TXA]) for the treatment of trauma-induced coagulopathy are increasingly recognized. We hypothesized that human fibrinogen concentrate (FC) and prothrombin complex concentrate (PCC), administered as combined therapy with TXA, would provide additive effects for reducing blood loss in an animal trauma model.

METHODS

Thirty-six pigs were subjected to 2 consecutive blunt liver injuries, resulting in severe hemorrhagic shock and coagulopathy. Intervention comprised saline (control group); TXA (15 mg kg, TXA group); TXA and FC (90 mg kg, TXA-FC); or TXA, FC, and PCC (20 U kg, TXA-FC-PCC). Blood loss, thromboelastometry (ROTEM), measures of thrombin generation, platelet activation, and global coagulation variables were monitored for 4 hours. Tissue sections were examined to determine the occurrence of thromboembolic events.

RESULTS

Total blood loss was similar in the TXA-FC and TXA-FC-PCC groups (mean ± SD: 1012 ± 86 mL and 1037 ± 118 mL, respectively; P = 1.000). These values were both lower (P < 0.001) than the TXA group (1579 ± 306 mL). Blood loss in all 3 intervention groups was lower (P < 0.001) than in the control group (2376 ± 478 mL). After trauma and resuscitation, but before study intervention, plasma fibrinogen levels were severely depleted (median for the whole study population: 66 mg dL; interquartile range: 51-108 mg dL) and clot strength was decreased (EXTEM whole-blood maximum clot firmness [MCF]: 53 ± 5 mm). Compared with controls, TXA inhibited fibrinolysis and stabilized MCF and clotting time. The addition of FC restored and stabilized hemostasis to a greater extent than TXA alone; the addition of PCC had no statistically significant impact on blood loss, clot strength (MCF), or clotting time, but it increased thrombin generation. There were no significant differences among the study groups regarding platelet activation. No thrombi or microthrombi were observed in any group at necropsy.

CONCLUSIONS

The early use of TXA and FC reduced blood loss and improved coagulation measurements in a porcine model of blunt liver injury and hemorrhagic shock. FC, administered in addition to TXA, was highly effective in reducing blood loss. The lack of statistically significant reduction in blood loss when PCC was added to TXA and FC may be attributable to the absence of thrombin generation impairment in this model.

Moderate plasma dilution using artificial plasma expanders shifts the haemostatic balance to hypercoagulation

Artificial plasma expanders (PEs) are widely used in modern transfusion medicine. PEs do not contain components of the coagulation system, so their infusion in large volumes causes haemodilution and affects haemostasis. However, the existing information on this effect is contradictory. We studied the effect of the very process of plasma dilution on coagulation and tested the hypothesis that moderate dilution with a PE should accelerate clotting owing to a decrease in concentration of coagulation inhibitors. The standard clotting times, a thrombin generation test, and the spatial rate of clot growth (test of thrombodynamics) were used to assess donor plasma diluted in vitro with various PEs. The pH value and Ca⁺² concentration were maintained strictly constant in all samples. The effect of thrombin inhibitors on dilution-induced hypercoagulation was also examined. It was shown that coagulation was enhanced in plasma diluted up to 2.0-2.5-fold with any PE. This enhancement was due to the dilution of coagulation inhibitors in plasma. Their addition to plasma or PE could partially prevent the hypercoagulation shift.

Adhesion of Blood Clots Can Be Enhanced When Copolymerized with a Macromer That Is Crosslinked by Coagulation Factor XIIIa

The adhesion of blood clots to blood vessels, such as through the adhesion of fibrin, is essential in hemostasis. While numerous strategies for initiating clot formation and preventing clot lysis are being developed to create improved hemostatic agents, strategies for enhancing clot adhesion have not been widely explored. Here, we show that adhesion of blood clots can be increased by adding a previously characterized synthetic polymer that is crosslinked by coagulation factor XIIIa during clotting. Addition of the polymer to normal plasma increased the adhesive strength of clots by 2-fold. It also recovered the adhesive strength of nonadhesive fibrinogen-deficient whole blood clots from <0.06 kPa to 1.9 ± 0.14 kPa, which is similar to the adhesive strength of a fibrinogen-rich clot (1.8 ± 0.64 kPa). The polymer also enabled plasma clots to remain adhered under fibrinolytic conditions. By demonstrating that the adhesive strength of clots can be increased with a synthetic material, this provides a potential strategy for creating advanced hemostatic materials, such as treatments for fibrinogen deficiency in trauma-induced coagulopathy.

Interventional Algorithms for the Control of Coagulopathic Bleeding in Surgical, Trauma, and Postpartum Settings: Recommendations From the Share Network Group

Several clinical settings are associated with specific coagulopathies that predispose to uncontrolled bleeding. With the growing concern about the need for optimizing transfusion practices and improving treatment of the bleeding patient, a group of 9 Portuguese specialists (Share Network Group) was created to discuss and develop algorithms for the clinical evaluation and control of coagulopathic bleeding in the following perioperative clinical settings: surgery, trauma, and postpartum hemorrhage. The 3 algorithms developed by the group were presented at the VIII National Congress of the Associação Portuguesa de Imuno-hemoterapia in October 2013. They aim to provide a structured approach for clinicians to rapidly diagnose the status of coagulopathy in order to achieve an earlier and more effective bleeding control, reduce transfusion requirements, and improve patient outcomes. The group highlights the importance of communication between different specialties involved in the care of bleeding patients in order to achieve better results.

Topical hemostatic agents and dressings in the prehospital setting

PURPOSE OF REVIEW

Death from exsanguinating hemorrhage remains a priority in the management of combat casualties and civilian trauma patients with truncal and junctional injuries. Appropriate use of hemostatic agents and dressings in the prehospital setting may allow for earlier control and an improved survival rate.

RECENT FINDINGS

Third-generation chitosan-based hemostatic agents and dressings appear to be equally efficacious to the dressing currently deployed by the US military forces in the management of hemorrhage not amenable to tourniquet placement. Unfortunately, a lack of clinical trials places a heavy reliance on anecdotal reports and laboratory studies in agent selection and application.

SUMMARY

Efficacy of currently available hemostatic agents and dressings appears to have plateaued in recent years although new agents and delivery mechanisms under development may improve control in cases of severe hemorrhage.

Patterns of early resuscitation associated with mortality after penetrating injuries

BACKGROUND

Penetrating injuries are rare in European populations so their management represents a particular challenge. The aim was to assess early therapeutic aspects that are associated with favourable outcomes in patients with penetrating trauma.

METHODS

Patients with penetrating injuries documented from 2009 to 2013 in the TraumaRegister DGU® were analysed. Patients with a primary admission and an Injury Severity Score (ISS) of at least 9 were included. The Revised Injury Severity Classification (RISC) II score was used for mortality prediction, and a standardized mortality ratio (SMR) calculated per hospital. Hospitals with favourable outcome (SMR below 1) were compared with those with poor outcome (SMR 1 or more).

RESULTS

A total of 50 centres had favourable outcome (1242 patients; observed mortality rate 15.7 per cent) and 34 centres had poor outcome (918 patients; observed mortality rate 24.4 per cent). Predicted mortality rates according to RISC-II were 20.4 and 20.5 per cent respectively. Mean(s.d.) ISS values were 22(14) versus 21(14) (P = 0.121). Patients in the favourable outcome group had a significantly shorter time before admission to hospital and a lower intubation rate. They received smaller quantities of intravenous fluids on admission to the emergency room, but larger amounts of fresh frozen plasma, and were more likely to receive haemostatic agents. A higher proportion of patients in the favourable outcome group were treated in a level I trauma centre. Independent risk factors for hospital death following penetrating trauma identified by multivariable analysis included gunshot injury mechanism and treatment in non-level I centres.

CONCLUSION

Among penetrating traumas, gunshot injuries pose an independent risk of death. Treatment of penetrating trauma in a level I trauma centre was significantly and independently associated with lower hospital mortality.

Trauma-induced coagulopathy

Coagulopathy is the inability of blood to coagulate normally; in trauma patients, it is a multifactorial and complex process. Seriously injured trauma patients experience coagulopathies during the acute injury phase. Risk factors for trauma-induced coagulopathy include hypothermia, metabolic acidosis, hypoperfusion, hemodilution, and fluid replacement. In addition to the coagulopathy induced by trauma, many patients may also be taking medications that interfere with hemostasis. Therefore, medication-induced coagulopathy also is a concern. Traditional laboratory-based methods of assessing coagulation are being supported or even replaced by point-of-care tests. The evidence-based management of trauma-induced coagulopathy should address hypothermia, fluid resuscitation, blood components administration, and, if needed, medications to reverse identified coagulation disorders.

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.

[Prehospital resuscitation of patients with multiple injuries]

INTRODUCTION

Polytrauma is the leading cause of morbidity and mortality in young adults (aged 35-45 years). At 30-40%, traumatic hemorrhage is the most frequent preventable cause of death. Approximately every fourth patient with multiple injuries suffers from trauma-induced coagulopathy.

METHODS

The current knowledge of prehospital resuscitation of patients with multiple injuries based on a selective literature research and experience in a level I trauma center are presented.

RESULTS

Hemorrhagic shock is a clinical diagnosis and the recognition by the first responding emergency physician requires rapid evaluation of the accident situation, injury pattern and patient's hemodynamic status. In the future, tools will help to reliably estimate shock. Development of trauma-induced coagulopathy is multifactorial and is characterized by interaction of tissue damage, shock, hypothermia, acidosis and dilution. Preclinical therapy follows the concept of damage control resuscitation and involves bleeding hemostasis, permissive hypotension with a target systolic blood pressure between 80 and 90 mmHg (≥80 mmHg in presence of traumatic brain injury) by modest infusion of primarily crystalloid solutions, avoiding hypothermia and acidosis.

CONCLUSION

The current knowledge and therapy recommendations are presented.

Damage control resuscitation

The early recognition and management of hemorrhage shock are among the most difficult tasks challenging the clinician during primary assessment of the acutely bleeding patient. Often with little time, within a chaotic setting, and without sufficient clinical data, a decision must be reached to begin transfusion of blood components in massive amounts. The practice of massive transfusion has advanced considerably and is now a more complete and, arguably, more effective process. This new therapeutic paradigm, referred to as damage control resuscitation (DCR), differs considerably in many important respects from previous management strategies for catastrophic blood loss. We review several important elements of DCR including immediate correction of specific coagulopathies induced by hemorrhage and management of several extreme homeostatic imbalances that may appear in the aftermath of resuscitation. We also emphasize that the foremost objective in managing exsanguinating hemorrhage is always expedient and definitive control of the source of bleeding.

Transfusion of Blood and Blood Products

In transfusion medicine, several blood products can be prepared and used as replacement therapy; however, four of these products are more commonly used in general practice: RBCs, fresh frozen plasma (FFP), platelets and cryoprecipitate. RBC transfusions are mainly administered to improve tissue oxygenation in cases of anaemia or acute blood loss due to trauma or surgery. FFP, platelets and cryoprecipitate are used for the prevention and treatment of bleeding.

Prothrombin complex concentrate in trauma patients

BACKGROUND

Despite recent advances, trauma care providers nowadays face a number of coagulopathic patients. Coagulopathy in trauma patients can be secondary to the traumatic insult or therapeutic effect of the anticoagulants including the Vitamin K antagonist. The efficacy of a concentrated product of Vitamin K-dependent coagulation factors, prothrombin complex concentrate (PCC), to reverse coagulopathy has been tested mainly in nontrauma setting.

DATA SOURCES

Currently available literature on the use of PCC was identified by searches of electronic database. The indications (trauma vs nontrauma) and types of the PCC products (3 vs 4 factors) were also reviewed in each article.

CONCLUSIONS

There are small studies that show promising results regarding PCC use to reverse the Vitamin K antagonist-related coagulopathy in trauma patients. It remains unanswered whether PCC can be effective as an adjunct in patients who require massive transfusion.

Platelet aggregation and clot formation in comatose survivors of cardiac arrest treated with induced hypothermia and dual platelet inhibition with aspirin and ticagrelor; a prospective observational study

INTRODUCTION

We conducted a prospective observational study in cardiac arrest survivors treated with mild induced hypothermia, evaluating different platelet function tests at hypo- and normothermia. We also investigated the relation between gastric emptying and vasodilator stimulated phosphoprotein (VASP).

METHODS

Comatose survivors of out of hospital cardiac arrest were included and divided into two groups, depending on whether dual platelet inhibition with peroral ticagrelor and aspirin was given or not. The first blood samples (T1) were collected 12-24 hours after reaching target temperature (33°C) and were compared to blood samples collected 12-28 hours after reaching normothermia (37°C) (T2) within each group. All samples were analysed by Sonoclot viscoelasticity, flow cytometry based VASP and with multiple electrode aggregometry, Multiplate®; adenosine diphosphate (ADP), collagen (COL), thrombin receptor agonist peptide (TRAP) and arachidonic acid (ASPI). Sonoclot and Multiplate® instruments were set on in vivo temperatures. Gastric secretion from the nasogastric tube was measured to assess absorption of per orally administered antiplatelet drugs. Differences between T1 and T2 within each group were calculated using Wilcoxon matched pairs signed test. Significance levels were set at P <0.01.

RESULTS

In total, 23 patients were included. In patients with dual platelet inhibition (n =14) Multiplate®-analyses showed no changes in ADP stimulated platelets. COL, TRAP and ASPI aggregations were higher at T2 compared to T1. Sonoclot-analyses showed that activated clotting time (ACT) was unchanged but both clot rate (CR) and platelet function (PF) were higher at T2 compared to T1. VASP decreased from 53 ± 28(T1) to 24 ± 22(T2), (P <0.001). The average volume of gastric secretion aspirated before T1 correlated well with VASP (T1), r =0.81 (P <0.001). In patients with no platelet inhibition, (n =9) similar changes between T1 and T2 were seen as in patients with dual platelet inhibition while VASP was unchanged.

CONCLUSIONS

We have demonstrated increased platelet aggregation and strengthened clot formation over time in out of hospital cardiac arrest patients treated with hypothermia. In patients on oral dual platelet inhibition, the effect of ticagrelor was delayed, probably due to slow gastric emptying.

Perioperative coagulopathy monitoring

Coagulopathy is common in orthopedic surgery patients either due to acquired factors, such as surgery, trauma, medications, or hemorrhage. Perioperative monitoring of blood coagulation is critical to diagnose the causes of hemorrhage, guide hemostatic therapies, predict the risk of bleeding during surgical procedures, and reduce risk of postoperative cardiac and thromboembolic events. In contrast to previous interventions that measure specific portions of the clotting cascade (such as intrinsic or extrinsic pathways or platelet aggregation), "Point-of-care" coagulation monitoring devices assess the viscoelastic properties of whole blood. These techniques have the potential to measure the entire clotting process, starting with fibrin formation, clot retraction, and fibrinolysis. Furthermore, the coagulation status of patients is assessed in whole blood, allowing the plasmatic coagulation system to interact with platelets and red cells, and thereby providing useful additional information on platelet function. Improved monitoring of coagulopathy is particularly important as new anticoagulant drugs emerge that affect the clotting cascade in novel ways, including the inhibition of intrinsic and extrinsic pathways and platelet function. It is important for orthopedic surgeons to understand the pharmacology and reversal of these drugs in the perioperative setting. The purpose of this review is to review the current techniques to monitoring perioperative coagulopathy and to identify the manner in which novel anticoagulant medications affect the clotting cascade with particular interest in trauma and spine surgery.

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.

Trauma-induced coagulopathy: from biology to therapy

Trauma is a leading cause of death and disability. Hemorrhage is the major mechanism responsible for death during the first 24 hours following trauma. One quarter of severely injured patients present in the emergency room with acute coagulopathy of trauma and shock (ACOT). The drivers of ACOT are tissue hypoperfusion, inflammation, and activation of the neurohumoral system. ACOT is a result of protein C activation with cleavage of activated factor VIII and V and inhibition of plasminogen activator inhibitor-1 (PAI-1). The resuscitation-associated coagulopathy (RAC) is secondary to a combination of acidosis, hypothermia and dilution from intravenous blood and fluid therapy. RAC may further aggravate acidosis and hypoxia resulting in a vicious cycle. This review focuses on the biology of the trauma-associated coagulopathy, and reviews current therapeutic strategies.

TEG and ROTEM: technology and clinical applications

Initially described in 1948 by Hertert thromboelastography (TEG) provides a real-time assessment of viscoelastic clot strength in whole blood. Rotational thromboelastometry (ROTEM) evolved from TEG technology and both devices generate output by transducing changes in the viscoelastic strength of a small sample of clotting blood (300 µl) to which a constant rotational force is applied. These point of care devices allow visual assessment of blood coagulation from clot formation, through propagation, and stabilization, until clot dissolution. Computer analysis of the output allows sophisticated clot formation/dissolution kinetics and clot strength data to be generated. Activation of clot formation can be initiated with both intrinsic (kaolin, ellagic acid) and extrinsic (tissue factor) activators. In addition, the independent contributions of platelets and fibrinogen to final clot strength can be assessed using added platelet inhibitors (abciximab and cytochalasin D). Increasingly, ROTEM and TEG analysis is being incorporated in vertical algorithms to diagnose and treat bleeding in high-risk populations such as those undergoing cardiac surgery or suffering from blunt trauma. Some evidence suggests these algorithms might reduce transfusions, but further study is needed to assess patient outcomes.

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.

Fibrin patch in a pig model with blunt liver injury under severe hypothermia

BACKGROUND

Rapid control of hemorrhage is one of the key aspects in trauma handling. To cope with bleeding, local hemostatic approaches are useful, along with surgical and systemic homostatic therapy. In this experimental study, we investigated the efficacy of a fibrinogen/thrombin containing collagen patch (TachoSil) in a coagulopathic pig model with blunt liver trauma under severe hypothermia.

METHODS

Eighteen anesthetized pigs underwent hemodilution by exchanging 70% of the blood volume with Ringer Lactate solution and hydroxyethyl starch 130/0.4 (1:1). Ten minutes after induction of a grade III blunt liver trauma, the animals randomly received treatment with TachoSil (FT-patch, n = 9) or a collagen patch (Tachotop, control group, n = 9). Blood loss, hemodynamics, and coagulation parameters were observed for 2 h. To confirm the consistency of liver trauma, pathologic examination of the liver tissue was performed.

RESULTS

Hypothermia (33.5°C ± 0.5°C) and hemodilution led to severe coagulopathy as measured by thromboelastometry and coagulation parameters. After trauma and patch application, thromboelastometry and coagulation parameters in the control group showed further deterioration compared with the stable parameters in the FT-patch group. The total blood loss was significantly reduced in the FT-patch group (FT-patch: 1195 mL; control group: 2495 mL; P < 0.001). Concordantly, the control animals were hemodynamically jeopardized to a higher degree. Microscopy confirmed a similar degree of liver injury.

CONCLUSIONS

Despite severe hypothermia and coagulopathy, TachoSil provided effective hemorrhage control in pigs with blunt liver injury. Therefore, TachoSil demonstrated usefulness as an additional early therapy in cases of uncontrolled bleeding following severe trauma.

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.

Logistics of transfusion support for patients with massive hemorrhage

PURPOSE OF REVIEW

Traditionally, trauma resuscitation protocols have advocated sequential administration of therapeutic components, beginning with crystalloid solutions infused to replace lost intravascular volume. However, rapid restoration of the components of blood is essential for ensuring adequate tissue perfusion and for preventing acidosis, coagulopathy, and hypothermia, referred to as the 'lethal triad' in trauma settings. The review summarizes practical approaches for transfusion support of patients with massive hemorrhage.

RECENT FINDINGS

Massive transfusion protocols for blood transfusion support are reviewed, including practical considerations from our own. We maintain an inventory of thawed, previously frozen plasma (four units each of blood group O and A), which can be issued immediately for patients in whom the blood type is known. As frozen plasma requires 45 min to thaw, liquid AB plasma (26 day outdate) functions as an excellent alternative, particularly for patients with unknown or blood group B or AB types.

SUMMARY

Close monitoring of bleeding and coagulation in trauma patients allows goal-directed transfusions to optimize patients' coagulation, reduce exposure to blood products, and to improve patient outcomes. Future studies are needed to understand and demonstrate improved patient outcomes.

Potential value of protocols in substantially bleeding trauma patients

PURPOSE OF REVIEW

Early identification of shock and coagulopathy coupled with damage control resuscitation are central tenets of early trauma management. In traumatic injury, haemorrhage is responsible for almost 50% of deaths occurring within the first 24 h of injury and up to 80% of intraoperative trauma mortalities. Immediate haemorrhagic mortality constitutes the largest group of potentially preventable deaths in the initial 24-h period. This review will discuss the recent changes and advancement of early traumatic coagulopathy and the important role of substantial bleeding protocols (SBPs).

RECENT FINDINGS

Ho et al. examined survivor bias and determined when accounting for survivor bias improved survival outcome with higher fresh frozen plasma: red blood cell ratios. The PROMMTT study, a 10-centre observation trial, highlighted the variable nature of infusion, the importance of time and improved outcomes with higher product ratios.

SUMMARY

An SBP addresses the organizational issues necessary to respond to massive blood loss in an immediate and sustained manner. It reduces provider variability, facilitates staff communication and compliance, and simplifies the administration of predefined ratios of blood components. A transfusion subcommittee should be formed to directly address the complex issues of implementing a SBP system.

Hemodilution as a result of aggressive fluid resuscitation aggravates coagulopathy in a rat model of uncontrolled hemorrhagic shock

BACKGROUND

The relationship between dilution caused by fluid resuscitation and blood coagulability during ongoing, uncontrolled hemorrhagic shock (UHS) remains unclear. We hypothesized that dilution caused by fluid resuscitation may impair blood coagulability in UHS.

METHODS

Eighteen rats underwent under halothane anesthesia. The UHS model consisted of the following phases: (1) an initial blood withdrawal of 2.5 mL per 100 g during 15 minutes, followed by UHS via tail amputation and fluid resuscitation with lactated Ringer's (LR) solution (0-60 minutes); (2) hemostasis and reinfusion of withdrawn blood and additional LR solution (60-100 minutes); and (3) observation of awake rats for 72 hours. Rats were randomized into three resuscitation regimens (n = 6 per group) during Phase I. LR solution was infused at a rate of 0.1 mL/min in Group 1, 0.25 mL/min in Group 2, and 0.75 mL/min in Group 3. Blood coagulability was assessed with a Sonoclot analysis, and survival to 72 hours were compared between groups.

RESULTS

Both resuscitation regimens of Groups 2 and 3 increased the blood pressure and bleeding volume from the tail stump compared with Group 1 (p < 0.05). At the end of Phase I, the hematocrit decreased to 29% (3%) in Group 1, 23% (3%) in Group 2, and 12% (3%) in Group 3 (p < 0.05). Sonoclot analysis revealed a decreased clot rate of 16 (9) clot signal per minute in Group 2 and 14 (10) clot signal per minute in Group 3 compared with Group 1 (40 [10] clot signal per minute; p < 0.01). There was a significant correlation between clot rate and hematocrit values (r = +0.67, p < 0.01). Compared with Group 1, survival improved in Groups 2 and 3 (p < 0.05).

CONCLUSION

In a rat model of UHS, aggressive fluid resuscitation aggravated hemodilution and blood coagulability as well as and bleeding but improved the hemodynamics and survival. There was a positive correlation between hemodilution and coagulation indexes. Hemodilution, as part of fluid therapy, may affect coagulopathy in UHS.

The volume-expanding effects of autologous liquid stored plasma following hemorrhage

BACKGROUND

Plasma use has increased since studies have suggested that early treatment with blood components in trauma with severe hemorrhage may improve outcome. Plasma is also commonly used to correct coagulation disturbances in non-bleeding patients. Little is known about the effects of plasma transfusion on plasma volume. We report a prospective interventional study in which the plasma volume-expanding effect of autologous plasma was investigated after a controlled hemorrhage.

METHODS

Plasma obtained by plasmapheresis from nine healthy regular blood donors was stored at 2-6°C. Five weeks after donation the subjects were bled of 600 ml and then transfused with 600 ml of autologous plasma. Plasma volume was estimated using (125)I-albumin before and after bleeding, and immediately after plasma transfusion. Plasma volume changes were then estimated by measuring changes in hematocrit during the following 3-h period.

RESULTS

Estimated plasma volume after bleeding was 3170 ± 320 ml and 3690 ± 380 ml (mean ± standard deviation) immediately following the transfusion of plasma (p 0.05). This increase in plasma volume corresponds to 86 ± 13% of the infused volume. Three hours after transfusion, plasma volume was still 3680 ± 410 ml.

CONCLUSIONS

Stored liquid plasma has a plasma volume expanding effect up to 86% of its infused volume with a duration of at least 3 h.

Treatment of Acute Coagulopathy Associated with Trauma

Coagulopathy is frequently present in trauma. It is indicative of the severity of trauma and contributes to increased morbidity and mortality. Uncontrolled bleeding is the most frequent preventable cause of death in trauma patients reaching hospital alive. Coagulopathy in trauma has been long thought to develop as a result of hemodilution, acidosis, and hypothermia often related to resuscitation practices. However, altered coagulation tests are already present in 25–30% of severe trauma patients upon hospital arrival before resuscitation efforts. Acute coagulopathy associated with trauma (ACoT) has been recognized in recent years as a distinct entity associated with increased mortality, morbidity, and transfusion requirements. Transfusion and nontransfusion strategies aimed at correcting ACoT, particularly in patients with massive bleeding and massive transfusion, are currently available. Early administration of tranexamic acid to bleeding trauma patients safely reduces the risk of death. It has been proposed that early aggressive blood product transfusional management of ACoT with a red blood cell : plasma : platelets ratio close to 1 : 1 : 1 could result in decreased mortality from uncontrolled bleeding.

The microcirculation: linking trauma and coagulopathy

Survival after severe traumatic shock can be complicated by a number of pathophysiologic processes that ensue after the initial trauma. One of these is trauma-induced coagulopathy (TIC) whose onset may occur before initial fluid resuscitation. The pathogenesis of TIC has not yet been fully elaborated, but evolving evidence appears to link severe tissue hypoxia and damage to the endothelium as key factors, which evolve into measurable structural and biochemical changes of the endothelium resulting in a coagulopathic state. This paper will provide a general review of these linkages and identify knowledge gaps as well as suggest new approaches and areas of investigation, which may both limit the development of TIC as well as produce insights into its pathophysiology. A better understanding of these issues will be necessary in order to advance the practice of remote damage control resuscitation.