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Page 1: SMARTPHONES AND BURN SIZE ESTIMATION: “RAPID … · • “Lund-Browder Chart ... The Lund-Browder charts7take into account body pro-portions associated with different ages and

Annals of Burns and Fire Disasters - vol. XXVII - n. 2 - June 2014

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Introduction

It is important that the assessment of burn size be per-formed accurately and adequately as the outcome can im-pact on the decision whether or not to transfer the patientto a burn center and on the initial volume requirement forfluid resuscitation, among other things.

The majority of assessments of percentages of total burnsurface area (%TBSA) to-date have revealed inaccuracies,mostly related to human error, with overestimations of morethan 100% identified in emergency departments.1-4

Three predominantly used and established methods ofburn size estimation are:

• “Rule of Palm”5

• “Rule of Nines”6

• “Lund-Browder Chart”7

In adults, the “Rule of Nines” is used to determine thetotal percentage of burned regions per body segment.6 In

some cases, burn injuries only partially affect a region oreven extend beyond it, and thus such burns are measuredusing the palm of the injured person as a reference repre-sentative of 1% of body surface area (“Rule of Palm”).5

According to previous reports, the Rule of Palm (Fig. 1)can lead to overestimations of about 10–20%8,9 because, inadults, the surface area of the palm, including the fingers,represents only 0.8 %TBSA in men and 0.7 %TBSA inwomen. Excluding the fingers, the averages are as low as0.5 and 0.4 %TBSA in men and women respectively. Inchildren, the palm approximates 0.92 and 0.52 %TBSAwith and without the fingers, respectively. According toWallace, and cited by Knaysi,6 the Rule of Nines (Fig. 1)is quite accurate in persons weighing about 10–80kg. How-ever, overestimations of %TBSA by use of the Rule ofNines occur,10 especially in persons with higher body-massindices.11 To overcome this, a proportionate adaptation pre-viewed a “Rule of Five” for persons >80 kg, and a “Rule

SMARTPHONES AND BURN SIZE ESTIMATION: “RAPID BURNASSESSOR”

Kamolz L.P.,1** Lumenta D.B.,1*,** Parvizi D.,1 Dirnberger J.,2 Owen R.,2 Höller J.,3

Giretzlehner M.2

1 Division of Plastic, Aesthetic and Reconstructive Surgery, Research Unit for Tissue Regeneration, Repair and Reconstruction,Department of Surgery, Medical University of Graz, Graz, Austria

2 Research Unit Medical-Informatics, RISC Software GmbH, Johannes Kepler University Linz, Hagenberg, Austria3 Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Graz, Austria

SUMMARY. Estimation of the total body surface area burned (%TBSA) following a burn injury is used in determining whether totransfer the patient to a burn center and the required fluid resuscitation volumes. Unfortunately, the commonly applied methods ofestimation have revealed inaccuracies, which are mostly related to human error. To calculate the %TBSA (quotient), it is necessaryto divide the burned surface area (Burned BSA) (numerator in cm2) by the total body surface area (Total BSA) (denominator in cm2).By using everyday objects (eg. credit cards, smartphones) with well-defined surface areas as reference for estimations of Burned BSAon the one hand and established formulas for Total BSA calculation on the other (eg. Mosteller), we propose an approximation methodto assess %TBSA more accurately than the established methods. To facilitate distribution, and respective user feedback, we have de-veloped a smartphone app integrating all of the above parameters, available on popular mobile device platforms. This method repre-sents a simple and ready-to-use clinical decision support system which addresses common errors associated with estimations of BurnedBSA (=numerator). Following validation and respective user feedback, it could be deployed for testing in future clinical trials. Thisstudy has a level of evidence of IV and is a brief report based on clinical observation, which points to further study.

Keywords: burns, decision support systems, clinical, fluid therapy, burn surface area estimation

* Corresponding author: David Benjamin Lumenta, MD, Division of Plastic, Aesthetic and Reconstructive Surgery, Research Unit for Tissue Regeneration, Repairand Reconstruction Department of Surgery, Medical University of Graz Auenbruggerplatz 29, A-8036 Graz, Austria. Tel.:+43-316-385-14685; fax:+43-316-385-14690;email: [email protected]** Both authors contributed equally to this work.

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of Eight” for those <10 kg of body weight.12

The Lund-Browder charts7 take into account body pro-portions associated with different ages and are more precisethan the Rule of Nines. Even so, overestimations have stillbeen reported: Alm13 reported an average overestimation of17.8% in 90% of cases, Nichter4 reported 12.4% and Berry11

identified overestimations of 154% in 25 out of 60 cases. Furthermore, we have previously demonstrated that,

regardless of the chosen methodology for estimating sur-face areas, notably small, scattered burn areas pose a prob-lem when estimating total burn surface area.1

In order to optimize clinical decision-making follow-ing a burn or scald injury, objectivation of TBSA assess-ments is well warranted and new methods predominantlybased on computer-aided technologies have emerged.14-17

Smartphones based on different mobile platforms (eg. iOS,Android, Blackberry, Windows Mobile etc.) are not justvery popular among the general population, but also amongmedical staff. These mobile devices are able to performautomated calculations and to transmit data securely.

This report is based on the idea that everyday objects(eg. credit cards, smartphones) have a distinct well-definedsurface area, and that these objects can serve as referencefor surface area estimations.

Methods

For calculation of the %TBSA, it is necessary to di-vide the burned surface area (Burned BSA) (numerator, incm2) by the total body surface area (Total BSA) (denom-inator, in cm2).

In a mobile application, we incorporated well-definedsurface areas (in cm2) of everyday objects like credit cardsor smartphones as a reference tool for burn surface areaestimations. For known objects, these surface areas havebeen predefined, but a free input option for other dimen-sions of known surface areas of other squared or rectan-gular devices is available (Fig. 2).

In our proposed scenario, the user estimates how oftena predefined known surface area object (as mentioned above)fits into a burn surface area (Fig. 3), which will render theburned surface area as calculated by the app in cm2.

The other parameters to be entered in the app areweight and height of the patient, which will calculate thetotal body surface area by use of the selected predefinedformula in cm2 (eg. Mosteller, DuBois DuBois). The finalresult of the entered parameters is the then calculated %TBSA by the app (Fig. 4).

VerificationFor verification of the app, 30 burnt areas (test areas)

have been designed using a special liquid on three man-nequins (one male, one female and one child - burn sizesranging from 1% to 15% TBSA, 10 burnt areas on each

mannequin) (Fig. 5).After completion of test size estimations, these test ar-

eas have been pulled off and transferred onto a flat-bedscanner (Brother MFC-9420CN) and the area (in cm2) wasmeasured by use of ImageJ™ for computer based plani-metric measurements. For calculation of the %TBSA, thetest areas (in cm2) were divided by the total body surfaceareas (TBSA in cm2).

In order to evaluate the total body surface areas of the

Fig. 1 - “Rule of Nines” and “Rule of Palm”.

Fig. 2 - Graphical user interface(GUI) AThe user can choose between dif-ferent preinstalled references ofknown surface area (= “Device”,eg. smartphones). Optionally,new devices for burn size esti-mation (eg. credit card) can beadded by defining its surface areadimensions and saving it under anew device name (e.g. creditcard).

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mannequinns, all 3 mannequins have been scanned by useof the TOF-3D-Scanner and by use of the Software Re-constructMe™ (Profactor) and the total body surface areain % was calculated.

Results

To put to use this simple method of %TBSA estima-tions, we have developed a free mobile application called

the “Rapid Burn Assessor” for Apple iOSTM and GoogleAndroidTM, which has integrated the above-mentioned for-mulas and calculation methods. In order to validate the re-sults, we took 30 test areas in the range from 62.7cm² to966.3cm² on 3 mannequins. The differnce (in %) betweenthe test areas (in cm²) assessed with the RBA-Tool andthe measured areas was 6.16%. The difference concerningTBSA burned (in %) was 0.1% TBSA.

Discussion

To optimize resources for transfers to burn centers andinitial fluid resuscitation volumes, we have developed asimple and cost-efficient tool for health-care professionals(eg. first-responders, GPs, nursing staff, medical/surgicalspecialists etc.) for improving %TBSA estimations. Esti-mation errors related to and/or based on incorrect %TB-SA assessments may affect clinical decision-making and,in the extreme, can result in either hypovolemic shock andcardiac failure (under-estimation) or abdominal/extremitycompartment syndrome, pulmonary edema and electrolyteimbalance (over-estimation).1

Although our proposed method of estimation is sub-ject to some inaccuracies (resulting from human error, vari-ations of body weight/height), it does at least represent asimplified approximation that reduces the common errors

Fig. 3 - Graphical user interface (GUI) BComparable to the “Rule of Palm”, the user estimates how often thesurface area of a predefined device (e.g. iPhone) fits into the burnsurface area.

Fig. 4 - Graphical user interface(GUI) CHaving selected the height andweight of the patient, the app cal-culates the total burn surfacearea (Total BSA). After the userhas selected the number of timesthe predefined device fits into theburn surface area, the app thencalculates the burn surface area(Burned BSA) and reveals thecalculated %TBSA.

Fig. 5 - Example: Test area (# F5) left shoulder and breast- Total body surface area of the mannequinn = 15335 cm2- The iPhone 4 fits 3.5 times into the test area: 3.5 times iPhone 4

= 236 cm2236/15335= 1.54 % of the TBSA (estimated by the Rapid BurnAssessor)

- Real size of the test area= 251.3 cm2 251/15335= 1.63% (measured by the scanner)

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associated with burn surface area estimations by using aneveryday reference of known size. Even though the ideaof a reference tool (eg. Rule of Palms) is not new, to thebest of our knowledge, this is the first published attemptin over 30 years to improve one side of the mathematicalformula, namely the burn surface area.

This approach can be useful for small-scattered burnsurface areas, which are the most common kind of burninjury encountered in daily clinical practice and have beendemonstrated to result in the most inaccurate assessmentsby the above-cited methods.1,17

In order to improve %TBSA estimations, further ob-jectivity is required, which could include, for example, fullbody scans with mobile scanners used to assess total bodysurface area burned.

In this context, the “Rapid Burn Assessor” is a verysimple and cost-efficient support system for clinical deci-sion-making related to burn/scald injuries, applicable andready to use, even in an emergency setting. This brief re-port encourages active user feedback to facilitate deploy-ment and improvement of the mobile application for fu-ture validation and testing in clinical trials.

RÉSUMÉ. L’estimation de la totale de la surface corporelle brûlée (% de la SCT) à la suite d’une brûlure est importante en déter-minant le transfert du patient vers un centre de brûlés et les volumes nécessaires des fluides de réanimation. Malheureusement, lesméthodes d’estimation couramment appliquées ont révélé des inexactitudes, qui sont principalement liés à l’erreur humaine. Pour cal-culer le % de la SCT il faut diviser la surface brûlée (numérateur en cm2) de la surface corporelle totale (dénominateur en cm2). Enutilisant des objets du quotidien (par exemple cartes de crédit et smartphones) avec des surfaces bien définies comme référence pourles estimations de la SC brûlée d’une part, et des formules établies pour le calcul de la SC totale sur l’autre (par exemple Mostel-ler), nous proposons une méthode d’approximation d’évaluer le % de la SCT brûlée plus de précision que les méthodes établies.Pour faciliter la distribution, et les commentaires des utilisateurs, nous avons développé une application intégrant tous les paramètresci-dessus, disponibles sur les plates-formes d’appareils mobiles populaires. Cette méthode représente un système simple et prêt àl’emploi aide à la décision clinique qui traite les erreurs courantes associées aux estimations de BSA brûlé (= numérateur). Après lavalidation et la rétroaction des utilisateurs, il pourrait être déployé pour les tests dans les futurs essais cliniques. Cette étude a unniveau de preuve IV et elle présente un bref rapport basé sur l’observation clinique, qui pointe vers une étude plus approfondie.

Mots-clés: brûlures, les systèmes d’aide à la décision, une fluidothérapie clinique, brûlent surface estimation

BIBLIOGRAPHY

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Conflict of interest. NoneFunding. None

This paper was accepted on 18 January 2014.