Effect of indacaterol on arterial blood gases in patients suffering from acute exacerbation of COPD.

Aim: The administration of β2-agonists to patients with airways obstruction often results in transient decrease in PaO2 despite concomitant bronchodilation. This effect is potentially dangerous for patients suffering from acute exacerbation of COPD (AECOPD). In this study, we investigated the effect of indacaterol 150 μg and 300 μg on the arterial blood gas tensions of hospitalised patients with AECOPD.

Methods: We explored the acute effects on arterial blood gases and spirometry of two doses of indacaterol Breezhaler (150 and 300 μg) in 12 patients hospitalised because of an AECOPD in 2 non-consecutive days under open-label, randomized, crossover conditions, with blind evaluation. Blood specimens were taken just before the inhalation and at 15, 30, 60, 120, 240 and 360 min after inhalation of each treatment, and spirometry was performed at the same time points.

Results: Both doses of indacaterol did not cause significant changes in blood gases, although some patients with relatively well-preserved PaO2 presented transient episodes of oxygen desaturation that normalize spontaneously in a very short time. Moreover, they induced a significant mean increase in FEV1 and FVC, although the improvement caused by indacaterol 300 μg was larger.

Conclusions: Indacaterol up to 300 μg is a potent bronchodilator that may induce small, transient decrease in PaO2 mainly in patients with relatively well-preserved PaO2. There appeared to be no clinical consequences of these PaO2 abnormalities in patients suffering from AECOPD.