Optimizing physician staffing and resource allocation: sine-wave variation in hourly trauma admission volume.

BACKGROUND: Trauma centers are faced with the challenge of managing an increasing volume of patients in an era of fewer trauma care providers and fewer hospitals providing trauma care. The purpose of this study was to determine the relationship between hourly admission volume, injury severity, resource utilization, and outcomes.
METHODS: All patients in the National Trauma Data Bank admitted between 1999 and 2002 were selected. Analysis included demographics, temporal information, injury severity, and outcome parameters.
RESULTS: A total of 421,997 patients were admitted to participating centers. The 24-hour admission distribution described a sine-wave pattern with a trough at 6:00 am and a peak at 7:00 pm. The sine-wave pattern persisted regardless of the subgroup analyzed. Patients admitted between 12:00 am and 6:00 am were more likely to be severely injured, require intensive care unit admission, undergo emergent operation, and die during hospitalization when compared with patients admitted between 7:00 am and 12:00 pm.
CONCLUSIONS: Trauma admissions conform to a sine-wave pattern with a 3.5-fold increase in admissions between morning and evening hours. This has significant implications for manpower and resource allocation with additional resources needed in the hours around 7:00 pm and later. Educational and administrative activities are best scheduled during low-volume morning hours. Nighttime admissions are higher risk and thus more likely to need senior-level expertise and consume hospital resources. Trauma centers should use these findings to improve outcomes by developing optimal staffing patterns and matching resource allocation to need as a function of time.