No relationship between emergency department activity and triage categorization

Objective: To examine the consistency of Australasian National Triage Scale (NTS) categorization in a large hospital ED, especially in relation to daily activity. Methods: This was a prospective, observational study of the relationship between NTS category, presenting features, and disposition in a large Australian adult ED. The "admission rate" was defined as the percentage of presentations whose dispositions were recorded as admitted to hospital, transferred to another hospital for admission, or died in the ED, A "busy" weekday was defined as one during which >140 presentations were recorded in the 24 hours from midnight. For a "busy" weekend day, a figure of 100 presentations in 24 hours was used. "Nonbusy" days were defined as those during which presentation numbers were less than or equal to these thresholds. Results: Data describing triage and disposition were available for 94,681 presentations in the 2-year period, representing 100% of ED presentations. "Busy" weekday admission rates in the 5 triage categories were 93.2%, 67.6%, 43.6%, 15.4%, and 1.6%, respectively. "Nonbusy" weekday admission rates were 91.4%, 68.3%, 43.7%, 15.6%, and 2.0%. Weekend days had a higher admission rate in NTS category 4 and 5 patients, but none of the differences between "busy" and "nonbusy" days reached statistical significance at the 0.05 level. Admission rates varied according to the time of day of presentation and increased with age, but did not change significantly over the 2 years of the study. Conclusions: In this ED, triage categorization according to the Australasian NTS does not vary with daily activity and has been consistent over time. Further study in other settings is required, particularly to identify variation dependent on the presenting population.