Emergency Department Asthma "Spacing Trials": Institutional Variability and Time Cost

Some admitting physicians request a medication-free interval ("spacing trial") in the emergency department (ED) to determine whether a patient with an acute exacerbation of asthma can be safely admitted to a hospital ward bed, where bronchodilators are only available every 4 h.

Our objectives were to estimate the frequency of ED spacing trials in different hospitals and their associated time cost.

This multicenter retrospective cohort study examined patients admitted for asthma from 2015 to 2018. We included all university records and a random sample of records from two community hospitals in the same urban area. Two team members abstracted data from each record using recommended methods, with group consensus to resolve differences. Proportion confidence intervals were calculated using normal binomial approximation. We calculated mean differences in ED stay associated with spacing trials, using multivariable linear regression to adjust for age, hospital type, history of intubation, initial pulse, initial respiratory rate, initial signs of distress.

We collected data from 274 patients in the university hospital, and 71 and 70 cases from the community hospitals. An explicit spacing trial was noted in 52 of 274 (19%) university hospital records vs. 3 of 141 (2%) community hospital records, with a difference of 17% (95% confidence interval [CI] 11-23%). Delayed patient decompensation occurred in 3%, with no difference between hospitals. Spacing trials were associated with an adjusted mean of 159 min (95% CI 102-217 min) increase in ED stay.

The practice of spacing varies widely between hospitals and is associated with substantial delay without an apparent benefit.