Intravenous or nebulised MgSO ( 4 ) did not significantly decrease rates of hospital admission and breathlessness compared with placebo : intravenous MgSO ( 4 ) was associated with an odds ratio of 073 ( 95 % CI 051 to 104 ; p = 0083 ) for hospital admission and a change in VAS breathlessness of 26 mm ( -16 to 68 ; p = 0231 ) compared with placebo ; nebulised MgSO ( 4 ) was associated with an odds ratio of 096 ( 065 to 140 ; p = 0819 ) for hospital admission and a change in VAS breathlessness of -26 mm ( -70 to 18 ; p = 0253 ) compared with placebo .