SHORT PAPERS Predictors of Occult Carbon Monoxide Poisoning in Patients with Headache and Dizziness

Headache and dizziness occur at carboxyhemoglobin levels of greater than 10%. We studied 89 patients with headache or dizziness for evidence of carbon monoxide exposure. The mean carboxyhemoglobin level was 2.87%. Number of cigarettes smoked per day (r = 0.47 l;p < 0.00002), use of gas kitchen stoves for heating purposes (r = 0.252, p < 0.02), problems with the home heating system (r = 0.278, p < 0.01), and cohabitants with concurrent headache or dizziness (r = 0.427, p < 0.01) correlated with carboxyhemoglobin levels. Multiple regression analysis identified number of cigarettes smoked daily, use of stoves for heat, and concurrently symptomatic cohabitants as significant predictors of carboxyhemoglobin level (F = 13.939 [3, 8 5]; p < 0.01). Obtaining carboxyhemoglobin levels from patients who used stoves for heat or had similarly affected cohabitants identified 4 of 4 patients with levels greater than 10 % (sensitivity, 100%) and excluded 47 of 85 patients with lower levels (specificity, 55.3%). The 4 patients with carboxyhemoglobin levels in excess of 10% may represent occult carbon monoxide poisoning in this population