Measuring coagulation in burns: an evidence-based systematic review

Efficacy of tranexamic acid versus placebo in reducing blood loss during burn excisional surgery: a multi-center, double-blind, parallel, randomized placebo-controlled clinical trial (TRANEX)

BACKGROUND

Despite an increase in knowledge, blood loss during burn excisional surgery remains a major challenge and is an independent predictor of mortality. During burn surgery, limited measures are available to control the bleeding. Increased fibrinolysis could be one of the contributing factors of blood loss during burn excisional surgery. Tranexamic acid inhibits the fibrinolytic response, and a small body of evidence shows positive effects of tranexamic acid on the volume of blood loss.

METHODS

The main objectives of this study are twofold, (1) to investigate whether tranexamic acid reduces blood loss and (2) to investigate the changes in coagulation after burn trauma and during burn excisional surgery. This study is a multicenter double-blind randomized clinical trial in patients scheduled for burn excisional surgery within the Dutch burn centers. All adult patients scheduled for burn surgery with an expected blood loss of ≥ 250 are eligible for inclusion in this study. The study is powered on a blood loss reduction of 25% in the intervention group. In total, 95 subjects will be included. The intervention group will receive 1500 mg tranexamic acid versus placebo in the other group. Primary endpoint is reduction of blood loss. Secondary endpoints include occurrence of fibrinolysis during surgery, graft take of the split skin graft, and differences in coagulation and blood clot formation.

DISCUSSION

This protocol of a randomized controlled trial aims to investigate the efficacy of tranexamic acid in reducing blood loss during burn excisional surgery. Furthermore, this study aims to clarify the coagulation status after burn trauma and during the surgical process.

TRIAL REGISTRATION

EudraCT: 2020-005405-10; ClinicalTrial.gov: NCT05507983 (retrospectively registered in August 2022, inclusion started in December 2021).

Effectiveness of tranexamic acid in burn patients undergoing surgery - a systematic review and meta-analysis

BACKGROUND

Reducing blood loss during excisional surgery in burn patients remains a challenge. Tranexamic acid during surgery can potentially reduce blood loss. The use of tranexamic acid during excisional surgery in burn patients has recently been described in a review and meta-analysis. However, quality assessment on studies included was not performed and this review did not apply independent reviewers. Quality assessment of studies investigating the effectiveness of tranexamic acid in burn patients is crucial before concusions can be drawn. Therefore, we conducted a systematic review and meta-analysis of the literature investigating the effectiveness of tranexamic acid in burn patients undergoing surgery.

METHODS

A systematic review and meta-analysis of the literature was conducted. The study was pre-registered in PROSPERO database (CRD42023396183).

RESULTS

Five studies including two randomised controlled trials (RCTs) with a total of 303 patients were included. Risk of bias of the included studies was moderate to high. Individual results of the studies were heterogeneous. In three studies of moderate quality the administration of tranexamic acid resulted in a reduction of blood loss per unit excised area, accounting as moderate level of evidence. In two low-quality studies and one moderate quality study the administration of tranexamic acid resulted in a reduction of transfused packed Red Blood Cells (pRBC's), accounting for moderate level of evidence. Postoperative haemoglobin levels were higher after tranexamic acid administration in one study, accounting for insufficient evidence. Meta-analysis pooling overall blood loss from two separate RCTs failed to detect a statistically significant reduction. Substantial heterogeneity was observed.

CONCLUSIONS

Moderate level of evidence indicates that tranexamic acid reduces blood loss per unit of excised area and transfusion of packed Red Blood Cells. Results indicate that tranexamic acid can be beneficial in burn patients undergoing surgery. More high-quality research is needed to confirm these results. Future studies should focus on the dosing of tranexamic acid, the administration approaches, and even consider combining these approaches.

TRIAL REGISTRATION

PROSPERO: CRD42023396183.

Burn wound conversion: clinical implications for the treatment of severe burns

The identification of novel treatments for severe burn wounds relies on accurate clinical assessments of the extent of injury. However, evaluation of burn wound depth can be challenging due to the tendency for burn wounds to progress over time in a little-understood process known as 'burn wound conversion'. Local factors affecting the burn wound, such as inflammation, oxidative stress-induced tissue damage, vasostasis and bacterial infections, lead to increased cell death by apoptosis or oncosis, while systemic events may promote burn wound conversion. Acute shock, metabolic derangements, age or immunomodulation can modify cytokine secretion, lower immune responses, decrease blood flow or cause bacterial infection at the burn wound site. Therefore, therapeutic approaches targeting specific mechanisms that reduce cell death, improve wound reperfusion and promote tissue regrowth should favourably enhance burn wound healing, and long-term functional and aesthetic outcomes. Our current understanding of these mechanisms mostly comes from animal studies, underscoring the need for extensive research in humans. A streamlined approach would be to investigate the parallels in other disease states that exhibit ischaemia and potential reperfusion, such as ischaemic stroke and myocardial infarction. Moreover, in view of the limited knowledge available on the subject, the need exists for further clinical research into burn wound conversion and novel target pathways to ameliorate its effects. This review describes events that affect the viability of cells at the burn wound site resulting in burn wound conversion, and identifies potential targets for clinical interventions that may diminish burn wound conversion.

Coagulation Alterations in Major Burn Patients: A Narrative Review

Major burn patients (MBP) can present multifactorial coagulation alterations induced by trauma and endothelial damage, fluid replacement therapy, hypothermia, hypoperfusion, acidosis, and activation of the inflammatory cascade. However, the multiple coagulation alterations that occur are still poorly defined. The aim of this review is to combine the results of the different coagulation tests currently used to study coagulation changes in these patients. The PubMed database was searched for articles reporting factor levels or coagulation tests using the keywords "Burns" and "Blood Coagulation". Of the 720 articles retrieved from the search, 20 were finally included in the review. Coagulopathy in the MBP differs from that of the trauma patient, insofar as the former present with an increase in factors VIII, IX, and vW on admission accompanied by an increase in fibrin and thrombin production. This is followed by activation of fibrinolysis and prolonged prothrombin (PT) and thromboplastin (aPTT) times in the first 24 hours, increased fibrinogen after 48 hours, and thrombocytosis between the second and third week. Viscoelastic testing shows a pattern that shifts from normal coagulation to a hypercoagulable state with no evidence of hyperfibrinolysis. Alterations in PT and aPTT together with elevated Factor VIII have been associated with mortality, while normalization of antithrombin, and protein C and S levels are associated with a good prognosis. Although standard coagulation tests initially show alterations, the MBP does not appear to be hypocoagulable, and viscoelastic testing shows a trend toward hypercoagulability over time. Coagulation disorders affect prognosis in the MBP.

SHock-INduced Endotheliopathy (SHINE): A mechanistic justification for viscoelastography-guided resuscitation of traumatic and non-traumatic shock

Irrespective of the reason for hypoperfusion, hypocoagulable and/or hyperfibrinolytic hemostatic aberrancies afflict up to one-quarter of critically ill patients in shock. Intensivists and traumatologists have embraced the concept of SHock-INduced Endotheliopathy (SHINE) as a foundational derangement in progressive shock wherein sympatho-adrenal activation may cause systemic endothelial injury. The pro-thrombotic endothelium lends to micro-thrombosis, enacting a cycle of worsening perfusion and increasing catecholamines, endothelial injury, de-endothelialization, and multiple organ failure. The hypocoagulable/hyperfibrinolytic hemostatic phenotype is thought to be driven by endothelial release of anti-thrombogenic mediators to the bloodstream and perivascular sympathetic nerve release of tissue plasminogen activator directly into the microvasculature. In the shock state, this hemostatic phenotype may be a counterbalancing, yet maladaptive, attempt to restore blood flow against a systemically pro-thrombotic endothelium and increased blood viscosity. We therefore review endothelial physiology with emphasis on glycocalyx function, unique biomarkers, and coagulofibrinolytic mediators, setting the stage for understanding the pathophysiology and hemostatic phenotypes of SHINE in various etiologies of shock. We propose that the hyperfibrinolytic phenotype is exemplified in progressive shock whether related to trauma-induced coagulopathy, sepsis-induced coagulopathy, or post-cardiac arrest syndrome-associated coagulopathy. Regardless of the initial insult, SHINE appears to be a catecholamine-driven entity which early in the disease course may manifest as hyper- or hypocoagulopathic and hyper- or hypofibrinolytic hemostatic imbalance. Moreover, these hemostatic derangements may rapidly evolve along the thrombohemorrhagic spectrum depending on the etiology, timing, and methods of resuscitation. Given the intricate hemochemical makeup and changes during these shock states, macroscopic whole blood tests of coagulative kinetics and clot strength serve as clinically useful and simple means for hemostasis phenotyping. We suggest that viscoelastic hemostatic assays such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are currently the most applicable clinical tools for assaying global hemostatic function-including fibrinolysis-to enable dynamic resuscitation with blood products and hemostatic adjuncts for those patients with thrombotic and/or hemorrhagic complications in shock states.

The effect of hyperoxia on the hemostasiological status of severely burned patients

The state of the hemostasis system was studied in 9 patients of the middle age group (44 ± 9.94 years) who received thermal trauma on an area of more than 32% (49.4 ± 18.3) of the body surface, accompanied by the development of burn shock. The standard therapy for burn injury was supplemented with HBO sessions. Treatment with hyperbaric oxygen was carried out in pressure chambers BLKS-307, BLKS-307/1. The state of the coagulation, anticoagulant and fibrinolytic links of the hemostasis system, as well as the viscoelastic properties of the blood, were assessed immediately before the HBO session and immediately after it. The total number of comparison pairs was 45. Under the influence of HBO therapy, there was an increase in the activity of antithrombin III (ATIII), protein C (PrS) and a decrease in the viscoelastic properties of blood (p <0.05). Positive deviations in the values of ATIII, Pr C, von Willebrand factor, APTT, prothrombin and thrombin time, fibrinogen, factor XIII, XIIa-dependent fibrinolysis, D-dimers and thromboelastography parameters were revealed. The maximum frequency of their occurrence was recorded for ATIII (95%), the minimum - for the D-dimer (62%). After HBO procedures, undesirable deviations of the hemostatic system parameters were also noted. They were chaotic, were compensated by an increase in the activity of physiological anticoagulants and were not accompanied by complications of a thrombogenic nature. Thus, conducting HBO therapy sessions in the acute period of burn disease increases the activity of physiological anticoagulants and stabilizes the viscoelastic properties of blood. There is a high frequency of occurrence of positive effects of hyperoxia on the components of the hemostasis system. The identification of its undesirable effects indicates the need to monitor the state of the hemostasis system during HBO procedures.

Coagulopathies in Intensive Care Medicine: Balancing Act between Thrombosis and Bleeding

Patient Blood Management advocates an individualized treatment approach, tailored to each patient's needs, in order to reduce unnecessary exposure to allogeneic blood products. The optimization of hemostasis and minimization of blood loss is of high importance when it comes to critical care patients, as coagulopathies are a common phenomenon among them and may significantly impact morbidity and mortality. Treating coagulopathies is complex as thrombotic and hemorrhagic conditions may coexist and the medications at hand to modulate hemostasis can be powerful. The cornerstones of coagulation management are an appropriate patient evaluation, including the individual risk of bleeding weighed against the risk of thrombosis, a proper diagnostic work-up of the coagulopathy's etiology, treatment with targeted therapies, and transfusion of blood product components when clinically indicated in a goal-directed manner. In this article, we will outline various reasons for coagulopathy in critical care patients to highlight the aspects that need special consideration. The treatment options outlined in this article include anticoagulation, anticoagulant reversal, clotting factor concentrates, antifibrinolytic agents, desmopressin, fresh frozen plasma, and platelets. This article outlines concepts with the aim of the minimization of complications associated with coagulopathies in critically ill patients. Hereditary coagulopathies will be omitted in this review.

Protective Effects of Melatonin against Severe Burn-Induced Distant Organ Injury: A Systematic Review and Meta-Analysis of Experimental Studies

Extensive burns result in a local wound response and distant-organ injury (DOI) caused by oxidative-stress and inflammation. Melatonin (MT) shows promise in alleviating oxidative-stress and inflammation, but its role in thermal injury is largely unexplored. The present systematic review and meta-analysis were designed to assess the effects of MT on oxidative-stress and inflammatory markers against severe burn-induced DOI. Mean difference (MD)/standard mean difference (SMD) with 95% confidence interval (CI) were estimated using fixed-effect/random-effects models. Eighteen experimental studies met the inclusion criteria. Compared with the control group, MT significantly decreased the levels of malondialdehyde (SMD, −1.03; 95% CI, −1.30, −0.76, p < 0.00001) and 4-hydroxynonenal (MD, −1.06; 95% CI, −1.57, −0.56, p < 0.0001). Additionally, MT increased the levels of glutathione (SMD, 1.94; 95% CI, 1.27, 2.61, p < 0.00001) and superoxide-dismutase (SMD, 0.76; 95% CI, 0.08, 1.45, p = 0.03). Finally, MT significantly decreased the levels of tumor necrosis factor-α (SMD, −1.34; 95% CI, −1.92 to −0.77; p < 0.00001) and C-reactive protein (MD, −12.67; 95% CI, −16.72 to −8.62; p < 0.00001). Meta-analysis indicates that severe burn followed by immediate MT (10 mg/kg) intervention shows significant beneficial effects after 24-h against DOI by regulating oxidative-stress and the inflammatory response.

Trajectories of longitudinal biomarkers for mortality in severely burned patients

This study aimed to investigate the differences in the trajectory of blood biomarkers routinely assessed through forward- and backward-looking approaches among burn patients. This cohort study included patients above 18 years of age from February 2007 to December 2018. All the biomarkers were estimated from admission to discharge from the intensive care unit. Significant differences were observed in the platelet count at 40 days, prothrombin time (PT) at 32 days, white blood cell count at 26 days, creatinine levels at 22 days, and lactate and total bilirubin levels at 19 days before death. In reverse order, significant differences were observed in the fitted model in platelet count at 44 days and in the platelet count and PT at 33 days. We obtained more valuable information from the longitudinal biomarker trajectory using the backward-looking method than using the forward-looking method. The platelet count served as the earliest predictor of mortality among burn patients.

Is major burn injury associated with coagulopathy? The value of thrombelastometry in the detection of coagulopathy in major burn injury: A prospective observational study

BACKGRUND

The coagulation status of burn patients is generally impaired and is a major factor of the deteriorating burn patients' overall situation. In trauma and other patient groups, the differential diagnosis of coagulation impairment has been largely improved by the use of rotational thromboelastometry (ROTEM®). The aim of this prospective observational study was the differentiated observation of coagulopathy in severely burned patients using standard parameters and ROTEM® thrombelastometry during the relevant stages of burn disease.

PATIENTS AND METHODS

Twelve patients that sustained at least 20% third degree burns of total body surface area (TBSA) were included in the study. Standard and ROTEM® coagulation analyses were performed on admission and then twice daily during the first 14 days following burn trauma.

RESULTS

Although the initial assessment of DIC was similar for both standard labs and ROTEM® measurements, more patients were detected to be in a state of worsening coagulation status for a longer time in ROTEM® than in standard measurements. In addition, one patient was rated in to be in decompensated DIC for 3 days according to ROTEM® measurements, while no patient was rated to be in a decompensated DIC based on standard parameters.

CONCLUSION

This study points towards a more complex picture and higher occurrence of DIC in burn patients when thrombelastometric measurements like ROTEM® are taken into account in addition to standard coagulation parameters.

Challenges in anaesthesia and pain management for burn injuries

Burn-injured patients provide unique challenges to those providing anaesthesia and pain management. This review aims to update both the regular burn anaesthetist and the anaesthetist only occasionally involved with burn patients in emergency settings. It addresses some aspects of care that are perhaps contentious in terms of airway management, fluid resuscitation, transfusion practices and pharmacology. Recognition of pain management failures and the lack of mechanism-specific analgesics are discussed along with the opioid crisis as it relates to burns and nonpharmacological methods in the management of distressed patients.

Design and evaluation of a LIS-based autoverification system for coagulation assays in a core clinical laboratory

Background

The autoverification system for coagulation consists of a series of rules that allow normal data to be released without manual verification. With new advances in medical informatics, the laboratory information system (LIS) has growing potential for the autoverification, allowing rapid and accurate verification of clinical laboratory tests. The purpose of the study is to develop and evaluate a LIS-based autoverification system for validation and efficiency.

Methods

Autoverification decision rules, including quality control, analytical error flag, critical value, limited range check, delta check and logical check, as well as patient’s historical information, were integrated into the LIS. Autoverification limited range was constructed based on 5 and 95% percentiles. The four most commonly used coagulation assays, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and fibrinogen (FBG), were followed by the autoverification protocols. The validation was assessed by the autoverification passing rate, the true-positive cases, the true-negative cases, the false-positive cases, the false-negative cases, the sensitivity and the specificity; the efficiency was evaluated in the turnaround time (TAT).

Results

A total of 157,079 historical test results of coagulation profiles from January 2016 to December 2016 were collected to determine the distribution intervals. The autoverification passing rate was 77.11% (29,165/37,821) based on historical patient data. In the initial test of the autoverification version in June 2017, the overall autoverification passing rate for the whole sample was 78.75% (11,257/14,295), with 892 true-positive cases, 11,257 true-negative cases, 2146 false-positive cases, no false-negative cases, sensitivity of 100% and specificity of 83.99%. After formal implementation of the autoverification system for 6 months, 83,699 samples were assessed. The average overall autoverification passing rate for the whole sample was 78.86% and the 95% confidence interval (CI) of the passing rate was [78.25, 79.59%]. TAT was reduced from 126 min to 101 min, which was statistically significant (P < 0.001, Mann-Whitney U test).

Conclusions

The autoverification system for coagulation assays based on LIS can halt the samples with abnormal values for manual verification, guarantee medical safety, minimize the requirements for manual work, shorten TAT and raise working efficiency.

Burn injury and blood transfusion

PURPOSE OF REVIEW

Blood transfusion is ubiquitous in major burn injury. The present article describes recent research findings directly impacting blood transfusion strategies in major burn injury both in the operating room and the ICU.

RECENT FINDINGS

Transfusion strategies have been the focus of recent burn investigations. First, a randomized prospective trial encompassing both the ICU and operating room reported that a restrictive red blood cell transfusion threshold (7 g/dl) had equivalent outcomes to a traditional threshold (10 g/dl) for burns more than 20% in terms of mortality, infection, length of stay, duration of mechanical ventilation, and wound healing despite receiving significantly fewer transfusions. The second burn transfusion advance addresses coagulation. Although burn patients initially have elevated fibrinogen, thrombocytopenia and other coagulation disorders develop during excision. Blood product repletion should be based on measurements such as thromboelastography in addition to traditional tests. Finally, a recent randomized trial suggests that fresh-frozen plasma and platelets during burn excision more than 20% may decrease transfusion requirements.

SUMMARY

A restrictive transfusion practice during burn excision and grafting is well tolerated and effective in reducing the number of transfusions without increasing complications. Repletion of coagulation products should focus on measured deficits of platelets, fibrinogen, and factors.

Measuring coagulation in burns: an evidence-based systematic review

Introduction

Dynamic monitoring of coagulation is important to predict both haemorrhagic and thrombotic complications and to guide blood product administration. Reducing blood loss and tailoring blood product administration may improve patient outcome and reduce mortality associated with transfusion. The current literature lacks a systematic, critical appraisal of current best evidence on which clinical decisions may be based.

Objectives

Establishing the role of different coagulation markers in burn patients, diagnosing coagulopathy, tailoring blood product administration and indicating prognosis.

Methods

Literature during 2004-2017 from the Cochrane Library, PubMed, Scopus, Medline and Embase was reviewed. Eligibility criteria included randomised controlled trials, systematic reviews, multi-/single-centre study and meta-analyses. Keywords searched were 'burns', 'blood coagulation disorders', 'rotem', 'blood coagulation' and 'thromboelastography'. The PRISMA flow system was used for stratification and the CASP framework for appraisal of the studies retrieved.

Results

In total, 13 articles were included after inclusion/exclusion criteria had been applied to the initial 79 studies retrieved. Hypercoagulation increases in proportion to the severity of thermal injury. Whole blood testing, using thrombelastography (TEG) and rotation thromboelastometry (ROTEM), was superior to standard plasma based tests, including prothrombin time (PT) and activated partial thromboplastin time (APTT) at detecting burn-related coagulopathies.

Conclusions

Routine laboratory markers such as PT/APTT are poor indicators of coagulation status in burns patients. Viscoelastic tests, such as TEG and ROTEM, are efficient, fast and have a potential use in the management of burn patients; however, strong evidence is lacking. This review highlights the need for more randomised controlled trials, to guide future practice.