New research from the UBC Sauder School of Business reveals that Metro Vancouver emergency patient acuity levels sometimes come second to wait time targets, largely due to doctors being unclear on existing emergency room prioritization guidelines. The study found that patient acuity levels are considered more seriously once wait time targets have passed.

The study is the first of its kind to statistically analyze doctor decision making in the emergency room and the impacts it can potentially have. Through an analysis of more than 186 000 emergency department admissions between April 2013 and November 2014 in the four largest emergency departments in Metro Vancouver, the researchers modeled how decision-makers chose which patient was seen by the next available physician.

Metro Vancouver emergency departments currently use the Canadian Triage and Acuity Scale (CTAS) to classify patients into priority levels. While each level, ranging from one to five (most acute/serious to least acute/serious) has a suggested wait time for patients, it can still be difficult for ED physicians to decide who should be seen next.

Researchers found that once triage level-2 patients waited beyond 13.3 minutes and triage level-3 patients waited beyond 18.9 minutes, physicians put more consideration on other attributes, such as acuity level, chief complaint system, age, and so on, rather than waiting time.

The study’s authors suggest future policy revision should call for detailed guidelines on how wait times can be weighed against the patient’s acuity level, rather than simple targets based on wait times.

The article, “Patient prioritization in emergency department triage systems: An empirical study of Canadian Triage and Acuity Scale (CTAS),” was published in the journal Manufacturing & Service Operations Management.