The decrease in clinical efficacy of oxygen therapy takes place in patients suffering from chronic pulmonary obstructive disease who continue smoking even if the intensity of smoking is getting lower. It is explained by the damage of oxygen utilization regardless of normalization of arterial blood saturation indices and perfusion oxygen saturation indices in blood flow
Starodumov N.I., Zarubina E.G., Prokhorenko I.O. Comparative efficacy of oxygen therapy in patients (smokers and non-smokers) with chronic pulmonary obstructive disease // Saratov Journal of Medical Scientific Research, Vol. 7, Issue 2, 2011, pp. 420-422