Background: Systematic reviews of approximately 13 randomized trials support treatment with intravenous magnesium sulfate (MgSO(4)) in patients with severe acute asthma; however, little is known about its actual clinical use.
Objective: We sought to examine the use of intravenous MgSO(4) in the emergency department (ED) and physician attitudes toward its use.
Methods: Data for MgSO(4) use were obtained from observational cohort studies of ED patients with acute asthma. Investigators were asked about MgSO(4) through a brief Internet-based survey. The main outcomes were the percentage of sites reporting MgSO(4) use and patient factors that potentially modified the use of this agent.
Results: Among 9745 ED patients with acute asthma, 240 (2.5%) received MgSO(4). Increasing age, previous intubation, higher initial respiratory rate, lower initial PEF, higher number of beta-agonists in the ED, and use of systemic corticosteroids were associated with MgSO(4) use (P < .01). Overall, 103 (87%) of 119 potential sites completed the survey. Most (92%) respondents stated their EDs had MgSO(4) available, and 64% had recently used it. More respondents listed severity (96%) and failure to respond to initial beta-agonists (87%) as factors prompting their use of MgSO(4). Other factors, such as age, sex, and duration of exacerbation, less commonly influenced MgSO(4) use.
Conclusion: Most ED physicians accept the efficacy of MgSO(4) in acute asthma. Despite this belief and the ready availability of MgSO(4), its ED use remains uncommon (2.5% of cases). In both practice and theory, emergency physicians appear to appropriately restrict its use to patients with severe acute asthma.