Carbon monoxide poisoning

Sources: faulty boilers/heaters, smoke inhalation, BBQs/generators in enclosed space, methylene chloride (paint stripper) metabolised to CO. Cluster of symptoms in same household → think CO. Features: headache, nausea, dizziness, confusion, chest pain, syncope, seizures, coma. Cherry-red skin is uncommon and late. SpO₂ pulse oximeter is FALSELY NORMAL (does not distinguish HbCO from HbO₂) — must use co-oximeter. ABCDE; remove from source; high-flow oxygen via non-rebreather mask 15 L/min immediately (do not wait for level). Bloods: VBG/ABG including HbCO (co-oximetry), lactate, glucose, troponin, paracetamol/salicylate, U&E, ECG. Pregnancy test in women of reproductive age.