CO Poisoning - More on Symptoms

Commonly Seen Table of Symptoms:

The following is a list of symptoms which have been applied mainly to acute CO poisoning. Many sources suggest they can be closely related to blood COHb level. Please note that in practice, severity of symptoms DO NOT correlate well with COHb level. This is also true for the longterm, neuropsychological effects of CO poisoning, ie. there is little relationship between the effects and the COHb level at presentation. Thus, any conclusions about COHb from symptoms, or vice versa, should be drawn with the greatest caution! I DO NOT endorse this kind of simplistic approach to the effects of CO poisoning.

Less than 5%
• No obvious symptoms

5%-10%
• Decreased tolerance for exercise in persons with existing pulmonary disease
• Decreased angina threshold
• Decreased threshold for visual stimuli

10%-20%
• Headaches
• Dizziness
• Confusion
• Decreased visual acuity

20%-30%
• Severe headache
• Nausea
• Dizziness
• Increased respiration
• Irritability
• Impaired judgement
• Visual disturbance

30%-40%
• Vomiting
• Decreased awareness
• Cardiac irregularities
• Muscle weakness

40%-50%
• Fainting

50%-60%
• Convulsions
• Paralysis

60%-70%
• Coma
• Usually death in a few minutes

Greater than 70%
• Immediately fatal