Burny burns Flashcards
Discuss pathophysiology of burnsnv
Exposure of the skin to energy in the form of heat. Skin of children and the elderly is relatively thin and they are more prone to deeper burns.
A large number of cells are irreversibly damaged by exposure to the most extreme injury condition where as those surrounding them are exposed to lesser insults putting them at risk of death due to stasis or reduction in blood flow.
The are classically three zones of burns described by Jackson, a central zone of irreversible necrosis, the intermediate and potentionally reversible zone of stasis and the outermost reversible zone of inflammation
Burn injuries are also characterized by a cataoblic state with an up to threefold increase in metabolic rate often necessitating enteral or parenteral nutrition.
Discuss smoker inhalation associated lung injury
occurs in approximatley 2% of burn victims with <20%TBSA burns and in 14% of burns with 80 -99% TSBA and contributes greatly to mortalityu.
Although more common with large burns inhlation injury can exist with or without cutaneous burns. Its present is associated with a 3x higher mortality.
Anatomically injuries from smoke inhalation may invovle direct heat to the upper airway, chemical injury to the lower airway and systemic toxicity such as with inhaltion of CO or cyanide. Unless exposed to steam the heat dissapation properties of the upper airway generally restrict thermal burns to the upper airway.
Chemical burns of the lower ariway from ( sulfur dioxide, cyanide, nitrogen dioxide, ammonia and chlorine) damage epithelial and endothelial cells of the ariway and their blood vessels leading to the formation of pseudomembranes or airwya casts consisting of cellular debris and mucin that obstruc the airways and cause significant V/Q mismatch. Mucocilary transport is also impaired leading to bacterial impaired bacterial clearance. Loss of surfactant can also lead to airway collapse.
Discuss clinical estimation of burn depth
Poor accuracy is only 50-75% – burns also extremely dynamic and need to be monitored for progression.
Superficial burns - epidermis only are characterized by red skin without blisters, blanch with pressure, sensitivity ++, soft – heal within a week and do not need grafting or excision
Superficial partial thickness- epidermis and upper dermis (most adnexal structures are intact) are characterized by red skin with blisters blanch with pressure, sensitivity ++, soft – heal wihtihn 1-2 weeks and do not need grafting or excision
Deep partial thickness (involve epidermis and significant part of dermis only deep adenexal structures intact)– red or white without blisters, may or may not blanch with pressure, reduced sensation , slightly tense heal 2-3 weeks
Full thickness leather like and charred - dot no blanch with pressure and has no sensitivity - stiff and leath like > unlilkey to heal spontaneously will need grafting
What is the Baux score
Sum of the pateints age and percentage of TBSA and predicts mortality
Baux score of 160 predicts mortality of 100%, where as a baux score of 109.6 predicts 50% mortality
Discuss techniques to estimate TBSA
Rule of 9s for large burns in adults – 9% for head and neck, 9% for each upper limb, 9% for each of the anterior and posterior surfaces of the lower limb, 9% for half the anterior or posterior surface of the chest. 1% for hands and genitals
Lund Brower charts should be used for children which adjust for age related difference in anatomy
For small burns the patients palm can be estimated to be 1%
Discuss severity classification of burns
Children/elderly
- mild <5% TBSA
- moderate 5-10% TBSA
- Severe >10% TBSA
Adults
- mild >10%
- moderate 10-20% TBSA
- severe >20%
All
- mild <2% full thickness
- mdoerate 2-5% full thickness, high voltage, inhalation injyury, circumferential, co morbid disease
- Severe >5% full thickness, significant burn to face, eyes ,ears, genitalia or joints
Mild can be dsicharged
moderate admission
severe should be transferred to a specialised burns unit
Discuss investigations in burns
Routine IX have little role in minor burns
In those who inhalation injury is suscpected a CXR and CO level should be performed
In those who require admission baseline bloods should be taken
Discuss first aid
Remove source of injury, and any garments or jewlery from the affected area
Cool with running room temperature water 20 minutes
Fluid resus if large burns
Analgesia as needed
Discuss airway management in burns
Need to consider intubation early as injury to the upper airway may result in massive swelling of the tounge, epiglottic and aryepiglottic folds.
Clinical signs such as facial burns, hoarseness, drooling, carbonaceous sputum, stridoer and singed nasal hairs should raise concerns. History of enclosed or confined spaces increase the risk
Early intubation should be encouraged if significant concern however is not without complications, including development of ARDS, VAP
Best way to ascertain weather there is upper airway ionvolvement is with a video laryngoscope or fibreoptic camera – presence of signicant oedema or soot should prompt intubation – can consider small dose ketamin 10-20mg to fascilitate visuliastion, can also use glycopyrolate to manage secretion.
RSI should be avoided unless fibreoptic or video laryngoscope appear that it would be an easy intuabtion. Otherwise awake fibreoptic intubation should be first line
Discuss indication for intubation in burns
Upper airway obstruction inability to handle secretion hypoxemai despite 100% o2 patient obtundation muscle fatigue suggested by a high or low RR hypoventilation
Discuss breathing management in burns
Supplemental o2 to maintain sats >92%
CO levels
Always suspect cyanide poisoning for patient in an enclosed space especially with combustion of plastics and in the presence of lactic acidosis.
If ETT indicated should vent at lower tidal volumes 6-8mls/kg RR 8-12, 12-45 in kids, platue pressures <25cmh20, Peep 5-8cm h20. To achieve pressure targets premissive hypercapnia so long as under 60mmhg, ph >7.2 and HD Stable. may benifit from prone venting
Secretion management with bronchoscopic lavage and frequent suction. Inhaled anticoagulatns have been shown to improve survival and decrease mortality wihtout altering systemic markes of clotting and anticoagulation. – helpful as intra-airway coagulation and firbin deposition play and important rule in the pathophys of inhalation injury
Discuss circulation management of burns
Burns injuries results in significant fluids loss and shift due to loss of the epidermal barrier and an increase in capillary permeability - leakage of plasma proteins into the interstitial space increase the oncotic pressure furhter leading to fluid shift.
Fluid resus required if >15-20% in adults and >10% in children
There are number of formulas used to estimate fluid resus with parkland being the most commonly used (4ml/kg/TBSA with half in the first 8 hours and the rest in the following 16 - uses hartmans). These should only be used as a starting place with more dynamic measurments guiding resus such as ( vital signs, Mental status and Urine output)
Several studies have showed the overestimation of fluid need leading to fluid creep which leads to devestating consequences such as worsening of local tissue oedeam with burn conversion, extremity compartment syndrome, abdomainl compartment and APO.
Due to the risk of fluids creep the modified Brooks formula which calls for a 2ml/kg/TBSA (3ml/kg/tbsa in children) to be used as the starting point
Colloids have not shown to be benificial in the first 12 hours of resus and should be reserved for 12-24 hour period in particularly difficult patient to resus
Discuss the utility of escharotomy and technique
With deep burns a leather necrotic eschar which is stiff and ineleastic covers the wound – if circumferential can compress underlying neurovascular structure and lead to compartment syndrome
Similarly if on the thorax can interfere with ventialtion.
When this occurs urgent releaes of pressure via an incision in the eschar is required. As the tissue is necrotic escharotomy is generally associated with little pain or blood loss.
Diathermy ideal - down to viable tissues and until wound opens up. Incise at least 1 cm into normal skin- cut along lines
Discuss local wound therapies in burns
Local therapies focus on protected the burn wound, preventing further injury or infection and maintaining a most wound environement.
Dress with mepilex Ag avoid flemazine
Discuss criterai for referral to burn cetnre (8)
- Partial thickness burns greater than10% TBSA or 5% for children
- Burns on specialised areas
- Full thickness greater than 5% anyone
- Electrical or chemical bruns
- inhalation injury
- Burns with comorbidies that could impair or complicate management
- Concomitant trauma
- Hospital wihtout gualified personnel or equipement – especially children
