[Carboxyhemoglobin levels in relation with home heating]

To study carboxyhemoglobin levels (HbCO) associated with use of different types of home heating and to evaluate the usefulness of measuring hemoglobin oxygen saturation. Nonsmoking patients with chronic respiratory insufficiency who were initially prescribed home oxygen therapy were enrolled in the study. One hundred four patients were studied in winter and summer (when heating was not used). The control group consisted of 92 hospitalized patients not exposed to carbon monoxide. Of the 104 patients 74.1% were men. Mean age was 72.33 (range 17 to 97 years) and 57.9% lived in rural areas. Mean HbCO in the control group was 1.53 +/- 0.96% (p = 0.01). Among the 39% who burned slack coal for heat, the mean HbCO was 4.63 +/- 2.87%. The 23.7% with central heating had HbCO levels of 2.15 +/- 0.87% (p < 0.0001). Pulse oximetry (SpO2) estimated higher hemoglobin oxygen than direct measurement (SaO2): 87.12 +/- 6% and 83.3 +/- 8%, respectively (p < 0.001). High HbCO concentrations are related to chronic exposure to slack coal fumes. Pulse oximetry, as opposed to SaO2, overestimates hemoglobin oxygen saturation in such cases.