Authors: Jonathan Matthews, Rajan Atwal / Editors: Paramjeet Deol, Shashank Patil, Jorge Leon-Villapalos / Codes: C3AP1e / Published: 30/10/2017 / Review Date: 30/10/2020
- Burns are a major public health problem globally. In addition to physical damage, they can leave a long lasting psychological and social impact.1,2
- In the UK 130,000 people each year visit the Emergency Department with burns injuries.2
- Approximately 8% (10,000) of these patients are admitted.2
- Although the majority of burns injuries in the UK are not life threatening, there are still around 200 deaths a year.3
A burn is defined as a traumatic injury to the skin or other organic tissue primarily caused by thermal or other acute exposures.
There a various types of burns which include:
- Thermal: This is the most common type of burn and includes flame burns, scalds (from hot liquids) and contact burns (from hot objects e.g. an iron or radiator).
- Chemical: Alkalis and acids found in household chemical products can produce very deep burns through coagulative and liquefactive necrosis.4 They will continue to burn the skin until completely removed. It is therefore essential that the skin is thoroughly irrigated.4 Alkalis penetrate deeper than acids and those presenting with alkali burns (commonly due to cement) will require immediate attention.
- Electrical: As an electrical current travels through the body it creates an entry and exit point, damaging tissue along its path as it is converted from electrical to thermal energy. Electrical burns from domestic low voltage exposures tend to be less severe than high voltage electrical burns which can cause extensive tissue damage and limb loss. It is still very important that domestic electrical burns are taken seriously and an ECG is performed as the alternating nature of domestic current can cause arrhythmias.
- Cold exposure (frostbite): These burns are caused by ice crystals which can form both intra and extracellularly.5 The subsequent fluid and electrical fluxes cause cell membrane lysis and cell death and a damaging inflammatory process is set up.5
- Radiation: Radio frequency energy or ionizing radiation causes tissue damage and the most common type of radiation burn is sun burn.5 Other patients at risk of getting radiation burns are those undergoing radiation therapy for cancer treatment.
- Overall, flame injuries are the most common cause of burns, followed by scalds. Electrical and chemical injuries are much less common.1
- However, the types of burn sustained are different in different groups of people; in children the most common type of burn is a scald, whereas in adults flame burns are the most common.1,6
- Figure 1 shows the causes of burns by type and figure 2 shows the incidence of burns by age.
Burn injuries result in both local and systemic responses
Pathophysiology Local response
Jacksons Burn wound model is made up of 3 zones (figure 3). This helps us to understand the pathophysiology of a burn injury.
- Zone of Coagulation: occurs at the point of maximum damage i.e. the nearest point to the heat source. There is irreversible tissue necrosis here due to coagulation of proteins.
- Zone of Stasis: surrounding the zone of coagulation, this area is characterised by decreased tissue perfusion. It is damaged but potentially viable. If the burn is managed incorrectly it can evolve into an area of full necrosis, hence the need for good burns management.
- Zone of Hyperaemia: the outer most zone as its name suggests is where there is increased tissue perfusion. This is a reversible zone.
- The release of cytokines and other inflammatory mediators at the site of injury has a systemic effect once the burn reaches 20- 30% of total body surface area.
- Cardiovascular changesCapillary permeability is increased, leading to loss of intravascular proteins and fluids into the interstitial compartment. Peripheral and splanchnic vasoconstriction occurs. Myocardial contractility is decreased. These changes, coupled with fluid loss from the burn wound, result in systemic hypotension and end organ hypoperfusion.
- Respiratory changesInflammatory mediators cause bronchoconstriction, and in severe burns, adult respiratory distress syndrome can occur.
- Metabolic changesThe basal metabolic rate increases up to three times its original rate. This, coupled with splanchnic hypoperfusion, necessitates early and aggressive enteral feeding to decrease catabolism and maintain gut integrity.
- Immunological changesNon-specific down regulation of the immune response occurs, affecting both cell mediated and humoral pathways.
Assessment, investigation and management occur simultaneously at each stage of the approach. 9,10,11
The airway is at risk by three major mechanisms:
- Generalized oedema as a systemic response from an increasing burn size and depth can cause swelling of the airway and compromise airflow9, 10.
- Localized oedema as a result or direct thermal damage to the airway can obstruct airflow9
- Inhalation injury as a result of heat, smoke or toxic chemicals can cause damage to the airway.9
Factors that increase the suspicion of airway obstruction or inhalation injury include: 10
|Raised carbon monoxide (CO)|
|Deep facial burns|
|A history of burns in an enclosed space|
|Respiratory distress/ stridor|
adapted from Airway swelling after laryngeal burn induced by swallowing hot food: Korean J Otorhinolaryngol-Head Neck Surg. 2015 Sep;58(9):634-636.
- Sit patient upright9
- Any suspected airway injury necessitates senior anaesthetic review to identify and predict deterioration9.
- If indicated, early intubation with an uncut tube9 prevents the tube moving in the event of further swelling10
Failure to recognise or predict the deteriorating airway.
Gas exchange can be compromised for a number of reasons:
- Direct lower airway and gas exchange surface damage from inhalation injury
- Carbon monoxide (CO) can quickly build up impairing oxygen carrying capacity 9,10.
Burnt tissues with significant loss of the elasticity in superficial fibres are known as an eschar. This creates a constricting effect and inhibits expansion (figure 11). When circumferential around the chest/torso/neck this can lead to impaired chest expansion and subsequent ventilation9,10,11
- Exposure of the chest to perform comprehensive assessment of ventilation and any injury to the chest
- Prompt assessment of oxygenation with saturation probe9,10,11
- Baseline ABG/VBG (if there is a reliable saturation trace) to assess oxygenation, ventilation and CO9,10,11
- Supplementary oxygen to target appropriate saturations of 94-98%9,10
- Immediate discussion with burns center if any restriction of movement of chest9,10
- Suspected inhalation injury may warrant intubation9,10
- Failure to recognise rising CO level.
- Failure to recognise poor ventilation and the need for a escharotomy
- Escharotomy can be a lifesaving procedure that relieves restriction of movement and allows chest expansion. This is an emergency situation this will be discussed later
- Cyanide poisoning is common in patients that have been exposed to inhalation of burnt household items. In profound hypoxia consider early administration of cyanokit .10
- Burns >15% BSA in Adults and >10% in children can cause profound circulatory shock that can occur from both large fluid losses through tissue damage and from a systemic inflammatory response10.
- Haemodynamic instability is rarely due to the burn alone and should prompt us to look for other causes
- Circumferential limb burns can compromise blood supply distally
- A thorough assessment of the extent of a burn is paramount: Burns <15% in adults and <10% in children do not require immediate fluid resusitation9
- Capillary refill time (CRT), blood pressure and mucous membrane assessment are important indicators of hydration status but may be hard to measure due to location of the burn10.
- Though rarely immediately helpful in the Emergency Department setting, early catheterization is important as urine output is a reliable sign that can demonstrate poor perfusion and serve as a guide to ongoing resuscitation9, 10, 13.
- In a significant burn there can be an increased metabolic demand on the patient which can cause organ dysfunction. Therefore, important baseline tests to consider are full blood count, urea and electrolytes, coagulation profile, liver function tests, amylase, C-reactive protein and capillary blood glucose. This also helps to identify any other issues impacting on the patient. If the patient is likely to go to theatre a serum group and save is warranted.
- In circumferential limb burns, blood supply to the extremities should be checked regularly. If unable to do this clinically, a Doppler ultrasound can be used9,10, 11, 13.
- Immediate intravenous (IV) access and, if required, fluid resuscitation are critical steps in initial care9, 10, 11, 13.
- Blood tests
- Evaluate any areas of circumferential burns in limbs and regularly reassess perfusion
- Any deterioration in the circulation to a limb could indicate ischemia or a compartment syndrome. This warrants immediate discussion with a burns center and may require urgent intervention such as escharotomy or fasciotomy9,10.
- IV access is paramount. If it is not possible to get IV or IO access thought unburnt skin, access is mandated through burnt tissue.
- Creatine kinase is a useful test to perform to assess muscle breakdown9.
Like any trauma patient disability and exposure cannot be ignored.
Appropriate exposure is fundamental for the assessment of patients with burns. A thorough assessment of size and depth of burns is impossible without full exposure and a good secondary survey9,10,11,13. However patients with burns are physiologically vulnerable to getting cold so it is critical to keep them warm and minimize fluid loss9,10.
- Consideration should be made to maintain body temperature by both active and passive warming.9, 10 This is balanced with the need to adequately expose the burn in order to asses, photograph and clean.10.
- Clean the burn with normal saline and cover with strips of cling film. Do not use cling film on the face.
- Consider imaging e.g. X-ray, CT etc. based on findings of the secondary survey
- Missing other injuries not related to burns g. traumatic head injury or long bone fractures in a blast injury
- Failure to give adequate analgesia
- Have all members of the team present during exposure of an area to simultaneously evaluate and photograph the areas to avoid repeated unnecessary exposure and heat loss
The burning process is exceptionally painful and analgesia should be given early. Both pharmacological and non-pharmacological methods should be used to control pain.
- Non-pharmacological methods include cooling the burn under cold running water and covering with cling film. Cling film also helps to reduce heat loss and the risk of infection.
- Pharmacological treatment includes simple analgesia such as paracetamol and NSAIDs, as well as stronger analgesia like opioids and ketamine.
In order to guide management goals it is important to assess both extent and depth of the burn.
In order to assess the extent of a burn it is vital to expose all areas to accurately estimate correct % BSA affected. This can help:
- Predict the physiological response the body will have to the burn
- Calculate the fluid requirement during the initial resuscitation period
- Burns are graded into Severe and Non Severe according to the physiological effect exerted on the body11.
- Severe burns are defined as a >10% BSA in a child and >15% BSA in an Adult10
Common tools of estimating % burn of BSA are:
- Lund Browder charts published charts at different ages estimating how much % of BSA each body sector equates to9, 12 figure 12a
- Using the patients palm (not examiners) with the fingers and thumb adducted, as an estimate of 1% of BSA9,10
- Using an estimation of each body sector as either 9% or a multiple of 9% See figure 12b
- Mersey burns app (figure 13) Interactive app enabling the user to highlight areas of burn tissue on a model to accurately estimate the % BSA affected14
adapted from: https://rphcm.allette.com.au/publication/cpm/Burns.htmlRule of 9s9,10, 13
Ref: Modified from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC449823/
Mersey Burns App
- Accurate estimation of % of BSA
- Intuitive and usable15
- Calculates appropriate fluid requirement directly from the app
- Recommends referral criteria
- Epidermal burns are not included when calculating the size of the burn
To make an accurate assessment of the depth of a burn, skin needs to be cleaned, blisters removed (except for small non-tense blisters [<6mm]) and capillary refill time tested.
Guidance on which blisters to de-roof and how to do it by the London and South East of England Burn Network (LSEBN) can be found here.
The depth of the burn can be classified into 1 of 4 types. The British Burn Association (BBA) accepted definition has replaced the older 1st, 2nd and 3rd degree classification.
[Table adapted from reference 7 & 8]
- In clinical practice burn wounds are not homogenous but often are of mixed depths, as shown in Figure 15
Property of Burns unit, Chelsea & Westminster Hospital
The white areas are Full Thickness burns (FT), with the deeper red and paler pink areas showing Deep Partial Thickness (DPT) and Superficial Partial thickness (SPT) burns respectively.
Patients with severe burns (> 10% in a child and 15% BSA in an adult) have a significant fluid requirement. There are a number of methods to calculate appropriate fluid replacement. One of the most used is the Parkland equation9, 10:
This estimates the recommended total fluid administration over 24 hours. Half of this volume should be administered over the first 8 hours from the time of the burn. This fluid, ideally a warmed physiological crystalloid e.g. Hartmanns should be administered in addition to the maintenance fluids. Careful monitoring is paramount as adjustments may be needed to achieve an appropriate urine output of 0.5ml/kg/hr9.
Remove loose clothing, but do not remove anything that is adherent or melted.
Irrigate and cool thermal burns with cold running tap water for 20 minutes. This can be beneficial up to 3 hours post burn injury.
Irrigate chemicals from skin/eyes immediately with warm running water for at least 15 minutes
Do not use ice/iced water/ice packs
Clean the wound with normal saline and cover the thermal burn with loose longitudinal strips of cling film
Do not use cling film on the face
Cover the chemical burn with a wet compress
Tetanus status needs to be determined and adequate cover given9
- In certain circumstances it is recommended patients are discussed with and referred to the local burns centre. Figure 16 highlights some of these circumstances.
- An important one not to miss is non-accidental injury (NAI). It should always be considered in paediatric presentations and particular attention given to whether the history is consistent with the pattern, location, and type of burn seen. Elderly patients are also at risk of NAI.
- Toxic shock syndrome (TSS) is another key situation to discuss with the local burns service. Any patient, with any size burn, with any of the symptoms below are at risk:
- Temperature > 380C
- Diarrhoea & vomiting
- General malaise
- Not eating or drinking
- Reduced urine output
Deep partial thickness & full thickness
Burns with trauma
Suspected Toxic Shock Syndrome
Progressive non burn skin loss (TENS, Necrotising Fasciitis)
Significant co-morbidities (e.g. diabetes) or immunocompromised patients
Cold burns with full thickness skin loss
Any other cases that cause concerns
>1% BSA in children
>3% BSA in adults
Any neonatal burn
Consider in older people (60+)
Not healed within 2 weeks
Face, hands, genitals, feet, joints, scalp, ears
Adapted from LSEBN: Burns referral criteria
- When referring to a burns centre the national burns image transfer website TRIPS (www.trips.nhs.uk)provides a safe and secure method for sending images.
With Full Thickness & Deep Partial Thickness Burns, the dermis can become very stiff. If this occurs circumferentially over the chest it can restrict chest wall movement and lead to mechanical respiratory failure. Equally if there are circumferential burns to the limbs this can cause limb ischaemia. In these cases an emergency escharotomy needs to be undertaken to release the rigid skin to allow: adequate ventilation (if the chest is involved) or circulation (in the limb).19
The process of the dermis stiffening takes time and the majority of patients requiring escharotomies often go to theatre for this at a later stage. However, knowledge of the procedure can be life and limb saving in the emergency setting.
- The limb should be kept in the anatomical position.
- The area is cleaned and incised along the anatomical lines (see figure 11) with a scalpel down to the fat
- The incision should not go down to the muscle or fascia
- For the limbs the incisions need to release both medial and lateral aspects
- For the chest the incision needs to release the whole breast plate
- Peck MD: Epidemiology of burn injuries globally, uptodate.com, Topic 822 Version 13.0, 2016
- NHS commissioning board: Specialised Burn Care (All Ages), Service specification D06/S/a, 2013
- Benson A, Dickson WA, Boyce DE: Burns, BMJ 649-652, 2006
- Hettiaratchy S, Dziewulski P: Pathophysiology and types of burns, BMJ 1427-1429, 2004
- Rice PL, Orgill DP: classification of burns, uptodate.com, Topic 819 Version 12.0, 2016
- Hettiaratchy S, Dziewulski P: ABC of burns introduction, BMJ 328:1366, 2004
- British Burn Association: European practice guidelines for Burn Care Based by the Copenhagen EBA meeting, September 2002
- The depth of the burn can be classified into 1 of 4 types. The British Burn Association (BBA) accepted definition has replaced the older 1st, 2nd and 3rd degree classification.
- Clinical Knowledge Summaries: Burns and scalds, 2015
- American College of Surgeons ATLS Course Manual 9th Ed Chapter Thermal Injuries, 2012
- London and South East Burns Network Initial Management of Severe Burns, 2015
- Stander et al The emergency management and treatment of Severe burns Emergency medicine International 2011; 2011: 161375.
- Remote PHC Manuals Burns, 2014
- Hettiarachy et al Initial management of burns II assessment and resuscitation BMJ 2004 Jul 10; 329(7457): 101103.
- Mersey Burns St Helens and Knowsley teaching hospital NHS trust, 2014
- Barnes et al The Mersey Burns App: evolving a model of validation EMJ Emerg Med J doi:10.1136/emermed-2013-203416
- Hoon et al Airway Obstruction after Laryngeal Burn Induced by Swallowing Hot Food Korean J Otorhinolaryngol-Head Neck Surg. 2015 Sep;58(9):634-636. Korean.
- Gillies et al Use of cut endotracheal tubes should be avoided in the initial resuscitation of the burned patient Emerg Med J 2003;20:109 doi:10.1136/emj.20.1.109
- London and South East Burns Network Burns Referral Guidelines: criteria for referral 2015
- New Zealand National Burn Service, Escharotomy Guidelines