Burns Lecture Notes PDF

Burns Wadie Rassam PGY4 Doctor Learning objectives Understand the initial assessment (total body surface area and depth) and management (first aid, primary and secondary assessment, related injuries) of burns Describe the mechanisms of disordered fluid movement and how this may present in severe bur...

Burns Wadie Rassam PGY4 Doctor Learning objectives Understand the initial assessment (total body surface area and depth) and management (first aid, primary and secondary assessment, related injuries) of burns Describe the mechanisms of disordered fluid movement and how this may present in severe burns (also covered by Dr Miller) Outline the important aspects of fluid replacement therapy following severe burns (also covered by Dr Miller) Outline the important aspects of ongoing management of severe burns and their complications (escharotomy, nutrition, infection, debridement, skin grafts, pain management) Explain the processes involved in the immunological response to burns (e.g., inflammation) and wound healing (also covered by Dr Gopalan) Overview Use a system! What are the benefits of this? Underlying sciences Definition Types/Classification Aetiology Pathophysiology Natural History Symptoms/signs Diagnostics/Investigations Differentials Treatment Complications Prognosis Overview Underlying sciences Definition Types/Classification Aetiology Pathophysiology Natural History Symptoms/signs Diagnostics/Investigations Differentials Treatment Complications Prognosis Basic Sciences Nomenclature: The skin comprises 3 components: - cutis (epidermis + dermis) hypodermis = subcutaneous tissue = subcutis - appendages - hair, nails, glands Cutis: Epidermis Comprises keratinocytes Sublayers 5 sublayers stratum corneum etc. Cutis: Papillary dermis Cutis: Hypodermis/subcu Reticular dermis taneous tissue connective tissue collagen fibres, fibres, mechanoreceptors mechanoreceptors , white blood cells , skin appendages superficial dermis = papillary dermis deep dermis = reticular dermis Function barrier, regeneration sensory receptors, sensory receptors, nutrients to structural integrity, epidermis, temp appendage reg, functions Degree of burn involvement 1st degree 2nd degree, 2nd degree, deep partial thickness thickness subcutaneous fat, mechanoreceptors, superficial veins, free nerve endings (note can also be present in reticular dermis) NA 3rd degree Overview Underlying sciences Definition Types/Classification Aetiology Pathophysiology Natural History Symptoms/signs Diagnostics/Investigations Differentials Treatment Complications Prognosis Definition Tissue injury by a thermal or non-thermal cause Overview Underlying sciences Definition Types/Classification Aetiology Pathophysiology Natural History Symptoms/signs Diagnostics/Investigations Differentials Treatment Complications Prognosis Types/Classification Classification - according to level of involvement 1st degree/superficial - to level of epidermis 2nd degree superficial partial - to papillary dermis 2nd degree deep partial - to reticular dermis 3rd degree/full thickness - to subcutaneous tissue 4th degree/deeper injury - to deeper structures e.g. muscles, bone, fascia Underlying sciences Overview Definition Types/Classification Aetiology Causes Associations Risk factors Epidemiology Pathology specific factors (triggers, inheritance, transmission, pathogen) Pathophysiology Natural History Symptoms/signs Diagnostics/Investigations Differentials Treatment Complications Prognosis Aetiology Cause - type of offending agent, type of intention/motive offending agent thermal fire - both to skin and inhalation from smoke contact e.g. hot surface scalding e.g. boiling water, steam non-thermal radiation x-rays e.g. radiotherapy UV radiation e.g. sunlight infrared waves e.g. microwaves nuclear radiation e.g. nuclear accidents electrical indoors e.g. power outlets outdoors e.g. power lines environmental e.g. lightning strikes friction likely with hard surfaces and higher speeds e.g. fall of motorbike onto bitumen chemical many types - acids, alkalis, bleach, metals etc. intention/motive unintentional/accidental - most common intentional - suspect in vulnerable populations Aetiology Associations - may occur with other injuries thermal - inhalation injury radiation – radiation poisoning electrical - muscular and cardiac pathology Chemical – mucosal membrane injury frictional - traumatic injuries e.g. bony fractures, traumatic brain injury Risk factors - factors which exacerbate burns severity Young and old age Poor circulation – smoking, diabetes Epidemiology More common in kids and young people – less supervision, higher risk behaviour More common in males - less supervision, higher impulsivity Overview Underlying sciences Definition Types/Classification Aetiology Pathophysiology the underlying cause what are the consequences - local, systemic what are the compensation mechanisms Natural History Symptoms/signs Diagnostics/Investigations Differentials Treatment Complications Prognosis Pathophysiology 1) The underlying cause: depending on the type of offending agent, the mechanism of damage will vary. broadly: thermal - heat transfer from source to skin; inhalation of smoke non-thermal radiation - waves cause DNA damage and subsequent apoptosis electrical - electrical current flows through an entry and exit point. note that with lower voltages (1000V), the entry/exit points are further, causing localised and systemic effects chemical - penetration of chemical agent. note that alkali agents cause deeper penetration than acidic agents and are more likely to cause deeper burns/systemic effects friction - frictional injury causes direct trauma and heat transfer. this is more severe with hard surfaces and higher speeds e.g. motorbike accident, no protective equipment Pathophysiology - local 2), 3) What are the consequences, what are the compensation mechanisms Locally – for all burns bacterial colonisation —> high infection risk inflammatory response —> increased vascular permeability —> protein extravasation —> increased interstitial oncotic pressure —> evaporative fluid loss especially for thermal burns, local changes according to the ‘Jackson model’ zone of coagulation coagulative necrosis (irreversible) zone of stasis - ischaemic but viable (salvageable) zone of hyperaemia inflammation with increased perfusion (viable) treatment goal = salvage zone of stasis Pathophysiology - local 2), 3) What are the consequences, what are the compensation mechanisms Locally - for 3rd degree burns formation of eschars (dried, necrotic skin tissue) —> loss of skin elasticity —> causes constrictive effect —> ischaemia for circumferential eschars, the pressure can exceed mean arterial pressure —> at risk of compartment syndrome (occurs in limbs and abdomen) Pathophysiology - systemic 2), 3) What are the consequences, what are the compensation mechanisms Systemically - thermal burns - occurs with higher degree burns and high TBSA massive inflammatory response —> SIRS can lead to massive fluid loss - increased vascular permeability —> protein extravasation —> increased interstitial oncotic pressure —> evaporative fluid loss —> can lead to hypovolaemic shock Massive inflammatory response can cause immune dysregulation  immunocompromised state bacterial colonisation combined with deeper burns can lead to sepsis —> distributive shock Postburn hypermetabolism – huge sympathetic response to provide blood to healing wound and maintain adequate circulation  significant weight loss, muscle wasting  patients require strict feeding regimens haemolysis risk of disseminated intravascular coagulation Systemically – other points specific to non-thermal burns radiation - risk of radiation poisoning e.g. cancer electrical - risk of cardiac arrhythmia chemical - risk of mucosal membrane erosion e.g. vision loss, gastrointestinal structuring and perforation frictional - risk of other injuries from high impact trauma e.g. bony fractures, TBI NB: shocked state will cause inadequate end organ perfusion e.g. acute kidney injury, Curling ulcer etc. Overview Underlying sciences Definition Types/Classification Aetiology Pathophysiology Natural History (skip) Symptoms/signs Diagnostics/Investigations Differentials Treatment Complications Prognosis Overview Underlying sciences Definition Types/Classification Aetiology Pathophysiology Natural History Symptoms/signs primary assessment history/symptoms - system involved, other systems examination/signs - system involved, other systems Diagnostics/Investigations Differentials Treatment Complications Prognosis Clinical features Primary assessment - ABCDE Airway oxygen desaturation, tachypnoea facial burns, singed facial hair stridor vocal impairment e.g. dysphonia Breathing oxygen desaturation, tachypnoea respiratory distress e.g. increased work of breathing chest auscultation Circulation hypotension, tachycardia pallor, cyanosis heart auscultation peripheral pulses and warmth Disability Temperature, BSL, GCS Exposure expose patient’s skin and examine - see next slide Questions Primary assessment - ABCDE On the previous slide, we discussed oxygen desaturation in relation to inhalation injury. What if a patient is speaking full sentences and breathing comfortably, is saturating at 99% on their right hand but saturating at 87% when the probe is put on their left hand? Is inhalation injury likely? For patients with severe inhalation injury, intubation (placing an endotracheal tube into the patient’s trachea to then facilitate mechanical ventilation) is often required - why is this vital to do as early as possible, before fluid replacement? Clinical features In your clinical assessment, especially of severe burns - always primary assessment first! Now you can move onto patient history and examination: This is centred around: Classifying the burn Quantifying the area of the burn Clinical features Symptoms, signs - classify the burn, quantify the area 1st degree burn 2nd degree, partial thickness 2nd degree, deep thickness 3rd degree, 4th degree initially painful then subsides no CRT Neurological painful painful either painful or non-painful (why?) Vascular rapid CRT moderate CRT sluggish CRT Dermatological appearance erythema, swelling, dry skin. ’looks like sunburn’ erythema, swelling, moist skin, blistering necrotic black/white/gray leathery or inelastic appearance, dry erythema and/or white patches, swelling, moist skin, blistering, for 4th - also visualise deep structures Clinical features Symptoms, signs - classify the burn, quantify the area Clinical features Symptoms, signs - classify the burn, quantify the area Clinical features Symptoms, signs - classify the burn, quantify the area Clinical features Symptoms, signs - classify the burn, quantify the area Clinical features Symptoms, signs - classify the burn, quantify the area - ‘TBSA’ (total body surface area) Notes: - ‘rule of nines’ - in adults, the body is divided into 11 x 9% regions (plus final 1% for groin) - in kids, their heads are proportionally bigger so rule of nines doesn’t apply instead the Lund & Browder chart is used - the palm + fingers of a patient’s hand equals approximately 1% TBSA - 1st degree burns are NOT COUNTED in the calculation Clinical features Symptoms, signs - classify the burn, quantify the area - ‘TBSA’ (total body surface area) Larger regions can be roughly subdivided e.g. total surface area of one leg is 18%, so upper leg and lower leg are about 9% each Example calculation A 32 year old male presents to ED following a cooking related accident in his home. This caused explosion of a gas bottle. The reviewing resident documents his burns as follows: entire anterior aspect of both upper limbs - erythematous, painful, blistering burn with adequate capillary refill entire anterior aspect of right thigh - grey leathery appearing burn, initially painful but now pain free, no capillary refill patchy areas over abdomen and chest equating to the area of 3 hands erythematous, painful, dry burn with brisk capillary refill Calculate the TBSA for this patient Example calculation A 32 year old male presents to ED following a cooking related accident in his home. This caused explosion of a gas bottle. The reviewing resident documents his burns as follows: entire anterior aspect of both upper limbs - erythematous, painful, blistering burn with adequate capillary refill entire anterior aspect of right thigh - grey leathery appearing burn, initially painful but now pain free, no capillary refill patchy areas over abdomen and chest equating to the area of 3 hands erythematous, painful, dry burn with brisk capillary refill Calculate the TBSA for this patient Overview Underlying sciences Definition Types/classification Aetiology Pathophysiology Natural History Symptoms/signs Diagnostics/Investigations Bedside tests Blood tests Orifices Imaging Procedural Differentials Treatment Complications Prognosis Diagnostics Note: this is a list of tests to consider. You would not routinely do all of these in every case. For example, in minor burns, no investigations are required. Bedside ECG Compartment pressures Bloods Full blood count – haemolysis UEC – electrolyte derangement, acute kidney injury LFT – hypoalbuminaemia VBG – acidosis, lactaemia Coagulation profile – DIC evidence Orifices Wound swabs Overview Underlying sciences Definition Types/classification Aetiology Pathophysiology Natural History Symptoms/signs Diagnostics/Investigations Differentials Treatment Complications Prognosis Differentials Whilst it will usually be obvious that burns are the cause of a patient’s symptoms, they are not always aware! For example, a patient with diabetes complains to you of ‘diabetic foot ulcers’ but was walking around barefoot a few days ago: Overview Underlying sciences Definition Types/classification Aetiology Pathophysiology Natural History Symptoms/signs Diagnostics/Investigations Differentials Treatment Break up into acute and subacute/chronic (ward, after discharge) Acute: resuscitation and first aid, medical, surgical, referral Subacute/chronic: Lifestyle, medical, surgical, counselling, referral, logistic, follow up Complications Prognosis Treatment Minor burns - OUTPATIENT care: Acute management first aid: remove foreign objects e.g. clothing run under cool water for at least 20 minutes irrigation to remove debris avoid ice - why? medical: analgaesia tetanus update wound care - moisturiser for 1st degree burns, antiseptic ointment e.g. flamazine and dressings e.g. paraffin coated, mepilex for 2nd degree burns surgical, urgent referrals - nil Subacute/chronic management lifestyle - avoid sun exposure medical - wound dressing changes referral/follow up - GP logistics - ensure if non-accidental injury then appropriate report made e.g. child abuse Treatment Moderate/major burns - INPATIENT care: Acute management ABCDE Airway - intubation for inhalation injury and high TBSA; may require circumferential escharotomy of the neck Breathing - oxygen supplementation; may require circumferential escharotomy of the chest Circulation - crystalloid fluid resuscitation e.g. CSL in accordance with the Parkland formula: exclude 1st degree burns from TBSA Parkland formula - 4mL x TBSA x body weight (kg) in the first 24 hours, give half the total in the first 8 hours and half the total in the remaining 16 hours insert a urinary catheter to monitor urine output when large volumes are required. aim for 0.5mL/kg/hour urine output Disability monitor temperature and consider warm fluids if hypothermia results Treatment Moderate/major burns - INPATIENT care: Acute management First aid as for minor burns - remove foreign objects, cool running water, irrigate burn wound Medical analgaesia tetanus update may require treatment for concurrent sepsis Surgical debridement of necrotic tissue —> facilitate graft/flap reconstruction if circumferential eschar —> monitor for compartment syndrome; low threshold for escharotomy +/fasciotomy Referral Involvement of general surgery and plastic surgery (most commonly involved teams) Treatment Moderate/major burns - INPATIENT care: Subacute management Medical strict fluid monitoring and ongoing replacement admission in a Burns Unit PPI prophylaxis - why? nutritional support - enteral preferred to parenteral Surgical post debridement of necrotic tissue, for large exposed areas, need a graft and/or flap to close wound, lower infection risk, lower fluid/electrolyte loss Graft vs flap: graft = skin transferred without a blood supply full thickness skin graft (FTSG) - epidermis and dermis taken from a donor site with redundant skin e.g. lateral thigh —> better postoperative cosmetic outcome but high risk of necrosis and less healing from donor site split thickness skin graft (STSG) - epidermis and upper dermis taken —> can be stretched to 3-6 times its original size and cover a large area, heals well and donor site heals better but scar formation very likely and more fragile flap = skin or muscle transferred with blood supply intact Treatment Moderate/major burns - INPATIENT care: Subacute/chronic management lifestyle - avoid sun exposure, avoid certain activities during wound healing e.g. swimming, optimise wound healing e.g. smoking cessation medical - wound dressing changes, postoperative cares referral/follow up - burns unit, GP logistics - ensure if non-accidental injury then appropriate report made e.g. child abuse Example calculation Calculate the volume of fluid to give to the following patient: 1st degree burn entire left upper limb 2nd degree burn entire chest and abdomen 2nd degree burn entire anterior aspect of right lower limb 80kg male patient Overview Underlying sciences Definition Types/classification Aetiology Pathophysiology Natural History Symptoms/signs Diagnostics/Investigations Differentials Treatment Complications Acute Chronic Prognosis Complications We have discussed many of these this lecture. To summarise: Acute, subacute: shock - hypovolaemic (third spacing of fluids), distributive (sepsis) respiratory failure compartment syndrome curling ulcers mucous membrane related complications e.g. visual loss, oesophageal perforation offending agent related complications e.g. arrhythmia in electrical burns, brain injury in trauma post-burn hypermetabolism Chronic: Marjolin ulcer - SCC that arises from non-healing wounds e.g. burns keloid formation scarring mental health complications e.g. depression Overview Underlying sciences Definition Types/classification Aetiology Pathophysiology Natural History Symptoms/signs Diagnostics/Investigations Differentials Treatment Complications Prognosis Prognosis Depends on degree of burn, TBSA, resultant complications and patient profile 1st degree - heals within 1 week; no scarring 2nd degree partial - heals within 1-3 weeks; no scarring 2nd degree deep - healing can take several months; long term scarring 3rd degree - non-healing; medical/surgical management is necessary Thank you! Please send questions and feedback to: [email protected] All the best 