Technology overview

This briefing describes the regulated use of the technology for the indication specified, in the setting described, and with any other specific equipment referred to. It is the responsibility of healthcare professionals to check the regulatory status of any intended use of the technology in other indications and settings.

About the technology

CE marking

Medicapps was awarded a class I CE mark for Mersey Burns for use with iPad, iPhone, iPod touch, Android devices, BlackBerry PlayBook and HTML5‑compatible browsers in September 2011.

The Medicines and Healthcare Products Regulatory Agency has issued guidance that explains what medical device software applications are and how this type of technology is regulated.


Mersey Burns is a mobile application (app) for use by clinicians in managing burn injuries caused by any means. It has been developed to calculate the percentage of the body surface area affected and the amount of replacement fluid required intravenously (referred to in the app as the fluid prescription) in the first 24 hours to ensure the patient remains haemodynamically stable. It also calculates the additional intravenous background (or maintenance) fluids needed by children younger than 16 years.

The app calculates the TBSA using the Lund and Browder method, the resuscitation fluids using the Parkland formula and background fluids for children. The mobile device versions of the app allow details about the burn and the fluid prescription to be emailed, for example to the receiving hospital.

Mersey Burns is free to download and requires iOS 6.0 or later, Android OS v2.3.3 or later, BlackBerry PlayBook or a HTML5‑compatible browsers.

There have been 8 versions of Mersey Burns:

  • 1.0.0 – First release.

  • 1.1.0 – New icon, fixed the location of the turn button on the iPad in landscape orientation, fixed the '1 hr ago' and '4 hrs ago' buttons when they cross midnight, fixed warning text on startup, added shake to clear, changed clear to also reset age, weight, time and fluid rate, lowered minimum iOS version to 4.0 from 5.0.

  • 1.2.0 – Made the user's manual available offline within the app, added a German language translation.

  • 1.3.0 – Added warning about weights more 30% different to the estimate, added warning about simple erythema, new disclaimer agreement added, added automated testing, and described testing procedures in the manual, switched weight estimation formula to be 3×age+7, instead of 3×age+3, fixed a bug that meant changing the age reset the burn area if it was set manually, estimated weights now rounds to 5 kg in the same way as the manual user interface.

  • 1.4.0 – Added support for retina displays and the iPhone 5, refreshed manual, reduced from 10,000 to 5,000 automatic tests to allow for slower devices.

  • 1.5.0 – Released Android version, released HTML5 version, released PlayBook version, there was no release of this version on iOS.

  • 1.5.1 – iOS bug fixes, there was no release of this version on Android, HTML or Playbook.

  • 1.6.0 – Switched to an all‑integer code path for calculations for better reproducibility and testability, added 3 ml fluids option, support for iOS 7.

  • 1.6.2 – New information governance wording in email.

On opening the app, the device screen shows a diagram of the front of a person's body. Regions of the body are shown by dividing lines. A diagram of the back of the body is displayed by tapping on the 'turn' button. Scrolling up and down allows the full body to be seen. These diagrams are used for people of both sexes and all ages. Areas affected by the burn can be 'drawn' on the diagram by selecting the 'draw' button, and highlighting the relevant area. Both full and partial thickness burns can be drawn. Buttons allow the user to partially erase or clear the burn area. The TBSA is calculated as the burn is being drawn on the diagram and displays in a label on the screen. Alternatively, if the percentage area is already known, it can be added by tapping the burn area label and selecting the appropriate percentage in 1% increments. A pop‑up message advises the user not to include simple erythema.

The user also enters the patient's age and weight and the time of the burn injury. The default setting is for an adult weighing 60 kg with a burn occurring 5 minutes earlier. The age can be set using the 'birthday cake' button. This allows the selection of a specific age for those under 18 years, or 'adult' for those 18 years and over. An average weight for age can be selected, or the patient's weight can be entered using the 'scales' button. Weight measurements are in 1 kg increments up to 30 kg and in 5 kg increments thereafter. The time of the burn injury is set using the 'clock' button.

When details have been entered, the 'fluid bag' button should be tapped. The recommended intravenous fluid prescription is displayed, separated into the first 8 hours after the burn injury and the next 16 hours. For children younger than 16 years, the rate of intravenous background fluids needed is also displayed. The user can select from 2 ml/hour, 3 ml/hour and 4 ml/hour infusion rates depending on the clinical assessment. The manufacturer's instructions for use recommend that calculated values should always be checked manually and that clinical judgement should be applied.

The mobile device version of the app can email details about the burn and the fluid prescription if the user presses the 'envelope' button. The app itself does not allow patient identifiers to be entered or stored, but these can be added manually to the text of the email. Emails are marked as 'medical in confidence'. The app includes (from version 1.6.2) an information governance warning that person‑identifiable information must only be sent and received by email accounts.

The app is validated each time it starts. A battery of 5000 test cases are run, as if the data has been entered manually. The results of these calculations are compared with the test case solutions stored in the app. If there is a difference between the results, the app will not run to avoid a risk to patient safety.

Setting and intended use

The Mersey Burns app would be used in any healthcare setting, both in and out of hospital, but it may be particularly useful in acute care settings such as emergency departments. The app is intended for use by qualified medical professionals, with or without specialist experience in burns injury management. It can be used if the patient is not present as long as the TBSA and other details are available.

Current NHS options

Superficial (minor) burns and scalds are generally managed in primary care. More severe, complex burns may need to be treated in specialist departments.

There are no guidelines about when to refer someone presenting with a burn injury in primary care to an emergency department. This is also noted in the NICE clinical knowledge summary on burns and scalds. The Joint Royal Colleges Ambulance Liaison Committee Guideline Development Group (JRCALC) has produced the UK Ambulance Services Clinical Practice Guidelines (2013) for paramedics, which includes guidance on assessing and managing burns and scalds in adults and children. The National Network for Burn Care provides guidance for primary and secondary care providers on when to refer to specialised burn care services (National Burn Care Referral Guidance, 2012).

NICE is not aware of any other CE‑marked devices that have a similar function to the Mersey Burns app, although a review of smartphone applications related to burns (Wurzer et al. 2015) identified 13 calculator apps in the Google Play Store, of which 6 were free to download, and 21 calculator apps in Apple's App Store, of which 8 were free to download. None of these apps are CE marked.

Costs and use of the technology

Mersey Burns is available to download for free by anyone with an iPad, iPhone, iPod touch, Android device, BlackBerry PlayBook or HTML5‑compatible web browsers. It does not require any consumables. Users should download any updates to the app when they become available. Network issues may limit access to the HTML version of Mersey Burns or delay the receipt of updates to the app.

The manufacturer states that Mersey Burns has been adopted by the Midlands Burns Operational Delivery Network (MB ODN), which serves about 20% of the population in England.

Likely place in therapy

Mersey Burns would be used to calculate fluid requirements for adults and children with recent burn injuries. Use of the device is not expected to change the current clinical pathway. It would replace the need for manual calculations using the Lund and Browder chart or other methods for estimating TBSA. It may also facilitate faster and more accurate fluid resuscitation calculations than manual calculations using the Parkland formula. The device would most likely be used in acute care settings and could also be used remotely, with the results emailed to the treating clinical team (in accordance with information governance arrangements).

Specialist commentator comments

Three specialist commentators stated that they had experience of using the Mersey Burns app, and 1 commentator said its use is encouraged in their department. The same commentator believed that Mersey Burns is relevant to all healthcare professionals in the burn care pathway. One specialist commentator indicated that a burns network is using Mersey Burns but no data were available to assess if there had been an impact on fluid resuscitation. Three specialist commentators agreed that Mersey Burns was useful and simple to use; most also felt that the app was quick to use.

One specialist commentator stated that many healthcare professionals have smartphones which they use to access an array of other health‑related information. One specialist commentator stated that many clinicians prefer the app‑based technology to traditional paper‑based systems. Another suggested that the user manual should be more accessible when the app is being used, and should have clear links to the specific sections from every screen. Two specialist commentators noted that the email facility would be a useful way of supplementing a telephone referral or for discussion with specialist burns services.

One specialist commentator noted that there is no warning in the app about the importance of measuring a patient's weight accurately. The commentator also noted the importance of accurately estimating the burn size and that this was a benefit of Mersey Burns. Two specialist commentators noted that estimating TBSA is difficult and that variation can occur between healthcare professionals, with 1 specialist commentator suggesting that this can lead to inaccuracies in fluid calculations. One specialist commentator emphasised that Mersey Burns eliminates the need to do consecutive calculations that can be subject to human error, particularly when people are under pressure.

One specialist commentator noted that other factors such as intravenous cannula siting, catheterisation, recording of fluid and monitoring of cardiovascular state (measuring heart rate, urine output and blood pressure) must also be considered during fluid resuscitation. The commentator added that Mersey Burns does not alert the user to specific situations where caution is needed, for example, in elderly patients or patients with heart failure; or that discussion should take place with an experienced burns clinician if there is concern about a particular patient. The commentator also said that there is no option to account for fluids that have already been administered, and expressed concern about advice given in the app for burn injuries which may have happened 6 or more hours earlier. They stated that in such cases, Mersey Burns would advise giving large volumes of fluid in a short space of time, which could be potentially dangerous and would have to be balanced against the risk of developing abdominal compartment syndrome. The commentator suggested that it would be useful to have a warning in the app to highlight this, but that determining the threshold for this would need specialist input.

Equality considerations

NICE is committed to promoting equality, eliminating unlawful discrimination and fostering good relations between people with particular protected characteristics and others. In producing guidance, NICE aims to comply fully with all legal obligations to:

  • promote race and disability equality and equality of opportunity between men and women

  • eliminate unlawful discrimination on grounds of race, disability, age, sex, gender reassignment, marriage and civil partnership, pregnancy and maternity (including women post‑delivery), sexual orientation, and religion or belief (these are protected characteristics under the Equality Act 2010).

The severity of a burn may be affected by a person's age and the presence of other injuries or disease. Age and disability are protected characteristics under the Equality Act 2010.