What are the clinical manifestations of a lower airway lung injury associated with burns?

Last updated: August 2022

Burns are cutaneous lesions caused by exposure to heat, electricity, chemicals or radiation. They cause significant pain and may threaten survival and/or compromise function.

Classification of burns

Severe burns: one or more of the following parameters:

• Involving more than 10% of the body surface area (BSA) in children and 15% in adults
• Inhalation injury (smoke, hot air, particles, toxic gas, etc.)
• Major concomitant trauma (fracture, head injury, etc.)
• Location: face, hands, neck, genitalia/perineum, joints (risk of functional deficit)
• Electrical and chemical burns or burns due to explosions
• Age < 3 years or > 60 years or significant co-morbidities (e.g. epilepsy, malnutrition)

Minor burns: involving less than 10% of the BSA in children and 15% in adults, in the absence of other risk factors

Evaluation of burns

Extent of burns

Lund-Browder table – Percentage of body surface area according to age

This table helps to accurately calculate the % of BSA involved according to patient’s age: e.g. burn of the face, anterior trunk, inner surface of the lower arm and circumferential burn of left upper arm in a child 2 years of age: 8.5 + 13 + 1.5 + 4 = 27% BSA.

Depth of burns

Apart from first-degree burns (painful erythema of the skin and absence of blisters) and very deep burns (third-degree burns, carbonization), it is not possible, upon initial examination, to determine the depth of burns. Differentiation is possible after D8-D10.

Evaluation for the presence of inhalation injury

Dyspnoea with chest wall indrawing, bronchospasm, soot in the nares or mouth, productive cough, carbonaceous sputum, hoarseness, etc.

Treatment of severe burns

I. Initial management

On admission

• Ensure airway is patent; high-flow oxygen, even when SpO2 is normal.
• Establish IV access, through unburned skin if possible (intraosseous access if IV access is not possible).
• Ringer lactate (RL): 20 ml/kg during the first hour, even if the patient is stable.
• Morphine SC: 0.2 mg/kg (Step 1 and Step 2 analgesics are not effective).
• In the event of chemical burns: flush with copious amounts of water for 15 to 30 minutes, avoiding contamination of healthy skin; do not attempt to neutralize the chemical agent.

Once the patient is stabilized

• Remove clothes if they are not adherent to the burn.
• Take history of the burn injury: mechanism, causative agent, time, etc.
• Assess the burn injury: extent, depth, carbonization; ocular burns, burns at risk of secondary functional deficits; circumferential burns of the extremities, chest or neck. Wear face mask and sterile gloves during the examination.
• Assess for associated injuries (fractures, etc.).
• Protect the patient and keep him warm: clean/sterile sheet, survival blanket.
• Insert a urinary catheter if burns involve > 15% of BSA, and in the case of electrical burns or burns of the perineum/genitalia.
• Insert a nasogastric tube if burns involve > 20% of BSA (in the operating room while carrying out dressing procedure).
• Calculate and initiate fluid and electrolyte requirements for the first 24 hours.
• Intensive monitoring: level of consciousness, heart rate, blood pressure, SpO2, respiratory rate (RR) hourly; temperature and urine output every 4 hours.
• Additional testing: haemoglobin, blood group, urine dipstick test.
• Prepare the patient for the first dressing procedure in the operating room.

Notes:

• Burns do not bleed in the initial stage: check for haemorrhage if haemoglobin level is normal or low.
• Burns alone do not alter the level of consciousness. In the case if altered consciousness, consider head injury, intoxication, postictal state in epileptic patients.
• Clinical manifestations of electrical burns vary significantly according to the type of current. Look for complications (arrhythmia, rhabdomyolysis, neurological disorders).

II. General measures during the first 48 hours

Resuscitative measures

Intravenous replacement fluid to correct hypovolaemia:

Fluid and electrolyte requirements during the first 48 hours according to age

Note: increase replacement volumes by 50% (3 ml/kg x % BSA for the first 8 hours) in the event of inhalation injury or electrical burn. For burns > 50% BSA, limit the calculation to 50% BSA.

This formula provides a guide only and should be adjusted according to systolic arterial pressure (SAP) and urine output. Avoid fluid overload. Reduce replacement fluid volumes if urine output exceeds the upper limit.

Target endpoints for IV replacement fluids

In patients with oliguria despite adequate fluid replacement:
dopamine IV: 5 to 15 micrograms/kg/minute by IV pump
or
epinephrine IV: 0.1 to 0.5 micrograms/kg/minute by IV pump
Stop the infusion after 48 hours, if fluid requirements can be met by the oral route or gavage.

Respiratory care

• In all cases: continuous inhalation of humidified oxygen, chest physiotherapy.
• Emergency surgical intervention if necessary: tracheotomy, chest escharotomy.
• Do not administer corticosteroids (no effect on oedema; predisposition to infection). No specific treatment for direct bronchopulmonary lesions.

Analgesia

See Pain management

Nutrition

Start feeding early, beginning at H8:

• Daily needs in adults
  • calories: 25 kcal/kg + 40 kcal/% BSA
  • proteins: 1.5 to 2 g/kg
• High energy foods (NRG5, Plumpy'nut, F100 milk) are necessary if the BSA is > 20% (normal food is inadequate).
• Nutritional requirements are administered according to the following distribution: carbohydrates 50%, lipids 30%, proteins 20%.
• Provide 5-10 times the recommended daily intake of vitamins and trace elements.
• Enteral feeds are preferred: oral route or nasogastric tube (necessary if BSA > 20%).
• Start with small quantities on D1, then increase progressively to reach recommended energy requirements within 3 days.
• Assess nutritional status regularly (weigh 2 times weekly).
• Reduce energy loss: occlusive dressings, warm environment (28-33 °C), early grafting; management of pain, insomnia and depression.

Patients at risk of rhabdomyolysis

In the event of deep and extensive burns, electrical burns, crush injuries to the extremities:

• Monitor for myoglobinuria: dark urine and urine dipstick tests.
• If present:  induce alkaline diuresis for 48 hours (20 ml of 8.4% sodium bicarbonate per litre of RL) to obtain an output of 1 to 2 ml/kg/hour. Do not administer dopamine or furosemide.

Infection control 

Precautions against infection are of paramount importance until healing is complete. Infection is one of the most frequent and serious complications of burns:

• Hygiene precautions (e.g. sterile gloves when handling patients).
• Rigorous wound management (dressing changes, early excision).
• Separate “new” patients (< 7 days from burn) from convalescent patients (≥ 7 days from burn).
• Do not administer antibiotherapy in the absence of systemic infection.
  Infection is defined by the presence of at least 2 of 4 following signs: temperature > 38.5 °C or < 36 °C, tachycardia, tachypnoea, elevation of white blood cell count by more than 100% (or substantial decrease in the number of white blood cells).
• In the event of systemic infection, start empiric antibiotherapy:
  cefazolin IV
  Children > 1 month: 25 mg/kg every 8 hours 
  Adults : 2 g every 8 hours
  + ciprofloxacin PO
  Children > 1 month: 15 mg/kg 2 times daily 
  Adults: 500 mg 3 times daily 
• Local infection, in the absence of signs of systemic infection, requires topical treatment with silver sulfadiazine. Not to be applied to children under 2 months.

Other treatments

• Omeprazole IV from D1
  Children: 1 mg/kg once daily
  Adults: 40 mg once daily
• Tetanus vaccination (see Tetanus, Chapter 7).
• Thromboprophylaxis: low molecular weight heparin SC beginning 48 to 72 hours post-injury.
• Physiotherapy from D1 (prevention of contractures), analgesia is necessary.
• Intentional burns (suicide attempt, aggression): appropriate psychological follow-up.

III. Local treatment

Regular dressing changes a  prevent infection, decrease heat and fluid losses, reduce energy loss, and promote patient comfort. Dressings should be occlusive, assist in relieving pain, permit mobilisation, and prevent contractures.

Basic principles

• Rigorous adherence to the principles of asepsis.
• Dressing changes require morphine administration in the non-anaesthetised patient.
• The first dressing procedure is performed in the operating room under general anaesthesia, the following in an operating room under general anaesthesia or at the bedside with morphine.

Technique

• At the time of the first dressing procedure, shave any hairy areas (armpit, groin, pubis) if burns involve the adjacent tissues; scalp (anteriorly in the case of facial burns, entirely in the case of cranial burns). Cut nails.
• Clean the burn with povidone iodine scrub solution (1 volume of 7.5% povidone iodine + 4 volumes of 0.9% sodium chloride or sterile water). Scrub gently with compresses, taking care to avoid bleeding.
• Remove blisters with forceps and scissors.
• Rinse with 0.9% sodium chloride or sterile water.
• Dry the skin by blotting with sterile compresses.
• Apply silver sulfadiazine directly by hand (wear sterile gloves) in a uniform layer of 3-5 mm to all burned areas (except eyelids and lips) to children 2 months and over and adults.
• Apply a greasy dressing (Jelonet® or petrolatum gauze) using a back and forth motion (do not use a circular movement).
• Cover with a sterile compresses, unfolded into a single layer. Never encircle a limb with a single compress.
• Wrap with a crepe bandage, loosely applied.
• Elevate extremities to prevent oedema; immobilise in extension.

Frequency

• Routinely: every 48 hours.
• Daily in the event of superinfection or in certain areas (e.g. perineum).

Monitoring

• Distal ischaemia of the burned limb is the main complication during the first 48 hours. Assess for signs of ischaemia: cyanosis or pallor of the extremity, dysaesthesia, hyperalgia, impaired capillary refill.
• Monitor daily: pain, bleeding, progression of healing and infection.

IV. Surgical care

Emergency surgical interventions

• Escharotomy: in the case of circumferential burns of arms, legs or fingers, in order to avoid ischaemia, and circumferential burns of chest or neck that compromise respiratory movements.
• Tracheotomy: in the event of airway obstruction due to oedema (e.g. deep cervicofacial burns). Tracheotomy can be performed through a burned area.
• Tarsorrhaphy: in the event of ocular or deep eyelid burns.
• Surgery for associated injuries (fractures, visceral lesions, etc.).

Burn surgery

• Excision-grafting of deep burns, in the operating room, under general anaesthesia, between D5 and D6: excision of necrotic tissue (eschar) with simultaneous grafting with autografts of thin skin. This intervention entails significant bleeding risk, do not involve more than 15% of BSA in the same surgery.
• If early excision-grafting is not feasible, default to the process of sloughing-granulation-reepithelisation. Sloughing occurs spontaneously due to the action of sulfadiazine/ petrolatum gauze dressings and, if necessary, by mechanical surgical debridement of necrotic tissue. This is followed by granulation, which may require surgical reduction in the case of hypertrophy. The risk of infection is high and the process is prolonged (> 1 month).

V. Pain management

All burns require analgesic treatment. Pain intensity is not always predictable and regular assessment is paramount: use a simple verbal scale (SVS) in children > 5 years and adults and NFCS or FLACC scales in children < 5 years (see Pain, Chapter 1).

Morphine is the treatment of choice for moderate to severe pain. Development of tolerance is common in burn patients and requires dose augmentation. Adjuvant treatment may complement analgesic medication (e.g. massage therapy, psychotherapy).

Continuous pain (experienced at rest)

• Moderate pain:
  paracetamol PO + tramadol PO (see Pain, Chapter 1) 
• Moderate to severe pain:
  paracetamol PO + sustained release morphine PO (see Pain, Chapter 1) 
  In patients with severe burns, oral drugs are poorly absorbed in the digestive tract during the first 48 hours, morphine is administered by SC route.

Acute pain experienced during care

Analgesics are given in addition to those given for continuous pain.

• Significant medical interventions and extensive burns: general anaesthesia in an operating room.
• Limited non-surgical interventions (dressings, painful physiotherapy):
  • Mild to moderate pain, 60 to 90 minutes before giving care: 
    tramadol PO (see Pain, Chapter 1) rarely allows treatment to be completed comfortably. In the event of treatment failure, use morphine.
  • Moderate or severe pain, 60 to 90 minutes before giving care:
    immediate release morphine PO: initial dose of 0.5 to 1 mg/kg; the effective dose is usually around 1 mg/kg, but there is no maximum dose.
    or morphine SC: initial dose of 0.2 to 0.5 mg/kg; the effective dose is usually around 0.5 mg/kg, but there is no maximum dose.

Note: these doses of morphine are for adults, dosing is the same in children > 1 year, should be halved in children less than 1 year, and quartered in infants less than 3 months.

• Pain management using morphine during dressing changes at the bedside requires:
  • A trained nursing team.
  • Availability of immediate release oral morphine and naloxone.
  • Close monitoring: level of consciousness, RR, heart rate, SpO2, every 15 min for the first hour following dressing change, then routine monitoring.
  • Assessment of pain intensity and sedation during the intervention and for 1 hour thereafter.
  • Necessary equipment for ventilation by mask and manual suction.
  • Gentle handling of the patient at all times.
• Adjustment of morphine doses for subsequent dressings:
  • If pain intensity (SVS) is 0 or 1: continue with the same dose.
  • If SVS score ≥ 2: increase the dose by 25 to 50%. If pain control remains inadequate, the dressing change should be carried out in the operating room under anaesthesia.
• Take advantage of the residual analgesia following dressing changes to carry out physiotherapy.
• As a last resort (morphine unavailable and no facilities to give general anaesthesia), in a safe setting (trained staff, resuscitation equipment, recovery room), adding ketamine IM at analgesic doses (0.5 to 1 mg/kg) reinforces the analgesic effect of the paracetamol + tramadol combination given before a dressing change.

Chronic pain (during the rehabilitation period)

• The treatment is guided by self-evaluation of pain intensity, and utilises paracetamol and/or tramadol. Patients may develop neuropathic pain (see Pain, Chapter 1).
• All other associated pain (physiotherapy, mobilization) should be treated as acute pain.

Minor burns

• Treat as outpatients.
• Wound care: dressings with silver sulfadiazine (to children 2 months and over and adults) or petrolatum gauze (except for first degree superficial burns).
• Pain: paracetamol ± tramadol usually effective.

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