The use of magnesium sulfate in acute asthma: Rapid uptake of evidence in North American emergency departments
Received 3 July 2005; received in revised form 21 August 2005; accepted 12 September 2005. published online 29 November 2005.
Background
Systematic reviews of approximately 13 randomized trials support treatment with intravenous magnesium sulfate (MgSO4) in patients with severe acute asthma; however, little is known about its actual clinical use.
Objective
We sought to examine the use of intravenous MgSO4 in the emergency department (ED) and physician attitudes toward its use.
Methods
Data for MgSO4 use were obtained from observational cohort studies of ED patients with acute asthma. Investigators were asked about MgSO4 through a brief Internet-based survey. The main outcomes were the percentage of sites reporting MgSO4 use and patient factors that potentially modified the use of this agent.
Results
Among 9745 ED patients with acute asthma, 240 (2.5%) received MgSO4. Increasing age, previous intubation, higher initial respiratory rate, lower initial PEF, higher number of β-agonists in the ED, and use of systemic corticosteroids were associated with MgSO4 use (P < .01). Overall, 103 (87%) of 119 potential sites completed the survey. Most (92%) respondents stated their EDs had MgSO4 available, and 64% had recently used it. More respondents listed severity (96%) and failure to respond to initial β-agonists (87%) as factors prompting their use of MgSO4. Other factors, such as age, sex, and duration of exacerbation, less commonly influenced MgSO4 use.
Conclusion
Most ED physicians accept the efficacy of MgSO4 in acute asthma. Despite this belief and the ready availability of MgSO4, 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.
aFrom the Department of Emergency Medicine, University of Alberta, and Capital Health, Edmonton
bDepartment of Emergency Medicine, Massachusetts General Hospital, and the Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston
Reprint requests: Brian Rowe, MD, MSc, Department of Emergency Medicine, University of Alberta, 1G1.43 WMC, 8440-112th St, Edmonton, Alberta, Canada T6G 2B7.
Dr Rowe is supported by the Canadian Institute of Health Research (CIHR) Chairs Program (Ottawa, Canada). Dr Camargo is supported by grant HL-63841 from the National Institutes of Health (Bethesda, Md). MARC is supported by grant HL-63253 from the National Institutes of Health.
Disclosure of potential conflict of interest: B. Rowe has consulted with Beohringer-Ingelheim on a COPD care map and has received grants from AstraZeneca, Trudell-Monaghan, Abbott, GlaxoSmithKline, and Boehringer-Ingelheim. C. Camargo has consultant arrangements with AstraZeneca, GlaxoSmithKline, Aventis, Dey, Discovery, Genentech, Merck, Novartis, Schering, and Sepracor; has received grant money from Abbott, AstraZeneca, Boehringer-Ingelheim, GlaxoSmithKline, Trudell-Monaghan, Aventis, Dey, Fovert, Merck, and Novartis; and is on the speakers' bureau for AstraZeneca, GlaxoSmithKline, and Schering.
ABSTRACT