The effect of emergency department crowding on length of stay and medication treatment times in discharged patients with acute asthma.

Objectives: This study sought to determine if emergency department (ED) crowding was associated with longer ED length of stay (LOS) and time to ordering medications (nebulizers and steroids) in patients treated and discharged with acute asthma and to study how delays in ordering may affect the relationship between ED crowding and ED LOS.
Methods: A retrospective cohort study was performed in adult ED patients aged 18 years and older with a primary International Classification of Diseases, 9th Revision (ICD-9), diagnosis of asthma who were treated and discharged from two EDs from January 1, 2007, to January 1, 2009. Four validated measures of ED crowding (ED occupancy, waiting patients, admitted patients, and patient-hours) were assigned at the time of triage. The associations between the level of ED crowding and overall LOS and time to treatment orders were tested by analyzing trends across crowding quartiles, testing differences between the highest and lowest quartiles using Hodges-Lehmann distances, and using relative risk (RR) regression for multivariable analysis.
Results: A total of 1,716 patients were discharged with asthma over the study period (932 at the academic site and 734 at the community site). LOS was longer at the academic site than the community site for asthma patients by 90 minutes (95% confidence interval [CI] = 79 to 101 minutes). All four measures of ED crowding were associated with longer LOS and time to treatment order at both sites (p < 0.001). At the highest level of ED occupancy, patients spent 75 minutes (95% CI = 58 to 93 minutes) longer in the ED compared to the lowest quartile of ED occupancy. In addition, comparing the highest and lowest quartiles of ED occupancy, time to nebulizer order was 6 minutes longer (95% CI = 1 to 13 minutes), and time to steroid order was 16 minutes longer (95% CI = 0 to 38 minutes). In the multivariable analysis, the association between ED crowding and LOS remained significant. Delays in nebulizer and steroid orders explained some, but not all, of the relationship between ED crowding and ED LOS.
Conclusions: Emergency department crowding is associated with longer ED LOS (by more than 1 hour) in patients who ultimately get discharged with asthma flares. Some but not all of longer LOS during crowded times is explained by delays in ordering asthma medications.