Determinants of blood loss during primary burn excision

Metabolic and Nutritional Support

Hypermetabolism is a hallmark of larger burn injuries. The hypermetabolic response is characterized by marked and sustained increases in catecholamines, glucocorticoids, and glucagon. There is an increasing body of literature for nutrition and metabolic treatment and supplementation to counter the hypermetabolic and catabolic response secondary to burn injury. Early and adequate nutrition is key in addition to adjunctive therapies, such as oxandrolone, insulin, metformin, and propranolol. The duration of administration of anabolic agents should be at minimum for the duration of hospitalization, and possibly up to 2 to 3 years postburn.

Pre-operative Blood Loss Prediction Formulas in Burn Surgeries: A Review

Extensive burn surgeries lead to a considerable amount of blood loss. Predicting pre-operative blood loss is essential for blood ordering and crossmatching. Accurate amount of ordered blood units ensures patients' safety and minimizes cost. However, blood loss estimation is complicated due to a variety of factors influencing blood loss, including patient and operative-related variables. Currently, no standard method to predict blood loss exists prior to surgery. Our goal is to review factors influencing blood loss and formulas that can predict blood loss. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) and MEDLINE databases for studies investigating blood loss in burn surgeries with a clear quantitative outcome. Fifteen studies were included, comprising 1613 subjects. All studies calculated blood loss and assessed possible related factors, and four studies proposed preoperative blood loss prediction formulas. Larger areas of tissue excised and grafted, younger age, and delayed surgery were correlated with increased blood loss. Varying decrease in blood loss was observed with tumescent usage and other bleeding control methods. Other variables produced inconsistent results. From four prediction formulas, only one formula, Dye's Formula, had been applied and proven effective in reducing unused blood units clinically by up to 40% of cross-matched blood. Various confounding factors and dissimilarities between studies make reliable prediction method construction challenging. With consideration of diverse patient characteristics, some study develops formulas to achieve optimal patient care and avoid unnecessary hospital expenditure. Further research with consistent variables should be done to construct a standardized blood loss estimation formula.

Incidence and predictors of perioperative atrial fibrillation in burn intensive care unit patients following burn surgery

BACKGROUND

Atrial fibrillation is a well-documented complication following cardiac surgery. It is associated with increased inpatient and long-term mortality. There have been few prior studies on perioperative atrial fibrillation following burn surgery in severely burned patients. The purpose of this study was to identify the incidence, predictors, and prognosis of perioperative atrial fibrillation after burn surgery in severely burned patients.

METHODS

Patients aged older than 18 years with 30% burned total body surface area (TBSA) were enrolled in this study. Patients who had a previous history of atrial fibrillation or atrial fibrillation on the preoperative electrocardiogram were excluded. We reviewed medical records retrospectively, and the data of 214 patients were studied.

RESULTS

A total of 214 critically ill burned patients and 1132 operations were available for analysis during the 5-year study period; 12 (1.1%) patients were diagnosed with newly developed atrial fibrillation after a burn operation, of whom 4 patients showed paroxysmal atrial fibrillation (all related to surgical stimulation) and none changed to persistent atrial fibrillation. The incidence of perioperative atrial fibrillation was associated with TBSA%, full-thickness TBSA%, and hypertension. Multiple logistic regression analysis indicated that TBSA% (OR=13.851, P < 0.001) and full-thickness TBSA% (OR=15.223, P = 0.018) were independent predictors for developing perioperative atrial fibrillation. All of our patients had at least one risk factor, with blood volume variation or burn sepsis occurring most commonly. Perioperative atrial fibrillation developed after a median of 0 days after burn surgery. Three patients died, and the causes of death were noncardiovascular events such as sepsis and multiple organ failure.

CONCLUSION

Atrial fibrillation was a relatively rare complication among severely burned patients admitted to surgery and was associated with TBSA% and full thickness TBSA%. All of our patients exhibited at least one of the modifiable risk factors for atrial fibrillation, confirming the importance of optimization of electrolytes and fluid status and limitation of sympathetic activation.

Temporal trends, predictors of blood transfusion and in-hospital outcomes among patients with severe burn injury in the United States-A national database-based analysis

BACKGROUND

Severe burn can be accompanied by life-threatening bleeding on some occasions, thus, blood transfusion is often required in these patients during their hospitalization. Therefore, we aimed to examine temporal trends, predictors, and in-hospital outcomes of blood transfusion in these patients in the United States.

METHODS

The National Inpatient Sample was used to identify severe burn patients between January 2010 and September 2017 in the United States. Trends in the utilization of blood transfusion were analyzed using the Cochran-Armitage trend test. Moreover, propensity score matching (PSM) was employed, and then in-hospital outcomes were compared between these two groups in the matched cohort. Multivariable logistic regressions were further used to validate the results of PSM.

RESULTS

Among 27,260 severe burn patients identified during the study period, 2120 patients (7.18%) received blood transfusion. Blood transfusion rates decreased significantly from 9.52% in 2010 to 5.02% in 2017 (p for trend <.001). In the propensity-matched cohort (2120 pairs with and without transfusion), patients transfused were at increased risk of in-hospital mortality (13.3% vs 8.77%, p < .001), overall postoperative complications (88.3% vs 72.59%, p < .001), longer hospital stays (defined as > median hospital stays = 5 d) (73.8% vs 50.6%, p < .001) and increased overall cost (defined as > median overall costs = 30,746) (81.6% vs 57.3%, p < .001). This was also the case for the multivariable analysis.

CONCLUSIONS

Blood transfusion following severe burn injury may be associated with worse clinical outcomes. The utility for blood transfusion in burn patients warrants further prospective exploration.

Treatment of Anaemia in Patients with Acute Burn Injury: A Study of Blood Transfusion Practices

Objective: To determine blood transfusion practices, risk factors, and outcomes associated with the use of blood products in the setting of the acute management of burn patients at the Victorian Adult Burn Service. Background: Patients with burn injuries have variable transfusion requirements, based on a multitude of factors. We reviewed all acute admissions to the Victorian Adult Burns Service (VABS) between 2011 and 2017: 1636 patients in total, of whom 948 had surgery and were the focus of our analysis. Method and results: Patient demographics, surgical management, transfusion details, and outcome parameters were collected and analyzed. A total of 175 patients out of the 948 who had surgery also had a blood transfusion, while 52% of transfusions occurred in the perioperative period. The median trigger haemoglobin in perioperative was 80mg/dL (IQR = 76–84.9 mg/dL), and in the non-perioperative setting was 77 mg/dL (IQR = 71.61–80.84 mg/dL). Age, gender, % total body surface area (TBSA) burn, number of surgeries, and intensive care unit and hospital length of stay were associated with transfusion. Conclusions: The use of blood transfusions is an essential component of the surgical management of major burns. As observed in our study, half of these transfusions are related to surgical procedures and may be influenced by the employment of blood conserving strategies. Furthermore, transfusion trigger levels in stable patients may be amenable to review and reduction. Risk adjusted analysis can support the implementation of blood transfusion as a useful quality indicator in burn care.

Cell salvage in burn excisional surgery

BACKGROUND

Hemostasis during burn surgery is difficult to achieve, and high blood loss commonly occurs. Bleeding control measures are limited, and many patients require allogeneic blood transfusions. Cell salvage is a well-known method used to reduce transfusions. However, its evidence in burns is limited. Therefore, this study aimed to examine the feasibility of cell salvage during burn surgery.

STUDY DESIGN AND METHODS

A prospective, observational study was conducted with 16 patients (20 measurements) scheduled for major burn surgery. Blood was recovered by washing saturated gauze pads with heparinized saline, which was then processed using the Cell Saver. Erythrocyte concentrate quality was analyzed by measuring hemoglobin, hematocrit, potassium, and free hemoglobin concentration. Microbial contamination was assessed based on cultures at every step of the process. Differences in blood samples were tested using the Student's t-test.

RESULTS

The red blood cell mass recovered was 29 ± 11% of the mass lost. Patients' preoperative hemoglobin and hematocrit levels were 10.5 ± 1.8 g/dL and 0.33 ± 0.05 L/L, respectively. The erythrocyte concentrate showed hemoglobin and hematocrit levels of 13.2 ± 3.9 g/dL and 0.40 ± 0.11 L/L thus showing a concentration effect. The potassium level was lower in the erythrocyte concentrate (2.5 ± 1.5 vs. 4.1 ± 0.4 mmol/L, p < 0.05). The free hemoglobin level was low (0.16 ± 0.21 μmol/L). All cultures of the erythrocyte concentrate showed bacterial growth compared to 21% of wound cultures.

CONCLUSION

Recovering erythrocytes during burn excisional surgery using cell salvage is possible. Despite strict sterile handling, erythrocyte concentrates of all patients showed bacterial contamination. The consequence of this contamination remains unclear and should be investigated in future studies.

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.

Postburn Hypermetabolism: Past, Present, and Future

Hypermetabolism is the ubiquitous response to a severe burn injury, which was first described in the nineteenth century. Despite identification of important components of this complex response, hypermetabolism is still not well understood in its entirety. This article describes this incredibly fascinating response and the understanding we have gained over the past 100 years. Additionally, this article describes novel insights and delineates treatment options to modulate postburn hypermetabolism with the goal to improve outcomes of burn patients.

Propranolol attenuates hemorrhage and accelerates wound healing in severely burned adults

Introduction

Propranolol, a nonselective β-blocker, exerts an indirect effect on the vasculature by leaving α-adrenergic receptors unopposed, resulting in peripheral vasoconstriction. We have previously shown that propranolol diminishes peripheral blood following burn injury by increasing vascular resistance. The purpose of this study was to investigate whether wound healing and perioperative hemodynamics are affected by propranolol administration in severely burned adults.

Methods

Sixty-nine adult patients with burns covering ≥30% of the total body surface area (TBSA) were enrolled in this IRB-approved study. Patients received standard burn care with (n = 35) or without (control, n = 34) propranolol. Propranolol was administered within 48 hours of burns and given throughout hospital discharge to decrease heart rate by approximately 20% from admission levels. Wound healing was determined by comparing the time between grafting procedures. Blood loss was determined by comparing pre- and postoperative hematocrit while factoring in operative graft area. Data were collected between first admission and first discharge.

Results

Demographics, burn size, and mortality were comparable in the control and propranolol groups. Patients in the propranolol group received an average propranolol dose of 3.3 ± 3.0 mg/kg/day. Daily average heart rate over the first 30 days was significantly lower in the propranolol group (P <0.05). The average number of days between skin grafting procedures was also lower in propranolol patients (10 ± 5 days) than in control patients (17 ± 12 days; P = 0.02), indicative of a faster donor site healing time in the propranolol group. Packed red blood cell infusion was similar between groups (control 5.3 ± 5.4 units vs. propranolol 4.4 ± 3.1 units, P = 0.89). Propranolol was associated with a 5 to 7% improvement in perioperative hematocrit during grafting procedures of 4,000 to 16,000 cm² compared to control (P = 0.002).

Conclusions

Administration of propranolol during the acute hospitalization period diminishes blood loss during skin grafting procedures and markedly improves wound healing in severely burned adults. As burn patients require serial surgical interventions for motor and cosmetic repair, restricting blood loss during operative intervention is optimal.

Medical management of paediatric burn injuries: best practice part 2

Burns remain a leading cause of injury in the paediatric population in Australia despite efforts in prevention. Advances in surgical management include novel debridement methods and blood conserving techniques. Patients with severe burns (>20%) remain significantly more complex to manage as a result of extensive alterations in metabolic processes. There appears increasing evidence to support the use of pharmacological modulators of the hyper-metabolic state in these patients. The management of a child with burns involves acute, subacute and long-term planning. This holistic approach seems optimally co-ordinated by a Burns Unit in which each discipline required to provide care to these children in order to achieve optimal outcomes is represented.

Determination of burn patient outcome by large-scale quantitative discovery proteomics

OBJECTIVES

Emerging proteomics techniques can be used to establish proteomic outcome signatures and to identify candidate biomarkers for survival following traumatic injury. We applied high-resolution liquid chromatography-mass spectrometry and multiplex cytokine analysis to profile the plasma proteome of survivors and nonsurvivors of massive burn injury to determine the proteomic survival signature following a major burn injury.

DESIGN

Proteomic discovery study.

SETTING

Five burn hospitals across the United States.

PATIENTS

Thirty-two burn patients (16 nonsurvivors and 16 survivors), 19-89 years old, were admitted within 96 hours of injury to the participating hospitals with burns covering more than 20% of the total body surface area and required at least one surgical intervention.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We found differences in circulating levels of 43 proteins involved in the acute-phase response, hepatic signaling, the complement cascade, inflammation, and insulin resistance. Thirty-two of the proteins identified were not previously known to play a role in the response to burn. Interleukin-4, interleukin-8, granulocyte macrophage colony-stimulating factor, monocyte chemotactic protein-1, and β2-microglobulin correlated well with survival and may serve as clinical biomarkers.

CONCLUSIONS

These results demonstrate the utility of these techniques for establishing proteomic survival signatures and for use as a discovery tool to identify candidate biomarkers for survival. This is the first clinical application of a high-throughput, large-scale liquid chromatography-mass spectrometry-based quantitative plasma proteomic approach for biomarker discovery for the prediction of patient outcome following burn, trauma, or critical illness.

Burn surgery and blood loss – a review

Objectives: Blood loss has long been recognised as a significant problem in burn surgery. Efforts have been made in the past to quantify this loss and determine what factors influence it the most. Several researchers have been able to produce and validate formulae that predict the volume of blood loss during excisional surgery. Accurately determining this allows appropriate volumes of blood to be ordered, reducing risk to patients and saving scarce resources. This article reviews the literature on blood loss in burns surgery, including influencing factors, methods of prediction and effective management.

Methods: A literature review was conducted to examine methods used to measure, calculate and reduce blood loss in burn surgery. The validity of these methods and the limitations on accuracy will be discussed. Alternative methods shall also be considered.

Results: Most current methods of estimating blood loss attempt to determine the volume of erythrocytes required to return haemoglobin concentrations to their pre-operative level. Various formulae have been developed to calculate this volume.

Conclusions: Several authors have produced formulae that predict the volume of blood loss to a significant degree of accuracy. Different techniques have been shown to significantly reduce blood loss. In other areas of surgery, thromboelastometry has been used to identify the levels of specific blood component defects. The use of this method in burns surgery could, in the future, help develop a protocol for operative blood transfusion.

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.

Microalbuminuria: A marker of systemic endothelial dysfunction during burn excision

INTRODUCTION

Systemic endothelial dysfunction characterises both burn injury and surgery and can be monitored by serial immunoassay of urine albumin (microalbuminuria). The aim of this study was to assess microalbuminuria before and during burn excision and identify factors that may influence it.

METHODS

Serial half-hourly urine albumin/creatinine ratio (ACR, normal <2.3mg/mmol) was measured in 25 adult patients during 44 burn-excision procedures, at a median of 5 days post-injury. Median total body surface area (TBSA) excised was 12%.

RESULTS

Pre-operative median ACR was normal rising to 3.25mg/mmol at 1.5h of surgery (p<0.05). Per-operative ACR at 0.5, 1, 2 and 2.5h were all associated with % TBSA burn excised (p<0.04). Median intraoperative ACR at 1h was 2.3mg/mmol for surgery within 48h post-injury, 1.6 for surgery at 2-7 days and 25.5 during excisions later than 1 month after injury (p<0.05). ACR at 1h was associated with CRP at 48h post-surgery (p=0.04). Per-operative ACR was also significantly correlated with post-operative complications.

CONCLUSION

Systemic endothelial dysfunction of acute thermal injury assessed by microalbuminuria recurs with surgery, is minimal at 2-7 days post-burn and affected by % TBSA burn excised and post-operative complications.

Burn injuries

PURPOSE OF REVIEW

To summarize new advances and research findings that relate to the treatment of burn victims.

RECENT FINDINGS

Recent advances in burn resuscitation and critical care reflect a better understanding of the acute phase pathophysiology of severe burns. Aggressive management of the unstable burn airway is always the most important clinical priority. Emphasis has been placed on the early identification of inhalation injury and its impact on fluid resuscitation, as well as on a protective lung strategy to reduce the development of pulmonary edema, acute lung injury and pneumonia, and to reduce the risk of barotrauma. New blood markers, such as serum cholinesterase and inflammatory cytokines, have been introduced to assist in the prognosis of morbidity and mortality, beyond the traditional vital signs. At this time, however, these are available only for research purposes. Finally, early burn wound excision and coverage with new biodegradable materials results in less pain and more rapid healing for the patient.

SUMMARY

The combination of innovative approaches and a dedicated burn team is expected to continue to improve survival in the next few years even in the most severe cases.

Blood transfusions are associated with increased risk for development of sepsis in severely burned pediatric patients

OBJECTIVE

To determine the risk of developing sepsis following transfusion of blood products in severely burned pediatric patients.

DESIGN

Retrospective, cohort study.

SETTING

Shriners Hospital for Children and University Hospital.

PATIENTS

Severely burned pediatric patients with >30% total body surface area (TBSA) burn.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred seventy-seven pediatric burn patients over a period of 7 yrs (1997-2004) were included in the study, with 25 patients being septic at admission and therefore excluded. Patients were stratified according to TBSA burn and presence or absence of inhalation injury. The amounts of packed red blood cells (RBCs) and fresh frozen plasma (FFP) were recorded during hospital stay before the development of sepsis. Blood product administration was normalized for the number of surgeries and divided into two groups: high (RBCs>20/FFP>5) or low (RBCs<20/FFP<5) amount of blood products. Sepsis was diagnosed based on the criteria set by the Society of Critical Care Medicine in conjunction with positive blood culture or presence of organisms in the organs at autopsy. By stratifying the groups into low and high blood transfusion, we found that patients with >60% TBSA burn with inhalation injury have an 8% risk of developing sepsis in the low RBC group, which increases to 58% in the high RBC group (p<.05). Similar results were found for RBCs per operation, FFP, and FFP per operation (p<.05). There were no differences in age and gender between groups.

CONCLUSIONS

Pediatric burn suffering from a 60% TBSA burn with concomitant inhalation injury are more likely to develop sepsis if they are given high amounts of blood products, indicating an immunocompromised state following blood transfusion.

Rescue treatment with recombinant factor VIIa is effective in patients with life-threatening bleedings secondary to major wound excision: a report of four cases

Major burn wound excision is associated with excessive perioperative blood loss. Treatment of massive microvascular bleeding represents a special problem in the burn setting, characterized by extensive damage at the capillary level, and resulting in a profound blood loss; which together with the consumptive states makes adequate replacement therapy with coagulation factors and platelets difficult. We described our experience with rescue treatment with rFVIIa in four patients undergoing major wound excision, developing life-threatening perioperative bleeding, and not responding to conventional therapy. Hemostasis was achieved within 15 minutes of intravenous rFVIIa administration, at a dose of 100 microg/kg, in all patients. No treatment-related adverse events, in particular, no thromboembolic events were observed. We conclude that rFVIIa may be an effective hemostatic treatment for patients undergoing major wound excision developing life-threatening bleedings.

Analysis of skin-graft loss due to infection: infection-related graft loss

This prospective study was performed to analyze the causes of infection-related skin-graft loss in a general population of plastic and reconstructive surgery patients. One hundred thirty-two patients who received either full- or split-thickness skin grafts to reconstruct soft-tissue defects were included. The tissue defects were grouped according to the cause as follows: vascular ulcers (9.2%), burns (14.5%), traumatic tissue defects (36.6%), and flap donor-site defects (39.7%). In all cases, the preoperative evaluation indicated an adequate wound-bed preparation. However, graft loss secondary to infection was recorded in 31 patients (23.5%). The microbiological cultures revealed Pseudomonas aeruginosa in 58.1% of the cases (P<0.05), followed by Staphylococcus aureus, Enterobacter, enterococci, and Acinetobacter; 58.3% of grafts in vascular ulcers, 47.4% of grafts in burns, 16.7% of grafts in traumatic-tissue defects; and 13.5% of grafts in donor-site defects were lost due to infection. Vascular ulcers and burns were more commonly associated with graft losses due to infection than other tissue defects (P<0.001). No correlation was found between the etiological cause of the defects and the microorganisms cultured. However, Pseudomonas infections were more fulminant and caused an increased reoperation rate 4.2 times (P<0.05). Full-thickness grafts were more resistant to infection than split-thickness grafts (P<0.05). Graft loss due to infection was also more common in grafts applied to the lower extremities or when performed at multiple sites. In conclusion, 23.7% of skin grafts were lost due to infection in a group of general plastic surgery patients. Infection-related graft loss was more commonly encountered in vascular ulcers and burn wounds, and the most common cause was Pseudomonas aeruginosa.

Damage limitation in burn surgery

Burn injury differs from other types of trauma in the apparent lack of urgency for treatment. We argue that in order to limit physiological damage and the development of multi-organ failure, management of the burn wound must be immediate and aggressive. Supportive fluid treatment should be judicious in order to prevent excessive oedema causing wound extension. Some potential strategies utilising oral fluid resuscitation are discussed, and potential pharmacological interventions. When associated with other trauma, major burn injury has a detrimental effect on morbidity and mortality, and surgical management of both aspects of a patient's injuries are altered.