[Smoking and carbon monoxide consumption (author's transl)].Respiration. 1980; 40(3):136-41.R
Among 2,069 patients subjected to pulmonary function tests, 20% were smokers with a mean oxyhemoglobin (HbCO) level of 5.2%. Similar values for HbCO (2.4%) were found in non-smokers and ex-smokers. A positive correlation was observed between daily tobacco consumption and HbCO level, i.e. HbCO = 0.123 (g/day) + 3.433. For a similar consumption (16 g/day), smokers who inhaled the smoke had a significantly higher level of HbCO than smokers who did not (5.8 vs. 4.7%). The interval separating the time when the last cigarette was smoked from HbCO measurement is of utmost importance: for a similar tobacco consumption (10 g/day) HbCO ranged from 6.5 +/- 0.5% when the interval was 1 h to 4.6 +/- 0.3% when it was 3 h (p < 0.005). In some cases, there were discrepancies between the number of cigarettes smoked as indicated by the subjects and the measured levels of HbCO. Possible inhalation of exogenous CO from other sources than smoking or increased production of endogenous CO could account for these differences.