Safe and successful restriction of transfusion in burn patients

A Contemporary Review of Blood Transfusion in Critically Ill Patients

Blood transfusion is a common therapeutic intervention in hospitalized patients. There are numerous indications for transfusion, including anemia and coagulopathy with deficiency of single or multiple coagulation components such as platelets or coagulation factors. Nevertheless, the practice of transfusion in critically ill patients has been controversial mainly due to a lack of evidence and the need to consider the appropriate clinical context for transfusion. Further, transfusion carries many risk factors that must be balanced with benefits. Therefore, transfusion practice in ICU patients has constantly evolved, and we endeavor to present a contemporary review of transfusion practices in this population guided by clinical trials and expert guidelines.

Ultra-restrictive red blood cell transfusion strategies in extensively burned patients

In recent years, due to the shortage of blood products, some extensive burn patients were forced to adopt an "ultra-restrictive" transfusion strategy, in which the hemoglobin levels of RBC transfusion thresholds were < 7 g/dl or even < 6 g/dl. This study investigated the prognostic impacts of ultra-restrictive RBC transfusion in extensive burn patients. This retrospective multicenter cohort study recruited extensive burns (total body surface area ≥ 50%) from three hospitals in Eastern China between 1 January 2016 and 30 June 2022. Patients were divided into an ultra-restrictive transfusion group and a restrictive transfusion group depending on whether they received timely RBC transfusion at a hemoglobin level < 7 g/dl. 1:1 ratio propensity score matching (PSM) was performed to balance selection bias. Modified Poisson regression and linear regression were conducted for sensitive analysis. Subsequently, according to whether they received timely RBC transfusion at a hemoglobin level < 6 g/dl, patients in the ultra-restrictive transfusion group were divided into < 6 g/dl group and 6-7 g/dl group to further compare the prognostic outcomes. 271 eligible patients with extensive burns were included, of whom 107 patients were in the ultra-restrictive transfusion group and 164 patients were in the restrictive transfusion group. The ultra-restrictive transfusion group had a significantly lower RBC transfusion volume than the restrictive transfusion group (11.5 [5.5, 21.5] vs 17.3 [9.0, 32.5] units, p = 0.004). There were no significant differences between the two groups in terms of in-hospital mortality, risk of infection, hospital length of stay, and wound healing time after PSM or multivariate adjustment (p > 0.05). Among the ultra-restrictive transfusion group, patients with RBC transfusion threshold < 6 g/dl had a significantly higher hospital mortality than 6-7 g/dl (53.1% vs 21.3%, p = 0.001). For extensive burn patients, no significant adverse effects of ultra-restrictive RBC transfusion were found in this study. When the blood supply is tight, it is acceptable to adopt an RBC transfusion threshold of < 7 g/dL but not < 6 g/dL.

Safety and efficacy of waterjet debridement vs. conventional debridement in the treatment of extremely severe burns: A retrospective analysis

INTRODUCTION

Patients with extremely severe burns often require rapid wound closure with a tangential excision or escharectomy combined with a skin graft to reduce life-threatening complications such as infection. Traditional tangential excision surgery using the Watson or Humby knife does not allow accurate excision of necrotic tissue and often removes too much active tissue, which is detrimental to the rapid healing of the wound. Importantly, the Versajet hydrosurgical system, with its smaller handle, allows for more precise excision of necrotic burn tissue and preserves more active dermal tissue, positively affecting wound healing and scarring. This study compared the safety and efficacy of hydrosurgical combined with autologous skin grafting to conventional excision combined with autologous skin grafting in patients with extremely severe burn.

METHODS

Information of sixty burn patients with total body surface area (TBSA) > 50 % treated at the first affiliated hospital of Anhui Medical University from January 2019 to August 2022 were analyzed. The patients were divided into a conventional debridement group (n = 37) and a hydrosurgical debridement group (n = 23) according to the approach used. The hydrosurgical debridement group and the conventional debridement group were compared from the difference between the duration of the first debridement surgery, wound healing time, the changes of red blood cells and hemoglobin concentration postoperative, total blood transfusion, hospitalization cost, skin grafting frequency, procalcitonin, wound bacterial culture, albumin and prealbumin.

RESULTS

Information on age, gender, weight, inhalation injury, hypovolemic shock, preoperative procalcitonin, preoperative albumin, preoperative prealbumin, the operation frequency (n ≥ 3), preoperative trauma culture and postoperative trauma culture were compared between both groups (P > 0.05). Operative time and wound healing time were significantly shorter in patients with hydrosurgical debridement combined with autologous skin grafting than those in the control group (P < 0.05), while hospitalization costs were not significantly different between the two groups (P > 0.05). The changes of red blood cells and hemoglobin concentration during the postoperative period in the hydrosurgical debridement group were less significantly than those in the conventional debridement group (P < 0.05). The total amount of red blood cells transfused during hospitalization was significantly lower in the hydrosurgical debridement group than that in the conventional debridement group (P < 0.05), but the total amount of fresh frozen plasma transfused during hospitalization was not statistically significant between the two groups (P > 0.05). Albumin on the third day after surgery and prealbumin on the first, third and fifth day after surgery improved more significantly than those in the control group(P < 0.05), however, there were no significant differences between the two groups in albumin on the first and fifth postoperative days (P > 0.05). The PCT level in the conventional debridement group was significantly higher than that in the hydrosurgical debridement group on the first, third and fifth days after surgery(P < 0.05).

CONCLUSION

The hydrosurgical debridement group presented with shorter operative time, less blood loss during surgery, faster postoperative nutritional recovery, less postoperative inflammatory response and faster wounds healing, and did not increase the hospitalization cost, postoperative bacterial culture of the wounds and the number of skin grafting surgeries. In patients with extremely severe burn, hydrosurgical debridement combined with autologous skin grafting group is safer and more effective than those in the conventional debridement combined with autologous skin grafting group.

Reducing Blood Loss in a Burn Care Unit: A Review of Its Key Determinants

Patients with a major burn injury differ considerably from the typical critical ill and trauma population. Very often, burn patients suffer from anemia throughout their hospital stay. This is caused both by combination of persistent blood loss with decreased erythropoiesis. Therefore, burn patients do have major transfusion requirements. However, transfusion is not devoid of risks or costs. We hereby review the best surgical techniques and medical approaches, aiming to reduce blood loss in a burn patient and optimize red cell production, so that we can reduce the need of RBC transfusion. The implementation of a combination of surgical techniques aiming to reduce blood loss and medical care approaches to prevent anemia, rather than single attitudes, should be adopted in burn care. There is an urgent need for clear guidelines that can easily be accepted, applied, and spread across different burn units to methodically implement measures to reduce blood loss and transfusion needs, and ultimately improve burn patients' outcome and the health care financial status.

Choosing wisely in burn care

BACKGROUND

The Choosing Wisely Campaign was launched in 2012 and has been applied to a broad spectrum of disciplines in almost thirty countries, with the objective of reducing unnecessary or potentially harmful investigations and procedures, thus limiting costs and improving outcomes. In Canada, patients with burn injuries are usually initially assessed by primary care and emergency providers, while plastic or general surgeons provide ongoing management. We sought to develop a series of Choosing Wisely statements for burn care to guide these practitioners and inform suitable, cost-effective investigations and treatment choices.

METHODS

The Choosing Wisely Canada list for Burns was developed by members of the Canadian Special Interest Group of the American Burn Association. Eleven recommendations were generated from an initial list of 29 statements using a modified Delphi process and SurveyMonkey™.

RESULTS

Recommendations included statements on avoidance of prophylactic antibiotics, restriction of blood products, use of adjunctive analgesic medications, monitoring and titration of opioid analgesics, and minimizing 'routine' bloodwork, microbiology or radiological investigations.

CONCLUSIONS

The Choosing Wisely recommendations aim to encourage greater discussion between those involved in burn care, other health care professionals, and their patients, with a view to reduce the cost and adverse effects associated with unnecessary therapeutic and diagnostic procedures, while still maintaining high standards of evidence-based burn care.

Plasma TNFα and Unknown Factor/s Potentially Impede Erythroblast Enucleation Obstructing Terminal Maturation of Red Blood Cells in Burn Patients

INTRODUCTION

In this study, using burn patient's peripheral blood mononuclear cells (PBMCs), we have shown that the Epo independent stage of terminal enucleation to reticulocyte formation is impeded in the presence of autologous plasma (BP). Furthermore, substitution with allogeneic control plasma (CP) from the healthy individual in place of BP rectified this enucleation defect. The exclusive role of burn microenvironment in late-stage erythropoiesis defect was further demarcated through control healthy human bone marrow cells cultured in the presence of CP, BP, and cytokines.

METHODS

PBMCs and human bone marrow (huBM) were differentiated ex vivo to enucleated reticulocytes in the presence of required growth factors and 5% CP or BP. Effect of systemic mediators in burn microenvironment like IL-6, IL-15, and TNFα was also explored. Neutralization experiments were carried out by adding varying concentrations (25 ng-400 ng/mL) of Anti-TNFα Ab to either CP+TNFα or BP.

RESULTS

Reticulocyte proportion and maturation index were significantly improved upon substituting BP with CP during differentiation of burn PBMCs. In the huBM ex vivo culture, addition of IL-6 and IL-15 to CP inhibited the proliferation stages of erythropoiesis, whereas TNFα supplementation caused maximum diminution at erythroblast enucleation stage. Supplementation with anti-TNFα in the BP showed significant but partial restoration in the enucleation process, revealing the possibility of other crucial microenvironmental factors that could impact RBC production in burn patients.

CONCLUSION

Exogenous TNFα impairs late-stage erythropoiesis by blocking enucleation, but neutralization of TNFα in BP only partially restored terminal enucleation indicating additional plasma factor(s) impair(s) late-stage RBC maturation in burn patients.

Increased risk of blood transfusion in patients with diabetes mellitus sustaining non-major burn injury

BACKGROUND

Due to the increased mortality and morbidity associated with blood transfusion, identifying modifiable predictors of transfusion are vital to prevent or minimise blood use. We hypothesised that burn patients with diabetes mellitus were more likely to be prescribed a transfusion. These patients tend to have increased age, number of comorbidities, infection risk and need for surgery which are all factors reported previously to be associated with blood use.

OBJECTIVE

To determine whether patients with diabetes mellitus who have sustained a burn ≤20% total body surface area (TBSA) are at higher risk of receiving red blood cell transfusion compared to those without diabetes mellitus.

METHOD

This was a retrospective cohort study including patients admitted to the major Burns Unit in Western Australia for management of a burn injury. Only the first hospital admission between May 2008 to February 2017 were included.

RESULTS

Among 2101 patients with burn injuries ≤20% TBSA, 48 (2.3%) received packed red blood cells and 169 (8.0%) had diabetes. There were 13 (7.7%) diabetic patients that were transfused versus 35 (1.8%) non-diabetic patients. Patients with diabetes were 5.2 (p = 0.034) times more likely to receive packed red blood cells after adjusting for percentage TBSA, haemoglobin at admission or prior to transfusion, number of surgeries, total comorbid burden and incidence of infection. As percentage TBSA increases, the probability of packed red blood cell transfusion increases at a higher rate in DM patients.

CONCLUSIONS

This study showed that diabetic patients with burn injuries ≤20% TBSA have a higher probability of receiving packed red blood cell transfusion compared to patients without diabetes. This effect was compounded in burns with higher percentage TBSA.

Management of bleeding in major burn surgery

Major burn surgery is often associated with excessive bleeding and massive transfusion, and the development of a coagulopathy during major burn surgery is associated with increased morbidity and mortality. The aim of this study was to review the literature on intraoperative haemostatic resuscitation of burn patients during necrectomy to reveal strategies applied for haemostatic monitoring and resuscitation. We searched PubMed, EMBASE, and CENTRAL for studies published in the period 2006-2017 concerning bleeding issues related to burn surgery i.e. coagulopathy, transfusion requirements and clinical outcomes. In a broad search, a total of 1375 papers were identified. 124 of these fulfilled the inclusion criteria, and six of these were included for review. The literature confirmed that transfusion requirements increases with burn injury severity and that haemostatic monitoring by TEG^® (thrombelastography) or ROTEM^® (rotational thromboelastometry) significantly decreased intraoperative transfusions and was useful in predicting and goal-directing haemostatic therapy during excision surgery. Resuscitation of bleeding during major burn surgery in many instances was neither standardized nor haemostatic. We suggest that resuscitation should aim for normal haemostasis during the bleeding phase through close haemostatic monitoring and resuscitation. Randomised controlled trials are highly warranted to confirm the benefit of this concept.

Factor XIII-guided treatment algorithm reduces blood transfusion in burn surgery

Background and objectives

Major burn surgery causes large hemorrhage and coagulation dysfunction. Treatment algorithms guided by ROTEM^® and factor VIIa reduce the need for blood products, but there is no evidence regarding factor XIII. Factor XIII deficiency changes clot stability and decreases wound healing. This study evaluates the efficacy and safety of factor XIII correction and its repercussion on transfusion requirements in burn surgery.

Methods

Randomized retrospective study with 40 patients undergoing surgery at the Burn Unit, allocated into Group A those with factor XIII assessment (n = 20), and Group B, those without assessment (n = 20). Erythrocyte transfusion was guided by a hemoglobin trigger of 10 g.dL⁻¹ and the other blood products by routine coagulation and ROTEM^® tests. Analysis of blood product consumption included units of erythrocytes, fresh frozen plasma, platelets, and fibrinogen. The coagulation biomarker analysis compared the pre- and post-operative values.

Results and conclusions

Group A (with factor XIII study) and Group B had identical total body surface area burned. All patients in Group A had a preoperative factor XIII deficiency, whose correction significantly reduced units of erythrocyte concentrate transfusion (1.95 vs. 4.05, p = 0.001). Pre- and post-operative coagulation biomarkers were similar between groups, revealing that routine coagulation tests did not identify factor XIII deficiency. There were no recorded thromboembolic events. Correction of factor XIII deficiency in burn surgery proved to be safe and effective for reducing perioperative transfusion of erythrocyte units.

Discrete β-adrenergic mechanisms regulate early and late erythropoiesis in erythropoietin-resistant anemia

BACKGROUND

Anemia of critical illness is resistant to exogenous erythropoietin. Packed red blood cells transfusions is the only treatment option, and despite related cost and morbidity, there is a need for alternate strategies. Erythrocyte development can be divided into erythropoietin-dependent and erythropoietin-independent stages. We have shown previously that erythropoietin-dependent development is intact in burn patients and the erythropoietin-independent early commitment stage, which is regulated by β1/β2-adrenergic mechanisms, is compromised. Utilizing the scald burn injury model, we studied erythropoietin-independent late maturation stages and the effect of β1/β2, β-2, or β-3 blockade in burn mediated erythropoietin-resistant anemia.

METHODS

Burn mice were randomized to receive daily injections of propranolol (nonselective β1/β2 antagonist), nadolol (long-acting β1/β2 antagonist), butoxamine (selective β2 antagonist), or SR59230A (selective β3 antagonist) for 6 days after burn. Total bone marrow cells were characterized as nonerythroid cells, early and late erythroblasts, nucleated orthochromatic erythroblasts and enucleated reticulocyte subsets using CD71, Ter119, and Syto-16 by flow cytometry. Multipotential progenitors were probed for MafB expressing cells.

RESULTS

Although propranolol improved early and late erythroblasts, only butoxamine and selective β3-antagonist administrations were positively reflected in the peripheral blood hemoglobin and red blood cells count. While burn impeded early commitment and late maturation stages, β1/β2 antagonism increased the early erythroblasts through commitment stages via β2 specific MafB regulation. β3 antagonism was more effective in improving overall red blood cells through late maturation stages.

CONCLUSION

The study unfolds novel β2 and β3 adrenergic mechanisms orchestrating erythropoietin resistant anemia after burn, which impedes both the early commitment stage and the late maturation stages, respectively.

Determinants and time to blood transfusion among thermal burn patients admitted to Mulago Hospital

Background

Blood transfusion, a practice under re-evaluation in general, remains common among thermal burn patients due to the hematological alterations associated with burns that manifest as anemia. Today advocacy is for restrictive blood transfusion taking into account individual patient characteristics. We went out to identify the parameters that may determine transfusion requirement and the time to blood transfusion for thermal burn patients in Mulago Hospital in order to build statistics and a basis to standardize future practice and Hospital protocol.

Methods

112 patients with thermal burns were enrolled into a prospective cohort study conducted in the Surgical Unit of the Accidents and Emergency Department and Burns Unit of Mulago Hospital. Relevant data on pre-injury, injury and post-injury factors was collected including relevant laboratory investigations and treatment modalities like surgical intervention. Patients were clinically followed up for a maximum period of 28 days and we identified those that were transfused.

Results

22.3% of patients were transfused. The median time to transfusion was 17 days from time of injury and varied with different patient characteristics. The median pre-transfusion hemoglobin (Hb) level was 8.2 g/dL. Transfusion was significantly related to; admission to the intensive care unit (p = 0.001), a body mass index (BMI) <2 kg/m² (p = 0.021), % total burn surface area (TBSA) >20 (p = 0.049), pre-existing illness (p = 0.046), and white blood cell (WBC) count <4000 or >12,000/μL (p = 0.05).

Conclusion

Pre-existing illnesses, a low BMI, TBSA of >20%, admission to the intensive care unit and abnormalities in the WBC count are useful predictors of blood transfusion among thermal burns patients admitted to Mulago Hospital. The precise time to transfusion from time of burns injury cannot be generalized. With close monitoring of each individual patient lies the appropriateness and timeliness of their management.

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.

Patient Safety in Burn Care: Application of Evidence-based Medicine to Improve Outcomes

This article reviews 5 areas in burn care that increasingly use evidence-based medicine to optimize quality and safety: resuscitation protocols, transfusion practices, vascular access, venous thromboembolic prophylaxis, and rational use of antibiotics.

Myelo-erythroid commitment after burn injury is under β-adrenergic control via MafB regulation

Severely injured burn patients receive multiple blood transfusions for anemia of critical illness despite the adverse consequences. One limiting factor to consider alternate treatment strategies is the lack of a reliable test platform to study molecular mechanisms of impaired erythropoiesis. This study illustrates how conditions resulting in a high catecholamine microenvironment such as burns can instigate myelo-erythroid reprioritization influenced by β-adrenergic stimulation leading to anemia. In a mouse model of scald burn injury, we observed, along with a threefold increase in bone marrow LSK cells (lin^neg Sca1⁺cKit⁺), that the myeloid shift is accompanied with a significant reduction in megakaryocyte erythrocyte progenitors (MEPs). β-Blocker administration (propranolol) for 6 days after burn, not only reduced the number of LSKs and MafB⁺ cells in multipotent progenitors, but also influenced myelo-erythroid bifurcation by increasing the MEPs and reducing the granulocyte monocyte progenitors in the bone marrow of burn mice. Furthermore, similar results were observed in burn patients' peripheral blood mononuclear cell-derived ex vivo culture system, demonstrating that commitment stage of erythropoiesis is impaired in burn patients and intervention with propranolol (nonselective β1,2-adrenergic blocker) increases MEPs. Also, MafB⁺ cells that were significantly increased following standard burn care could be mitigated when propranolol was administered to burn patients, establishing the mechanistic regulation of erythroid commitment by myeloid regulatory transcription factor MafB. Overall, results demonstrate that β-adrenergic blockers following burn injury can redirect the hematopoietic commitment toward erythroid lineage by lowering MafB expression in multipotent progenitors and be of potential therapeutic value to increase erythropoietin responsiveness in burn patients.

Transfusion medicine in the Formosa Fun Coast water park explosion: The role of combined tissue and blood banking

The Formosa Fun Coast explosion, occurring in a recreational water park located in the Northern Taiwan on 27 June 2015, made 499 people burn-injured. For those who had severe burn trauma, surgical intervention and fluid resuscitation were necessary, and potential blood transfusion therapy could be initiated, especially during and after broad escharotomy. Here, we reviewed the literature regarding transfusion medicine and skin grafting as well as described the practicing experience of combined tissue and blood bank in the burn disaster in Taiwan. It was reported that patients who were severely burn-injured could receive multiple blood transfusions during hospitalization. Since the use of skin graft became a mainstay alternative for wound coverage after the early debridement of burn wounds at the beginning of the 20th century, the development of tissue banking program was initiated. In Taiwan, the tissue banking program was started in 2006. And the first combined tissue and blood bank was established in Far Eastern Memorial Hospital in 2010, equipped with the non-sterile, clean and sterile zones distinctly segregated with a unidirectional movement in the sterile area. The sterile zone was a class 10000 clean room equipped with high efficiency particulate air filter (HEPAF) and positive air pressure ventilation. The combined tissue and blood bank has been able to provide the assigned blood products and tissue graft timely and accurately, with the concepts of centralized management. In the future, the training of tissue and blood bank technicians would be continued and fortified, particularly on the regulation and quality control for further bio- and hemovigilance.

The Use of Blood Products in Adult Patients with Burns

Introduction:

Burn anemia represents a common complication following a burn injury. Burn anemia etiology carries distinct features occurring at each stage of the post-injury and treatment periods resulting from different causes. We aimed to analyze the use of blood components in Finnish burn victims and to identify patient- and injury-related factors influencing their use.

Methods:

To study the use of blood products in burn patients, we used data collected from the Optimal Use of Blood registry, developed through co-operation between 10 major hospital districts and the Finnish Red Cross Blood Service. Burn patients ⩾18 years treated at the Helsinki University Hospital between 2005 and 2011 with an in-hospital stay ⩾1 day who received at least one transfusion during their hospital stay were included in this study.

Results:

Among all 558 burn patients, 192 (34%) received blood products during their hospital stay. The transfused cohort comprised 192 burn patients. The study cohort received a total of 6087 units of blood components, 2422 units of leukoreduced red blood cells, 1728 units of leukoreduced platelets, and 420 units of single-donor fresh frozen plasma or, after 2007, 1517 units of Octaplas® frozen plasma. All three types of blood components were administered to 29% of patients, whereas 45% received only red blood cells and 6% received only Octaplas. Transfused patients were significantly older (p < 0.001), experienced fire-/flame-related accidents and burns to multiple locations (p < 0.001), and their in-hospital mortality exceeded that for non-transfused burn patients fivefold (p < 0.05).

Discussion:

We show that Finnish adult burn patients received ample transfusions. The number of blood components transfused varied according to the anatomical location of the injury and patient survival. Whether the additional mortality is related directly to transfusions or is merely a manifestation of the more severe burn injury remains unknown.

Burns management in ICU: Quality of the evidence: A systematic review

BACKGROUND

The objective of this study was to assess the quality of readily available evidence regarding critical care aspects of the management of patients with severe burn injuries.

METHOD

PUBMED, EMBASE, Cochrane Databases and bibliographies of included studies and burns review articles were searched from inception of databases to end of February 2015. We included systematic reviews, randomised controlled trials (RCTs) and cohort studies with concurrent controls on the topics of (a) fluid resuscitation (b) analgesia (c) haemodynamic monitoring and targets (d) ventilation (e) blood transfusion. The quality of the studies was assessed using validated tools.

RESULTS

Fifty six studies fulfilled the inclusion criteria. Twenty three on fluid resuscitation, 22 on analgesia, nine on haemodynamic monitoring and two on ventilation. No studies were found on blood transfusion practice. There were ten systematic reviews, 38 RCTs and eight cohort studies with concurrent controls. The majority of studies were single centre trials with small numbers of patients, surrogate outcomes and high risk of bias.

CONCLUSIONS

There is very little high quality evidence to guide clinical practice in early management of the severely burnt patient. Eleven of 56 studies found in our search of critical care topics were of good methodological quality with low risk of bias.

Impact of Anemia in Critically Ill Burned Casualties Evacuated From Combat Theater via US Military Critical Care Air Transport Teams

BACKGROUND

US military Critical Care Air Transport Teams (CCATT) transport critically ill burn patients out of theater. Blood transfusion may incur adverse effects, and studies report lower hemoglobin (Hgb) value may be safe for critically ill patients. There are no studies evaluating the optimal Hgb value for critically ill burn patients prior to CCATT evacuation.

OBJECTIVE

The aim of the study was to determine if critically ill burn casualties with an Hgb of 10 g/dL or less, transported via CCATT, have similar clinical outcomes at 30 days as compared with patients with an Hgb of greater than 10 g/dL.

METHODS

We conducted an institutional review board-approved retrospective cohort study involving patients transported via CCATT. We separated our study population into two cohorts based on Hgb levels at the time of theater evacuation: Hgb ≤10 g/dL or Hgb ≥10 g/dL. We compared demographics, injury description, physiologic parameters, and clinical outcomes.

RESULTS

Of the 140 subjects enrolled, 29 were Hgb ≤10, and 111 were Hgb ≥10. Both groups were similar in age and percent total body surface area burned. Those Hgb ≤10 had a higher injury severity score (34 ± 19.8 vs. 25 ± 16.9, P = 0.02) and were more likely to have additional trauma (50% vs. 25%, P = 0.04). Modeling revealed no persistent differences in mortality, and other clinical outcomes measured.

CONCLUSIONS

Critical Care Air Transport Teams transport of critically ill burn patients with an Hgb of 10 g/dL or less had no significant differences in complications or mortality as compared with patients with an Hgb of greater than 10 g/dL. In this study, lower hemoglobin levels did not confer greater risk for worse outcomes.

Perturbed MafB/GATA1 axis after burn trauma bares the potential mechanism for immune suppression and anemia of critical illness

Patients who survive initial burn injury are susceptible to nosocomial infections. Anemia of critical illness is a compounding factor in burn patients that necessitates repeated transfusions, which further increase their susceptibility to infections and sepsis. Robust host response is dependent on an adequate number and function of monocytes/macrophages and dendritic cells. In addition to impaired RBC production, burn patients are prone to depletion of dendritic cells and an increase in deactivated monocytes. In steady-state hematopoiesis, RBCs, macrophages, and dendritic cells are all generated from a common myeloid progenitor within the bone marrow. We hypothesized in a mouse model of burn injury that an increase in myeloid-specific transcription factor V-maf musculoaponeurotic fibrosarcoma oncogene homolog B at the common myeloid progenitor stage steers their lineage potential away from the megakaryocyte erythrocyte progenitor production and drives the terminal fate of common myeloid progenitors to form macrophages vs. dendritic cells, with the consequences being anemia, monocytosis, and dendritic cell deficits. Results indicate that, even though burn injury stimulated bone marrow hematopoiesis by increasing multipotential stem cell production (Lin^negSca1^poscKit^pos), the bone marrow commitment is shifted away from the megakaryocyte erythrocyte progenitor and toward granulocyte monocyte progenitors with corresponding alterations in peripheral blood components, such as hemoglobin, hematocrit, RBCs, monocytes, and granulocytes. Furthermore, burn-induced V-maf musculoaponeurotic fibrosarcoma oncogene homolog B in common myeloid progenitors acts as a transcriptional activator of M-CSFR and a repressor of transferrin receptors, promoting macrophages and inhibiting erythroid differentiations while dictating a plasmacytoid dendritic cell phenotype. Results from small interfering RNA and gain-of-function (gfp-globin transcription factor 1 retrovirus) studies indicate that targeted interventions to restore V-maf musculoaponeurotic fibrosarcoma oncogene homolog B/globin transcription factor 1 balance can mitigate both immune imbalance and anemia of critical illness.

The effects of intravenous vitamin C on point-of-care glucose monitoring

Ascorbic acid (vitamin C) decreases systemic inflammation and lowers fluid requirements after thermal injury; therefore it has been adopted in many burn centers as an adjunct to resuscitation. However, recent concerns have been expressed over clinically significant hypoglycemic events caused by vitamin C interference with the point-of-care (POC) glucose measurements. This case series presents a direct comparison of POC and laboratory reference glucose values in the patients receiving vitamin C infusion. Vitamin C was administered at 66 mg/kg/hour in seven patients with burns >30% TBSA. The baseline characteristics and burn characteristics were recorded. POC glucose measurements were made with a commonly used hand-held device, and the laboratory values were obtained using standard spectrophotometric methods. POC and laboratory glucose values drawn within the same hour were compared. Hemoglobin, which is known to cause interference in POC testing, was also recorded. All the patients demonstrated falsely elevated POC glucose values during and/or immediately after the infusion period, with discrepancies ranging from 10 to 200 mg/dl. These findings were irregular, unpredictable and unrelated to hemoglobin levels. The findings suggest an idiosyncratic reaction that cannot be easily corrected at the bedside using mathematical equations. POC glucose monitoring should be avoided during and after vitamin C therapy.

Acute blood loss during burn and soft tissue excisions: An observational study of blood product resuscitation practices and focused review

BACKGROUND

Many military and civilian centers have shifted to a damage-control resuscitation approach, focused on providing oxygen-carrying capacity while simultaneously mitigating coagulopathy with a balanced ratio of platelets and plasma to red blood cells. It is unclear to what degree this strategy is used during burn or soft tissue excision. Here, we characterized blood product transfusion during burn and soft tissue surgery and reviewed the published literature regarding intraoperative coagulation changes. We hypothesized that blood product resuscitation during burn and soft tissue excision is not hemostatic and would be insufficient to address hemorrhage-induced coagulopathy.

METHODS

Consented adult patients were enrolled into an institutional review board-approved prospective observational study. Number, component type, volume, and age of the blood products transfused were recorded during burn excision/grafting or soft tissue debridement. Component bags (packed red blood cells, fresh frozen plasma, platelets, and cryoprecipitate) were collected, and the remaining sample was harvested from the bag and tubing. Aliquots of 1/1,000th the original volume of each blood product were obtained and combined, producing an amalgam sample containing the same ratio of product transfused. Platelet count, rotational thromboelastometry, and impedance aggregometry were measured. Significance was set at p < 0.05.

RESULTS

Amalgamated transfusate samples produced abnormally weak clots (p ≤ 0.001) particularly if they did not contain platelets. Clot strength (48.8 [2.6] mm; reference range, 49-71 mm) for platelet-containing amalgams was below the lower limit of the reference range despite platelet-red blood cell ratios greater than 1:1. Platelet aggregation was abnormally low; transfused platelets were functionally inferior to native platelets.

CONCLUSION

Our study and focused review demonstrate that further work is needed to fully understand the needs of patients undergoing tissue excision. The three studies reviewed and the results of our observational work suggest that coagulopathy and thrombocytopenia may contribute to intraoperative hemorrhage. Blood product resuscitation during burn and soft tissue excision is not hemostatic.

LEVEL OF EVIDENCE

Epidemiologic study, level V.

Clinical review: the critical care management of the burn patient

Between 4 and 22% of burn patients presenting to the emergency department are admitted to critical care. Burn injury is characterised by a hypermetabolic response with physiologic, catabolic and immune effects. Burn care has seen renewed interest in colloid resuscitation, a change in transfusion practice and the development of anti-catabolic therapies. A literature search was conducted with priority given to review articles, meta-analyses and well-designed large trials; paediatric studies were included where adult studies were lacking with the aim to review the advances in adult intensive care burn management and place them in the general context of day-to-day practical burn management.

Major burn injury is not associated with acute traumatic coagulopathy

BACKGROUND

The pathophysiology and time course of coagulopathy after major burns are inadequately understood. Our study objectives were to determine whether acute traumatic coagulopathy (ATC) is seen in burn patients at admission and to determine the changes in international normalized ratio (INR), activated partial thromboplastin time (aPTT), platelet count (PLT), and hemoglobin (Hgb) in the first 7 days after injury.

METHODS

We conducted a retrospective study of patients with burn injury of at least 15% total body surface area who presented to the University of North Carolina. Data on patient demographics, injury characteristics, and laboratory data (INR, aPTT, PLT, and Hgb) at admission and within the first 7 days after injury were recorded. We defined ATC as INR of 1.3 or greater, aPTT of 1.5 or greater times the mean normal limit, and normal PLT at admission.

RESULTS

We studied the hematologic profile of 102 patients with burn injury of 15% to 100% total body surface area but did not identify a single patient with ATC at admission. The screening hematologic profile at admission was not influenced by burn severity. In the first 7 days after injury, the INR and aPTT were relatively preserved, while the PLT quickly recovered to baseline after an early decline and the Hgb remained stable at around 10 g/dL; all these changes occurred during the time when the burn patients had received large amounts of fluid resuscitation.

CONCLUSION

The screening hematologic profile of burn patients at admission is normal, and the standard screening assays do not suggest the existence of ATC at admission. While this is a relatively small study, it provides evidence to suggest that ATC is unique to trauma patients.

LEVEL OF EVIDENCE

Prognostic study, level III.

Blood utilization in patients with burn injury and association with clinical outcomes (CME)

BACKGROUND

Uncontrolled bleeding is an important cause of increased transfusion in burn victims; however, description of blood utilization patterns in the burn population is lacking.

STUDY DESIGN AND METHODS

We conducted a single-institution, retrospective cohort study to measure blood utilization in 89 consecutive burn patients with 15% to 65% total body surface area (TBSA) burn within 60 days of injury. We also evaluated the relationship of blood product utilization with clinical variables including anticoagulant usage and mortality.

RESULTS

We determined that: 1) the predictors for increased red blood cells (RBCs) and plasma transfusions were high TBSA burn and the use of argatroban anticoagulation (for suspected heparin-induced thrombocytopenia [HIT]); 2) TBSA burn and patient age were independent predictors of mortality, but not RBC or plasma transfusion; and 3) the incidence of symptomatic venous thromboembolic events is not uncommon (11.2%), although HIT is rare (1.1%).

CONCLUSION

Despite concerns about adverse correlation between increased number of transfusions and mortality in other clinical settings, we did not find this association in our study. However, we demonstrated that the type and intensity of anticoagulation carries substantial risk for increased RBC as well as plasma usage.

Classifying transfusions related to the anemia of critical illness in burn patients

BACKGROUND

Critically ill patients require transfusions because of acute blood loss and the anemia of critical illness. In critically ill burn patients, typically, no distinction is made between transfusions related to acute surgical blood loss and those related to the anemia of critical illness. We sought to identify the percentage of blood transfusions due to the anemia of critical illness and the clinical characteristics associated with these transfusions in severely burned patients.

METHODS

Sixty adult patients with ≥20% total body surface area (TBSA) burn who were transfused at least 1 unit of packed red blood cells during their hospitalization were studied. Clinical variables including age, %TBSA burn, Acute Physiology and Chronic Health Evaluation (APACHE) II score, number of ventilator days, inhalation injury, and number of operative events were correlated with the total number of packed red blood cell units and percentage of nonsurgical transfusions in these patients. Nonsurgical transfusions were defined as transfusions occurring after postoperative day 1 for each distinct operative event and were classified as being caused by the anemia of critical illness.

RESULTS

Patients were transfused an average of 16.6 units ± 21.2 units. Nonsurgical transfusions accounted for 52% of these transfusions. APACHE II score, %TBSA burn, number of ventilator days, and number of operative events, all correlated with total transfusions. However, nonsurgical transfusions correlated with only APACHE II score (p = 0.01) and number of ventilator days (p = 0.03). There was no correlation between nonsurgical transfusions and other clinical variables.

CONCLUSION

The anemia of critical illness is responsible for >50% of all transfusions in severely burned patients. The initial severity of critical illness (APACHE II score) and duration of the critical illness (number of ventilator days) correlated with transfusions related to anemia of critical illness. Further investigation into the specific risk factors for these transfusions may help to develop strategies to further reduce transfusion rates.

Red blood cell transfusion following burn

A severe burn will significantly alter haematologic parameters, and manifest as anaemia, which is commonly found in patients with greater than 10% total body surface area (TBSA) involvement. Maintaining haemoglobin and haematocrit levels with blood transfusion has been the gold standard for the treatment of anaemia for many years. While there is no consensus on when to transfuse, an increasing number of authors have expressed that less blood products should be transfused. Current transfusion protocols use a specific level of haemoglobin or haematocrit, which dictates when to transfuse packed red blood cells (PRBCs). This level is known as the trigger. There is no one 'common trigger' as values range from 6 g dl(-1) to 8 g dl(-1) of haemoglobin. The aim of this study was to analyse the current status of red blood cell (RBC) transfusions in the treatment of burn patients, and address new information regarding burn and blood transfusion management. Analysis of existing transfusion literature confirms that individual burn centres transfuse at a lower trigger than in previous years. The quest for a universal transfusion trigger should be abandoned. All RBC transfusions should be tailored to the patient's blood volume status, acuity of blood loss and ongoing perfusion requirements. We also focus on the prevention of unnecessary transfusion as well as techniques to minimise blood loss, optimise red cell production and determine when transfusion is appropriate.

What's new in critical care of the burn-injured patient?

The number of cases of mortality after burn injury continues to decline, in part because of advances in respiratory, fluid, and sepsis management. However, care needs to be exercised in the application of these new techniques and technologies, many of which have never been assessed or have been incompletely studied in patients who have burn injury. Use of any of these advances in critical care needs to be individualized for any given patient and altered based on the patient's response to therapy. Future advances in the critical care of burns will require multicenter prospective trials at dedicated burn centers to define the optimal therapy for the patient who has burn injury.

Glycemic control in the burn intensive care unit: focus on the role of anemia in glucose measurement

Glycemic control with intensive insulin therapy (IIT) has received widespread adoption secondary to findings of improved clinical outcomes and survival in the burn population. Severe burn as a model for trauma is characterized by a hypermetabolic state, hyperglycemia, and insulin resistance. In this article, we review the findings of a burn center research facility in terms of understanding glucose management. The conferred benefits from IIT, our findings of poor outcomes associated with glycemic variability, advantages from preserved diurnal variation of glucose and insulin, and impacts of glucometer error and hematocrit correction factor are discussed. We conclude with direction for further study and the need for a reliable continuous glucose monitoring system. Such efforts will further the endeavor for achieving adequate glycemic control in order to assess the efficacy of target ranges and use of IIT.

Modern trends in fluid therapy for burns

The majority of burn centres use the crystalloid-based Parkland formula to guide fluid therapy, but patients actually receive far more fluid than the formula predicts. Resuscitation with large volumes of crystalloid has numerous adverse consequences, including worsening of burn oedema, conversion of superficial into deep burns, and compartment syndromes. Resuscitation fluids influence the inflammatory response to burns in different ways and it may be possible, therefore to affect this response using the appropriate fluid, at the appropriate time. Starches are effective volume expanders and early use of newer formulations may limit resuscitation requirements and burn oedema by reducing inflammation and capillary leak. Advanced endpoint monitoring may guide clinicians in when to 'turn off' aggressive fluid therapy and therefore avoid the problems of over-resuscitation.

The impact of intensive insulin protocols and restrictive blood transfusion strategies on glucose measurement in American Burn Association (ABA) verified burn centers

The prevalence of intensive insulin and restrictive blood use protocols in burn centers is unknown, which may be problematic as the combined impact of these therapies is to concomitantly increase the prevalence of anemia and hypoglycemia in intensive care unit patients. Such a development is important because point-of-care (POC) glucometers report erroneously high values in the presence of low hematocrit (HCT), potentially masking the presence of hypoglycemia. We hypothesized that most American Burn Association (ABA) verified burn centers have adopted intensive insulin therapy while simultaneously restricting blood transfusions potentially increasing risk of hypoglycemia. All ABA verified burn centers (N = 44) were contacted. Clinical practices regarding intensive insulin therapy, restrictive transfusion practices, and the use of POC glucometers were evaluated. Intensive insulin protocols were implemented at 73% of ABA centers (defined as upper glucose target of < or = 120 mg/dl) and POC glucometers measurement was nearly universal; 95% of ABA centers use them routinely. Anemia is prevalent in intensive care units and may be increasing because of recent changes in practice. Defined hemoglobin and HCT levels trigger blood transfusion at 84% of centers, and of these, 51% restrict transfusion to hemoglobin < 7 g/dl or HCT < 22%. Most ABA centers now use intensive insulin protocols, many in combination with restrictive transfusion strategies. The combination of a higher prevalence of hypoglycemia in the presence of near universal anemia is concerning, particularly given the pervasiveness of glucometer use among burn centers.

Advances in burn care

PURPOSE OF REVIEW

This article reviews and critiques new developments in the critical care of burn patients.

RECENT FINDINGS

The practice of restrictive transfusion is slowly gaining traction. Abdominal compartment syndrome is associated with resuscitation volumes of 300 ml/kg per 24 h, and percutaneous decompression may be a treatment option. Adrenal insufficiency is common, but whom and when to treat are unclear. Imaging or noninvasive monitoring may confirm renal perfusion before urine output, and the concept of permissive hypovolemia should be explored. There is progress in the laboratory in smoke inhalation and myocardial depression, but no human translation. Antibiotic pharmacokinetics in large burns are unpredictable, and so aminoglycosides (measurable concentrations) are not obsolete. Selective digestive decontamination remains controversial. Nutritional predictions by formula are inaccurate. Oxandrolone is safe and effective in promoting anabolism in large burns. Deep venous thrombosis prophylaxis remains guided only by expert opinion. Females fare worse than male patients after burns.

SUMMARY

The application of the scientific method to burn care is improving slowly. Randomized controlled trials are becoming more common. There is a need for translation of excellent animal work to the human arena.