Hypercoagulability after burn injury

Factor XIII in major burns coagulation

BACKGROUND

In the days following a burn injury, major burn patients (MBP) present a multifactorial coagulation disorder known as acute burn-induced coagulopathy. Several studies have investigated coagulation in MBPs; however, Factor XIII (FXIII), which converts fibrin monomers into a stable clot and promotes wound healing, has not yet been studied.

OBJECTIVE

To determine the kinetics of FXIII and other coagulation factors and cofactors in MBPs in order to clarify coagulopathy in these patients and its potential relationship with surgical bleeding.

METHODS

Prospective observational pilot study of the kinetics of FXIII and other coagulation factors and cofactors in MBPs during the first 30 days of burn injury.

RESULTS

FXIII levels show a significant decline of 75.10% in the interval between the burn injury and surgery, and a decline of 87.70% in the 24 h following surgery. Patients undergo surgery with a median antigenic FXIII of 32%. Plasma levels of most factors decrease significantly 24 h after the burn injury.

CONCLUSION

MBPs experience a significant decrease in plasma levels of FXIII from the time of admission up to 24 h after surgery. Abnormally low levels were observed at the time of surgery that could not be detected by other coagulation tests. The decrease in most factors at 24 h seems to be associated with dilution due to intensive fluid resuscitation.

The use of NexoBrid™ enzymatic debridement and coagulation abnormalities

OBJECTIVES

Current evidence on how the use of bromelain-based enzymatic debridement techniques (NexoBrid™) affect patient coagulation is limited. A single patient case report [1] suggests that a patient with 15% total body surface area (TBSA) burn developed decreased coagulation activity following debridement with NexoBrid™ enzymatic debridement (ED). Regional Burns Centres in the United Kingdom may be reluctant to use ED, particularly in larger burns, citing concerns regarding coagulation. At our centre we have routinely used ED on deep partial thickness burns since 2017 including on patients with burns over 15% TBSA. This study aims to investigate whether there is a significant disruption in coagulation in patients undergoing ED with burns > 15% TBSA or admitted to intensive care compared to the standard of care (SOC) which is surgical debridement in theatre.

METHODS

This single-centre retrospective study includes all patients with a burn treated with ED at Pinderfields General Hospital Regional Burns Centre intensive care unit (ITU) from 2017 to 2020. Patients were matched to those treated with SOC at the same centre by age, % TBSA burn and presence of inhalational injury. These parameters correlate with the Baux score [9]. Percentage of burn debrided was matched as closely as possible, with coagulation profiles and platelet count taken the day before, the day of and three days following surgery.

RESULTS

Thirty-one patients were treated with ED in the intensive care unit between 2017 and 2020. Four patients were excluded due to insufficient records and one patient was anti-coagulated. Twenty-six patients were included and matched as described above. Average age of patients receiving ED was 44 years, the same in the matched group. Average TBSA burn is 35.5% (35.8% in matched group). No statistically significant difference in coagulation was seen between patients undergoing ED compared to SOC when considering prothrombin time (PT), activated partial thromboplastin time (aPTT) and platelet count. Both groups slightly breached the upper limit of normal on day 2 post ED and SOC. There was a slight breach of the lower limit of the average platelet count on day 2 post-ED which was neither statistically nor clinically significant.

CONCLUSIONS

Large burns are associated with coagulation abnormalities, therefore isolating a single variable in this cohort is challenging. However, this study found no significant change following ED use when compared to SOC and therefore no convincing evidence that ED is associated with coagulation abnormalities. This study represents one of the largest focusing on coagulation abnormalities following the use of ED, as the current literature is limited. Our study suggests that concerns regarding coagulation abnormalities should not prevent patients with large, deep partial thickness burns or full thickness burns being treated with ED.

Characteristics of blood clotting on thromboelastography in patients with early burns

BACKGROUND

Thromboelastography (TEG) is a viscoelastic test that may be used to evaluate the hemostatic function of whole blood, and it may be useful for burn patients with multiple hemostatic defects.

METHODS

We retrospectively recruited patients with burns between January 2019 and July 2021. Blood samples were drawn on admission and subjected to coagulation parameter assessment, including conventional coagulation tests and TEG assessment. Receiver operating characteristic (ROC) analysis was performed to predict the occurrence of complications in patients with early burns.

RESULTS

Ninety-three patients with early burns met the inclusion criteria. Patients with minor, moderate, severe, and extremely severe burns accounted for 19.4 %, 36.6 %, 16.1 %, and 27.9 % of all patients, respectively. Compared with the healthy controls, patients with early burns showed significant reductions in the R and K values, and significant elevation in the maximum amplitude (MA), coagulation index (CI), and alpha angle. Compared with minor and moderate burn patients, patients with severe and extremely severe burns had lower K values and thrombin time and higher alpha angle, CI, prothrombin time, international normalized ratio, D-dimer, and fibrin degradation products. Patients with hypercoagulation had lower R and K values, longer MA, longer CI, and greater alpha angle. After ROC analysis, the areas under the ROC curve for acute lung injury, acute kidney injury, and bleeding were 0.789, 0.802, and 0.900, respectively.

CONCLUSION

TEG provides insight into the hemostatic state of patients with early burns, and can predict complications in early burn patients when combined with conventional coagulation tests.

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.

Persistent fibrinolysis shutdown is associated with increased mortality in traumatic pancreatic injury

PURPOSE

The features of fibrinolytic system modifications and their relationship with prognosis are still unknown in traumatic pancreatic injury. The object of this prospective cohort research was to identify fibrinolytic characteristics in patients with pancreatic trauma and to identify the correlation to mortality.

METHOD

A prospective screening of traumatic pancreatic injury patients was done for five years. The fibrinolytic status of patients was determined by thromboelastography (TEG). The percentage reduction in clot strength 30 min (LY30) after the time of maximal clot strength was utilized to distinguish the fibrinolytic phenotype of individuals, including fibrinolytic shutdown (SD), physiologic fibrinolysis (PHYS) and hyperfibrinolysis (HF). Two cohorts, transient fibrinolytic shutdown (TSD) and persistent fibrinolytic shutdown (PSD), were divided according to whether fibrinolytic shutdown persisted within one week. Demographics, injury severity, characteristics of pancreatic injury, treatment, and outcomes were compared.

RESULT

A total of 180 cases enrolled, aged 42(interquartile range 32-51) years, 88% males, 97% were blunt trauma. The median ISS was 19(IQR 10-25), and 76% were AAST grade III to V (high-grade). At admission, there were 159 cases of SD (88%), 15 cases of PHYS (8%) while 6 cases of HF (3%). Of these, the TSD cohort included 54 patients (34%), while the PSD cohort included 105 patients (66%). Compared with the TSD cohort, the PSD cohort had more severe injury (ISS 21[IQR 12-27] vs 16[IQR 9-22], p = 0.006) and a higher proportion of AAST high-grade (83% vs 67%, p = 0.035). Persistent fibrinolytic shutdown was associated with operative treatment (odds ratio [OR] 3.111; 95%CI 1.146-8.447; p = 0.026), associated intra-abdominal injury (OR 8.331; 95% CI 1.301-53.336; p = 0.025) and admission LY30 (OR 0.016; 95% CI 0.002 - 0.120; p < 0.001). It was an independent predictor of mortality (adjusted odds ratio [AOR] 4.674; 95% CI 1.03 to 21.14; p = 0.045).

CONCLUSION

Fibrinolytic shutdown especially persistence of this phenotype is more common in traumatic pancreatic injury than PHYS and HF, which related with mortality. Risk factors including LY30 at admission, intra-abdominal injury and operative treatment were associated with the persistent fibrinolytic shutdown. Sheltered the patients from these risk factors seems to be beneficial, which need to be confirmed by further large-scale studies.

Clinical significance of R-TEG in severe burn patients with coagulation dysfunction

INTRODUCTION

The aim of this study was to retrospectively analyze Thrombelastography (TEG) data of severe burn patients to provide a clinical basis for timely diagnosis and treatment of coagulation dysfunction.

METHODS

The present study comprised burn patients with full thickness TBSA ≥ 60%. The patients included in the study were admitted to the Third Affiliated Hospital of Inner Mongolia Medical University between March 2019 and March 2022 and died within 10 days. Patient demographic and clinical data, including abbreviated burn severity index (ABSI) score, full thickness and overall total surface burn area (TBSA), injury cause, International Society on Thrombosis and Hemostasis (ISTH) score, were retrieved from the electronic medical record system. TEG data (including ACT, K, α, MA and LY30), platelet count (PLT), mean platelet volume (MPV) and platelet distribution width (PDW) data were obtained from the records of included patients for analysis.

RESULTS

A total of 9 patients were enrolled. The average burn area was 90.0% TBSA and the full-thickness TBSA was 72.0%. The results showed that α, MA and PLT count values were significantly lower relative to those at obtained throughout admission period (all p < 0.05). PDW and MPV were significantly higher compared with the values at admission (all p < 0.05). ACT time was significantly longer from day 2 after severe burn compared with the ACT time at admission (all p < 0.05). LY30 value from day 3 after severe burn was significantly higher compared with the value at admission (p < 0.05). One patient was diagnosed with diffuse intravascular coagulation (DIC) on admission, whereas eight patients were diagnosed with DIC on the day of death.

CONCLUSION

Coagulation dysfunction after severe burn is mainly characterized by procoagulant disorders and hyperfibrinolysis, which can be timely detected by TEG. Coagulation after severe burn exhibits a gradual aggravation, and can lead to death of patients.

Platelet Priming and Activation in Naturally Occurring Thermal Burn Injuries and Wildfire Smoke Exposure Is Associated With Intracardiac Thrombosis and Spontaneous Echocardiographic Contrast in Feline Survivors

Wildfires pose a major health risk for humans, wildlife, and domestic animals. We previously discovered pathophysiologic parallels between domestic cats with naturally occurring smoke inhalation and thermal burn injuries and human beings with similar injuries; these were characterized by transient myocardial thickening, cardiac troponin I elevation and formation of intracardiac thrombosis. While the underlying mechanisms remain unclear, results from murine models suggest that platelet priming and activation may contribute to a global hypercoagulable state and thrombosis. Herein, we evaluated and compared the degree of platelet activation, platelet response to physiologic agonists and levels of platelet-derived microvesicles (PDMV) in 29 cats with naturally occurring wildfire thermal injuries (WF), 21 clinically healthy cats with subclinical hypertrophic cardiomyopathy (HCM) and 11 healthy cats without HCM (CC). We also quantified and compared circulating PDMVs in WF cats to CC cats. In addition, we examined the association between thrombotic events, severity of burn injuries, myocardial changes, and the degree of platelet activation in cats exposed to wildfires. Flow cytometric detection of platelet surface P-selectin expression showed that WF cats had increased platelet response to adenosine diphosphate (ADP) and thrombin compared to the two control groups indicating the presence of primed platelets in circulation. In addition, cats in the WF group had increased circulating levels of PDMV, characterized by increased phosphatidylserine on the external leaflet. Cats in the WF group with documented intracardiac thrombosis had elevated platelet activation and platelet priming in the presence of ADP. While high dose arachidonic acid (AA) mostly resulted in platelet inhibition, persistent response to AA was noted among cats in the WF group with intracardiac thrombosis. Univariate and multiple logistic regression analyses demonstrated that increased platelet response to AA was independently associated with thrombotic events. This is the first study reporting the significant association between platelet priming and intracardiac thrombosis in domestic cats with naturally occurring wildfire-related injuries and smoke inhalation. Further studies are required to delineate additional mechanisms between inflammation and thrombosis, especially regarding platelet primers and the cyclooxygenase pathway.

Coagulation dysfunction of severe burn patients: A potential cause of death

BACKGROUND

Research on coagulation dysfunction following burns is controversial. This study aimed to describe the coagulation changes in severe burn patients by examining coagulation parameters.

METHODS

Patients with third-degree total body surface area (TBSA) burns of ≥30% were enrolled between 2017 and 2020. Platelet (PLT) count and coagulation indexes (including APTT, INR, FIB, DD, and AT Ⅲ) were measured at admission and once weekly for 8 weeks, and statistical analysis was performed. The patient medical profiles were reviewed to extract demographic and clinical data, including TBSA, third-degree TBSA, and inhalation injury. The total intravenous fluids and transfusions of crystalloids, fresh frozen plasma (FFP), and red blood cells (RBC) were calculated during the forty-eight-hour period. The number of sepsis cases was recorded.

RESULTS

We enrolled 104 patients , and while the overall coagulation trend fluctuated, inflection points appeared around one week and demonstrated hypercoagulability. INR was significantly higher in the non-survival group than in the survivors' group from admission to three weeks after burn (all p<0.01). From post-injury week 1 to post-injury week 3, the APTT in the non-survival group was greater than in the survival group, but the non-survival group's PLT count was lower than that in the survival group (all p<0.05). At two and three weeks after burns, the FIB levels in the non-survival group were significantly lower than those of the survival group (both p<0.01). The prevalence of inhalation injury and the proportion of sepsis cases were significantly higher in the non-survival group than in the survival group ( p ＜ 0.05, p ＜ 0.001, respectively). At the time of death, APTT, INR, and FDP levels were significantly higher in the non-survival group in the survivor group, and FIB, ATIII, and PLT were significantly lower than in the survivor group (all p<0.01). On the day of death, nine of the 12 dead patients had disseminated intravascular coagulation (DIC).

CONCLUSIONS

Coagulation dysfunction was most prominent in severe burn patients 1 week after injury and presented as hypercoagulability. Large-area burn injury, large amounts of fluid resuscitation, inhalation injury, and sepsis may all contribute to coagulation dysfunction, which can further develop into DIC and even death in severe burns patients.

Heparin resistance in severe thermal injury: A prospective cohort study

BACKGROUND

Low molecular-weight heparin (LMWH) is routinely administered to burn patients for thromboprophylaxis. Some studies have reported heparin resistance, yet the mechanism(s) and prevalence have not been systematically studied. We hypothesized that nucleosomes, composed of histone structures with associated DNA released from injured tissue and activated immune cells in the form of neutrophil extracellular traps (NETs or NETosis), neutralize LMWH resulting in suboptimal anticoagulation, assessed by reduction in anti-factor Xa activity.

METHODS

Blood was sampled from >15% total body surface area (TBSA) burn patients receiving LMWH on days 5, 10 and 14. Peak anti-factor Xa (AFXa) activity, anti-thrombin (ATIII) activity, cell-free DNA (cfDNA) levels and nucleosome levels were measured. Mixed effects regression was adjusted for multiple confounders, including injury severity and ATIII activity, and was used to test the association between nucleosomes and AFXa.

RESULTS

A total of 30 patients with severe burns were included. Mean TBSA 43% (SD 17). Twenty-three (77%) patients were affected by heparin resistance (defined by AFXa activity <0.2 IU/mL). Mean peak AFXa activity across samples was 0.18 IU/mL (SD 0.11). Mean ATIII was 81.9% activity (SD 20.4). Samples taken at higher LWMH doses were found to have significantly increased AFXa activity, though the effect was not observed at all doses, at 8000 IU no samples were heparin resistant. Nucleosome levels were negatively correlated with AFXa (r = -0.29, p = 0.050) consistent with the hypothesis. The final model, with peak AFXa as the response variable, was adjusted for nucleosome levels (p = 0.0453), ATIII activity (p = 0.0053), LMWH dose pre-sample (p = 0.0049), drug given (enoxaparin or tinzaparin) (p = 0.03), and other confounders including severity of injury, age, gender, time point of sample.

CONCLUSIONS

Heparin resistance is a prevalent issue in severe burns. Nucleosome levels were increased post-burn, and showed an inverse association with AFXa consistent with the hypothesis that they may interfere with the anticoagulant effect of heparin in vivo and contribute to heparin resistance. Accurate monitoring of AFXa activity with appropriate therapy escalation plans are recommended with dose adjustment following severe burn injury.

A Review on the Use of Plasma During Acute Burn Resuscitation

The problem of fluid creep has generated renewed interest in the use of colloids during acute burn resuscitation. Currently, human albumin solution is usually chosen as the resuscitation colloid. However, human plasma was a fundamental component of numerous burn resuscitation formulas historically, but it largely fell out of favor due to concerns surrounding transmission of infectious viruses. Nevertheless, plasma is an effective volume expander which has been demonstrated to reduce overall volume requirements during burn resuscitation. Furthermore, plasma may have beneficial effects on the endothelium by diminishing the microvascular leak that follows a major burn injury. Fresh frozen plasma (FFP) is now much safer from a disease transmission standpoint, and newer forms of solvent-detergent-treated plasma and lyophilized plasma offer potentially even greater safety and efficacy. The use of FFP and newer forms of plasma, which have not been extensively studied, should be investigated as potential adjuncts to acute burn resuscitation.

Implementation and Validation of Free Flaps in Acute and Reconstructive Burn Care

Microsurgical free flap reconstruction in acute burn care offers the option of reconstructing even challenging defects in a single stage procedure. Due to altered rheological and hemodynamic conditions in severely burned patients, it bears the risk of a higher complication rate compared to microsurgical reconstruction in other patients. To avoid failure, appropriate indications for free flap reconstruction should be reviewed thoroughly. Several aspects concerning timing of the procedure, individual flap choice, selection and preparation of the recipient vessels, and perioperative measures must be considered. Respecting these specific conditions, a low complication rate, comparable to those seen in microsurgical reconstruction of other traumatic limb defects, can be observed. Hence, the free flap procedure in acute burn care is a relatively safe and reliable tool in the armamentarium of acute burn surgery. In reconstructive burn care, microsurgical tissue transfer is routinely used to treat scar contractures. Due to the more robust perioperative condition of patients, even lower rates of complication are seen in microsurgical reconstruction.

Role, Management, and Outcome of Free Flap Reconstruction for Acute Full-Thickness Burns in Hands

INTRODUCTION

Severe thermal trauma to the hand can result in major impairment and reduced function due to defective healing or even extremity loss. Full-thickness injuries frequently incur exposure of tendons or bone and require an early and stable coverage with soft tissue transplants to allow for rapid induction of exercise and to preserve structures and hand function. Free tissue transfer to the hand after thermal trauma is a rare indication, and safety, management, and outcome of free flap surgery for severe acute burn injuries to the hand remains underreported.

METHODS

Patients with primary reconstructions of full-thickness burn injuries to the hand undergoing microsurgical free tissue transfer surgery were retrospectively assessed in a period from 2013 to 2016. Salvage strategy of the extremity, postoperative complications, length of hospital stay, and primary reconstructive result were quantified and analyzed. Functional outcome measures (range of motion and grip strength) were assessed during clinical follow-up examinations.

RESULTS

During the investigated period, 13 patients were identified undergoing reconstruction of 14 hands via free flap transplantation after severe burn injury in the acute phase. Nine anteriolateral thigh flaps (64%), 3 latissimus dorsi flaps (18%), 1 serratus anterior flap, and 1 tensor fasciae lata flap (7%) were performed. In all cases, salvage of the affected extremity was achieved, although 1 flap (7%) was lost during the early postoperative period requiring secondary reconstruction via pedicled groin flap. Further complications were venous thrombosis (n = 2; 14%) and hematoma (n = 2; 14%). Mean length of hospital stay was 51 days. Functional outcome during follow-up examination after an average of 9.3 months was inhomogeneous depending on the pattern of injury and ranged from complete recovery to nearly entire loss of hand function.

CONCLUSIONS

Free flap transfer can be a mandatory and valuable tool to cover full-thickness burn injuries of the hand early in the clinical course of thermal trauma and may provide extremity salvage by favorable means of reconstruction to achieve acceptable functional outcomes, in the most severe cases. Although microsurgical failure rates in burn patients are slightly higher than in free flap transfer to the upper extremity in general, it can be performed with reasonable risk-to-benefit ratio.

Early protein C activation is reflective of burn injury severity and plays a critical role in inflammatory burden and patient outcomes

BACKGROUND

Navigating the complexities of a severe burn injury is a challenging endeavour where the natural course of some patients can be difficult to predict. Straddling both the coagulation and inflammatory cascades that feature strongly in the burns systemic pathophysiology, we propose the pleiotropic protein C (PC) system may produce a viable biomarker to assist traditional evaluation methods for diagnostic and prognostic purposes.

METHODS

We enrolled 86 patients in a prospective observational cohort study. Over three weeks, serial blood samples were taken and measured for PC, activated (A)PC, their receptor endothelial protein C receptor (EPCR), and a panel of inflammatory cytokines including C-reactive protein (CRP), tumour necrosis factor-α, interleukin (IL)-1β, IL-6, IL-8, and IL-17. Their temporal trends were analysed alongside clinical factors including burn size, burn depth, presence of inhalational injury, and a composite outcome of requiring increased support.

RESULTS

(i) APC increased from a nadir on Day 3 (2.3±2.1ng/mL vs 4.1±2.5ng/mL by Day 18, p<0.0005), only becoming appropriately correlated to PC from Day 6 onwards (r=0.412-0.721, p<0.05 for all Days 6-21). (ii) This early disturbance in the PC system was amplified in the more severe burns (≥30% total body surface area, predominantly full thickness, or with inhalational injury), which were characterised by a marked fall in PC activation (approximated by APC/PC ratio) and APC levels during Days 0-3 with low unchanged PC levels. Critically low levels of this cytoprotective agent was associated with greater inflammatory burden, as reflected by significantly elevated CRP, IL-6, and IL-8 levels in the more severe compared to less severe burns, and by negative correlations between both PC and APC with most inflammatory cytokines. (iii) Alongside clinical markers of severity at admission (burn size, burn depth, and presence of inhalational injury), only Day 0 APC/PC ratio (OR 1.048 (1.014-1.083), p=0.006), APC (OR 1.364 (1.032-1.803), p=0.029), PC (OR 0.899 (0.849-0.953), p<0.0005), and not any inflammatory cytokines were predictive markers of requiring increased support. Uniquely, decreased Day 0 PC was further individually associated with each increased total length of stay, ICU length of stay, intravenous fluid resuscitation, and total surgeries, as well as possibly mortality.

CONCLUSION

An early functional depletion of the cytoprotective PC system provides a physiological link between severe burns and the cytokine storm, likely contributing to worse outcomes. Our findings on the changes in APC, PC and PC activation during this pathological state support APC and PC as early diagnostic and prognostic biomarkers, and provides a basis for their therapeutic potential in severe burn injuries.

Inhalation Injury Does Not Influence the Amount of Blood Transfused to Major Burn Patients: A Secondary Analysis from the Transfusion Requirement in Burn Care Evaluation Study

Patients with major burn injuries typically require numerous blood transfusions. It is not known if an inhalation injury (INHI) directly influences the need for blood transfusion. The purpose of this study was to determine whether INHI increases the amount of blood transfused to major burn patients. A secondary analysis from the Transfusion Requirement in Burn Care Evaluation (TRIBE) study was conducted. Patients with INHI were compared with patients without INHI. The number of red blood cell (RBC) transfusions per day (RBC per day) between INHI and No INHI was analyzed with a multivariable regression. Patients with INHI (n = 78) had significantly larger burns (P = .0004), larger full-thickness burns (P = .0007), greater admission APACHE score (P < .0001), higher admission multiple organ dysfunction scores (P < .0001), and were transfused more RBC per day (P = .009) than No INHI patients (n = 267). In the multivariable regression analysis, RBC per day was significantly associated with the %TBSA burn (P < .0001), age of the patient (P = .004), the need for more than 1 day of mechanical ventilation (P < .0001), the occurrence of at least one blood stream infection (BSI; P = .044), and being assigned to the liberal transfusion arm of TRIBE (P < .001) but not the presence of INHI (P = .056). The null hypothesis that INHI exerts no influence on the amount of blood transfused could not be rejected. Larger burn size, advanced patient age, mechanical ventilation, and BSIs are important determinants of the blood transfusion rate in major burn patients.

Lightning Injury with Multi-System Involvement

Lightning leads to trauma and disability such as burns, hearing loss, blindness, cardiac arrhythmia, cardiac arrest, stroke, kidney injury, and can also lead to death. Such cases are seldom reported, and hence their database is scanty. We present a case of a 40-year-old female with lightning injury with four such manifestations, which is not commonly encountered. We have elaborated on these complications of lightning injury and their timely management, which has led us to good patient outcome.

Hypercoagulability After Resection of Thoracic Malignancy: A Prospective Evaluation

BACKGROUND

Rates of venous thromboembolism are increased in thoracic malignancy; however, coagulation patterns are not established. We hypothesize that patients with esophageal and lung malignancy have similar hypercoagulable pre- and postoperative profiles as defined by rotational thromboelastometry (ROTEM).

METHODS

Prospective study was conducted in 47 patients with esophageal and lung cancer undergoing surgical resection. ROTEM evaluated pre/postoperative coagulation status.

RESULTS

Patients with thoracic malignancy were hypercoagulable by ROTEM, but not by conventional coagulation tests. Preoperative hypercoagulability was higher in lung versus esophageal cancer (64 vs. 16%, p = 0.001). Lung cancer patients that were hypercoagulable preoperatively demonstrated decreased maximum clot firmness (MCF) (p = 0.044) and increased clot time (p = 0.049) after surgical resection, suggesting reversal of hypercoagulability. Resection of esophageal cancer increased hypercoagulability (16 vs. 56%, p = 0.002) via elevated MCF (reflecting platelet activity). Hypercoagulability remained at follow-up clinic for both lung and esophageal cancer patients.

CONCLUSIONS

Hypercoagulability in patients with lung malignancies reversed following complete surgical resection, whereas hypercoagulability occurred only postoperatively in those with esophageal malignancies. In both, hypercoagulability was associated with fibrin and platelet function.

Difficult to Treat Infections in the Burn Patient

Background: Unusual infections can lead to complications in more severely burned patients and pose major challenges in treatment. Methods: The published literature of retrospective reviews and case series of the uncommon infections of osteomyelitis, polymicrobial bacteremia, recurrent bacteremia, endocarditis, central nervous system (CNS), and rare fungal infections in burned patients have been summarized and presented. Results: When compared with infections occurring in the non-burn population, these infections in burn patients are more likely to be because of gram-negative bacteria or fungi. Because of hyperdynamic physiology and changes in immunomodulatory response secondary to burns, the clinical presentation of these infections in a patient with major burns differs from that of the non-burn patient and may not be identified until the post-mortem examination. Some of these infections (osteomyelitis, endocarditis, CNS, rare fungal infections) may necessitate surgical intervention in addition to antimicrobial therapy to achieve cure. The presence of the burn and allograft can also present unique challenges for surgical management. Conclusions: These difficult and unusual infections in the severely burned patient necessitate an index of suspicion, appropriate diagnosis, identification and sensitivities of the putative pathogen, effective systemic antimicrobial therapy, and appropriate surgical intervention if recovery is to be achieved.

Incidence and Prognostic Value of Acute Coagulopathy After Extensive Severe Burns

Acute burn-induced coagulopathy (ABIC) occurs after severe burns. However, the incidence, prognostic value, and clinical significance of ABIC after an extensive severe burn remain inconclusive due to wide variances in burn severity and coagulation profile evaluation timings in previous studies. This retrospective study explored the incidence and clinical and prognostic significance of early phase ABIC in 129 adult patients with extensive burns (&gt;50% total body surface area [TBSA]) admitted to the burn centers of two hospitals within 10 hours postburn injury during 2009–2017. Demographics (age and sex) and clinical data (burn severity, vital signs, prehospital fluid replacement volume, hemodynamic parameters, coagulation profile, blood gas, and blood biochemical indicators) were collected upon admission. The incidence of ABIC in patients with severe burns and its relationship with their survival and clinical significance were analyzed. The average postburn interval was 5.7 ± 2.7 hours, and the incidence of ABIC was 31% (40/129). A logistic regression analysis identified ABIC as an independent predictor of 4-week severe mortality due to severe burn. The incidence of ABIC was significantly associated with the total burn area, lactic acid levels upon admission, and postburn admission interval, but not with the prehospital fluid replacement volume. In conclusion, approximately 30% of patients with severe burns developed ABIC within 10 hours postburn, and this condition strongly predicts 4-week mortality. Although burn severity and tissue ischemia/hypoxia are main risk factors for ABIC, the pathogenesis is not fully understood and should be explored in future studies.

Preoperative Heparin for Lung Cancer Resection Increases Risk of Reoperation for Bleeding

Lung cancer patients are at risk for venous thromboembolism (VTE). Preoperative heparin administration may increase the risk of bleeding requiring reoperation. The purpose of this study was to evaluate preoperative heparin's effect on reoperation for bleeding. A retrospective review compared outcomes for patients undergoing pulmonary resection for primary lung cancer from January 2006 to April 2018. Preoperative heparin was administered at the discretion of the attending surgeon. Comparisons were performed between preoperative subcutaneous heparin (5000 U) and no heparin groups. A total of 3325 lung resections were reviewed, 1.4% (n = 48) required reoperation for bleeding. VTE occurred in 1.1% (n = 38). Four hundred sixty-four patients (14.0%) did not receive preoperative heparin. The preoperative heparin group had increased rates of prior thoracic surgery (5.1% [n = 146] vs 1.7% [n = 8], P < 0.001), minimally invasive approach (40.2% [n = 1150] vs 10.6% [n = 49], P < 0.001), and sublobar resections (17.7% [n = 506] vs 10.6% [n = 49], P < 0.001). There were no differences in blood loss/transfusions. Reoperation for bleeding was significantly increased in the preoperative heparin group (1.6% [n = 47] vs 0.2% [n = 1], P = 0.017). There were no differences in VTE (1.5% [n = 7] vs 1.1% [n = 31], P = 0.424). On logistic regression, preoperative heparin was independently associated with increased reoperation for bleeding (odds ratio 8.13, P = 0.039); however, preoperative heparin was not independently associated with VTE. Preoperative heparin was associated with increased reoperation for bleeding. VTE rates are low after pulmonary resection for lung cancer and are not decreased by preoperative heparin. Preoperative heparin use should be determined by risk factor stratification for VTE and reoperation for bleeding in patients undergoing lung cancer resection.

The Utility of Thromboelastography to Guide Blood Product Transfusion

OBJECTIVES

To provide an overview of the clot viscoelastic testing technology and to describe its utility in guiding blood product transfusions.

METHODS

A case scenario will be discussed as well as interpretation of thromboelastography (TEG) tracings. In addition, literature examining the utility of viscoelastic testing in guiding patient management and blood product transfusions will be reviewed.

RESULTS

TEG/rotational thromboelastometry (ROTEM) is useful in evaluating clot kinetics in trauma and acutely bleeding patients. TEG/ROTEM parameters are reflective of values measured using standard coagulation assays; however, TEG/ROTEM parameters are more rapidly available and more costly. TEG and ROTEM are used in three main settings: cardiac surgery, liver transplantation, and trauma to assess global hemostasis and administration of blood products.

CONCLUSIONS

TEG/ROTEM can be helpful in guiding resuscitation and blood product transfusion. Several studies have demonstrated a reduction in transfusion of blood components with TEG/ROTEM; however, other studies have suggested that TEG/ROTEM is not clinically effective in guiding transfusion.

Utilizing Plasma Composition Data to Help Determine Procoagulant Dynamics in Patients with Thermal Injury: A Computational Assessment

INTRODUCTION

The development of methods that generate individualized assessments of the procoagulant potential of burn patients could improve their treatment. Beyond its role as an essential intermediate in the formation of thrombin, factor (F)Xa has systemic effects as an agonist to inflammatory processes. In this study, we use a computational model to study the FXa dynamics underlying tissue factor-initiated thrombin generation in a small cohort of burn patients.

MATERIALS AND METHODS

Plasma samples were collected upon admission (Hour 0) from nine subjects (five non-survivors) with major burn injuries and then at 48 hours. Coagulation factor concentrations (II, V, VII, VIII, IX, X, TFPI, antithrombin (AT), protein C (PC)) were measured and used in a computational model to generate time course profiles for thrombin (IIa), FXa, extrinsic tenase, intrinsic tenase and prothrombinase complexes upon a 5 pM tissue factor stimulus in the presence of 1 nM thrombomodulin. Parameters were extracted from the thrombin and FXa profiles (including max rate (MaxRIIa and MaxRFXa) and peak level (MaxLIIa and MaxLFXa)). Procoagulant potential was also evaluated by determining the concentration of the complexes at select times. Parameter values were compared between survivors and non-survivors in the burn cohort and between the burn cohort and a simulation based on the mean physiological (100%) concentration for all factor levels.

RESULTS

Burn patients differed at Hour 0 (p < 0.05) from 100% mean physiological levels for all coagulation factor levels except FV and FVII. The concentration of FX, FII, TFPI, AT and PC was lower; FIX and FVIII were increased. The composition differences resulted in all nine burn patients at Hour 0 displaying a procoagulant phenotype relative to 100% mean physiological simulation (MaxLIIa (306 ± 90 nM vs. 52 nM), MaxRIIa (2.9 ± 1.1 nM/s vs. 0.3 nM/s), respectively p < 0.001); MaxRFXa and MaxLFXa were also an order of magnitude greater than 100% mean physiological simulation (p < 0.001). When grouped by survival status and compared at the time of admission, non-survivors had lower PC levels (56 ± 18% vs. 82 ± 9%, p < 0.05), and faster MaxRFXa (29 ± 6 pM/s vs. 18 ± 6 pM/s, p < 0.05) than those that survived; similar trends were observed for all other procoagulant parameters. At 48 hours when comparing non-survivors to survivors, TFPI levels were higher (108 ± 18% vs. 59 ± 18%, p < 0.05), and MaxRIIa (1.5 ± 1.4 nM/s vs. 3.6 ± 0.7 nM/s, p < 0.05) and MaxRFXa (13 ± 12 pM/s vs. 35 ± 4 pM/s, p < 0.05) were lower; similar trends were observed with all other procoagulant parameters. Overall, between admission and 48 hours, procoagulant potential, as represented by MaxR and MaxL parameters for thrombin and FXa, in non-survivors decreased while in survivors they increased (p < 0.05). In patients that survived, there was a positive correlation between FX levels and MaxLFXa (r = 0.96) and reversed in mortality (r= -0.91).

CONCLUSIONS

Thrombin and FXa generation are increased in burn patients at admission compared to mean physiological simulations. Over the first 48 hours, burn survivors became more procoagulant while non-survivors became less procoagulant. Differences between survivors and non-survivors appear to be present in the underlying dynamics that contribute to FXa dynamics. Understanding how the individual specific balance of procoagulant and anticoagulant proteins contributes to thrombin and FXa generation could ultimately guide therapy and potentially reduce burn injury-related morbidity and mortality.

Anti-Xa guided enoxaparin dose adjustment improves pharmacologic deep venous thrombosis prophylaxis in burn patients

INTRODUCTION

Patients recovering from burn injury are at high risk of developing deep venous thrombosis (DVT). While 30-mg twice-daily enoxaparin is accepted as the standard prophylactic dose, recent evidence in injured patients suggests this dosing strategy may result in sub-optimal pharmacologic DVT prophylaxis. We hypothesized that standard enoxaparin dosing would result in inadequate DVT prophylaxis in burn patients.

METHODS

A retrospective review of an ABA-verified Burn center's registry from January 2012 - December 2016 identified patients with peak plasma anti-Xa levels to monitor the efficacy of pharmacologic DVT prophylaxis. Patients ≥18 years old were included if they received at least 3 doses of enoxaparin and had appropriately timed peak anti-Xa levels. We analyzed data including patient demographics, body weight, body mass index (BMI) and total body surface area burn (TBSA). Diagnosis of DVT was collected.

RESULTS

During the study period, 393 patients were screened with a plasma anti-Xa levels. Of the 157 patients that met inclusion criteria, 81 (51.6%) achieved target peak plasma anti-Xa levels (0.2-0.4 IU/mL) on standard 30-mg twice-daily prophylactic enoxaparin and 76 (48.4%) had sub-prophylactic levels. Sub-prophylactic patients were more likely to be male, have increased body weight and elevated BMI. 49 of the 76 sub-prophylactic patients received a dose-adjustment in order to reach target anti-Xa levels; 37 patients required 40mg twice-daily, 10 required 50mg twice-daily and 2 required 60mg twice-daily. The overall DVT rate was 3.8%.

CONCLUSIONS

The current recommended prophylactic dose of 30-mg twice-daily enoxaparin is inadequate in many burn patients. Alternate dosing strategies should be considered to increase the number of burn patients achieving target prophylactic anti-Xa levels. Determining whether prophylactic enoxaparin dose adjustment decreases DVT rates in burn injured patients should be evaluated in future prospective trials.

Prophylactic anti-coagulation after severe burn injury in critical care settings

BACKGROUND

Severely burnt patients are at an increased risk of thromboembolic complications, hence sufficient prophylactic anticoagulation is of paramount importance. Local guidelines at the Burns Centre in the Queen Elizabeth Hospital, Birmingham therefore advise increasing the standard dose of low molecular weight heparin in these patients. An audit was carried out to assess the current practice in burns patients to ensure adequate anticoagulation and adherence to guidelines.

MATERIALS AND METHODS

Retrospective data was collected on all burns patients in the Burns Centre over a two-year period. The main objectives were to assess:anticoagulation regimes prescribed to severe burns patientsmonitoring of Anti-Factor Xa levelsadjustment of dosing based on the resultsThe locally produced trust guidelines were used as the comparator.

RESULTS

All burns patients were prescribed anticoagulation, but often the dose was not increased as suggested in the guidelines. Although most of the severely burnt patients were prescribed adjusted higher doses of anti-coagulation, only 60% of these patients were monitored with Anti-Factor Xa assays. Of these assays, 66% showed sub-prophylactic levels. The majority of results led to the adjustment of the dose of anticoagulant. However, often dose changes were made late.

DISCUSSION AND CONCLUSIONS

The audit confirmed the need for increased doses of prophylactic anticoagulation in severe burns. The better adherence to the guidelines can be achieved by additional training and implementation of decision support via electronic prescribing system.

Correlation of the expression of inflammatory factors with expression of apoptosis-related genes Bax and Bcl-2, in burned rats

Correlation of the expression of inflammatory factors with expression of apoptosis-related genes, B-cell lymphoma 2 (Bcl-2) and Bcl-2 associated X protein (Bax), in burned rats was investigated. Forty healthy Sprague-Dawley rats were selected and randomly divided into SHAM group (n=10), I° burn group (n=10), II° burn group (n=10) and III° burn group (n=10). Changes in tumor necrosis factor-α (TNF-α), Bax messenger ribonucleic acid (mRNA), Bcl-2 mRNA, Bax protein and Bcl-2 protein expression levels were detected. The correlation of TNF-α, Bax and Bcl-2 with the degree of burn in rats was observed, and the correlation of TNF-α with Bax and Bcl-2 was also analyzed. Moreover, Bax mRNA and Bcl-2 mRNA were detected via reverse transcription-quantitative polymerase chain reaction, and TNF-α, Bax protein and Bcl-2 protein were detected via enzyme-linked immunosorbent assay. In burn groups, TNF-α, Bax mRNA and Bax protein levels were significantly increased at each time point compared with those at the previous time point (P<0.05), but Bcl-2 mRNA and protein levels were significantly decreased compared with those at the previous time point (P<0.05). At the same time point, TNF-α, Bax mRNA, Bcl-2 mRNA, Bax protein and Bcl-2 protein expression levels had statistically significant differences between any given two groups (P<0.05). The TNF-α expression level was positively correlated with Bax expression levels and negatively correlated with Bcl-2 expression levels. Additionally, TNF-α, Bax mRNA and Bax protein had positive correlations with the degree of burn and time after burn, while Bcl-2 mRNA and Bcl-2 protein had negative correlations with the degree of burn and time after burn. Continuous monitoring of changes in the TNF-α level can be used as a means to evaluate the degree of burn and apoptosis, and to prevent the deepening of burn wounds, thus facilitating the early clinical evaluation of prognosis.

Thrombin generation in patients with severe thermal injury

BACKGROUND

Severe burns can induce a hypercoagulable state which is not depicted in conventional coagulation assays. The thrombin generation assay allows global assessment of coagulation and can identify hypercoagulability. We report changes in thrombin generation in patients after severe burn injury.

METHODS

We measured TGA, rotational thrombelastometry and conventional assays in 20 consecutive patients with a total body surface area burned of >20% over a 2-week period: the day after burn trauma (A), the morning after surgical excision of burn wounds (B) and on post-admission days 7 (C) and 14 (D).

RESULTS

Thrombin generation assay showed a procoagulatory state: there was an increase in the velocity of thrombin generation (increase in time to peak of +13%, increase in velocity index of +22%), and peak amount of thrombin (+25%) between days A and B. All parameters reached their highest levels on day C and returned towards normal on day D. Rotational thrombelastometry showed a hypercoagulable state with an increase in clot firmness and alpha angle. Conventional coagulation tests remained within reference values.

CONCLUSIONS

In the first two weeks following burn, both the thrombin generation assay and rotational thrombelastometry show a hypercoagulable state, while conventional coagulation tests remain normal.

Clinical Cellular Therapeutics Accelerate Clot Formation

Clinical cellular therapeutics (CCTs) have shown preliminary efficacy in reducing inflammation after trauma, preserving cardiac function after myocardial infarction, and improving functional recovery after stroke. However, most clinically available cell lines express tissue factor (TF) which stimulates coagulation. We sought to define the degree of procoagulant activity of CCTs as related to TF expression. CCT samples from bone marrow, adipose, amniotic fluid, umbilical cord, multi-potent adult progenitor cell donors, and bone marrow mononuclear cells were tested. TF expression and phenotype were quantified using flow cytometry. Procoagulant activity of the CCTs was measured in vitro with thromboelastography and calibrated thrombogram. Fluorescence-activated cell sorting (FACS) separated samples into high- and low-TF expressing populations to isolate the contribution of TF to coagulation. A TF neutralizing antibody was incubated with samples to demonstrate loss of procoagulant function. All CCTs tested expressed procoagulant activity that correlated with expression of tissue factor. Time to clot and thrombin formation decreased with increasing TF expression. High-TF expressing cells decreased clotting time more than low-TF expressing cells when isolated from a single donor using FACS. A TF neutralizing antibody restored clotting time to control values in some, but not all, CCT samples. CCTs demonstrate wide variability in procoagulant activity related to TF expression. Time to clot and thrombin formation decreases as TF load increases and this procoagulant effect is neutralized by a TF blocking antibody. Clinical trials using CCTs are in progress and TF expression may emerge as a safety release criterion. Stem Cells Translational Medicine 2018;7:731-739.

Impact of thrombelastography in paediatric intensive care

We assessed the clinical impact of thrombelastography (TEG®) results (TEG® 5000, Haemonetics Corporation, Braintree, MA, USA) by measuring their ability to cause changes in a theoretical treatment plan and contribute to the understanding of haemostasis. We prospectively included paediatric intensive care unit (PICU) patients who had standard tests of haemostasis and TEG ordered and had an arterial catheter or extracorporeal access port in situ. Blood for standard tests and TEG was taken simultaneously. Independent of patient care, general patient information and results of standard laboratory tests were presented to five clinicians who were asked to document their theoretical treatment plan. Clinicians were then shown TEG results and asked if they caused a change in their plan, if they confirmed initial standard laboratory test results, if they enabled a better understanding of haemostasis and if they provided additional information. Inter-rater agreement between the clinicians was determined. Forty-two TEG results were obtained from 34 patients. Overall, the inclusion of TEG results led to a change in treatment plan in 97 of 207 occasions (47%), confirmed standard laboratory test results in 177 of 204 occasions (87%), enabled a better understanding of haemostasis in 140 of 204 occasions (69%) and provided additional information in 131 of 204 occasions (64%). Variation existed between clinicians, seemingly due to individual differences, with poor inter-rater agreement. We conclude that TEG results led to changes in treatment plans almost half the time, confirmed findings of standard tests and provided a better understanding of haemostasis, but randomised controlled trials are required to determine the role and influence of TEG results on patient outcome.

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.

Platelet and coagulation function before and after burn and smoke inhalation injury in sheep

BACKGROUND

Smoke inhalation and burn injury remain a major source of morbidity and mortality. There is known dysregulation of hemostasis in burn patients, but either hypercoagulation or hypocoagulation states are reported. Sheep are an established animal model for studying burn pathology and provide robust data on hemostatic function at baseline and after injury.

METHODS

After an IACUC-approved protocol, 15 sheep were anesthetized and subjected to a 40% full thickness burn with smoke inhalation. Blood was sampled at baseline, 1 day postinjury (early effects) and days 2, 3, and 4 (late effects) after injury. Assays at each timepoint assessed: hemostatic function by thromboelastography (TEG), platelet counts and function by flow cytometry and aggregometry, coagulation protein levels, and free hemoglobin. Data were analyzed by the Wilcoxon paired test (nonparametric) with significance set at less than 0.05.

RESULTS

By 24 hours postinjury, platelet counts had dropped, whereas the percent activated platelets increased. Absolute platelet functional response to the agonist adenosine diphosphate (ADP) decreased, whereas response to collagen showed no significant difference. On a per platelet basis, ADP response was unchanged, whereas the collagen response was elevated. Prothrombin time and activated partial thromboplastin time were prolonged. TEG parameters decreased significantly from baseline. Fibrinogen and factor V were trending up; coagulation proteins ATIII, factors IX and X were decreased.Late effects were followed in six animals. At day 4, platelet counts remained depressed compared with baseline with a nadir at day 2; responses to agonist on a per platelet basis remained the same for ADP and stayed elevated for collagen. Platelets continued to have elevated activation levels. Fibrinogen and factor V remained significantly elevated, whereas TEG parameters and prothrombin time, factors IX and X returned to near baseline levels.

CONCLUSION

Coagulation parameters and hemostasis are dysregulated in sheep after smoke inhalation and burn. By 24 hours, sheep were hypocoagulable and subsequently became hypercoagulable by day 4. These results suggest a three-stage coagulopathy in burn injuries with a known early consumptive hypercoagulable state which is followed by a relatively hypocoagulable state with increased bleeding risk and then a return to a relatively unknown hypercoagulability with increased susceptibility to thrombotic disorders.

Important Developments in Burn Care

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Explain the epidemiology of severe burn injury in the context of socioeconomic status, gender, age, and burn cause. 2. Describe challenges with burn depth evaluation and novel methods of adjunctive assessment. 3. Summarize the survival and functional outcomes of severe burn injury. 4. State strategies of fluid resuscitation, endpoints to guide fluid titration, and sequelae of overresuscitation. 5. Recognize preventative measures of sepsis. 6. Explain intraoperative strategies to improve patient outcomes, including hemostasis, restrictive transfusion, temperature regulation, skin substitutes, and Meek skin grafting. 7. Translate updates in the pathophysiology of hypertrophic scarring into novel methods of clinical management. 8. Discuss the potential role of free tissue transfer in primary and secondary burn reconstruction.

SUMMARY

Management of burn-injured patients is a challenging and unique field for plastic surgeons. Significant advances over the past decade have occurred in resuscitation, burn wound management, sepsis, and reconstruction that have improved outcomes and quality of life after thermal injury. However, as patients with larger burns are resuscitated, an increased risk of nosocomial infections, sepsis, compartment syndromes, and venous thromboembolic phenomena have required adjustments in care to maintain quality of life after injury. This article outlines a number of recent developments in burn care that illustrate the evolution of the field to assist plastic surgeons involved in burn care.

Persistent Fibrinolysis Shutdown Is Associated with Increased Mortality in Severely Injured Trauma Patients

BACKGROUND

Acute fibrinolysis shutdown is associated with early mortality after trauma; however, no previous studies have investigated the incidence of persistent fibrinolysis or its association with mortality. We tested the hypothesis that persistent fibrinolysis shutdown is associated with mortality in critically ill trauma patients.

STUDY DESIGN

Thromboelastography was performed on ICU admission in 181 adult trauma patients and at 1 week in a subset of 78 patients. Fibrinolysis shutdown was defined as LY30 ≤ 0.8% and was considered transient if resolved by 1 week postinjury or persistent if not. Logistic regression adjusted for age, sex, hemodynamics, and Injury Severity Score (ISS).

RESULTS

Median age was 52 years, 88% were male, and median ISS was 27, with 56% transient fibrinolysis shutdown, 44% persistent fibrinolysis shutdown and 12% mortality. Median LY30 was 0.23% (interquartile range [IQR] 0% to 1.20%) at admission and 0.10% (IQR 0% to 2.05%) at 1 week. Transient shutdown more often occurred after head injury (p = 0.019); persistent shutdown was more often associated with penetrating injury (29% vs 9%; p = 0.020), lower LY30 at ICU admission (0.10% vs 1.15%; p < 0.0001) and at 1 week (0% vs 1.68%; p < 0.0001), and higher mortality (21% vs 5%; p = 0.036). Persistent fibrinolysis shutdown was associated with admission LY30 (odds ratio [OR] 0.05; 95% CI 0.01 to 0.34; p = 0.002) and transfusion of packed RBCs (OR 0.81; 95% CI 0.68 to 0.97; p = 0.021) and platelets (OR 2.81; 95% CI 1.16 to 6.84; p = 0.022); moreover, it was an independent predictor of mortality (OR 8.48; 95% CI 1.35 to 53.18; p = 0.022).

CONCLUSIONS

Persistent fibrinolysis shutdown is associated with late mortality after trauma. A high index of suspicion should be maintained, especially in patients with penetrating injury, reduced LY30 on admission, and/or receiving blood product transfusion. Judicious use of tranexamic acid is advised in this cohort.

Circulating Microvesicles Are Elevated Acutely following Major Burns Injury and Associated with Clinical Severity

Microvesicles are cell-derived signaling particles emerging as important mediators and biomarkers of systemic inflammation, but their production in severe burn injury patients has not been described. In this pilot investigation, we measured circulating microvesicle levels following severe burns, with severe sepsis patients as a comparator group. We hypothesized that levels of circulating vascular cell-derived microvesicles are elevated acutely following burns injury, mirroring clinical severity due to the early onset and prevalence of systemic inflammatory response syndrome (SIRS) in these patients. Blood samples were obtained from patients with moderate to severe thermal injury burns, with severe sepsis, and from healthy volunteers. Circulating microvesicles derived from total leukocytes, granulocytes, monocytes, and endothelial cells were quantified in plasma by flow cytometry. All circulating microvesicle subpopulations were elevated in burns patients on day of admission (day 0) compared to healthy volunteers (leukocyte-microvesicles: 3.5-fold, p = 0.005; granulocyte-microvesicles: 12.8-fold, p<0.0001; monocyte-microvesicles: 20.4-fold, p<0.0001; endothelial- microvesicles: 9.6-fold, p = 0.01), but decreased significantly by day 2. Microvesicle levels were increased with severe sepsis, but less consistently between patients. Leukocyte- and granulocyte-derived microvesicles on day 0 correlated with clinical assessment scores and were higher in burns ICU non-survivors compared to survivors (leukocyte MVs 4.6 fold, p = 0.002; granulocyte MVs 4.8 fold, p = 0.003). Mortality prediction analysis of area under receiver operating characteristic curve was 0.92 (p = 0.01) for total leukocyte microvesicles and 0.85 (p = 0.04) for granulocyte microvesicles. These findings demonstrate, for the first time, acute increases in circulating microvesicles following burns injury in patients and point to their potential role in propagation of sterile SIRS-related pathophysiology.

Upon admission coagulation and platelet function in patients with thermal and electrical injuries

RATIONAL

There has been increased focus on hemostatic potential and function in the initial assessment of the patient with traumatic injuries, that not been extensively studied in patients with burns. We proposed to determine the hemostatic potential of patients with burns upon admission to the emergency department and contrasted their condition with that of healthy controls and patients with other traumatic injuries. In addition we assessed differences due to thermal versus electrical injury and evaluated the effect of burn size.

METHODS

This is a patient based prospective observational study conducted with delayed consented. Subjects at the highest level of trauma activation upon admission to the ED had a blood sample collected for research purposes and were subsequently consented. Hemostatic potential was measured by rapid thromelastography (r-TEG^®), thrombin generation by calibrated automated thrombogram (CAT) and platelet function by Multiplate^® using five activators. Burn subjects were compared to subjects with other traumatic injuries and controls. Within the burn subjects additional analysis compared mechanism (thermal vs. electrical) and burn size. Values are medians (IQR).

RESULTS

Two hundred and eighty two trauma patients (with burns n=40, 14%) and 27 controls were enrolled. Upon admission, compared to controls, subjects with burns or trauma were hyper-coagulable based on r-TEG and CAT, with increased rates of clot formation and thrombin generation. There were no differences in burns compared to other traumatic injuries. The presence of hyper-coagulation did not appear to be related to the type of burn or the percentage of total body surface area involved. Employing previous defined cut points for R-TEG driven therapeutic interventions burn patients had similar rates of hyper- and hypo-coagulation noted in patients with traumatic injuries.

CONCLUSION

Upon admission patients with burns are in a hyper-coagulable state similar to that of other trauma patients. Employing demonstrated cut points of hemostatic potential in trauma patients associated with increased risk of poor outcomes demonstrated the incidence in burn patients to be similar, suggesting that these values could be used in the early assessment of the patient with burns to guide treatment interventions.

Impact of Platelets and Platelet-Derived Microparticles on Hypercoagulability Following Burn Injury

An acute burn induced coagulopathy develops after scald injury, which evolves into a subacute, hypercoagulable state. Microparticles, specifically platelet-derived MPs (PMPs), have been suggested as possible contributors. We first developed a model of burn-induced coagulopathy and then sought to investigate the role of platelets and PMPs in coagulation after burn. We hypothesized that changes in circulating platelet and PMP populations after injury would contribute to the post-burn, hypercoagulable state. A murine scald model with 28% TBSA full thickness burn injury was utilized and blood samples were collected at intervals after injury. Circulating MP populations, platelet counts, overall coagulation, and platelet function were determined. Burn injury led to hypercoagulability on post-burn day one (PBD1), which persisted 6 days after injury (PBD6). On PBD1, there was a significant decrease in platelet numbers and a decline in platelet contribution to clot formation with a concomitant increase in circulating procoagulant PMPs. On PBD6, there was a significant increase in platelet numbers and in platelet activation with no change in PMPs compared with sham. Further, on PBD1 decreased ADP-induced platelet activation was observed with a contrasting increase in ADP-induced platelet activation on PBD6. We therefore concluded that there was a temporal change in the mechanisms leading to a hypercoagulable state after scald injury, that PMPs are responsible for changes seen on PBD1, and finally that ADP-induced platelet activation was key to the augmented clotting mechanisms 6 days after burn.

The application of platelet-rich plasma in the treatment of deep dermal burns: A randomized, double-blind, intra-patient controlled study

Platelet-rich plasma (PRP) is a fraction of blood with a platelet concentration above baseline. When platelets get activated, growth factors involved in wound healing are released. The application of PRP has shown good results in wound care, however, up to date no substantial research has been performed on the effect of PRP in burn treatment. This randomized double blind intra-patient controlled study investigates the effect of autologous PRP on wound healing in burns that require surgery with a meshed split skin graft (SSG). Fifty-two patients with various areas of deep dermal to full thickness burns, receiving surgery with a SSG were included after informed consent. Comparable study areas A and B (intra-patient) were appointed, randomized and either treated with a SSG and PRP or with a SSG alone. At day 5 to 7 postoperative, the epithelialization and graft take rate were assessed. Three, six, and twelve months postoperative, follow-up measurements were performed in the form of POSAS-questionnaires, DermoSpectroMeter, and Cutometer measurements. There was no statistically significant difference between the mean take rate nor the mean epithelialization rate at day 5-7 between the PRP-treated and control areas. However, PRP-treated wound areas showed more often better or equal epithelialization and take rates at day 5-7 than the standard treated areas. Minor effects were also seen in the reoperated and early operated subgroups. At 3, 6, and 12 months postoperative, POSAS scores from the patients and the observers, Dermaspectro-, and Cutometer measurements did not depict a significant difference between the PRP and standard treated areas. Concluding, the addition of PRP in the treatment of burn wounds did not result in improved graft take and epithelialization, nor could we demonstrate better scar quality. There was, however, a considerable variation in our clinical population.

Coagulopathy and its management in patients with severe burns

Severe burn injury is associated with systemic coagulopathy. The changes in coagulation described in patients with severe burns resemble those found patients with sepsis or major trauma. Coagulopathy in patients with severe burns is characterized by procoagulant changes, and impaired fibrinolytic and natural anticoagulation systems. Both the timing of onset and the severity of hemostatic derangements are related to the severity of the burn. The exact pathophysiology and time course of coagulopathy are uncertain, but, at least in part, result from hemodilution and hypothermia. As the occurrence of coagulopathy in patients with severe burns is associated with increased comorbidity and mortality, coagulopathy could be seen as a potential therapeutic target. Clear guidelines for the treatment of coagulopathy in patients with severe burns are lacking, but supportive measures and targeted treatments have been proposed. Supportive measures are aimed at avoiding preventable triggers such as tissue hypoperfusion caused by shock, or hemodilution and hypothermia following the usually aggressive fluid resuscitation in these patients. Suggested targeted treatments that could benefit patients with severe burns include systemic treatment with anticoagulants, but sufficient randomized controlled trial evidence is lacking.

Increased risk of ischemic stroke in patients with burn injury: a nationwide cohort study in Taiwan

Background

Conflicting results have been obtained by studies attempting to assess the risks of ischemic stroke in patients with burn injury, while the long-term risk of stroke in survivors of burn injury remains unexplored. We evaluated whether the risk of ischemic stroke in patients hospitalized with burn injury in Taiwan is higher when compared to the general population.

Methods

The data from one million National Health Insurance (NHI) adult beneficiaries were evaluated from January 1, 2005 until December 31, 2012 to identify those who developed ischemic stroke. Each identified patient with burn injury was matched with one hundred unexposed patients based on a high-dimensional propensity score. Cox regression models were applied to compare the risks of the development of ischemic stroke in the matched cohorts.

Results

A total of 743,237 patients were enrolled. After matching, 1,763 burn injury patients and 176,300 unexposed patients were selected and compared. The adjusted hazard ratio of ischemic stroke was significantly increased in burn injury patients (1.84; 95 % CI, 1.43–2.36). A subgroup analysis based on patients who survived longer than 12 months in the matched cohort also revealed higher hazard ratio in the burn injury patients (1.54; 95 % CI, 1.11–2.13).

Conclusion

The risk of ischemic stroke is significantly higher in patients hospitalized with burn injury than in the general population, and these risks may extend longer than expected.

In-depth analysis of clotting dynamics in burn patients

BACKGROUND

Studies associating coagulopathic changes with burn injury have relied on limited tests such as partial thromboplastin time (PTT) and international normalized ratio (INR). Understanding the clotting dynamics and associated risk factors after burn injury could influence management. This work aimed to identify real-time changes in coagulation after burn injury not indicated by PTT or INR alone.

MATERIALS AND METHODS

Nine burn-injured patients at a regional burn center were enrolled for blood collection at admission and set intervals over 96 h. Patient demographics, management, and laboratory data (PTT and INR) were collected. Plasma assays determined factors II, V, VII, VIII, IX, X, XI, antithrombin, and protein C functional activity as well as PAP, D-Dimer, fibrin monomer, TFPI, IL-1b, IL-6, IL-10, IL-12p.70, and TNF-α concentrations.

RESULTS

Overall, five patients died. These patients had higher mortality scores and were more acidotic. All patients had normal coagulation studies (INR < 1.5, PTT < 45 s) within 24 h of admission, and only two were abnormal after. Increased factor VIII and IX activity were identified in seven patients at admission. Decreased antithrombin and protein C activity were seen in all patients. Patients had increased PAP, D-Dimer, and fibrin monomer concentrations throughout their hospital course. At admission, increased fold changes were seen in IL-6 (2.5-117) and IL-10 (2.4-32), whereas IL-1b and TNF-α levels were depressed in all patients.

CONCLUSIONS

Extensive changes not identified by PTT or INR were seen after burn injury that may explain perturbed coagulation in these patients. This approach further characterizes the impact thermal injury has on coagulation.

Are burn patients really at risk for thrombotic events?

There continues to be debate about the routine use of deep vein thrombosis (DVT) prophylaxis in burn patients. The concern is that routine prophylaxis may lead to adverse events. The debate hinges on the incidence of DVT and its relation to the risk-benefit ratio. This study seeks to estimate the true rate of DVT in burn patients, and to evaluate possible risk factors to its development. The Nationwide Inpatient Sample was queried for all patients with age ≥18 years with ICD-9 codes for burn injuries. Demographic data, comorbidities, burn data, length of stay, total charges, procedures, presence of central venous catheter, and mortality were recorded. Patients were classified based on the presence of DVT. Student's t-test, χ test, and logistic regression were performed. 36,638 burn patients were identified. DVT rate was 0.8%. Patients with DVT were older, had longer hospitalizations, more procedures, and higher charges. On logistic regression, black race, TBSA ≥20%, history of previous venous thrombotic events, blood transfusion, and mechanical ventilation were the significant factors associated with DVT. Patients with DVT were almost twice as likely to die during the admission (P = .011). This is the largest series to date examining the risk factors for DVT in burn patients. DVT developed in approximately 0.8% of burn patients. Black race, TBSA ≥20%, blood transfusions, and mechanical ventilation were associated with approximately 2-fold odds of developing DVT. Identification of these additional risk factors may allow targeted patient prophylaxis. Additionally, patients with DVT incurred higher total charges and longer hospitalization.

Peripherally inserted central venous catheter safety in burn care: a single-center retrospective cohort review

The use of peripherally inserted central catheter (PICC) line for central venous access in thermally injured patients has increased in recent years despite a lack of evidence regarding safety in this patient population. A recent survey of invasive catheter practices among 44 burn centers in the United States found that 37% of burn units use PICC lines as part of their treatment protocol. The goal of this study was to compare PICC-associated complication rates with the existing literature in both the critical care and burn settings. The methodology involved is a single institution retrospective cohort review of patients who received a PICC line during admission to a regional burn unit between 2008 and 2013. Fifty-three patients were identified with a total of seventy-three PICC lines. The primary outcome measurement for this study was indication for PICC line discontinuation. The most common reason for PICC line discontinuation was that the line was no longer indicated (45.2%). Four cases of symptomatic upper extremity deep vein thrombosis (5.5%) and three cases of central line-associated bloodstream infection (4.3%, 2.72 infections per 1000 line days) were identified. PICC lines were in situ an average of 15 days (range 1 to 49 days). We suggest that PICC line-associated complication rates are similar to those published in the critical care literature. Though these rates are higher than those published in the burn literature, they are similar to central venous catheter-associated complication rates. While PICC lines can be a useful resource in the treatment of the thermally injured patient, they are associated with significant and potentially fatal risks.

Global assays of hemostasis

PURPOSE OF REVIEW

There exists an imbalance between our understanding of the physiology of the blood coagulation process and the translation of this understanding into useful assays for clinical application. As technology advances, the capabilities for merging the two areas have become more attainable. Global assays have advanced our understanding of the dynamics of the blood coagulation process beyond end point assays and are at the forefront of implementation in the clinic.

RECENT FINDINGS

We will review recent advances in the main global assays with a focus on thrombin generation that have potential for clinical utility. These assays include direct (thrombogram, whole blood, purified systems) and indirect empirical measures of thrombin generation (thromboelastography) and mechanism-based computational models that use plasma composition data from individuals to generate thrombin generation profiles.

SUMMARY

Empirical thrombin generation assays (direct and indirect) and computational modeling of thrombin generation have greatly advanced our understanding of the hemostatic balance. Implementation of these types of assays and visualization approaches in the clinic will potentially provide a basis for the development of individualized patient care. Advances in both empirical and computational global assays have made the goal of predicting precrisis changes in an individual's hemostatic state one step closer.