Mersey Burns User's Manual

This is the manual for version 1.6.1 of Mersey Burns.

www.merseyburns.com

support@merseyburns.com

You must carefully read and agree to the disclaimer agreement, available to read in the manual, before you use Mersey Burns.

Mersey Burns was written by Chris Seaton, Rowan Pritchard Jones MD FRCS(Plast), and Professor Paul McArthur PhD FRCS(Plast), and is a product of Medicapps Ltd. It is regulated in the UK by the MHRA.

Mersey Burns is copyright © 2010-2013 St Helens and Knowsley Teaching Hospitals NHS Trust. All rights reserved. Not to be reproduced in whole or part without the express permission of the copyright holder.

Introduction

Mersey Burns is a free clinical tool for calculating burn area percentages, prescribing fluids using Parkland, background fluids and recording patients details. It is designed for physicians and runs on the iPad™, iPhone®, iPod touch®, Android and BlackBerry PlayBook. This document describes how to use the app. The screenshots show the iPad but it works the same on all devices.


Topics


Drawing Burns

Do not include simple erythema in the burn area.

When you start the app, you will see the obverse outline of a male patient. The same outline is used for all ages and both sexes, with the model factoring in these details. You can tap the turn button, bottom left, to view the reverse of the patient.

Touch, hold for a moment and move to draw burnt areas onto the patient. To scroll the patient's outline, touch and move straight away.

Buttons at the top left allow you to draw, erase or clear. You can also clear by shaking the device. Buttons at the top right allow you to draw full thickness (FT) and partial thickness (PT) burns.

If you don't know where a patient is burned but do know the percentage burns, perhaps because you are not physically with the patient, you can set the percentage burns by clicking the burn area label and selecting the percentage.


Patient Age

To set the patient's age, tap the icon of a birthday cake in the toolbar at the bottom. Select a specific age if the patient is under 18, or simply select Adult. To automatically set an average weight for this age, click set weight.


Patient Weight

To set the patient's weight, tap the icon of a set of scales in the toolbar at the bottom. Weights are in 5kg increments, or 1kg increments under 30kg. If you don't know the weight of your patient, you can set the age and click set weight to set the weight based on an estimate.


Time of Burn

To set the time of the burn, tap the icon of a clock in the toolbar at the bottom. Times wrap around within 24 hours, so if you set a time 2 hours in the future, you are saying that the burn occurred 22 hours in the past.

To set the time to be now, an hour ago, or four hours ago, tap the buttons beneath the time picker.


Prescribing Fluids

When you have entered all the details of the patient and the burn, tap the icon of a fluids bag in the toolbar at the bottom for a recommended prescription of fluids. You must always check the calculated values manually.

You can select between a 2ml/hr and a 4ml/hr rate based on your assessment of the patient and burn.


Emailing

To email the details of the burn using the email app, tap envelope icon in the toolbar at the bottom.


Clinical Basis

This section describes the clinical basis for all calculations made by Mersey Burns.

Fraction of surface area for each body part

From Lund and Browder.

PartFraction
Front headA
Front neck0.0100
Front chest0.1300
Front right arm upper0.0200
Front right arm lower0.0150
Front right hand0.0150
Front left arm upper0.0200
Front left arm lower0.0150
Front left hand0.0150
Crotch0.0100
Front right upper legB
Front right lower legC
Front right foot0.0175
Front left upper legB
Front left lower legC
Front left foot0.0175
Back headA
Back neck0.0100
Back chest0.1300
Back right arm upper0.0200
Back right arm lower0.0150
Back right hand0.0150
Back left arm upper0.0200
Back left arm lower0.0150
Back left hand0.0150
Left buttock0.0250
Right buttock0.0250
Back right upper legB
Back right lower legC
Back right foot0.0175
Back left upper legB
Back left lower legC
Back left foot0.0175

Fractions that vary by age

Also from Lund and Browder.

Age (years)ABC
00.09500.02750.0250
10.08500.03250.0250
50.06500.04000.0275
100.05500.04500.0300
150.04500.04500.0325
180.03500.04750.0350

Linear interpolation of fractions that vary by age

Calculated using the Microsoft Excel forecast function.

Age (years)ABC
00.09500.02750.0250
10.08500.03250.0250
20.08000.03440.0256
30.07500.03630.0263
40.07000.03810.0269
50.06500.04000.0275
60.06300.04100.0280
70.06100.04200.0285
80.05900.04300.0290
90.05700.04400.0295
100.05500.04500.0300
110.05300.04500.0305
120.05100.04500.0310
130.04900.04500.0315
140.04700.04500.0320
150.04500.04500.0325
160.04170.04580.0333
170.03830.04670.0342
180.03500.04750.0350

Average weight by age

Average weight (kg) = 3 × age (years) + 7

As per Weight estimation in resuscitation: is the current formula still valid?, Mark Luscombe and Ben Owens, Arch Dis Child 2007;92:412-415.

Prescribed fluids

From Parkland:

If age < 18 and area burnt (fraction) < 10%; give no fluids

If age >= 18 and area burnt (fraction) < 15%; give no fluids

Total fluids = area burnt (fraction) × weight (kg) × rate (ml)

Rate = 2ml, 4ml

If the time since the burn is greater than or equal to 16+8 hours: give the total fluid now.

Else, if the time since the burn is greater than or equal to 8 hours; give half the total fluid now, and half in the subsequent (16+8 hours - hours since burn).

Else, give half the total fluid in (8 hours - hours since burn), and half in the subsequent 16 hours.

Background fluids

If age < 16:

Background fluids = 4ml for the first 10kg of weight + 2ml for the next 10kg of weight + 1ml for the rest of the weight, per hour

We also support a 3ml fluid rate, in addition to the standard 2ml and 4ml.


How Mersey Burns Is Tested

A battery of 5,000 test cases and solutions has been generated by an external program, and then compared against an independent implementation of the formulae by a third party. Each time the application starts, all 5,000 test cases are run as if a user had input them manually. The results of the application's calculations are compared against the test case solutions. Both individual values, and the completed narrative, are compared for equality. In the unlikely event that the specification of the underlying hardware or software changes or is corrupted to produce different results, the error will be detected and the application will not run.

These tests do not remove the need for sound professional clinical judgement.


Change Log

This section describes what changes have been made to Mersey Burns between each version.

Version 1.6.1

Version 1.6.0

Version 1.5.1

Version 1.5.0

Version 1.4.0

Version 1.3.0

Version 1.2.0

Version 1.1.0

Version 1.0.0