Burns Flashcards
Describe the pathophysiology of major burns.
Can be divided into 3 pathological processes which can exacerbate each other:
- SIRS - activation of inflammation, vascular permeability and oedema.
- Inhalation lung injury - ARDS, airway obstruction.
- Hypermetabolic state - increased protein catabolism, increased gluconeogenesis, decreased proteins synthesis - leading to immune suppression, poor wound healing, infection risk.
How is burn severity estimated?
- Burn area (%TBSA):
- Lund-Browder charts
- Rule of nines
- patient palms (=1%) area. - Burn depth:
- Superficial - involves epidermis only, red and painful but no blistering.
- Partial-thinkness - painful and with blistering
- Full-thickness - all skin layers involved, painless, white
What are the management priorities in a patient presenting with major burns?
Resusitation using ATLS A-E approach:
Airway and ventilatory management with c-spine control:
- facial burns
- carbonaceous sputum
- singed nasal or facial hair
- oropharyngeal oedema
- stridor
- hoarseness
- low GCS
- neck burns
- ventilatory failure
- uncut ETT >7.5
- Lung protective ventilation
Circulation:
- establish wide bore IV access and commence fluid resuscitation as per Parklands formula (4ml/kg x %TSBA burns)/24 hrs - half given in the first 8 hrs.
Disability:
- Analgesia
Exposure:
- avoid hypothermia
- consider early surgical management for circumferential burns
- establish history of circumstances (enclosed, blast, chemicals, CPR etc).
What is inhalation injury and how is it managed?
Inhalation injury is the exposure to smoke for a prolonged period of time.
It is particularly associated with entrapment in an enclosed space and carries a significant increased mortality.
It has two main mechanisms of injury:
- Thermal injury - causing swelling and oedema to upper airway
- Chemical irritation
- acid or alkaline compounds released from burning material cause epithelial and capillary damage.
- causes severe tracheobronchitis, loss of mucociliary clearance and loss of surfactant.
- ARDS picture
Managed with:
- early bronchoscopy and BAL
- LPV +/- ECMO
What is burn shock?
A combination of hypovolaemia, distributive and cariogenic shock seen in a major burn, which is refractory to fluid resuscitation.
When should infection be treated in major burns patients?
Difficult to differentiate infection from SIRS and hypermetabolism.
American Burn Association: Documented infection and 3 from: - temp <36.5 or >39 - Need for minute volume >12L/min - HR >110 - Glucose >12.8 in non-diabetic - Intolerance of enteral feed for >24hrs - Platelet count <100
How does carbon monoxide poisoning present and what is the management?
Carbon monoxide has much higher affinity for haemoglobin than oxygen. This cause a tissue and cellular hypoxia by:
- shifting oxygen-dissociation curve to the left
- inhibiting mitochondrial cytochrome oxidase.
Presents with:
- Neurological features: Headaches, confusion, coma, seizures
- GI features: Nausea and vomiting
- cherry-red skin
Investigate by checking HbCO on co-oximetry:
- normal is <1% (smokers <5%)
Management is:
- 100% O2
- IPPV if HbCO >25%
- hyperbaric (3atm) oxygen therapy (if HbCO >40%, pregnant and HbCO >15% or coma)
How does cyanide poisoning present and what is the management?
Cyanide inhibits mitochondrial cytochrome oxidase causing cellular hypoxia and forcing anaerobic metabolism.
Presents with:
- Neurology: Dizziness, psychomotor agitation, loss of consciousness
- Respiratory: breathlessness
Investigations:
- very high ScvO2
- lactic acidosis
- cyanide levels (take >3hrs to come back)
Management:
- Supportive therapy inc 100% O2 or IPPV
- chelators: tydroxycobalamin, dicobalte edetate, sodium thiosulphate
What are the criteria for referral to a burns centre?
- Age <5 or >60
- Comorbidities affecting healing
- Site: face, hands, feet, perineum, neck, circumferential or full thickness burns
- Inhalation injury
- Mechanism: chemical, ionising radiation, high pressure steam, electrical injury, cold injury, hydrofluoric acid injury, NAI
What are the potential complications of a major burns patient?
- Respiratory - airway occlusion, ARDS
- CVS - arrhythmias, cardiac failure, vasoplegia
- Neurological - pain, compartment syndrome
- Renal - AKI, abdominal compartment syndrome, rhabdo
- GI - hypermetabolism, stress ulcers
- Haematological - VTE
- Infective - soft tissue infection, pneumonia, line-related, MDR
- MSK - contracture, amputation
- Iatrogenic - over-resuscitation oedema, VAP.
- Psychological impact.
