Abstract
Background Intravenous magnesium has been shown to cause bronchodilation in acute severe asthma and in small trials in acute exacerbations of chronic obstructive pulmonary disease (AECOPD). There is also some evidence of benefit from nebulised magnesium in acute severe asthma. Our hypothesis was that adjuvant magnesium treatment administered via repeated nebulisation was effective in the management of AECOPD. Methods In this randomised double-blind placebo-controlled trial, we approached 161 patients with AECOPD presenting to the emergency departments at two New Zealand hospitals with a forced expiratory volume in 1 s (FEV1) <50% predicted 20 min after initial administration of salbutamol 2.5 mg and ipratropium 500 µg via nebulisation. Patients received 2.5 mg salbutamol mixed with either 2.5 ml isotonic magnesium sulphate (151 mg per dose) or 2.5 ml isotonic saline (placebo) on three occasions at 30 min intervals via nebuliser. The primary outcome measure was FEV1 at 90 min. Results 116 patients were randomised, 52 of whom were randomly allocated to the magnesium adjuvant group. At 90 min the mean (SD) FEV1 in the magnesium group (N=47) was 0.78 (0.33) l compared with 0.81 (0.30) l in the saline group (N=61) (difference −0.026 l (95% CI −0.15 to 0.095, p=0.67). No patients required non-invasive ventilation. There were 43/48 admissions to hospital in the magnesium group and 56/61 in the saline group (RR 0.98, 95% CI 0.86 to 1.10, p=0.69). Conclusions Nebulised magnesium as an adjuvant to salbutamol treatment in the setting of AECOPD has no effect on FEV1. Australian New Zealand Clinical Trials Registry ACTRN12608000167369.