Western Journal of Emergency Medicine: Integrating Emergency Care with Population Health

Introduction: Emergency department (ED) surge events, defined as the episodic clustering of high-acuity patients that transiently overwhelms available clinician capacity, are associated with delays in care and potential patient harm. Existing crowding metrics do not quantify real-time clinician-level workload. This paper describes the development and preliminary feasibility evaluation of a novel acuity-weighted metric—the cumulative weighted-average acuity level (CWAAL)—to detect physician-level surge conditions in real time.

Methods: This multiphase observational feasibility study was conducted at two rural community EDs. The CWAAL is defined as the sum of weighted acuity scores for all active patients under a single clinician’s management: it incorporates a feasibility threshold derived by combinatorial enumeration. The primary outcome was door-to-doctor time (DDT); secondary outcomes included length of stay (LOS) and CWAAL distribution. The DDT comparisons at Hospital B (n = 4 surge events per condition) used the Mann-Whitney U test. All data were obtained from the practice of a single physician.

Results: We evaluated a single emergency physician across 354 patients on 10 study dates at two rural community EDs, tracking 11 surge events and one proof of concept. A CWAAL feasibility threshold of ≤ 12 (±1)—equivalent to four simultaneous Level 3 patients (~120 minute demand within a 60-minute window)—emerged consistently across both sites. At Hospital B, surge-period DDTs were substantially lower with advanced practice clinician (APC) coverage than without (median, 31.5 minutes [interquartile range {IQR}, 24.7–38.0] vs 107.7 minutes [IQR, 85.7–133.5]); Mann-Whitney U = 0, P = .03, 2-tailed exact; rank-biserial r = 1.0), with complete distributional separation across eight surge events. All APC-supported events occurred at CWAAL ≤ 12; all unsupported events at CWAAL > 12. A proof-of-concept application on May 28, 2024, demonstrated operational feasibility; supplemental staffing reduced the physician’s weighted acuity burden by 31 points and normalized DDT and LOS.

Conclusion: In this development cohort, the physician reached functional care capacity at cumulative weighted average acuity level = 12 (four simultaneous Level 3 patients; ~120 minutes demand within a 60-minute physician-hour). Complete separation of APC-supported and unsupported outcomes across eight events supports this novel acuity-weighted metric as a meaningful operational signal. Formal prospective validation across independent datasets is required before generalizing.