How is carbon monoxide poisoning diagnosed?

1. The determination of blood COHb can use simple measurement methods, such as

①Addition and subtraction method: Take 1~2 drops of the patient's blood, dilute it with 3~4ml of distilled water, add 1~2 drops of 10% sodium hydroxide solution, and mix well. When the COHb in the blood increases, the blood remains light red after adding alkali, and the normal blood is green. This assay is only positive when the COHb concentration is as high as 50%.
② Spectroscopic examination method: take a few drops of blood, add 10ml of steamed water, and use a spectroscopic examination to see a special absorption band. Monitoring the concentration of COHb in blood not only confirms the diagnosis, but also helps in typing and estimating prognosis.
2. EEG examination showed diffuse low-amplitude slow waves, parallel to the progression of hypoxic encephalopathy.

3. Head CT examination When brain edema is seen, there are pathologically reduced areas of density in the brain.

Disease overview Etiology and pathology Clinical manifestations Examination and test Diagnosis and differentiation Complications Treatment Prognosis preventive diagnosis and differential diagnosis
According to the exposure history of inhaled high concentrations of carbon monoxide, the symptoms and signs of acute central nervous system damage, combined with the results of timely determination of blood COHb, according to the national diagnostic criteria (GB8781-88), the diagnosis of acute CO poisoning can be made.

Occupational CO poisoning is mostly accidental, and the exposure history is relatively clear. Those who are suspected of having live poisoning should inquire about the environmental conditions at the time of the onset, such as whether there is poor ventilation or leakage in the furnace chimney and whether other people in the same room have the same symptoms. Acute CO poisoning should be differentiated from cerebrovascular accident, concussion, meningitis, diabetic acidosis, and coma caused by other poisonings. Past history, physical examination, and laboratory tests are helpful in the differential diagnosis.

Blood COHb measurement is a valuable diagnostic indicator, but taking blood samples requires drawing venous blood as soon as possible within 8 hours of leaving the poisoning site. Because COHb gradually disappears after a few hours from the scene.