Inhalation injury below the larynx is rarely due to direct thermal injury because the upper airways are highly effective at conducting heat away. More commonly, injuries below the larynx are due to inhalation of combustion products causing chemical burns and foreign body-type inflammation.
The key elements producing chemical by-products are nitrogen, carbon, sulphur and phosphorous. These are produced excessively by combustion. Products include both acids and alkalis:
Microscopic carbon particles are deposited in the lungs and trigger inflammation and subsequent oedema.
Last reviewed 01/2018