Assessment of burn size in obese adults; a literature review

The correlation of BMI and insulin resistance in moderately burned patients

<b>Introduction:</b> Obesity is strongly related to serious comorbidities that might affect the healing process. Elevated Body Mass Index (BMI) and insulin resistance have a significant impact on the development of the metabolic syndrome often leading to lethal cardiovascular complications.<b>Aim:</b> The aim of the study was to verify the correlation of BMI and insulin resistance with clinical parameters of moderately burned patients.<b>Materials and methods:</b> There were 149 patients enrolled in the study and their clinical data was retrospectively analyzed. The laboratory tests, insulin demand, BMI, and surgical procedures were evaluated on admission and discharge.<b>Results:</b> Burned patients who required insulin were characterized by worse laboratory results on admission to the burn unit, they had lower hemoglobin (HGB) levels (P = 0.0001), higher creatinine levels by 0.323 units (P = 0.009), higher C-reactive protein (CRP) by approximately 94 units (P = 0.0001), as higher procalcitonin (PCT) by approximately 0.5 units (P = 0.001) as compared to non-insulin-treated patients. Moreover, burned patients who required insulin stayed in the hospital for an average of 10 days longer. All patients from the insulin-demand subgroup had elevated triglycerides (Tg) levels on admission with increased indexes of insulin resistance.<b>Discussion:</b> Our study suggests that the protective effect of a higher BMI in burned patients, known as the 'obesity paradox' may be compromised by insulin resistance.<b>Conclusions and significance of the study:</b> The results show that elevated Tg on admission to the burn unit coexisting with a BMI over 25 kg/m² may be used as an important prognostic factor and may help with prediction of insulin demand and worse outcome in moderately burned patients.

Evaluation and Optimization of the Wallace Rule of Nines for the Estimation of Total Body Surface Area in Obese and Nonobese Populations

BACKGROUND

Currently, the Wallace Rule of Nines is the most widely used method to measure total body surface area (TBSA) in burned patients due to its practicality and speed in its application; however, it often provides inaccurate estimations in obese patients, affecting the fluid resuscitation process.

OBJECTIVE

In this study, we aimed to modify and optimize the Rule of Nines' values for its application in these patients.

METHODS

We compared the estimations of the TBSA established by the Wallace Rule of Nines against the measurements of the three-dimensional (3D) software Skanect - Meshmixer 3.5Ⓡ in participants without different obesity grades. Based on our results, we generate an optimized guideline for the evaluation of TBSA in normal body mass index (BMI) and obese patients.

RESULTS

In our study, 32 participants were recruited with a mean age of 28.5 ± 3.3 years. In the general population, we observed a poor correlation between the Wallace Rule of Nines and the 3D method measures in all body regions (e.g., Anterior Trunk: 18.0 vs. 16.61 ± 2.11, p = 0.0008) except the anterior arm. Interestingly, these differences narrowed in the Trunk and Leg regions as the participants' BMI increased (e.g., Anterior Trunk in Obesity Grade II patients: 18.0 vs. 18.66 ± 1.69, p = 0.3089).

CONCLUSIONS

We found important differences in TBSA determination using the 3D Skanect-MeshmixerⓇ software compared with the Wallace Rule of Nines. Therefore, we generated a modified and optimized Wallace Rule of Nines estimations based on BMI. Future studies are needed to assess the safety and efficacy of this optimized table.

Examining Obesity and Its Association With Burn Injury: A Secondary Analysis of the Transfusion Requirement in Burn Care Evaluation Study

INTRODUCTION

Literature examining the connection between obesity and burn injuries is limited. This study is a secondary analysis of a multicenter trial data set to investigate the association between burn outcomes and obesity following severe burn injury.

MATERIALS AND METHODS

Body mass index (BMI) was used to stratify patients as normal weight (NW; BMI 18.5-25), all obese (AO; any BMI>30), obese I (OI; BMI 30-34.9), obese II (OII; BMI 35-39.9), or obese III (OIII; BMI>40). The primary outcome examined was mortality. Secondary outcomes included hospital length of stay (LOS), number of transfusions, injury scores, infection occurrences, number of operations, ventilator days, intensive care unit LOS, and days to wound healing.

RESULTS

Of 335 patients included for study, 130 were obese. Median total body surface area (TBSA) was 31%, 77 patients (23%) had inhalation injury and 41 patients died. Inhalation injury was higher in OIII than NW (42.1% versus 20%, P = 0.03). Blood stream infections (BSI) were higher in OI versus NW (0.72 versus 0.33, P = 0.03). Total operations, ventilator days, days to wound healing, multiorgan dysfunction score, Acute Physiology and Chronic Health Evaluationscore, hospital LOS, and intensive care unit LOS were not significantly affected by BMI classification. Mortality was not significantly different between obesity groups. Kaplan-Meier survival curves did not significantly differ between the groups (χ2 = 0.025, P = 0.87). Multiple logistic regression identified age, TBSA, and full thickness burn as significant independent predictors (P < 0.05) of mortality; however, BMI classification itself was not predictive of mortality.

CONCLUSIONS

No significant association between obesity and mortality was seen after burn injury. Age, TBSA, and percent full- thickness burn were independent predictors of mortality after burn injury, while BMI classification was not.

Application of multiple deep learning models for automatic burn wound assessment

PURPOSE

Accurate assessment of the percentage of total body surface area (%TBSA) burned is crucial in managing burn injuries. It is difficult to estimate the size of an irregular shape by inspection. Many articles reported the discrepancy of estimating %TBSA burned by different doctors. We set up a system with multiple deep learning (DL) models for %TBSA estimation, as well as the segmentation of possibly poor-perfused deep burn regions from the entire wound.

METHODS

We proposed boundary-based labeling for datasets of total burn wound and palm, whereas region-based labeling for the dataset of deep burn wound. Several powerful DL models (U-Net, PSPNet, DeeplabV3+, Mask R-CNN) with encoders ResNet101 had been trained and tested from the above datasets. With the subject distances, the %TBSA burned could be calculated by the segmentation of total burn wound area with respect to the palm size. The percentage of deep burn area could be obtained from the segmentation of deep burn area from the entire wound.

RESULTS

A total of 4991 images of early burn wounds and 1050 images of palms were boundary-based labeled. 1565 out of 4994 images with deep burn were preprocessed with superpixel segmentation into small regions before labeling. DeeplabV3+ had slightly better performance in three tasks with precision: 0.90767, recall: 0.90065 for total burn wound segmentation; precision: 0.98987, recall: 0.99036 for palm segmentation; and precision: 0.90152, recall: 0.90219 for deep burn segmentation.

CONCLUSION

Combining the segmentation results and clinical data, %TBSA burned, the volume of fluid for resuscitation, and the percentage of deep burn area can be automatically diagnosed by DL models with a pixel-to-pixel method. Artificial intelligence provides consistent, accurate and rapid assessments of burn wounds.

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.

The impact of subject positioning on body composition assessments by air displacement plethysmography evaluated in a heterogeneous sample

Introduction

This study sought to evaluate the impact of subject positioning on body composition assessments by air displacement plethysmography using the BOD POD®.

Methods

Eighty-two adults (42 men and 40 women), aged 26.1 ± 8.4 y (mean ± standard deviation), body mass index = 23.6 ± 4.8 kg/m2, were assessed by repeated measurements in two different positions: relaxed (legs apart, back away from the rear) and compact (legs together, arms near the body, back touching the rear). We relied on Bland-Altman analysis to quantify the agreement between results recorded in the two positions. Using body surface charts, we tested the hypothesis that posture-induced variability stems from differences in exposed skin area.

Results

Switching from compact to relaxed position resulted in a bias of -197 mL for body volume, -1.53% for percent body fat, and 1.085 kg for fat-free mass. The body surface area in contact with air was larger in relaxed position by 3632 ± 522 cm2. When body volume was expressed in terms of the actual area of exposed skin in the compact position, the percent body fat bias became 0.08%, with a 95% confidence interval of (-0.14, 0.29)%.

Conclusions

Subject posture is a source of significant variability in air displacement plethysmography. The disagreement between results obtained in different positions can be eliminated by adjusting the surface area artifact, suggesting that subject positioning in the BOD POD® should be controlled to avoid changes in the amount of air maintained under isothermal conditions by the body.

Review of History of Basic Principles of Burn Wound Management

Thermal energy is an essential and useful resource to humans in modern society. However, a consequence of using heat carelessly is burns. Burn injuries have various causes, such as exposure to flame, radiation, electrical, and chemical sources. In this study, we reviewed the history of burn wound care while focusing on the basic principles of burn management. Through this review, we highlight the need for careful monitoring and customization when treating burn victims at each step of wound care, as their individual needs may differ. We also propose that future research should focus on nanotechnology-based skin grafts, as this is a promising area for further improvement in wound care.

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.