Methaemoglobinaemia due to alkyl nitrites in a patient with suspected traumatic injuries.

A man in his 60s with no relevant previous medical history presented to an urban, major trauma centre by ambulance after being found with a head injury in a nightclub. The paramedics reported he was hypoxic, hypotensive and tachycardic with altered mental status. At the emergency department, he had oxygen saturations of 85% despite high-flow oxygen and was hypotensive at 88/43mmHg.