The use of nebulised magnesium sulphate in exacerbations of chronic obstructive pulmonary disease

INTERVENTION: 1. Control Arm: Salbutamol (2.5 mg in 2.5 ml) diluted in Normal Saline 2.5 ml to make up a 5 ml solution (placebo). 2. Experimental Arm: Salbutamol (2.5 mg in 2.5 ml) diluted in isotonic magnesium (2.5 ml of 0.25 mmol/ml [61.75 mg/ml] magnesium) to make up a 5 ml solution for nebulisation. CONDITION: Chronic Obstructive Pulmonary Disease (COPD) ; Respiratory ; Pulmonary Disease PRIMARY OUTCOME: 1. Forced expiratory volume in one second (FEV1) SECONDARY OUTCOME: 1. Forced Vital Capacity (FVC); 2. Discharge within 48 hours; 3. Risk of requiring NIV or intubation or escalation of treatment; 4. Length of hospital stay ‐ days; 5. Arterial blood gas tensions; 6. Modified Borg score INCLUSION CRITERIA: 1. 35 to 80 years old 2. Diagnosis of COPD as defined by the American Thoracic Society 3. Presentation to the ED with an acute exacerbation of COPD 4. FEV1 less than or equal to 70% 5. FEV1/Forced Vital Capacity (FVC) ratio less than 70% 6. 20 pack year smoking history