Effect of formoterol/budesonide combination on arterial blood gases in patients with acute exacerbation of COPD

Background: Patients with severe chronic airway obstruction might suffer dangerous hypoxemia after administration of a β-agonist despite bronchodilation. Methods: We first compared the acute effects on gas exchange of two doses of formoterol Turbuhaler (9 and 18 μg) in 10 patients with acute exacerbation of COPD. Afterwards, we compared the acute effects of formoterol Turbuhaler 9 μg with those of formoterol/budesonide combination in a single inhaler (Turbuhaler) 9/320 μg in 10 other patients with acute exacerbation of COPD. Finally, we compared the changes in PaO2 induced by formoterol Turbuhaler 9 μg or formoterol/budesonide combination in a single inhaler (Turbuhaler) 9/320 μg with those in FEV1 in 10 other patients with acute exacerbation of COPD. Each agent was given on separate days, and the patients' arterial blood gases were measured at baseline and at intervals of 120 min. Results: Small but statistically significant declines in PaO2 were found after administration of both formoterol 9 and 18 μg. In the second group of patients, formoterol 9 μg alone again induced a significant decrease in PaO2. However, the simultaneous administration of budesonide 320 μg significantly reduced the acute effect of formoterol on PaO2. In a third group of 10 patients we confirmed a small but significant decrease in PaO2 after formoterol alone and the reduction of this effect when budesonide was administered simultaneously. Moreover, we also documented that addition of budesonide amplified the fast onset of action of formoterol. Conclusions: These results suggest that when treating patients suffering from acute exacerbation of COPD with formoterol, it is prudent to check their arterial blood gases. In any case, combined administration of formoterol and budesonide reduces the potential for acute effects of formoterol on blood-gas tensions. © 2005 Elsevier Ltd. All rights reserved.