Differences in Burn Wound Size Estimation Between Points of Referral and the Burn Unit: Experience at a Major Burn Center in Southwestern Nigeria

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The management of burn injury is largely dependent on the burn severity.¹ The severity of burn injury is a function of burn size and depth. Burn size estimation has evolved over the years, with the Lund and Browder chart, the “rule of nines,” and the “rule of palm” gaining traction due to World War II as well as the Coconut Grove Nightclub disaster.² The Lund and Browder chart factors in proportional body growth and changes with age, while the “rule of nines” is very easy to use, especially in triaging and in adults. The “rule of palm” is useful in irregular, small, patchy burn.³ The “rule of nines” assigns 9% to each upper limb, 18% (or 2 nines) to each trunk, 18% to each lower limb, 9% to the head and neck, and 1% to the perineum.^2,3 The “rule of palm” assigns 1% to the palmer surface of the patient’s hand.^2,3 

Burn size is used in determining the need for referral to a burn center, the need for fluid resuscitation, and the estimated volume of fluid needed in resuscitation. The TBSA assessment should be reevaluated after debridement and deroofing of blisters. Inaccurate TBSA estimation has been documented to cause unnecessary referral to burn units.⁴ This unnecessary referral adds both transportation cost to the patient and resources consumption by the receiving hospital. These human and material resources often are scarce in low- and middle-income countries such as Nigeria. Proper burn severity assessment will enable better decision-making with regard to proceeding with immediate transfer to a burn unit, a telemedicine consultation, or referral to outpatient follow-up.⁵ 

Burn injury of at least superficial dermal thickness and involving more than 20% to 30% TBSA is associated with cytokine release that initiates a systemic response to the injury.^6,7 Patients with such burns will require resuscitation and the services of a specialized burn center. Accurate burn wound size estimation is important for resuscitation and subsequent management.⁸ Over-resuscitation may result in fluid overload and its complications, whereas under-resuscitation may result in shock and end-organ failure.⁹ Vulnerable groups include older adults, children, and patients with comorbidities.^10,11 

In Nigeria, there is no clear guideline for referral to the burn unit. This results in referral of minor and major burns to the burn unit, as well as management of some major burns in non-burn centers. Accurate assessment of burn size is a vital competence of referring physicians if burn centers are to efficiently develop a clear referral guideline. Use of such a guideline would create a sense of confidence in patient care while reducing unnecessary referral to the burn unit. A documented discrepancy in burn wound size estimation between referral sources and burn units has been reported outside Nigeria, with a tendency toward overestimation in children and of minor burns.^8,9,12,13 

The aim of the current study was to determine if the study authors face a similar challenge in their practice. In the authors’ sub-region, there are no pre-hospital emergency services, and many patients present to the authors’ facility between 4 hours and 3 weeks after injury. Typically, these patients are referred to the burn unit from private clinics, secondary health centers, other tertiary centers, and the emergency department (for adults) or the pediatric emergency department of the hospital. Typically, patients with major burns receive intravenous fluids and other first aid treatment before presentation to the authors’ burn unit. The authors presume that the fluids given before presentation to their unit are based on the estimated TBSA burn. Because many patients present late, it is also important to the authors of the current study that the correct amount of fluid is given based on accurate estimation of TBSA.

Study setting and design
This retrospective study was carried out at the burn unit of a tertiary hospital located in Ibadan, southwestern Nigeria. The hospital is a 1229-bed facility with a 12-bed burn center. As stated previously, patients are referred to the burn unit from private clinics, secondary health centers, other tertiary centers, and either the emergency department or the pediatric emergency department of the hospital. The wound estimation is carried out by medical personnel at the source of referral. On arrival in the burn unit, after the wound has been cleaned and blisters deroofed, the wound is reassessed by the most senior physician on duty (usually a Senior Registrar) and subsequently by a consultant. Plastic surgeons are the primary physicians in the burn unit. In the burn unit, TBSA is assessed using the Lund and Browder chart. This method is frequently supplemented by the “rule of palm” for patients with irregular, patchy burns.

The inclusion criteria comprised adults and children (≤16 years) referred to the burn unit between January 1, 2016, and October 31, 2019, whose records contained the initial TBSA evaluation at the source of referral and the TBSA estimation in the burn unit. Patients admitted during the study period whose records either could not be found or were incomplete were excluded from the study.

Burn injury types encompassed thermal, electrical, and chemical burns. Overestimation was defined as burn wound size discrepancy of 1% or more compared with the burn unit estimate, and underestimation was defined as burn wound size less than the burn unit estimate by 1% or more.¹⁴ TBSA assessment is a basic requirement for proper burn care, with established methods for estimation. When properly used, the TBSA value should be comparable regardless of whether it is determined by a burn unit physician or a non-burn unit physician.

Data collection and analysis
This retrospective review of data stored in the case notes was carried out in line with the Declaration of Helsinki in both the collection and analysis of the data. The records of patients seen in the authors’ burn unit between 2016 and 2019 were reviewed. Data collected include the date of admission, age, sex, and TBSA burn estimation at the source of referral and the burn unit. Data were stored in a Microsoft Excel document. Analysis was done using SPSS version 23 (IBM Corporation), the t test, and the chi-square test for inferential statistics. Alpha was set at .05 as the level of significance. 

A total of 96 records on patients with burn injury in the study period were reviewed. Most patients were male (56%), with a male-to-female ratio of 1.3:1 (Table 1). The majority of patients were children (55.2%).

Of the 96 records retrieved, 35 (36.5%) lacked a burn size estimation by the referring physicians prior to burn unit review (68.6% of them were children, and 31.4% were adults). In the group with an initial burn size estimation by the referring physicians, the mean initial TBSA was 24.95% ± 14.82 standard deviation and the mean final TBSA as estimated by the burn unit physicians was 22.21% ± 15.20. The difference in TBSA estimation between the referring physicians and burn unit physicians was statistically significant (t = 2.507; P = .015). Over 5% of patients with 1% to 10% TBSA estimation by burn unit physicians received a 21% to 30% TBSA estimation by referring physicians, whereas 16.7% of those with 41% to 50% TBSA estimation by burn unit physicians received an 11% to 20% TBSA estimation by the referring physicians (P ≤ .001) (Figure 1). 

Of the 61 patients with burn size estimation by the referring physicians, burn size was underestimated in 22.9% (mean underestimation, 7.4% ± 7.9; range, 1%-25%) (Table 2). For most patients, TBSA underestimation was less than or equal to 5%; however, burns greater than 20% TBSA were more likely to be underestimated. This finding was not statistically significant (P = .42) (Figure 2). Underestimation was more likely in adults than in children (57% and 43%, respectively; P = .1) (Figure 3).

Of the 61 patients with burn injury whose wounds were estimated by referring physicians, TBSA was overestimated in 30 (49.2%). The mean overestimation was 9.2% ± 6.2 (range, 2%-24%) (Table 2). Burn wounds of 1% to 10% TBSA (31%), and 11% to 20% TBSA (24.1%) were more likely to be overestimated (Figure 4). Most burn wounds of 11% to 20% TBSA were overestimated by 1% to 5%, then second most overestimated by 16% to 20% (P = .833) (Figure 4). Overestimation was more likely for children than adults (63% and 37%, respectively), with most overestimation of 16% to 20% TBSA occurring in children (P = .5) (Figure 5). Overall, it is more common for burn wounds to be overestimated than underestimated (t = 2.472, P = .016) (Table 2). Referring physicians estimated TBSA correctly in 27.9% (n = 17) of cases.

Burn wound size estimation is critical in the management of burn injuries. It guides the decision to refer a patient to a burn center, as well as the need for and volume of fluid resuscitation. 

The male-to-female ratio reported in the current study reflects the general sex pattern of burn injury in the authors’ facility as well as in Nigeria as a whole.^15-18 The ratio may be due to the high incidence of flame injuries, which are more common among males.¹⁹ The adult-to-child ratio in the current study is lower than that reported by Olawoye et al.¹⁹ This finding might be due to the exclusion of patients whose records were grossly deficient for the current study. Although adults rather than children constituted the largest proportion of those treated during the study period, most of the records of the adult population could not be found, which may have contributed to the higher proportion of children in the study. The adult proportion in the current study is also lower than the 67.6% reported by Wardhana et al.²⁰

The current study showed a statistically significant inaccurate estimation of burn size by referring physicians, with more burns overestimated than underestimated. This may be due to inconsistencies in the use of appropriate method of estimation. The overall overestimation of 47.5% in the current study was similar to the 45% overestimation reported by Ashworth et al²¹ and the 60.58% overestimation reported by Ho et al.²² Wardhana et al²⁰ reported overestimation of 6.7% in the emergency department compared with the burn unit. The reason for overestimation was thought to be the aggressive nature of the emergency department in terms of lifesaving resuscitation and the lack of time for accurately determining burn size in that setting compared with the burn unit setting.²⁰ 

In the current study, overestimation was more likely in children than in adults, likely due to inaccurate translation of the mathematical formula in the Lund and Browder chart. This difference may also be the result of use of the Wallace “rule of nines” in assessment of TBSA by referring physicians and use of the Lund and Browder chart by burn unit physicians. Each of these methods may result in different values for the same patient; for example, the trunk is 5% lower in the Lund and Browder chart compared with the “rule of nines.” Burn wound was overestimated in 41.9% of children in this study. This is lower than the 70% overestimation reported by Sadideen et al²³ in their study of 46 children. However, the finding in the current study is higher than that of Lewis et al,¹⁴ who reported overestimation in 33.6% of pediatric patients (45 of 134 children). The reasons attributed to the inaccurate estimations from that study was the estimation of pediatric burns using adult Lund and Browder charts, as well as estimation of a 3-dimensional burn using a 2-dimensional chart. 

The current study also found that burn injuries of less than 20% TBSA were more likely to be overestimated, with burn wounds of 1% to 10% TBSA having the highest proportion of overestimation. With over 30% of patients with 1% to 10% TBSA being overestimated by 11% TBSA or more, this would have resulted in unnecessary referral of these patients to the burn unit had a strict burn referral guideline been in place. This finding of overestimation is similar to that reported by Swords et al,²⁴ who noted that burn injuries with 10% to 19% TBSA were most likely to be overestimated. Brekke et al²⁵ observed a tendency toward overestimation of minor burns in a systematic review. Ashworth et al²¹ theorized that overestimation from a referring center might be due to the inclusion of areas of erythema in the initial estimation, and that such areas were likely to have resolved by the time of patient assessment in the burn center. Inclusion of areas of erythema in the initial estimation is unlikely to account for the problem of overestimation in the current study, however, because most of the patients presented late; as such, the areas of erythema only would have been clearer or resolved.

In the current study, 22.9% of burn injuries were underestimated, which is similar to the report by Yoo et al.²⁶ There was a tendency toward more frequent underestimation of major burns. This is similar to a report by Holm et al,²⁷ in which larger burns were more likely to be underestimated. Larger burns were more likely to be underestimated by more than 5%, with the largest degree of underestimation (by 21%-25% TBSA) occurring in those with a 41% to 50% TBSA burn. Additionally, underestimation was slightly more likely for adults than for children. Although underestimation was unlikely to have affected referral to a burn unit, it may have affected counseling and prognostication prior to referral. 

In the current study, one-third of patients arrived at the burn unit without TBSA estimation by the referring physician; nearly 70% of those patients were children. This may be owing to the challenge of estimating burn size in children, for which the easier “rule of nines” is not applicable. It suggests a need to increase education of pediatric emergency department physicians in burn size estimation. The finding of the current study is remarkably higher than the almost 20% of patients who arrived at the burn unit without TBSA estimation from the referring center in the study by Swords et al.²² 

The problems of inaccurate burn TBSA estimation identified in the current study can be remedied by emphasizing proper burn TBSA assessment during undergraduate medical training, as well as with regular professional development webinars.⁹ These webinars can be organized under the auspices of the local and regional medical association’s continuing medical education programs. Such training should incorporate the need for TBSA estimation of all patients with burn injury, documentation of the method of estimation, and the problems of inaccurate estimation. Additionally, a feedback system between the burn unit and referral sources should be developed. This feedback mechanism will enhance prompt identification of the challenges at the source of referral, and enable the burn unit to proffer solutions. 

This study has limitations. It was not possible to study the effect of differences in size estimation due to the retrospective nature of the study. The paucity of recent literature on the subject of accurate burn size estimation was another limiting factor. The authors were unable to definitively assess the effect of the differences in burn size estimation because referral in their region is not yet based on TBSA. Additionally, the exact method of burn size estimation by the referral sources are unknown and were not documented in the referral notes. 

There is a statistically significant difference in burn size estimation by referring physicians compared with burn unit physicians, with both overestimation and underestimation occurring. Remarkably, in the current study one-third of patients arrived at the burn unit without TBSA estimation by the referring physicians; most of these patients were children. Thus, there is a need for increased collaboration and more holistic education and training of the general practitioners who often refer these patients to teaching hospitals and referral centers with burn units.

Authors: Samuel Adesina Ademola, MBBS, FWACS, FACS^1,2; Ayodele Olukayode Iyun, MBBS, MSc, FWACS^1,2; Izegaegbe Ohiosimuan Obadan, MBBS, FWACS¹; Chinsunum Peace Isamah, MBBS, MWACS¹; Olayinka Adebanji Olawoye, MBChB, FWACS^1,2; Afieharo Igbibia Michael, MBBS, FMCS, FWACS^1,2; Rotimi Opeyemi Aderibigbe, MBBS, FWACS¹; and Odunayo Moronfoluwa Oluwatosin, MBBS, FMCS, FWACS^1,2

Affiliations: ¹Department of Plastic, Reconstructive, & Aesthetic Surgery, University College Hospital Ibadan, Ibadan, Nigeria; ²Department of Surgery, College of Medicine, University of Ibadan, Ibadan, Nigeria 

ORCID: Ademola, 0000-0003-1596-2061; Aderibigbe, 0000-0002-8208-6463; Isamah, 0000-0002-8443-8151; Michael, 0000-0002-6622-5152; Obadan, 0000-0003-2873-5028; Olawoye, 0000-0003-0812-5388

Disclosure: The authors disclose no financial or other conflicts of interest.

Correspondence: Chinsunum Peace Isamah, MBBS, MWACS; Senior Registrar, University College Hospital Ibadan, Plastic, Reconstructive & Aesthetic Surgery, Queen Elizabeth Road, Oritamefa, Ibadan, Oyo 200212 Nigeria; peaceisamah@gmail.com

Manuscript Accepted: December 5, 2023