The effects of salbutamol aerosol on lung function in patients with pulmonary emphysema.

The effects of inhaling 400 micrograms of salbutamol were compared with identical placebo inhaler in a double blind cross-over study of 20 patients with radiological evidence of pulmonary emphysema. There was a small but significant rise in the forced expiratory volume in one second (FEV1), but there was a much greater increase in vital capacity (VC), which was accompanied by a reduction in residual volume. Symptomatic improvement after salbutamol was reported by 14 of the patients and VC increased significantly in this group; there was no significant increase in VC in patients who did not prefer the active inhaler. There was no consistent change in the FEV1/VC ratio after salbutamol administration and this ratio is misleading as an indicator of bronchodilator responsiveness in patients with emphysema. Salbutamol is thus a valuable addition to treatment in patients with pulmonary emphysema and the response to treatment is best judged by measuring the improvement in VC.