Symptoms of Carbon Monoxide Poisoning
The symptoms of carbon monoxide poisoning are nonspecific. Mild exposures result in headache, myalgias, dizziness, or neuropsychological impairment. Severe exposures to carbon monoxide result in confusion, loss of consciousness, or death. Patients with subclinical exposures may recognize poisoning only after an acute event or on coincidental discovery of a carbon monoxide leak.
A carboxyhemoglobin level greater than 3% in nonsmokers or greater than 10% in smokers confirms exposure to carbon monoxide, but the level does not correlate with the presence or absence of initial symptoms or with later outcomes. Health care providers in the emergency department should consider hyperbaric oxygen for treating poisoned patients. Clinicians should consider that the level of carboxyhemoglobin on presentation may underestimate earlier levels because of carboxyhemoglobin elimination over time, which is hastened by the application of supplemental oxygen by emergency medical personnel before the patient arrives at the emergency department. Carbon monoxide causes hypoxia by forming carboxyhemoglobin and shifting the oxyhemoglobin dissociation curve to the left.
What is hyperbaric-oxygen therapy?
A: Hyperbaric-oxygen therapy is defined as the breathing of 100% oxygen by patients within hyperbaric chambers compressed to greater than 1.4 atmospheres of absolute pressure.
NEJM Vol. 360, No. 12, March 19, 2009