Diagnosis of Carbon Monoxide Poisoning
Diagnosis of carbon monoxide poisoning relies on recognising the symptoms and confirming elevated carbon monoxide levels in the blood. A timely diagnosis of carbon monoxide poisoning can save lives and prevent long-term complications.
Doctors begin by taking a detailed history, asking about recent exposure to fuel-burning appliances, enclosed spaces, and whether others in the environment are feeling unwell. Clues such as headache that improves outside or symptoms affecting multiple people often point to CO exposure.
The main diagnostic tool is a blood test to measure carboxyhaemoglobin (COHb) levels. Carbon monoxide binds with haemoglobin in the blood to form this compound. Normal COHb levels are under 2% in non-smokers and up to 9% in smokers. Levels above 10–15% suggest significant exposure. In severe cases, levels may exceed 50%.
Pulse oximeters, commonly used to measure oxygen saturation, can give false readings in CO poisoning because they cannot distinguish betwThere is a difference between oxyhaemoglobin and carboxyhaemoglobin, so hospitals use special equipment such as a CO-oximeter to obtain accurate results.
Other investigations may include:
- If a doctor suspects chest pain or myocardial strain, they may order an ECG and cardiac enzyme tests
- CT or MRI scans in severe cases with neurological symptoms
- Blood tests to check for metabolic acidosis or organ damage
Diagnosis of Carbon Monoxide Poisoning
In some cases, vague symptoms or symptoms mistaken for a viral illness or food poisoning can delay diagnosis. That’s why it’s crucial to ask about environmental exposures and the presence of CO sources.
When doctors confirm carbon monoxide poisoning, they begin treatment immediately—often before all test results are in—to prevent progression and tissue damage.
[Next: Treatment of Carbon Monoxide Poisoning →]
Treatment of carbon monoxide poisoning centres on removing the person from the source of exposure and delivering oxygen to eliminate the gas from the body. The primary goal of treatment of carbon monoxide poisoning is to restore oxygen delivery to vital organs and prevent complications.
The first step is immediate removal from the exposure site. This alone can stop the poisoning from worsening. Emergency services should ventilate the area, and patients should be transported to hospital promptly.
Once in a medical setting, treatment typically includes:
1. 100% Oxygen Therapy
High-flow oxygen is delivered through a tight-fitting mask to replace carbon monoxide with oxygen in the blood. This speeds up the removal of carboxyhaemoglobin and improves tissue oxygenation. Most people receive oxygen for several hours.
2. Hyperbaric Oxygen Therapy (HBOT)
In moderate to severe cases — especially with loss of consciousness, neurological symptoms, pregnancy, or COHb levels over 25% — hyperbaric oxygen therapy may be used. This involves breathing pure oxygen in a pressurised chamber and helps reduce long-term brain injury.
3. Supportive Care
This includes IV fluids, pain relief, anti-nausea medication, and continuous monitoring. If there are heart or brain complications, treatment is adjusted accordingly.
Treatment of Carbon Monoxide Poisoning
Hospital teams may consult cardiology or neurology if patients show evidence of organ damage. Pregnant women receive urgent oxygen therapy to protect the foetus, which is more vulnerable to CO.
After stabilisation, doctors will arrange follow-up tests to assess for delayed neurological symptoms, which can appear days or weeks after exposure.
A key part of treatment of carbon monoxide poisoning also includes ensuring that the source of CO exposure is identified and corrected, often involving environmental health officials or gas safety inspectors.
[Next: Complications and Recovery from Carbon Monoxide Poisoning →]
