Obesity and burns

The burn injury transfer feedback form: A 16 year Australian statewide review of burn inter-hospital transfer

INTRODUCTION

Modern burn care is centralised, and studies show that early, prompt referral to dedicated burn services improve clinical outcomes. We describe the use of a novel clinical instrument, the burn injury Transfer Feedback Form, to support and educate referring clinicians about the early assessment and management of burn injuries. Since 2005, Transfer Feedback Forms have been completed for all burn-injured patients with inter-hospital transfer to a specialised burn unit in the state of New South Wales (NSW), Australia. The aim of this study was to review physiological, procedural, and system or process issues in the care of both adult and paediatric burn-injured patients needing retrieval and transfer in NSW as identified by the Transfer Feedback Form. Secondary objectives were to determine any significant differences in these parameters between metropolitan and regional or remote referring institutions, and if any improvements occurred in these parameters over time.

METHODS

This was a retrospective analysis of all patients who were transferred to a burn unit in NSW between July 2005 and July 2021 using their prospectively completed Transfer Feedback Forms. Patients were divided into metropolitan and non-metropolitan referral sources based on geographic location. Clinical issues or deficiencies identified during each patient transfer were then classified into various groups. To determine if transfer-related clinical concerns had changed with time, two distinct periods before and after 2015, when the NSW Trauma App was introduced, were analysed. We compared trends in frequency of transfer-related concerns before and after App introduction by using interrupted time series analysis.

RESULTS

A total of 3233 patients had Feedback Forms submitted during the 16-year period. We included 929 children (28.7%) and 2304 adults (71.3%). Transfer-related clinical issues were identified in 904 adults (39.0%) and 484 children (52.0%). In both adult and paediatric patients, the most common transfer-related clinical deficiency was in relation to burn size estimation with 525 patients (43.7%) and 207 patients (30.6%), respectively. Between the time periods analysed, the number of issues arising during inter-hospital transfer fell significantly for both adults (from 46.1% to 26.1%; p < 0.05) and children (from 55.3% to 40.7%; p < 0.05). Segmented regression analysis demonstrated a significant break in the rate of transfer-related clinical issues in 2014 (p < 0.05) and 2015 (p < 0.01) for adults. Accurate body surface area estimations also increased significantly by 53% and 50% for adults and children (p < 0.05 for both), respectively, after 2015.

CONCLUSION

Our analysis indicates that the early care of burn-injured patients undergoing inter-hospital transfer is associated with clinical, technical, and logistical challenges. However, introduction of the burn injury Transfer Feedback Form has been associated with improvements in early burn care by referring centres both temporally and geographically. Smartphone-based applications such as the NSW Trauma App have also probably contributed to these findings. Adopting these simple, inexpensive strategies into burn care systems will augment inter-hospital transfer of burn-injured patients, and improve clinical outcomes.

Differences by age in the obesity paradox in severe burns

BACKGROUND

Many studies show a "obesity paradox", which seems to protect against death. Whether an obesity paradox space is present in severe burn patients remains a matter of great debate. Most research on the obesity paradox of burn injuries is classified by body mass index (BMI) rather than by age.

OBJECTIVE

To investigate whether the obesity paradox exists in severe burn patients stratified by age.

METHODS

Retrospective analysis was performed on 490 patients with severe burns who were ≥ 18 years of age and were admitted to Fujian Medical University Union Hospital from January 2005 to December 2020. Demographic and clinical characteristics were collected, including age, BMI, total body surface area (TBSA), presence of inhalation injury, abbreviated burn severity index (ABSI) score, diabetes comorbidities, hypertension comorbidities, and in-hospital mortality. The patients were divided into the younger group (18 ≤ age<65 years) and the older group (age ≥ 65 years). The important variables of the two groups were compared. The predictive value of BMI stratified by age on in-hospital mortality was evaluated by binary logistic regression analysis and the Cochran's and Mantel-Haenszel statistics.

RESULTS

A total of 490 patients were selected for this study, and were divided into the younger group (413) and the elderly group (77) according to their ages. In the younger group, logistic regression analyses indicated that high BMI remained significantly and independently associated with decreased in-hospital mortality (P = 0.021). That is, in-hospital mortality decreased by 17.8% when BMI increased by 1 kg/m². In the older group, BMI was not associated with in-hospital mortality (P = 0.808). In the younger group, the results of Pearson's chi-square test was less than 0.05, indicating a correlation between BMI and prognosis. In the older group, the conclusion was contrary with, no correlation between BMI and prognosis. If the confounding factors of age were not considered, this results in no correlation between BMI and prognosis. In the younger group, the survival/death ratio of patients with overweight and obesity was 2.078 times that of patients with normal weight.

CONCLUSION

In this study of patients with severe burns, overweight and obesity had protective effect on burn injury in the younger group (18 ≤ age<65 years), but not in the older group (age ≥ 65 years). Investigating the obesity paradox in burn patients needs to consider age differences. However, multicentre clinical trials are needed to verify the results.

Burn Outcomes at Extremes of Body Mass Index- Underweight is as problematic as Morbid Obesity

Limited evidence suggests that obesity adversely affects burn outcomes. However, the impacts of body mass index (BMI) across the continuum has not been fully characterized. Therefore, we aimed to characterize outcomes after burn injury across the BMI continuum. We hypothesized that 'normal' BMI (18.5-24.9) would have the lowest mortality and complication rates. The US National Trauma Data Bank (NTDB) was queried for adult burn-injured patients from 2007-2015. Admission BMI was calculated and grouped according to World Health Organization (WHO) classification. The primary outcome was in-hospital mortality. Secondary outcomes of time to wound closure, length of stay (LOS), and inpatient complications were similarly assessed. Of the 116,008 burn patient encounters that were identified, 7,243 underwent at least one operation for wound closure. Mortality was lowest in the overweight (p=0.039) and obese I cohorts (BMI 25-29.9, 30.0-34.9) at 2.9% and increased in both directions of the BMI continuum to 4.1% in the underweight (p=0.032) and 5.1% in the morbidly obese (class III) group (p=0.042). Time to final wound closure was longest in the two BMI extremes. BMI >40 was associated with increased ICU days, ventilator days, renal and cardiac complications. BMI <18.5 had increased hospital days and rates of sepsis. Aberrations in metabolism associated with both increases and decreases of body weight may cause pathophysiologic changes that lead to worsened outcomes in burn-injured patients. In addition to morbidly obese patients, underweight patients also experience increased burn-related death and complications. In contrast, overweight BMI patients may have greater physiologic reserves without the burden of obesity or sarcopenia.

Tolerance to Glucose and Lipid High Metabolic Reactions After Burns in an Obese Rat Model

The goal of this study was to determine what effect obese body weight and a burn injury can have on the metabolism of glucose and lipids in rats. We used a 3 * 3 factorial model design to provide basic glucose and lipid metabolic data characterizing the interaction between different weight and burn injury groups. Two hundred Sprague Dawley rats were categorized into three weight groups (normal, overweight, obese) and then further divided into control, second-degree, and third-degree burn groups. Our model compared interactions between weight and burn injury factors according to the above groups. Blood glucose and lipid metabolism indicators were monitored on the 1st, 3rd, 7th, and 14th days after burn injury occurred, and burned skin and blood samples were collected for testing. Compared with the normal weight group, the overweight group's fast blood glucose, fast insulin, and homeostasis model assessment of insulin resistance were higher (P < .05), and FBG in the obese group was higher than the normal weight group (P < .05). Burn injuries combined with obese body weight had an interactive effect on fast blood glucose, fast insulin, and homeostasis model assessment of insulin resistance after burn injury (P < .05). Burn injury combined with obese body weight had an interaction on low-density lipoprotein cholesterol on the 3rd day after burn injury (P < .05). Burn injury combined with obese weight had no interaction on triglyceride, total cholesterol, and high-density lipoprotein cholesterol (P > .05). Rats in the overweight and obese weight groups were observed to develop an adaptation and tolerance to a higher metabolic rate after burn injuries occurred.

Does the estimation of burn extent at admission differ from the assessment at discharge?

INTRODUCTION

Estimation of total body surface area (TBSA) burnt and burn depth are among the most central parts of acute burn assessment/treatment as they determine the level and type of care needed. Traditional methods for determining burn extent on admission often lead to inaccurate estimations, especially in paediatric or overweight patients.

AIM

To compare %TBSA at admission with validated %TBSA at discharge in different patient populations to investigate if significant over- or underestimation occurs.

METHOD

This retrospective observational study is based on a patient registry of all the patients (n = 863) treated at the Uppsala University Hospital's Burn Centre between 2010 and 2018. The patients were divided into subgroups based on age, gender, body mass index (BMI) and validated burn extent. The %TBSA estimated at admission was compared to the validated %TBSA in all groups separately.

RESULTS

As has been published before, we also found that the %TBSA in paediatric patients was more often overestimated as were the smaller injuries, whereas larger injuries were often underestimated. BMI did not clearly affect the estimations and there was no clear difference between the genders in estimated %TBSA.

CONCLUSION

Inaccurate estimations of %TBSA are common, particularly for paediatric patients and small or large injuries. We recommend a careful accurate approach when calculating %TBSA in the paediatric population to avoid over- and under-resuscitation. Increased education and training are recommended to improve accurate estimation in the future.

LAY SUMMARY

The correct estimation of both extent and depth of burn is very important. This assessment guides the lever of care needed, the necessary amount of fluid resuscitation, the predicted outcome and more. It has been proven notably difficult to correct assess, especially the extent of a burn. Despite different tools as the "Rule of Nine" (body area divided into multiples of 9% body surfaces), the "Rule of Palm" (Patient's palm, fingers included, approximates 1% of body surfaces), the Lund & Browder chart (detailed, age-specific body areas) and different more technical solutions. Often inaccurate estimations are done which thus affect the treatment. This depth and extent estimation is usually performed when the patient is admitted. However, it is known that burns change appearance during the first few days of care. In our Burn Center we have also performed this estimation when the patient is discharged. At this point it is known the true extent and depth of the initial burn. In this retrospective observational study, we compared the burn extent estimated on admission with the one on discharge to investigate whether the initial assessment is accurate. This study highlights the issue of frequent inaccurate burn extent estimations, especially in subgroups as overweight patient or pediatric patients.

The Influence of Obesity on Treatment and Outcome of Severely Burned Patients

Obesity and the related medical, social, and economic impacts are relevant multifactorial and chronic conditions that also have a meaningful impact on outcomes following a severe injury, including burns. In addition to burn-specific difficulties, such as adequate hypermetabolic response, fluid resuscitation, and early wound coverage, obese patients also present with common comorbidities, such as arterial hypertension, diabetes mellitus, or nonalcoholic fatty liver disease. In addition, the pathophysiologic response to severe burns can be enhanced. Besides the increased morbidity and mortality compared to burn patients with normal weight, obese patients present a challenge in fluid resuscitation, perioperative management, and difficulties in wound healing. The present work is an in-depth review of the current understanding of the influence of obesity on the management and outcome of severe burns.

A Systematic Review on Classification, Identification, and Healing Process of Burn Wound Healing

Because of the intrinsic complexity, the classification of wounds is important for the diagnosis, management, and choosing the correct treatment based on wound type. Generally, burn injuries are classified as a class of wounds in which injury is caused by heat, cold, electricity, chemicals, friction, or radiation. On the other hand, wound healing is a complex process, and understanding the biological trend of this process and differences in the healing process of different wounds could reduce the possible risk in many cases and greatly reduce the future damage to the injured tissue and other organs. The aim of this review is to provide a general perspective for the burn wound location among the other types of injuries and summarizing as well as highlighting the differences of these types of wounds with emphasizing on factors affecting thereof.

Does obesity impact the outcome of severely burned patients?

Although obesity appears to be an important predictor of mortality and morbidity, little data about the impact of body mass index (BMI) on the outcome of severely burned patients are available. Patients admitted to the General Hospital Vienna between 1994 and 2014, who underwent surgery because of burn injuries, were enrolled in this study. BMI was used to divide patients into five groups: BMI 18.5 to 24.9, 25 to 29.9, 30 to 34.9, 35 to 39.9, and > 40. The groups were compared in terms of difference of mortality and morbidity. Of 460 patients, 34.3% (n = 158) died. Mortality rates were the lowest in patients with obesity class III and the highest in patients with BMI 35 to 39.9 (BMI 18.5‐24.9: 30.5%, BMI 25‐29.9: 31.5%, BMI 30‐34.9: 41.3%, BMI 35‐39.9: 55.5%, BMI > 40: 30%; P = .031). BMI was not found to be an independent risk factor when corrected with age, percent total body surface area burned, full‐thickness burns, and inhalation injury. No significant differences in length of stay, inhalation trauma, pneumonia, wound infection, sepsis, and invasive ventilation were observed. BMI as an independent risk factor for severely burned patients could not be confirmed via multivariate analysis.

Human Wounds and Its Burden: An Updated Compendium of Estimates

Significance: A 2018 retrospective analysis of Medicare beneficiaries identified that ∼8.2 million people had wounds with or without infections. Medicare cost estimates for acute and chronic wound treatments ranged from $28.1 billion to $96.8 billion. Highest expenses were for surgical wounds followed by diabetic foot ulcers, with a higher trend toward costs associated with outpatient wound care compared with inpatient. Increasing costs of health care, an aging population, recognition of difficult-to-treat infection threats such as biofilms, and the continued threat of diabetes and obesity worldwide make chronic wounds a substantial clinical, social, and economic challenge. Recent Advances: Chronic wounds are not a problem in an otherwise healthy population. Underlying conditions ranging from malnutrition, to stress, to metabolic syndrome, predispose patients to chronic, nonhealing wounds. From an economic point of view, the annual wound care products market is expected to reach $15-22 billion by 2024. The National Institutes of Health's (NIH) Research Portfolio Online Reporting Tool (RePORT) now lists wounds as a category. Future Directions: A continued rise in the economic, clinical, and social impact of wounds warrants a more structured approach and proportionate investment in wound care, education, and related research.

Assessment of burn size in obese adults; a literature review

PURPOSE

Obesity causes changes in the total body surface area as well as the distribution of skin surfaces. In burn management, three methods are commonly used to determine the surface area burned: the patient's palm, the rule of nines, and the Lund-Browder chart. These methods rely on the distribution of skin surface, although none of these methods consider differences in body mass. This study investigates the relationship between body surfaces and body mass in the assessment of burn size to determine the validity of the conventional methods when applied to obese individuals.

METHODS

The current literature was reviewed using relevant electronic databases. The initial search yielded 247 results. Relevant articles were then reviewed. A total of seven publications fulfilled the inclusion criteria.

RESULTS

The palmar surface area ranged between 0.59%-1.22%, depending on BMI, gender, and ethnicity, compared to 1% according to conventional methods. The palmar surface area of obese individuals approximated 0.7% of the total body surface area in Caucasians. The surface areas comprised 5%-7.5% of the total body surface area for each arm, 15%-20% for each leg, and 40%-52% for the trunk in obese or morbidly obese individuals, compared to 9%, 18%, and 36%, respectively, for normal-weight adults.

CONCLUSIONS

The commonly used methods for assessment of burns should be used with caution when applied to obese burn patients, and the clinical parameters observed even more systematically.

Wound healing trajectories in burn patients and their impact on mortality

The rate of wound healing and its effect on mortality has not been well described. The objective of this article is to report wound healing trajectories in burn patients and analyze their effects on in-hospital mortality. The authors used software (WoundFlow) to depict burn wounds, surgical results, and healing progression at multiple time points throughout admission. Data for all patients admitted to the intensive care unit with ≥ 20% TBSA burned were collected retrospectively. The open wound size (OWS), which includes both unhealed burns and unhealed donor sites, was measured. We calculated the rate of wound closure (healing rate), which we defined as the change in OWS/time. We also determined the time delay (DAYS) from day of burn until day on which there was a reduction in OWS < 10%. Data are medians [interquartile range]. There were 38 patients with complete data; 25 had documentation of successful healing (H), and 13 did not (NH). H differed from NH on age (38 years [32-57] vs 63 [51-74]), body mass index (27 [21-28] vs 32 [19-52]), 24-hour fluid resuscitation (12 L [10-16] vs 18 [15-20]), pressors during first 48 hours (72% vs 100%), use of renal replacement therapy (32% vs 92%), and mortality (4% vs 100%). Repeated measures analysis of covariance showed a significant difference between survivors and nonsurvivors on OWS as a function of time (P<.001). Patients with a positive healing rate (+2%/day) after postburn day 20 had 100% survival whereas those with a negative healing rate (-2%/day) had 100% mortality. For H patients, median DAYS was 41 (28-54); median DAYS/TBSA was 1.3 (1.0-1.9). Survivors had a 0.62% drop in OWS/day, or 4.3%/week. In this cohort of patients with ≥ 20% TBSA, there was a difference in mortality after postburn day 20, between patients with a positive healing rate (+2%/day, 100% survival) and those with a negative healing rate (-2%/day, 100% mortality, P < .05).

Physiological and management implications of obesity in critical illness

Obesity is highly prevalent in the United States and is becoming increasingly common worldwide. The anatomic and physiological changes that occur in obese individuals may have an impact across the spectrum of critical illness. Obese patients may be more susceptible to hypoxemia and hypercapnia. During mechanical ventilation, elevated end-expiratory pressures may be required to improve lung compliance and to prevent ventilation-perfusion mismatch due to distal airway collapse. Several studies have shown an increased risk of organ dysfunction such as the acute respiratory distress syndrome and acute kidney injury in obese patients. Predisposition to ventricular hypertrophy and increases in blood volume should be considered in fluid management decisions. Obese patients have accelerated muscle losses in critical illness, making nutrition essential, although the optimal predictive equation to estimate nutritional needs or formulation for obese patients is not well established. Many common intensive care unit medications are not well studied in obese patients, necessitating understanding of pharmacokinetic concepts and consultation with pharmacists. Obesity is associated with higher risk of deep venous thrombosis and catheter-associated bloodstream infections, likely related to greater average catheter dwell times. Logistical issues such as blood pressure cuff sizing, ultrasound assistance for procedures, diminished quality of some imaging modalities, and capabilities of hospital equipment such as beds and lifts are important considerations. Despite the physiological alterations and logistical challenges involved, it is not clear whether obesity has an effect on mortality or long-term outcomes from critical illness. Effects may vary by type of critical illness, obesity severity, and obesity-associated comorbidities.

Burn wound healing and treatment: review and advancements

Burns are a prevalent and burdensome critical care problem. The priorities of specialized facilities focus on stabilizing the patient, preventing infection, and optimizing functional recovery. Research on burns has generated sustained interest over the past few decades, and several important advancements have resulted in more effective patient stabilization and decreased mortality, especially among young patients and those with burns of intermediate extent. However, for the intensivist, challenges often exist that complicate patient support and stabilization. Furthermore, burn wounds are complex and can present unique difficulties that require late intervention or life-long rehabilitation. In addition to improvements in patient stabilization and care, research in burn wound care has yielded advancements that will continue to improve functional recovery. This article reviews recent advancements in the care of burn patients with a focus on the pathophysiology and treatment of burn wounds.

Does obesity affect outcomes of adult burn patients?

BACKGROUND

Obesity negatively affects outcomes after trauma and surgery; results after burns are more limited and controversial. The purpose of this study was to determine the effect of obesity on clinical and economic outcomes after thermal injury.

METHODS

The National Inpatient Sample was queried for adults from 2005-2009 with International Classification of Diseases-9 codes for burn injury. Demographics and clinical outcomes of obese and nonobese cohorts were compared. Univariate and multivariate analysis using logistic regression models were performed. Data are expressed as median (interquartile range) or mean ± standard deviation and compared at P < 0.05.

RESULTS

In 14,602 patients, 3.3% were obese (body mass index ≥30 kg/m(2)). The rate of obesity increased significantly by year (P < 0.001). Univariate analysis revealed significant differences between obese and nonobese patients in incidence of wound infection (7.2% versus 5.0%), urinary tract infection (7.2% versus 4.6%), deep vein thrombosis in total body surface area (TBSA) ≥10% (3.1% versus 1.1%), pulmonary embolism in TBSA ≥10% (2.3% versus 0.6%), length of stay [6 d (8) versus 5 d (9)], and hospital costs ($10,122.12 [$18,074.72] versus $7892.07 [$17,191.96]) (all P < 0.05). Death occurred less frequently in the obese group (1.9% versus 4%, P = 0.021). Significant predictors of grouped adverse events (urinary tract infection, wound infection, deep vein thrombosis, and pulmonary embolism) on multivariate analysis include obesity, TBSA ≥20%, age, and black race (all P ≤ 0.05).

CONCLUSIONS

Obesity is an independent predictor of adverse events after burn injury; however, obesity is associated with decreased mortality. Our findings highlight the potential clinical and economic impact of the obesity epidemic on burn patients nationwide.

Obese patients in a burn care unit: a major challenge

OBJECTIVE

Obesity is an important predictor of mortality and morbidity during a hospital stay. There is very little data concerning the impact of the BMI on clinical outcomes in obese burn patients. The purpose of this study is to document the general epidemiological aspects of thermal injuries in an obese population and draw attention to topics relating to the management, rehabilitation and prognosis of burns in this emerging subpopulation of patients.

METHODS

All patients >16 years of age admitted to the burn unit between January 2008 and December 2012 and fulfilling the burn center referral criteria were enrolled in the study. SPSS version 20 (SPSS GmbH Software, Illinois, USA) was employed for data analysis.

RESULTS

Eleven extreme obese patients (men:women, 6:5) had a mean BMI of 38kg/m(2). Their incidence in our study was 5.5%. The mean length of stay was 41.5 days, almost twice that of the non-obese. The presence of co-morbidities such as diabetes, hypertension, cardiac disease, or pulmonary disease, the problematic wound healing and the burn wound infection were significantly higher in the obese patients than in the non-obese. The mortality of obese burned patients was 36.4%.

CONCLUSIONS

These facts indicate admission of these patients to a burn care unit for the best possible treatment although they might not always fulfill criteria for admission to burn intensive care unit. Burn centers must be also prepared in terms of special nursing equipment for obese patients.

Nutritional care of the obese adult burn patient: a U.K. Survey and literature review

Obesity is an emerging healthcare problem and affects an increasing number of burn patients worldwide. An email survey questionnaire was constructed and distributed among the 16 U.K. burn services providing adult inpatient facilities to investigate nutritional practices in obese thermally injured patients. Responses received from all dieticians invited to participate in the study were analyzed, and a relevant literature review of key aspects of nutritional care is presented. The majority of services believe that obese patients warrant a different nutritional approach with specific emphasis to avoid overfeeding. The most common algebraic formulae used to calculate calorific requirements include the Schofield, Henry, and modified Penn State equations. Indirect calorimetry despite being considered the "criterion standard" tool to calculate energy requirements is not currently used by any of the U.K. burn services. Gastric/enteral nutrition is initiated within 24 hours of admission in the services surveyed, and a variety of different practices were noted in terms of fasting protocols before procedures requiring general anesthesia/sedation. Hypocaloric regimens for obese patients are not supported by the majority of U.K. facilities, given the limited evidence base supporting their use. The results of this survey outline the wide diversity of dietetic practices adopted in the care of obese burn patients and reveal the need for further study to determine optimal nutritional strategies.