Carbon monoxide (CO) poisoning

(binds with cytochrome oxidase)

• Myocardial ischaemia: arrhythmias or myocardial infarction. 
• Cerebral oedema
• Rhabdomyolysis: myoglobinuria and renal failure. 
• Longer-term neuropsychiatric effects: 

• personality change, memory loss, concentration impairment. 
• extrapyramidal effects, urinary or fecal incontinence, gait disturbance 

Investigation:

• Measurement of carboxyhemoglobin: 

• for confirming exposure; 
• levels > 20% suggest significant exposure, 

• An ECG 
• Arterial blood gas analysis 
• Pulse oximetry: misleading oxygen saturation levels because the devices do not distinguish between carboxyhemoglobin and oxyhaemoglobin. 

Management 

• removed from exposure as soon as possible 
• high concentration of oxygen via a tightly fitting facemask
• IV fluid 
• Convulsions: diazepam. 
• Hyperbaric oxygen therapy: controversial.