28 The effect of paediatric emergency department wait time on diagnostic resource use

Background Emergency department (ED) crowding and prolonged wait times can impact the experience and satisfaction of patients, caregivers, and clinicians. However, little is known about how ED wait times affect clinical decision-making. No studies have examined the relationship between paediatric ED wait times and diagnostic resource use. Objectives The primary objective of the study is to examine the association between time spent waiting to see a physician and diagnostic testing for children in the paediatric ED. Design/Methods This is a retrospective cross-sectional health records study of ED visits at a tertiary care paediatric hospital from January 1, 2021, to December 31, 2023, with a chief complaint of fever, shortness of breath, cough / congestion, or abdominal pain assigned a Canadian Triage Acuity Scale (CTAS) score of 3-5. The primary outcome was having at least one of the following investigations ordered: bloodwork, x-ray, ultrasound, throat swab, or CT scan. We conducted a multivariable logistic regression to determine the relationship between wait time and the odds of investigation, adjusted for CTAS score, chief complaint, and patient age. We repeated the analysis for the first encounter only and for encounters discharged home. Results There were 43,722 ED encounters that met the inclusion criteria with a median patient age of 3.2 years (Interquartile Range [IQR] 1.3, 7.1). Of these, 94% were discharged home, 5% were admitted, and 1% were sent to clinic. Chief complaints included fever (44%), cough / congestion (23%), abdominal pain (21%), and shortness of breath (12%). The median (IQR) wait time was 3.7 (1.7, 4.9) hours. Investigations were ordered in 35% of encounters, which included x-rays (19%), bloodwork (17%), ultrasounds (9%), throat cultures (3%), and CT scans (1%). Among the 28,083 children waiting <=4 hours, each additional hour was associated with 7% lower odds of investigation (Odds Ratio [OR] 0.93, 95% Confidence Interval [CI] 0.90, 0.95, p<0.001). For the 15,639 children waiting >4 hours, each additional hour was associated 4% higher odds of investigation (OR 1.04, 95% CI 1.02, 1.05, p<0.001). Sensitivity analyses displayed similar results when encounters discharged home (n=39,441) and only the first ED encounter (n=32,291) were analyzed separately. Conclusion Wait times longer than 4 hours in the paediatric ED are associated with increased use of diagnostic resources, even in lower acuity patients who were discharged home. Further studies can investigate whether shortening paediatric ED wait times reduces potentially unnecessary diagnostic testing.