Criteria for mild inhalation injury:
(1) evidence of upper respiratory tract burn (burnt nasal vibrissae, swelling of oral mucosa, and/or facial burns)
(2) no evidence of airway obstruction
(3) able to maintain normal oxygen saturation on room air
Criteria for moderate inhalation injury:
(1) signs of mild inhalation injury
(2) hoarseness of voice
(3) carbonaceous sputum
(4) able to maintain adequate oxygen saturation when treated with 40% humidified oxygen delivered by either mask or naso-tracheal intubation
Criteria for severe inhalation injury:
(1) signs of mild and moderate inhalation injury
(2) unable to maintain adequate oxygen saturation on 40% humidified oxygen, with either PaO2 < 8 kPa (60 mm Hg) and/or PaCO2 > 5.5 kPa (41 mm Hg).
where:
• vibrissae are the hairs present at the nasal vestibule
• 1 mm Hg = 0.133 kPa
