Burn ICU Inhalational Injury Policy

Original Date: 09/2020 | Last Review Date: 12/2024
Purpose: To standardize the work up, classification, and treatment of burn inhalational injuries.

Assessment:

History and physical to assess risk of inhalational injury
- Mechanism – exposure to smoke, blast injury, steam burns, exposure to caustic fumes
- Intensity and duration of exposure (e.g. patient trapped in enclosed space, found unconscious, etc…)
- Physical Examination:
  - Carbonaceous sputum, stridor, hoarseness, drooling, and/or dysphagia are highly suggestive of inhalational injury.
  - Facial burns, singed eyebrows or nasal hair, and/or soot deposits on face may also be present, though they alone do not necessarily connote the presence of an inhalational injury.
  - Neurologic examination to assess risk of systemic poisoning when appropriate.

Determine the clinical concern for systemic toxicity:
- Suspected in any patient in an enclosed space fire
- Carbon monoxide poisoning can be difficult to diagnose as they lead to falsely elevated SpO2. A “Blood Gas w/ Coox Panel, Arterial” is necessary for diagnosis
  - Alternatively, a venous sample may be obtained using the same order with comments as follows “Please obtain from venous source”
- Cyanide toxicity often occurs with exposure to enclosed space fires involving couches, car seats, cushions, mattresses, etc.

Diagnosis/Management:

Work up to assess risk of inhalational injury
- Pulse oximetry
- Arterial blood gas with lactate, methemoglobin, and carboxyhemoglobin (COHb) level
  - Order “Blood Gas w/ Coox Panel, Arterial”
- Chest x ray

Determine clinical concern for Carbon Monoxide (CO) Poisoning:

The “COOX” part of the “Arterial Blood Gas w/ COOX” that you ordered – look for COHb
Remember: SpO2 levels can be falsely elevated in patients with CO exposure, therefore
- While COHb lab is pending, leave patient on 100% FiO2.
- If not intubated, patient should be placed on humidified 100% FiO2 via a non-rebreather until COHb levels return.
If COHb < 10%, wean FiO2 as tolerated
If COHb > 10%, continue 100% FiO2 and repeat COHb every hour until the value is <10%.

The table below depicts the likely symptoms associated with varying levels of COHb

COHb Level	Symptoms
0-10	Normal
15-20	Headache, Confusion
20-40	Disorientation, Fatigue, Nausea, Visual Disturbances
40-60	Hallucinations, Combativeness, Coma, Shock
60+	Cardiopulmonary arrest

Determine the clinical concern for Cyanide Poisoning (enclosed fire, unexplained unconsciousness)
- Hydrogen Cyanide is released by combustion of products with synthetic polymers (couches, car seats, cushions, mattresses)
- Cyanide toxicity is difficult to identify in a timely fashion and should be considered empirically in patients who were in an enclosed structure or vehicle fire.
- Administer Hydroxocobalamin (Cyanokit 5g IV) if:
  - Lactate levels > 10
  - Persistent and unexplained acidosis (unresponsive to IV fluids)
  - Unexplained hemodynamic instability (unresponsive to IV fluids)
    If given by prehospital personnel, do not give again unless directed by attending.
- The max dose of hydroxocobalamin is 10g (two doses max)
- Hydroxycobalamin can cause transient hypotension, will turn the urine dark red (not rhabdomyolysis), and may stain the skin red.
- NOTE: Hydroxycobalamin has been linked to AKI. It’s use is to be limited to the patient meeting any of the criteria above

Fiberoptic bronchoscopy is the standard diagnostic test for identifying inhalational injury and should be performed within 2 hours of injury.

Abbreviated Injury Score (AIS)
Grade	Class	Bronchoscopy	Description
0	No injury		No carbonaceous deposits, erythema, edema, bronchorrhea, or obstruction
1	Mild injury		Minor or patchy areas of erythema, carbonaceous deposits, bronchorrhea, or bronchial obstruction present
2	Moderate injury		Moderate erythema, carbonaceous deposits, bronchorrhea, or bronchial obstruction present
3	Sever injury		Severe inflammation with friability, copious carbonaceous deposits, bronchorrhea, or bronchial obstruction present
4*	Massive injury		Mucosal sloughing, necrosis, or endoluminal obstruction

*There will be patients for whom you have a clinical suspicion for inhalational injury but who do not meet the above criteria. Use discretion when deciding on whether to intubate that patient or consider nasopharyngeal endoscopy.*

Indications for intubation
- GCS < 8
- COHb level > 20%
- Respiratory failure with hypoxia or hypercarbia
- Extensive face and neck burns (swelling is progressive over the first 48 hours)
- Signs and symptoms of airway obstruction by edema (e.g. hoarseness, stridor, labored breathing, difficulty swallowing)
- Other clinical concern for impending airway obstruction

Inhalational injury treatments

All grade injuries:
- Supplemental humidified oxygen
- Nebulized 0.083% albuterol inhalational solution 2.49mg q4 hours inhaled (order under Nebulizer Treatment Orders Adult MPP)
For Grade 2 and higher injuries, also order:
- Nebulized heparin 10,000 units q4 hours inhaled
- Nebulized 3% sodium chloride 3 mL q4 hours inhaled (order under Nebulizer Treatment Orders Adult MPP)
High-frequency percussive ventilation (HFPV or VDR) may decrease pneumonia incidence and improve survival. Remains at the discretion of the provider to start it for Grade 3 or 4 Inhalation Injuries.

When to stop treatment (All grades of injuries):

- Extubation
- Resolution of inhalation injury on bronchoscopy
- 7 days of treatment

Inhalation Injury Protocol
Grade 0	Grade 1	Grade 2	Grade 3	Grade 4
No treatment	Humidified oxygen Nebulized albuterol	Humidified oxygen Nebulized albuterol Nebulized heparin q4h Nebulized 3% NaCl q4h	Humidified oxygen Nebulized albuterol Nebulized heparin q4h Nebulized 3% NaCl q4h Consider HFPV	Humidified oxygen Nebulized albuterol Nebulized heparin q4h Nebulized 3% NaCl q4h Consider HFPV

Ventilator management
- Settings:
  - No mode of ventilation has been shown to be superior in the setting of inhalational injuries. What HAS been shown to improve outcomes is Lung Protective Ventilatory Strategies (same as ARDS)
  - Lung Protective Ventilatory Strategies
    - 6-8 mL/kg predicted body weight tidal volumes (Start at 6 mL/kg and can work up to 8 mL/kg if Plateau Pressure allows)
    - Plateau pressure < 30 cm H2O
    - Driving pressure (P_plat–PEEP) goal <15 cm H2O
  - Volumetric Diffusive Respirator (VDR)
    - FiO2 95% and titrate to maintain SpO2> 90%. This includes the Fi02 setting on the Vapotherm that is teed in (Vapotherm should be set to 42C and 12-20 lpm of flow).
    - Peak inspiratory Pressure (PIP) sufficient to cause apical chest “wiggle” (usually 22 – 32 cmH20).
    - Pulse Frequency/Percussive (High Rate) 550 bpm
    - Sinusoidal/Convective (Low) Rate 10-12 bpm
    - Inspiratory to Expiratory (I:E) ratio – 1:1
    - Oscillatory PEEP 7-11 cm H20. Set this value such that it is sufficient to maintain slight chest wiggle.
    - Demand PEEP 3 cm H2O (arrow on dial is set at the 3 o’clock position).
    - Convective rise is off
    - Initial I:E ratio is 1:1. High rate (i:e) ratio is also 1:1 (“arrows up”).
    - Endotracheal tube cuff can be partially deflated to assist with CO2 removal
  - Airway Pressure Release Ventilation (APRV)
    - Pressure high (Phigh) – 2 cm H2O above plateau pressure
    - Pressure low (Plow) – 3 cm H2O
    - Time high (Thigh)
      - Start at 5.2
      - Shorten as needed to improve ventilation
      - The ideal Thigh is as long a patient can tolerate without inadequate ventilation
    - Time low (Tlow)
      - Set at 0.8 seconds and watch the volume flow curve
      - Decrease Tlow until you cut off the expiratory flow rate at 50-75%

*More information available in the Acute Respiratory Distress Syndrome Algorithm***

ARDS Algorithm

Considerations:

Repeat bronchoscopy:
- For inhalational injuries Grade 2 or higher, consider repeat daily bronchoscopy to assess progression of inhalational injury prior to extubation.
- Utilize the Olympus bronchoscopes for repeat bronchoscopies as they allow improved suction capabilities compared to the disposable bronchoscopes.
Extubation Criteria:
- Extubate as indicated, including presence of an adequate cuff leak
- Consider the following: Mucosal sloughing and risk of hypoxemia may be delayed up to 72 hours in Grade 2 or higher inhalation injuries
When to stop Inhalation Injury treatments: (Any of the following criteria are met)
- Extubation
- Bronchoscopy demonstrates complete resolution of inhalation injury
- 7 days of treatment
If the patient does not tolerate these ventilator strategies, consider:
- Consultation of the ECMO team