Carbon Monoxide (CO) Poisoning
Carbon monoxide poisoning is a common, potentially life‑threatening environmental intoxication that often presents with nonspecific symptoms and may affect whole households. Early recognition, immediate high‑flow oxygen and appropriate disposition - including consideration of hyperbaric oxygen therapy (HBOT) - are central to management.
Epidemiology and context
- In the UK there are several dozen accidental CO deaths and hundreds of hospital admissions each year.
- Outbreaks often involve multiple household members exposed to the same source (faulty appliances, blocked flues, portable generators, vehicle exhaust in enclosed spaces).
- CO is colourless and odourless; prevention relies on correct appliance installation and maintenance, adequate ventilation and compliant CO alarms (British/EN standard).
Pathophysiology
- CO binds haemoglobin with very high affinity to form carboxyhaemoglobin (COHb), which cannot carry oxygen and shifts the remaining oxyhaemoglobin dissociation curve to the left, reducing tissue O2 unloading.
- The brain and myocardium are most vulnerable.
- CO also impairs mitochondrial respiration and generates oxidative injury, contributing to delayed cellular damage.
- CO crosses the placenta; fetal COHb may be higher and clears more slowly than maternal levels.
Clinical features
- Presentation is variable and often nonspecific: headache, nausea, dizziness, malaise, confusion, syncope or collapse. Symptoms may develop rapidly or over hours.