Carbon Monoxide: Our Experience

Objective: To describe the characteristics of subjects with acute carbon monoxide (CO) intoxication attended by the emergency department and to assess the presence of a late syndrome. Methods: Retrospective study of all cases of CO intoxication presenting during 2004. A follow-up telephone survey at 40 days and 1 year after intoxication was conducted. Results: Acute intoxications accounted for 1.2% (1531 cases) of all patients (131,997) attended during the year 2004. A total of 19 cases of CO intoxication were collected, which accounted for 1.25% of all acute intoxications. The mean age was 40 ( plus or minus 19.2) years. A total of 36.8% were men, and 84.2% were transferred to the emergency room in ambulance with a high flow O sub(2) mask fitted. Most subjects presented during the winter season (47.4%), and 68.4% between 21:45 p.m. to 7:30 a.m. In 73.7% of cases, more than two people with CO intoxication due to the same cause presented. In 100% of cases oxygen saturation was > 95%. Respiratory rate was > 20 breaths/min in 75% of cases. In 61.6% of cases, heart rate was > 90 beats/min. Causes of CO intoxication included accidents in the household (31.6% fire, 10.5% brazier, 42.1% heater, and 15.8% stove). Symptoms were present in 100% of patients (digestive 42.1%, cardiovascular 21.1%, respiratory 26.3%, cutaneous 10.5%, mild neurological manifestations 84.2%, and behavior disturbances 5.3%). The Glasgow coma scale was 15 in 94.7% of patients. Mydriasis was observed in 10.5% of cases. The mean (SD) pH was 7.4 (0.03), HCO sub(3) 24.5 (2.6) mEq/L, and 20% showed elevated CK levels. The mean COHb was 10%. A total of 21.1% of subjects were discharged from the emergency department within the first 12 h, 63.2% remained in the emergency room for more than 12 h, and 15.8% were transferred to a hyperbaric chamber. These three patients had COHb level > 16%. At 40-day follow-up, 78.9% of patients did not show late syndrome, 10.5% presented headache, 5.3% visual impairment, and 5.3% lethargy. All patients were symptom-free after 1 year. Conclusions: CO intoxication should be suspected when two or more patients from the same household present to the emergency department with non-specific symptoms, mainly mild neurological manifestations. In the present clinical series, all patients were symptom-free one year after CO intoxication. It is important to educate the population on the need for appropriate servicing of domestic heating and/or water-heater equipment, as well a