Variability and Overcrowding Management

Abstract

Emergency department (ED) overcrowding has become a common situation with significant negative effects on the quality of care. The aim of this study is to detail the flow of patients and their variability and determine the existence of stable patterns that allow better planning of resources. We performed a retrospective descriptive observational study of emergencies attended from 2008 to 2010 in the ‘Juan Ramón Jiménez’ General Hospital (Huelva, Spain), with a sample of 343,233 visits. The time between consecutive arrivals of patients and the arrival patterns according to severity and clinical area was calculated using Microsoft Excel and Stat::Fit. Quarterly differences were determined using the Kruskal–Wallis test. The mean value of the inter-arrival time, independent of the quarter ( p < 0.05), was 2–4 minutes from 10:00 am to 10:00 pm and 15–20 minutes from midnight to 8:00 am. The Priority (P) I Patients arrived every 119.05 ± 136.71 minutes, the PII patients every 75.96 ± 97.58 minutes, the PIII patients every 22.62 ± 33.47 minutes and the PIV patients every 6.37 ± 10.53 minutes. PIV had a fluctuating pattern. The arrival rate peaks at 1:00 pm on Monday in the medical–surgical area, at 10:00 pm on Monday for the trauma area, and at 1:00 pm on Sunday for the paediatric area. The study shows that inter-arrival times and average arrival rates of patients have a defined and reproducible pattern for each level of severity and clinical area, which forces us to rethink the fixed capacity model and oriented towards flexibility of resources to reduce the overcrowding.