Increased liver weights in severely burned children: comparison of ultrasound and autopsy measurements

The use of propranolol in adult burn patients: Safety and outcome influence

OBJECTIVES

This study investigated safety and effect of propranolol on adult patients with severe burn.

METHODS

A prospective study was conducted on 124 severely adult burn patients who were randomly divided into propranolol and non-propranolol group. Propranolol was given by nasogastric tube to achieve the target of lowering 15-20% of initial heart rate.

RESULTS

Average dose of propranolol was 1.9 ± 0.5 mg/kg/day ranging from 0.9 to 3.3 mg/kg/day and was not affected by burn extent and inhalation injury. Mean heart rate reduced by 21.2% during the 28 day period. Recorded adverse events included hypotension (11.9%), bradycardia (1.6%), hypoglycemia (17.7%) and total number of held events was 8 occurring in 7 (11.3%) patients. Serum levels of glucose, total protein, albumin, cholesterol and triglyceride at different times were not significantly different between the two groups. Significantly lower resting energy expenditure on the 7^th and 14^th day were seen in propranolol group (p < 0.05). After 3 weeks, liver size in the propranolol group did not change significantly from admission, while in the non-propranolol group, liver size increased significantly (p < 0.05). The complete healing time of partial-thickness burns and donor sites were significantly shorter in propranolol group (p < 0.01). Duration of ventilation, length of stay in intensive care unit and in hospital, number of operations, rate of multiple organ failure, and death were not different between the two groups (p > 0.05).

CONCLUSION

For severely burned adults, propranolol was safe and effective on reducing energy expenditure, limited hepatomegaly, and accelerated partial burn wound and donor site closure, but does not affect length of stay in ICU, hospitalization, complication ormortality rate.

Hepatic functional pathophysiology and morphological damage following severe burns: a systematic review and meta-analysis

INTRODUCTION

Severe burns are devastating injuries affecting multiple organ systems. Little is known about the influence on the hepatic system and its physiology. This systematic review aimed to assess the current state of research on morphologic liver damage following severe burns.

METHODS

A search was conducted in Pubmed, Web of Science and Cochrane databases using PRISMA guidelines. Outcomes included serum levels of transaminases, fatty infiltration and necrosis. Weighted individual study estimates were used to calculate pooled transaminase levels and necrosis/fatty infiltration rates using a random-effects approach. Risk ratios (RRs) or Odds ratios (ORs) and 95% confidence intervals (CIs) were used to describe pooled estimates for risk factors.

RESULTS

The literature search retrieved 2548 hits, of which 59 studies were included into qualitative synthesis, and finally ten studies were included into meta-analysis. Studies were divided into those reporting autopsies and those reporting changes of serum transaminase levels. The majority of liver autopsies showed fatty infiltration 82% (95% CI39%-97%) or necrosis of the liver 18% (95% CI13%-24%).

DISCUSSION

Heterogeneity in studies on hepatic functional damage following severe burns was high. Only few were well-designed and published in recent years. Many studies could not be included because of insufficient numerical data. There is a high number of patients deceasing from burns that present with fatty infiltration or necrosis of hepatic tissue. Transaminases were elevated during the first days after burn. Further research on how severe burns affect the hepatic function and outcome, especially long-term, is necessary.

Clearance of Indocyanine Green in Severe Pediatric Burns

BACKGROUND

Clearance of indocyanine green dye (ICGc) reflects sinusoidal perfusion and hepatocyte cell membrane function. Thus, ICGc is a reflection of the functional reserve of intact hepatocytes. The purpose of this study was to identify predictors of ICGc in severely burned children during the acute hospitalization and at the time of discharge from the intensive care unit (ICU). A secondary aim was to determine the relationship between liver size and patient ICGc.

METHODS

Twenty-six children (0.8-17 years old) with 35% or greater total body surface area burned (%TBSA-B) were included. Assessment of ICGc (in milliliters per minute per meter squared) was done during the acute hospitalization (median: 6 days after admission, median: 14 days postburn) and at the time of discharge from the ICU (median: 19 days after admission, median: 27 days postburn). Age, TBSA-B, % third-degree burns, inhalation injury, preexisting chronic malnutrition, hematocrit, liver dysfunction, and time from burn injury were incorporated in multiple linear regressions as predictive variables of ICGc. Only variables with p < 0.05 were retained in the final models.

RESULTS

Time from injury and age were the strongest predictors of ICGc during the acute admission but not at the time of discharge from the ICU. Time from injury was negatively associated with ICGc, whereas age was positively associated. At the time of discharge from the ICU, ICGc was increased in proportion to the %TBSA-B, whereas inhalation injury and preexisting chronic malnutrition were associated with lower ICGc. There was no correlation between change-to-predicted liver length and ICGc.

CONCLUSIONS

The intrinsic ability of the liver to extract ICG from plasma was lower in younger burned patients during the acute admission and in those with preexisting chronic malnutrition and inhalation injury at the time of discharge from the ICU.

LEVEL OF EVIDENCE

Prognostic/Epidemiologic, level III.

Alcohol Modulation of the Postburn Hepatic Response

The widespread and rapidly increasing trend of binge drinking is accompanied by a concomitant rise in the prevalence of trauma patients under the influence of alcohol at the time of their injury. Epidemiological evidence suggests up to half of all adult burn patients are intoxicated at the time of admission, and the presence of alcohol is an independent risk factor for death in the early stages post burn. As the major site of alcohol metabolism and toxicity, the liver is a critical determinant of postburn outcome, and experimental evidence implies an injury threshold exists beyond which burn-induced hepatic derangement is observed. Alcohol may lower this threshold for postburn hepatic damage through a variety of mechanisms including modulation of extrahepatic events, alteration of the gut-liver axis, and changes in signaling pathways. The direct and indirect effects of alcohol may prime the liver for the second-hit of many overlapping physiologic responses to burn injury. In an effort to gain a deeper understanding of how alcohol potentiates postburn hepatic damage, the authors summarize possible mechanisms by which alcohol modulates the postburn hepatic response.

Nutrition and anabolic pharmacotherapies in the care of burn patients

Thermal injury is a devastating injury that results in a number of pathological alterations in almost every system in the body. Hypermetabolism, muscle wasting, depressed immunity, and impaired wound healing are all clinical features of burns. Failure to address each of these specific pathological alterations can lead to increased mortality. Nutrition supplementation has been recommended as a therapeutic tool to help attenuate the hypermetabolism and devastating catabolism evident following burn. Despite the wide consensus on the need of nutrition supplementation in burn patients, controversy exists with regard to the type and amount of nutrition recommended. Nutrition alone is also not enough in these patients to halt and reverse some of the damage done by the catabolic pathways activated following severe burn injury. This has led to the use of anabolic pharmacologic agents in conjunction with nutrition to help improve patient outcome following burn injury. In this review, we examine the relevant literature on nutrition after burn injury and its contribution to the attenuation of the postburn hypermetabolic response, impaired wound healing, and suppressed immunological responses. We also review the commonly used anabolic agents clinically in the care of burn patients. Finally, we provide nutrition and pharmacological recommendations gained from prospective trials, retrospective analyses, and expert opinions based on our practice at the Ross Tilley Burn Center in Toronto, Canada.

Association of postburn fatty acids and triglycerides with clinical outcome in severely burned children

CONTEXT

Free fatty acids (FFAs) and triglycerides (TGs) are altered postburn, but whether these alterations are associated with postburn outcomes is not clear.

OBJECTIVE

The aim of the present study was to analyze lipid metabolic profiles in pediatric burn patients and to correlate these profiles with patient outcomes and hospital courses.

DESIGN AND SETTING

We conducted a prospective cohort study at an academic pediatric hospital burn center.

PATIENTS

Our study included 219 pediatric burn patients.

MAIN OUTCOME MEASURES

Patients were stratified according to their plasma TG and FFA levels. Main patient outcomes, such as postburn morbidity and mortality, and clinical metabolic markers were analyzed.

RESULTS

All groups were similar in demographics and injury characteristics. Patients with elevated TGs had significantly worse clinical outcomes associated with increased acute-phase protein synthesis indicating augmented inflammation and hypermetabolism, whereas increased FFAs did not seem to profoundly alter postburn outcomes.

CONCLUSIONS

Elevated TGs, but not FFAs, postburn are associated with worsened organ function and clinical outcomes.

Five-year outcomes after oxandrolone administration in severely burned children: a randomized clinical trial of safety and efficacy

BACKGROUND

Oxandrolone, an anabolic agent, has been administered for 1 year post burn with beneficial effects in pediatric patients. However, the long-lasting effects of this treatment have not been studied. This single-center prospective trial determined the long-term effects of 1 year of oxandrolone administration in severely burned children; assessments were continued for up to 4 years post therapy.

STUDY DESIGN

Patients 0 to 18 years old with burns covering >30% of the total body surface area were randomized to receive placebo (n = 152) or oxandrolone, 0.1 mg/kg twice daily for 12 months (n = 70). At hospital discharge, patients were randomized to a 12-week exercise program or to standard of care. Resting energy expenditure, standing height, weight, lean body mass, muscle strength, bone mineral content (BMC), cardiac work, rate pressure product, sexual maturation, and concentrations of serum inflammatory cytokines, hormones, and liver enzymes were monitored.

RESULTS

Oxandrolone substantially decreased resting energy expenditure and rate pressure product, increased insulin-like growth factor-1 secretion during the first year after burn injury, and, in combination with exercise, increased lean body mass and muscle strength considerably. Oxandrolone-treated children exhibited improved height percentile and BMC content compared with controls. The maximal effect of oxandrolone was found in children aged 7 to 18 years. No deleterious side effects were attributed to long-term administration.

CONCLUSIONS

Administration of oxandrolone improves long-term recovery of severely burned children in height, BMC, cardiac work, and muscle strength; the increase in BMC is likely to occur by means of insulin-like growth factor-1. These benefits persist for up to 5 years post burn.

The effect of ketoconazole on post-burn inflammation, hypermetabolism and clinical outcomes

Background

Hypercortisolemia has been suggested as a primary hormonal mediator of whole-body catabolism following severe burn injury. Ketoconazole, an anti-fungal agent, inhibits cortisol synthesis. We, therefore, studied the effect of ketoconazole on post-burn cortisol levels and the hyper-catabolic response in a prospective randomized trial (block randomization 2∶1).

Methodology/Principal Findings

Fifty-five severely burned pediatric patients with >30% total body surface area (TBSA) burns were enrolled in this trial. Patients were randomized to receive standard care plus either placebo (controls, n = 38) or ketoconazole (n = 23). Demographics, clinical data, serum hormone levels, serum cytokine expression profiles, organ function, hypermetabolism measures, muscle protein synthesis, incidence of wound infection sepsis, and body composition were obtained throughout the acute hospital course. Statistical analysis was performed using Fisher’s exact test, Student’s t-test, and parametric and non-parametric two-way repeated measures analysis of variance where applicable. Patients were similar in demographics, age, and TBSA burned. Ketoconazole effectively blocked cortisol production, as indicated by normalization of the 8-fold elevation in urine cortisol levels [F(1, 376) = 85.34, p<.001] with the initiation of treatment. However, there were no significant differences in the inflammatory response, acute-phase proteins, body composition, muscle protein breakdown or synthesis, or organ function between groups.

Conclusions

Both groups were markedly hypermetabolic and catabolic throughout the acute hospital stay. Normalization of hypercortisolemia with ketoconazole therapy had no effect on whole-body catabolism or the post-burn inflammatory or hypermetabolic response, suggesting that hypercortisolemia does not play a central role in the post-burn hypermetabolic catabolic response.

Trial Registration

ClinicalTrials.gov NCT00675714; and NCT00673309

Nutrition in burns: Galveston contributions

Aggressive nutrition support is recommended following severe burn injury. Initially, such injury results in a prolonged and persistent hypermetabolic response mediated by a 10- to 20-fold elevation in plasma catecholamines, cortisol, and inflammatory mediators. This response leads to twice-normal metabolic rates, whole-body catabolism, muscle wasting, and severe cachexia. Thus, it is relevant to review the literature on nutrition in burns to adjust/update treatment. Failure to meet the increased substrate requirements may result in impaired wound healing, multiorgan dysfunction, increased susceptibility to infection, and death. Therefore, aggressive nutrition support is essential to ensure adequate burn care, attenuate the hypermetabolic response, optimize wound healing, minimize devastating catabolism, and reduce morbidity and mortality. Here, the authors provide nutrition recommendations gained from prospective trials, retrospective analyses, and expert opinions based on the authors' practices in Galveston, Texas, and Vienna, Austria.

Association between dietary fat content and outcomes in pediatric burn patients

BACKGROUND

The aim of the study was to compare a low fat/high-carbohydrate diet and a high-fat diet on clinical outcomes by a retrospective cohort study.

METHODS

Nine hundred forty-four children with burns ≥ 40% of their total body surface area (TBSA) were divided into two groups: patients receiving Vivonex T.E.N. (low-fat/high-carbohydrate diet; n = 518) and patients receiving milk (high-fat diet; n = 426). Patient demographics, caloric intake, length of hospital stay, and incidence of sepsis, mortality, hepatic steatosis, and organomegaly at autopsy were determined.

RESULTS

Demographics and caloric intake were similar in both groups. Patients receiving Vivonex T.E.N. had shorter (intensive care unit) ICU stays (Vivonex T.E.N.: 31 ± 2 d; milk: 47 ± 2 d; P < 0.01), shorter ICU stay per % TBSA burn (Vivonex T.E.N.: 0.51 ± 0.02 d/%; milk: 0.77 ± 0.03 d/%; P < 0.01), lower incidence of sepsis (Vivonex T.E.N.: 11%; milk: 20%; P < 0.01), and lived significantly longer until death than those receiving milk (Vivonex T.E.N.: 20 ± 3 d; milk: 10 ± 2 d; P < 0.01). There was no difference in overall mortality between the two groups (Vivonex T.E.N.:15% versus milk: 13%; P < 0.9). Autopsies revealed decreased hepatic steatosis and decreased enlargement of kidney and spleen in patients receiving Vivonex T.E.N.

CONCLUSIONS

The period with a low-fat/high-carbohydrate diet was associated with lower LOS, decreased incidence of organomegaly, infection, and hepatic steatosis post-burn compared with the period when a high-fat diet was used. These associations indicate the benefit of high carbohydrate/low fat nutrition; however, the findings in these time periods can also be likely due to the multifactorial effects of advances in burn care. We believe that these results have some relevance because high fat is associated with poorer outcomes compared with low fat.

Intensive insulin therapy in severely burned pediatric patients: a prospective randomized trial

RATIONALE

Hyperglycemia and insulin resistance have been shown to increase morbidity and mortality in severely burned patients, and glycemic control appears essential to improve clinical outcomes. However, to date no prospective randomized study exists that determines whether intensive insulin therapy is associated with improved post-burn morbidity and mortality.

OBJECTIVES

To determine whether intensive insulin therapy is associated with improved post-burn morbidity.

METHODS

A total of 239 severely burned pediatric patients with burns over greater than 30% of their total body surface area were randomized (block randomization 1:3) to intensive insulin treatment (n = 60) or control (n = 179).

MEASUREMENTS AND MAIN RESULTS

Demographics, clinical outcomes, sepsis, glucose metabolism, organ function, and inflammatory, acute-phase, and hypermetabolic responses were determined. Demographics were similar in both groups. Intensive insulin treatment significantly decreased the incidence of infections and sepsis compared with controls (P < 0.05). Furthermore, intensive insulin therapy improved organ function as indicated by improved serum markers, DENVER2 scores, and ultrasound (P < 0.05). Intensive insulin therapy alleviated post-burn insulin resistance and the vast catabolic response of the body (P < 0.05). Intensive insulin treatment dampened inflammatory and acute-phase responses by deceasing IL-6 and acute-phase proteins compared with controls (P < 0.05). Mortality was 4% in the intensive insulin therapy group and 11% in the control group (P = 0.14).

CONCLUSIONS

In this prospective randomized clinical trial, we showed that intensive insulin therapy improves post-burn morbidity. Clinical trial registered with www.clinicaltrials.gov (NCT00673309).

The hepatic response to thermal injury: is the liver important for postburn outcomes?

Thermal injury produces a profound hypermetabolic and hypercatabolic stress response characterized by increased endogenous glucose production via gluconeogenesis and glycogenolysis, lipolysis, and proteolysis. The liver is the central body organ involved in these metabolic responses. It is suggested that the liver, with its metabolic, inflammatory, immune, and acute phase functions, plays a pivotal role in patient survival and recovery by modulating multiple pathways following thermal injury. Studies have evaluated the role and function of the liver during the postburn response and showed that liver integrity and function are essential for survival, and that hepatic acute phase proteins are strong predictors for postburn survival. This review discusses these studies and delineates the pivotal role of the liver in patients following severe thermal injury.

Pathophysiologic response to severe burn injury

OBJECTIVE

To improve clinical outcome and to determine new treatment options, we studied the pathophysiologic response postburn in a large prospective, single center, clinical trial.

SUMMARY BACKGROUND DATA

A severe burn injury leads to marked hypermetabolism and catabolism, which are associated with morbidity and mortality. The underlying pathophysiology and the correlations between humoral changes and organ function have not been well delineated.

METHODS

Two hundred forty-two severely burned pediatric patients [>30% total body surface area (TBSA)], who received no anabolic drugs, were enrolled in this study. Demographics, clinical data, serum hormones, serum cytokine expression profile, organ function, hypermetabolism, muscle protein synthesis, incidence of wound infection sepsis, and body composition were obtained throughout acute hospital course.

RESULTS

Average age was 8 +/- 0.2 years, and average burn size was 56 +/- 1% TBSA with 43 +/- 1% third-degree TBSA. All patients were markedly hypermetabolic throughout acute hospital stay and had significant muscle protein loss as demonstrated by a negative muscle protein net balance (-0.05% +/- 0.007 nmol/100 mL leg/min) and loss of lean body mass (LBM) (-4.1% +/- 1.9%); P < 0.05. Patients lost 3% +/- 1% of their bone mineral content (BMC) and 2 +/- 1% of their bone mineral density (BMD). Serum proteome analysis demonstrated profound alterations immediately postburn, which remained abnormal throughout acute hospital stay; P < 0.05. Cardiac function was compromised immediately after burn and remained abnormal up to discharge; P < 0.05. Insulin resistance appeared during the first week postburn and persisted until discharge. Patients were hyperinflammatory with marked changes in IL-8, MCP-1, and IL-6, which were associated with 2.5 +/- 0.2 infections and 17% sepsis.

CONCLUSIONS

In this large prospective clinical trial, we delineated the complexity of the postburn pathophysiologic response and conclude that the postburn response is profound, occurring in a timely manner, with derangements that are greater and more protracted than previously thought.

Postburn trauma insulin resistance and fat metabolism

Hyperglycemia and insulin resistance have long been recognized in severe burn patients. More recently, it has been observed that controlling hyperglycemia, or alleviating insulin resistance, is associated with improved outcomes. This has led to a renewed interest in the etiology of insulin resistance in this population. The postinjury hyperglycemic response appears to be associated with multiple metabolic abnormalities, such as elevated basal energy expenditure, increased protein catabolism, and, notably, significant alterations in fat metabolism. The synergy of all of the responses is not understood, although many studies have been conducted. In this article we will review the present understanding of the relationship between fat metabolism and insulin resistance posttrauma, and discuss some of the recent discoveries and potential therapeutic measures. We propose that the insulin resistance is likely related to the development of "ectopic" fat stores, i.e., triglyceride (TG) storage in sites such as the liver and muscle cells. Deposition of TG in ectopic sites is due to an increase in free fatty acid delivery secondary to catecholamine-induced lipolysis, in conjunction with decreased beta-oxidation within muscle and decreased hepatic secretion of fats. The resultant increases in intracellular TG or related lipid products may in turn contribute to alterations in insulin signaling.

The effect of oxandrolone on the endocrinologic, inflammatory, and hypermetabolic responses during the acute phase postburn

OBJECTIVE AND SUMMARY BACKGROUND DATA

Postburn long-term oxandrolone treatment improves hypermetabolism and body composition. The effects of oxandrolone on clinical outcome, body composition, endocrine system, and inflammation during the acute phase postburn in a large prospective randomized single-center trial have not been studied.

METHODS

Burned children (n = 235) with >40% total body surface area burn were randomized (block randomization 4:1) to receive standard burn care (control, n = 190) or standard burn care plus oxandrolone for at least 7 days (oxandrolone 0.1 mg/kg body weight q.12 hours p.o, n = 45). Clinical parameters, body composition, serum hormones, and cytokine expression profiles were measured throughout acute hospitalization. Statistical analysis was performed by Student t test, or ANOVA followed by Bonferroni correction with significance accepted at P < 0.05.

RESULTS

Demographics and clinical data were similar in both groups. Length of intensive care unit stay was significantly decreased in oxandrolone-treated patients (0.48 +/- 0.02 days/% burn) compared with controls (0.56 +/- 0.02 days/% burn), (P < 0.05). Control patients lost 8 +/- 1% of their lean body mass (LBM), whereas oxandrolone-treated patients had preserved LBM (+9 +/- 4%), P < 0.05. Oxandrolone significantly increased serum prealbumin, total protein, testosterone, and AST/ALT, whereas it significantly decreased alpha2-macroglobulin and complement C3, P < 0.05. Oxandrolone did not adversely affect the endocrine and inflammatory response as we found no significant differences in the hormone panels and cytokine expression profiles.

CONCLUSIONS

In this large prospective, double-blinded, randomized single-center study, oxandrolone shortened length of acute hospital stay, maintained LBM, improved body composition and hepatic protein synthesis while having no adverse effects on the endocrine axis postburn, but was associated with an increase in AST and ALT.

Changes in liver function and size after a severe thermal injury

Hepatic homeostasis and metabolism are essential for survival in critically ill and severely burned patients. There is evidence that the liver undergoes hypertrophy after burn. However, the extension and the duration of liver enlargement are not known. The aim of the present study was to determine the changes in liver size, weight, and hepatic protein synthesis in a large prospective clinical trial throughout acute hospitalization and up to 12 months after burn. Liver size was measured by means of ultrasound, and liver weight was calculated weekly during short-term hospital stay and at 6, 9, and 12 months after burn. The liver size was then compared with the predicted liver size for each individual. The levels of hepatic proteins and enzymes were determined by using standard laboratory techniques. One hundred two children were included in the study, with 58% +/- 2% total body surface area and 45% +/- 2% third-degree burn. Liver size and weight significantly increased during the first week after burn (mean +/- SEM, 85% +/- 5%), peaked at 2 weeks after burn (mean +/- SEM, 126% +/- 19%), and, at discharge, increased by 89% +/- 10%. At 6, 9, and 12 months, the liver weight increased by 40% to 50% compared with the predicted liver weight. The hepatic protein synthesis was affected up to 9 months after burn. The liver demonstrates a significant enlargement during short-term hospitalization, accompanied with impairment in the hepatic protein synthesis. The treatment to prevent liver enlargement and the improved impaired function may result in a reduction of complications accompanied with liver hypertrophy and failure.

“Systemic apoptotic response” after thermal burns

The systemic pathophysiologic changes following thermal injuries affect multiple organs and body systems leading to clinical manifestations including shock, intestinal alterations, respiratory and renal failure, immunosuppression and others. Recent advances in the comprehension of mechanisms underlying systemic complications of thermal injuries have contributed to uncover part of the cellular and molecular basis that underlie such changes. Recently, programmed cell death (apoptosis) has been considered playing an important role in the development of such pathological events. Therefore, investigators utilizing animal models and clinical studies involving human primates have produced a large body of information suggesting that apoptosis is associated with most of the tissue damages triggered by severe thermal injuries. In order to draw the attention on the important role of apoptosis on systemic complications of thermal injuries, in this review we describe most of these studies, discuss possible cellular and molecular mechanisms and indicate ways to utilize them for the development of therapeutic strategies by which apoptosis may be prevented or counteracted.

Identification of factors contributing to hepatomegaly in severely burned children

Hepatomegaly is a common postmortem observation in severely burned children, with the liver often tripling in size when compared with normal livers for age, weight, and sex. Lesions identified at autopsy include deposition of large and small fat droplets in the hepatocyte, congestion, centrilobular necrosis, and cholestasis. The present study was designed to identify the primary causes of hepatomegaly in severely burned children postmortem. For this purpose, 41 autopsies were reviewed and, when available, blood and tissue samples were studied. Histopathologic findings showed that large intrahepatocytic fat droplets within hepatocytes and cholestasis were important contributors to hepatomegaly. Liver density and wet/dry weight ratios significantly decreased with increasing liver size. Hepatocyte volume increased with increasing liver size (P < 0.001) as did total fat content (P < 0.001). The liver enzymes, alanine aminotransferase and aspartate aminotransferase, remained normal except within 5 to 10 days of injury and 5 to 10 days of death. Triglycerides made up 4% to 70% of the total fat, with the percentage of triglycerides increasing with the severity of hepatomegaly. Saturated fatty acids represented about 85% of the total fatty acids in normal-sized livers, whereas in the largest livers (400% of predicted), only 25% of the fatty acids were saturated. This study provides evidence that 85% to 90% of the hepatomegaly observed in severely burned children postmortem is associated with hepatocyte enlargement, which includes up to 19% intracellular fat. Increases in extracellular protein, intracellular glycogen, and fluid accumulation may make a minor contribution to postburn hepatomegaly.

The use of beta-adrenergic blockade in preventing trauma-induced hepatomegaly

OBJECTIVE

The objective of this study was to test the hypothesis that hepatomegaly in burned children can be attenuated or reversed by blocking lipolysis and reducing free fatty acids delivered to the liver.

SUMMARY BACKGROUND DATA

Accelerated lipolysis in severely burned children has been shown to play an important role in the accumulation of hepatic TGs. Severely burned children who survive 10 days or more after injury commonly have enlarged livers often twice or more normal size for their sex, age, and weight.

METHODS

Ninety-eight children, 2 to 18 years of age, with burns covering more than 40% of their body surface and who received either propranolol (beta-adrenergic blockade) or placebo were studied. Liver weights were measured by ultrasonic scanning. Body composition changes were identified by dual-image x-ray absorptiometry and validated by whole-body potassium-40 scintillation counting. Discarded abdominal cutaneous adipose tissue was collected before and after propranolol or placebo for microarray analysis.

RESULTS

In 80% of severely burned children studied not receiving propranolol, liver sizes increased by 100% or more while 86% of burned children receiving propranolol showed a decrease or no change in liver size over the same period of time after injury. Gene expression patterns of adipose tissue after propranolol treatment showed that all of the identified genes related to lipid metabolism were down-regulated.

CONCLUSIONS

Data reported here support the hypothesis that beta-adrenergic blockade can reduce delivery of fatty acids to the liver and hepatic congestion commonly found in severely burned children by inhibiting lipolysis and reducing hepatic blood flow.