Documented nutritional therapy in relation to nutritional guidelines post burn injury e a retrospective observational study

Background & aims: Intensive nutritional therapy is an essential component of burn care. Regarding post-minor burn injuries, the literature is lacking. The aim of this study was to evaluate documented nutritional therapy in relation to international guidelines after both minor and major burn injuries. The secondary aim of this study was to evaluate the adequacy of energy and protein intake compared to individual nutritional goals post-burn injury. Methods: A retrospective observational single-centre study including patients admitted between 2017 and 2019 at a burn centre in Sweden was performed. The patients included in the study were (cid:1) 18 years old and in need of hospital care for (cid:1) 72 h post-burn injury. Information about patients' demographics, nutritional therapy, and clinical characteristics of burn injury was collected. The patients were divided according to total body surface area burnt (TBSA %) into minor burn injuries (TBSA < 20%) and major burn injuries (TBSA (cid:1) 20%). Descriptive statistics were used to analyse data. Adherence to guidelines was established by comparing 24 nutritional therapy recommendations to documented treatment. If documented nutritional treatment were in accordance with guidelines, adherence was considered high ( (cid:1) 80%), moderate (60 e 79.9%) or low ( < 59.9%). Results: One hundred thirty-four patients were included, 90 patients with minor burn injuries and 44 patients with major burn injuries. Documented adherence to the nutritional guideline was overall low. After minor burn injury, 8% (2/24) of nutritional therapy recommendations had a high adherence (fat intake < 35% of total energy intake and enteral nutrition as prioritized feeding route), 17% (4/24) a moderate adherence, and 75% (18/24) a low adherence. In patients treated after a major burn injury, there were two recommendations with documented high adherence (Vitamin C and Zinc); 25% (6/24) had moderate adherence, and 67% (16/24) had low adherence. In addition, quite a large amount of missing data was found. Adequacy of documented nutritional intake, compared to the individual documented goal, was 78% ( ± 23%) for energy and 66% ( ± 22%) for protein after minor burn injury. After major burn injury, the adequacy was 89% ( ± 21%) for energy and 78% ( ± 19%) for protein, respectively. Conclusions: This study revealed low adherence to nutritional guidelines in patients treated for minor and major burn injuries. Compared to major burn injuries, lower documented adequacy for both energy and proteins was found in minor burn injuries. Given the disparity between guidelines and documented nutritional therapy, and the lack of speci ﬁ c guidelines for minor burn injuries, there could be a considerable risk of inadequate nutritional therapy post-burn injury.


Introduction
Optimal nutritional therapy has become an important component in the management of acute burn injuries and in the treatment of post-burn injuries.Adequate intake of macro-and micronutrients, as well as metabolic modulation and glycemic control, are crucial for optimal outcomes after major burn injuries (defined as total body surface area burnt (TBSA %) !20%) [1e3].While several nutritional guidelines for the management of severely burned patients have been documented [1,4,5], no specific guidelines concerning the nutritional treatment for patients with minor burn injuries (defined as TBSA <20%) have yet been published.
There are few studies regarding the clinical application of postburn nutritional guidelines into clinical practice to improve the quality of care for critically ill burn patients.A large gap between recommendations and nutritional therapy in reported clinical practice has been found in a multicentre study involving 14 burn centres in the USA, Canada, Australia, and South Africa treating severe burn injuries [6].The achievement of nutritional goals was suboptimal for both energy (64.9%) and protein (65.6%) [6].In mechanically ventilated patients post-burn injury energy and protein deficits were associated with increased mortality [7].Although enteral nutrition rather than parenteral nutrition is the preferred feeding route after burn injuries [1], delayed enteral nutrition and interruption of enteral delivery are the common reasons for not reaching nutritional targets [7,8].A lack of agreement between nutritional treatment in clinical practice and the recommended macronutrient content of enteral nutrition formula or indication and use of parenteral nutrition was observed in several burn units from USA and Australia, according to a previous review [9].
Although much progress has been made in the establishment of nutritional guidelines, adherence to these guidelines and the optimal nutritional regimen for patients after minor burn injuries remain elusive.Therefore, the aim of this study was to evaluate documented nutritional therapy in relation to nutritional guidelines and to compare the adherence to nutritional guidelines between minor and major burn injuries.The secondary aim of this study was to evaluate documented energy and protein intake compared to individual nutritional goals post-minor and postmajor burn injury.

Study design, participants, and nutritional guidelines
A retrospective review of patients with burn injuries admitted to the Burn Centre in Uppsala University Hospital, Sweden, between January 2017 and December 2019 was undertaken.The inclusion criteria were subjects aged 18 years or older, with burn injury, and in need of hospital care for more than 72 h post-injury.Data were collected from the hospital's electronic patients' medical record system from admission until discharge or death or for 12 days after admission.These included demographic data (age, gender, relevant co-morbidities), hospital length of stay, daily nutrition data, the severity of burn injury and treatment, weight development, and nutritional therapy.Revised-Baux score (r-Baux score), a calculated score used to predict mortality after burn injury, was calculated using the equation: Guidelines on nutritional therapy post-major burn injury were published by the American Burn Association (ABA) in 2001 [13] and by the European Society for Clinical Nutrition and Metabolism (ESPEN) in 2013 [1].Clinical practice guidelines about nutritional therapy post-burn injury were developed and updated together with therapy guidelines for the critically ill adult patient by the Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (ASPEN) latest in 2022 [4], and by ESPEN 2019 [5].Adherence to guidelines was established by comparing 24 nutritional therapy recommendations established by ESPEN 2013 [1], SCCM/ASPEN 2022 [4], and ESPEN 2019 [5] with documented nutritional therapy.The items extracted are explained in Table 1.

Retrospective data collection process
The execution of this study was based on Patanwala's 2017 [14] practical guide to conducting and writing medical record review studies.Data were extracted by a registered dietitian (JD) with experience in clinical work with burn patients from two electronic patient data systems, COSMIC and Metavision (Cosmic ver.R8.3.03Cambio Healthcare Systems AB, Stockholm, Sweden, and Metavision Suite ver.6.11, IMDsoft, N. Harris Computer Corporation, Düsseldorf, Germany).A tool for data analysis and a case report form (CRF) was developed, tested, and modified prior to use.Data collection was performed between May 2021 and June 2022.To decrease subjectivity in the extraction of data and analyses, randomly selected medical records (n ¼ 24) containing items related to nutritional guidelines (Table 1) were decoded by the data abstractor (JD) and analysed by three independent observers (JD, AA, CL).Any discrepancies were resolved through discussion until consensus.
To minimise data entry errors, all sample minimums and sample maximums were checked for being physiologically adequate (for example, height and weight) and that each variable was within a reasonable number range (for example, TBSA >0 and 100).Percent of missing data per variable was analysed, and sufficient availability was considered when >80% of clinical and laboratory variables were available [15].

Statistical analysis
Continuous variables were reported as means with standard deviations (SD), and categorical variables as a percentage.Documented adherence to nutritional guidelines for each item was calculated on extracted documented values, excluding missing values.Missing values were presented separately.Energy/protein adequacy was calculated as the amount of energy/protein received as a percentage of the individual energy/protein goal prescribed for all patients evaluable nutrition days.Received calories and proteins included the total amount of energy and protein from parenteral-, enteral-, per oral intake, as well as calories from propofol infusion, and intravenous glucose infusion.
Sample size necessary to compare differences in, for example, received protein intake and targeted protein intake after minor and major burn injuries, using results from Chourdakis' study [6] in calculations, with alfa 0.05 and power 0.8, a sample size of 32 in each group was deemed necessary.The data variables were split into minor (TBSA <20%) and major (TBSA !20%) burn injuries and analysed through descriptive statistics for documented nutritional therapy in relation to nutritional guidelines.Items were analysed regarding if a significant difference existed between the groups post-minor and post-major burn injuries.Differences between groups for bivariate samples in independent groups were analysed using, since not equal variance and for skewed data, ManneWhitney U-test.Categorical data were analysed using Pearson's chi-square test.A probability value of 0.05 was considered a statistically significant level.The software Statistical Package for the Social Sciences (SPSS), IBM, ver.28.0.0.0, was used for analyses.

Ethics
The study was performed in accordance with the ethical principles for medical research involving human subjects that have their origin in the updated Declaration of Helsinki, and the study was approved by the Swedish Ethical Review Authority (approval no: 2020e03192, approved 26 August 2020 and 2021e02103 approved 24 May 2021).The need for informed consent from each participant was waived since this was a retrospective observational study without interventions.

Results
A total of 134 patients, 90 patients with minor burn injuries and 44 patients with major burn injuries, met the inclusion criteria and were included in the study.Patients' characteristics are presented in Table 2.There were no differences between the groups of patients with minor and major burn injuries in age, gender, or BMI.For burns classified as minor burn injuries (TBSA 20%), TBSA was 8.1% ± 5.0 (mean ± SD), and for those classified as major burn injuries, TBSA was 37.8% ± 17.2.After minor burn injuries 11% of the patients had an inhalation injury, and 28% of the patients needed mechanical ventilation for a period of mean 5.3 (±4.8) days.Inhalation injury affected 41% of the patients with major burn injuries.Mechanical ventilation was used for 91% of the patients after major burn injury, with mean of 13.2 (±23.2) days on mechanical ventilation.A significant higher r-Baux score was seen after major burn injuries, 93.1 (±24.6)compared to 64.1 (±21.5) after minor burn injuries, as well as longer hospital length (both p < 0.001).

Documented adherence to nutritional therapy guidelines
Documented adherence to nutritional therapy recommendations at our study site was overall low.A total of 24 documented items were evaluated according to guidelines.After minor burn injury, only 8% (2/24) of these items were documented as having high adherence, 17% (4/24) as moderate adherence, and the remaining 75% (18/24) indicated low adherence to guidelines (Table 3).Among those with major burn injuries, interestingly, only 8% (2/24) of items had a high adherence to guidelines documented, 25% (6/24) of items had moderate adherence, and the remaining 67% (16/24) of the items documented low adherence, Table 3.

Macronutrients and enteral nutrition
Eleven items regarding "macronutrients and enteral nutrition" were evaluated according to guidelines.Of them, only 18% (2/11) were recorded as having high adherence to guidelines post-minor and major burn injuries, there was no item recorded as having high adherence.A documented moderate adherence was seen in 18% (2/11) of records post-minor burn injury, and for a post-major burn injury, that number was 27% (3/11).The remaining items were documented as having low adherence to guidelines, Table 3. Statistically significant differences were seen between the groups in the measurement of indirect calorimetry (p < 0.0001), enteral nutrition (EN) as the prioritised feeding route (p ¼ 0.02), and EN started within 12 h from admission (p ¼ 0.032).Among the patients with major burn injuries, 79% received a mean protein goal between 1.5 and 2 g/kg/day in comparison with only 45% of the patients with minor burn injuries (p < 0.0001).Intake from fat <35% of total energy intake was found in 51% of patients with major burn injuries versus 87% of patients with minor injuries (p < 0.0001).Enteral route as a prioritised feeding route was recorded in 91% of patients' medical records post minor burn injury and in 70% of the patients with major burn injury (p ¼ 0.02).All patients with Table 1 Items extracted regarding nutritional therapy guidelines post burn injury [1,4,5].

Nutritional therapy recommendations Items extracted in medical record review
Nutritional guideline, burn injury ESPEN 2013 [1] Nutritional guideline, critically ill SCCM/ASPEN [4] Nutritional guideline, critically ill ESPEN 2019 [5] Macronutrients, energy, and enteral nutrition (11  EN had a nasogastric feeding tube.Parenteral nutrition (PN) was recorded in 31 patients as a feeding route at least one of the first 12 days after admission.Among them, ten patients received PN for conditions related to gastrointestinal intolerance (retention problems, n ¼ 4, vomiting, n ¼ 1), EN contraindicated (high abdominal pressure, n ¼ 2, fasting for NIV, n ¼ 1), or other problems related to enteral access (n ¼ 2).For 21 patients, PN had been prioritised before EN (in one to eight of the first twelve days after admission) for reasons other than previously stated, long fasting period (n ¼ 3) or not reaching nutritional goals (n ¼ 7).Unclear reasons/reasons not stated in patients' medical records were found in 11 patients.

Micronutrients
Seven items regarding micronutrients were evaluated according to the guidelines, Table 3.In the patients treated for minor burn injuries, no micronutrients were documented as having a high adherence to guidelines.A documented moderate adherence was extracted from 29% (2/7) of medical records after minor burn injuries (Vitamin C and Zinc).The remaining records had a documented low adherence to guidelines.Statistically significant differences regarding supplementation with micronutrients were seen between groups.For Vitamin B1 (p ¼ 0.002), Vitamin C (p ¼ 0.013), and Zinc (p < 0.0001), the patients with major burn injury more often had a documented supplementation compared to patients with post-minor burn injury.

Metabolic modulation, pharmaceuticals, and glycemic control
Six items regarding early excision within six days, pharmaceuticals for metabolic modulation (oxandrolone, propranolol), for increased tolerance to enteral nutrition (metoclopramide, erythromycin), and glycemic control were evaluated, Table 3.After minor burn injuries, all these items were documented as having low adherence according to guidelines.A proportion of 33% of patients with major burn injuries was documented as having a moderate adherence to guidelines, and the remaining 66% (4/6) had a low documented adherence to guidelines.In comparison with patients with minor burn injuries, the group with post-major burn injury had statistically significantly more often early excision (p ¼ 0.002), propranolol (p < 0.0001), and metoclopramide (p < 0.0001).

Intake, goal, and adequacy of energy and protein
Compared to major burn injuries lower documented adequacy for both energy and proteins was found in minor burn injuries (p < 0.05), Supplementary A. Adequacy of nutritional intake compared to individual goals after minor burn injuries were 78 ± 23 for energy and 66 ± 22% for protein.The adequacy of nutritional intake was slightly higher for major burn injuries regarding both energy 89 ± 21% and protein 78 ± 19%.The adequacy of documented nutritional intake compared to individual goals seem to increase over time (Figs. 1 and 2).Protein goals were 1.45 (±0.22) gram/kg/day and 1.65 (±0.24) gram/kg/day for patients with minor and major burn injuries, respectively.Documented protein intake was 0.83 (±0.33) g/kg/day for minor burn injury and 1.19 (±0.71) g/kg/day for major burn injury.

Missing data and weight development
Weight at 6-and 12-month post-burn injury had the highest number of missing data of all items extracted.In 77% of patients' medical records, data on weight at six months was missing.Of the missing data, 69% were weights not registered in medical records, and the remaining 31% of patients had no follow-up visit and, consequently, no weight taken.At 12 months post-burn injury, the number of missing data regarding weight was similar, 80%.For the  remaining patients (approximately 20%) with weight recorded in the medical record, weight development between weight before the injury to weight at six months post-burn injury was þ0.3 kg (þ0.4%) for patients post minor burn injury.For patients post-major burn injury, that number was þ1.0 kg (þ1.0%).Weight development between weight before the injury to weight at 12 months post-burn injury was À8.3 kg (À10.8%) after minor burn injuries and À8.8 kg (À10.5%) after major burn injuries.In addition to weight after 6-and 12 months post-burn injury, six extracted items regarding adherence to nutritional guidelines had high numbers of missing data (!20% missing data) post-minor burn injuries.The items with a high number of missing data were hours until 80% of protein goals were reached, fat intake 35 E %, glucose 4.5e8 mmol/L, protein goal g/day and g/kg/day, and adequacy of protein intake compared to protein goal.After major burn injuries, of all extracted items, only weight after 6-and 12 months post-burn injury had a high number of missing data.

Discussion
This study revealed low documented adherence to nutritional guidelines in both patients treated for minor and major burn injuries.These results align with previous studies that reported low adherence to nutritional guidelines in treating patients after burn injuries [6,9,19].The study also revealed that patients with minor burn injuries have lower documented adequacy of both energy and protein intake in comparison with those after major burn injuries.
The achievement of nutritional goals according to nutritional guidelines for patients after major burn injuries [1,4,5] is suboptimal.There is a lack of guidelines and studies investigating nutritional therapies post minor burn injuries.Low adherence to nutritional guidelines points to a potential risk of undernutrition.The documented reported intake was overall low in our study, 21.0 kcal/kg/day and 0.83 g protein/kg/day post-minor burns and 25.2 kcal/kg/day and 1.19 g protein/kg/day post-major burns.These values are considerably lower than the protein intakes recommended in the guidelines concerning post-burn injury [1,4,5].This raises questions about the accuracy of documented intake.If true, the risk of undernutrition is substantial, which could lead to, or enhance, malnutrition, increase complication frequencies, decrease wound healing, and have also been reported to increase mortality [20,21].In our study, only 31% of patients were screened for malnutrition.Optimising nutrition status considering also the risk of malnutrition must be integrated into the calculation of energy intake by using indirect calorimetry measurement [20].Energy intake calculations have biased results of ± 20% compared to the measures resulted by calorimetry [22].While indirect calorimetry is considered more objective than other methods, calorimetric measurements in our study were reported only in 23% of records post-minor and 77% in post-major burn injuries.In order to increase measurements by indirect calorimetry, new equipment was available last couple of years, which is more user-friendly and easier to calibrate and interpret [23,24].
Another method to reduce the risk of malnutrition post-burn injury is to ensure adequate energy and protein intake.The difficulties in reaching an adequate amount of feeding were described in earlier literature [25].Potential causes for the energy and protein deficits and post-burn injury have been identified as the delay in the start of enteral nutrition, interruptions in enteral nutrition, and intolerance to enteral nutrition [7].All of the above reasons have been documented also in our study.Enteral nutrition was initiated within 12 h for 75% of patients with post-minor burn injury and 56% of patients post major burn injury.The enteral route as the prioritised feeding route was found in 91% of patients after minor burn injuries and 70% of patients after major burn injuries.In a small group of patients with high abdominal pressure, gastrointestinal intolerance, long fasting periods, or in case of a problem with enteral access, PN was used as an alternative to enteral nutrition.All the patients presented in the study had nasogastric tube feeding.Significant improvement in tolerance could probably have been obtained by the placement of tube feeding in the small intestine [25] or by continued enteral tube feeding during fasting periods [20].Another way to increase the overall energy could have been using an enteral feeding protocol [4].This is a volume-based feeding protocol, where the whole volume for 24 h is targeted instead of hourly rates.Unfortunately, this strategy was underused in our study, as only 30% of patients on tube feeding had an enteral feeding protocol.Prokinetic medications (metoclopramide and erythromycin) could also have improved tolerance to gastric feeding [1].However, this strategy was underused in the study (metoclopramide 67% of the patients, and erythromycin 2% of the patients with post-major burn injuries).In 35% of patients with PN, no apparent cause for the choice of feeding route was documented in the records.
Although guidelines [1] only cover major burn injuries, TBSA !20%, we used these guidelines for both minor and major burn injuries in our study.Since the burn population is not homogenous, e.g., also in the population of minor burn injuries, there is a group of patients in need of intensive care treatment; in our study, 28% (n ¼ 25) who qualified for the use of guidelines for the intensive care setting [4,5].Considering there also were four patients (9%) post-major burn injury not in need of intensive care treatment, perhaps the division of patients according to TBSA is not the best way when thinking about nutritional therapy guidelines post-burn injury in the future.

Fig. 1 .
Fig. 1.Energy adequacy per study day.The amount of energy (kcal/day) received as a percentage of the individual energy goal (kcal/day) prescribed for all patients.

Fig. 2 .
Fig. 2. Protein adequacy per study day.The amount of protein (gram/day) received as a percentage of the individual protein goal (gram/day) prescribed for all patients.
Abbreviations: P-value: Probability value, SD: Standard Deviation, BMI: Body Mass Index, TBSA: Total Body Surface Area burnt.aStatistically significant differences in variable between groups of patients' after minor burn injuries and major burn injuries.Bold text indicates a statistically significant difference with a p-value <0.05.b Skewed distributions, non-parametric tests used in statistical analysis.

Table 3
Documented nutritional therapy compared to nutritional recommendations.
Probability value, TBSA: Total Body Surface Area burnt, Kg: Kilogram body weight, EN: enteral nutrition, mmol/L: millimoles per litre.a Statistically significant differences in variable between groups of patients' after minor and major burn injuries.Bold text indicates a statistically significant difference with a p-value <0.05.