Abstract: Objective Arterial blood carboxyhemoglobin concentrations(Hb-CO) increase in acute inflammatory pulmonary diseases.To investigate whether arterial Hb-CO is useful to monitoring disease severity in patients with chronic obstructive pulmonary disease(COPD) who have history of smoking.Methods We measured arterial Hb-CO,arteriovenous Hb-CO differences in 32 patients who smoking history with COPD and 20 non-smoking subjects.To analyze the changes of arterial blood carboxyhemoglobin concentrations,and study the relationship of that changes to patients' stages.Results Arterial Hb-CO concentrations increased in acute stage of patients with COPD(P<0.01),it was higher in subjects who had smoking history than that without smoking(P<0.01).Conclusion These findings suggest that the increased arterial Hb-CO may relate to severity in patients with COPD because of lung and systemic inflammation and production of reactive oxygen species.

Key words: carboxyhemoglobin, chronic obstructive pulmonary disease, smoking