Purpose: Emergency department (ED) CT utilization rates are steadily increasing. The aim of this study is to evaluate ED CT usage variability over different days of the weeks and calendar months.
Materials and Methods: All one tertiary hospital`s adults (≥18) ED visits were collected during a time frame of two calendar years (1/2015 – 12/2016). Data was retrieved from the hospital`s computerized records and included patients` demographics, date of ED visits and documentation of CT usage for each patient. The days of the week (Sunday to Saturday) and the calendar months (January to December) were retrieved using Microsoft Excel formulas. One-way ANOVA with Tukey post hoc test evaluated distribution differences between groups.
Results: Overall, during the study period there were 223,438 ED visits and 45,674 CT examinations. This constituted a CT utilization rate of 20.4% (number of CTs/number of ED visits). The average number of daily ED visits was 305.7±55.8 (176 - 443). Highest number of daily ED visits were observed in the first weekday (Sunday) 375.2±34.5 (p<0.001) and lowest in the two weekend days, Friday 255.9±21.8 (p<0.001) and Saturday 222.2±17.2 (p<0.001).
The average number of CTs per day of the week was 62.3±12.9 (26 - 95). A peak of CT usage was seen during the first weekday (Sunday) with 71.5±11.1 CTs (p<0.001), and a trough was seen in the two weekend days, Friday 57.7±9.0 (p<0.001), and Saturday 45.0±8.4 (p<0.001). CT utilization rate was significantly higher on Fridays with a rate of 22.6% (p<0.001) in comparison to an average daily rate of 20.5%.
The average monthly ED visits rate was 9,309.9±370.8 and the average monthly number of performed CTs was 1,896.5±88.1. There was no statistical difference between months for both ED visits (p=0.391) and number of CT examinations (p=0.311).
Conclusions: The highest numbers of ED visits and performed CTs were seen on the first weekday versus the lowest numbers seen in the two weekend days can be explained either by the tendency of religious patients to avoid when possible driving to medical facilities or by lower referrals from Family Physicians during weekends. There were no significant differences between the calendar months, both for ED visits and for performed CTs. Higher CT utilization rate on the weekend could be explained by lower patient load and by the fact that staff on weekends usually is less experienced compared to weekdays. Analysis of large data sets can help in the management of facilities’ resources, and also identify potential over usages.
