Association of patient-to-emergency department staff ratio with the incidence of cardiac arrest: A retrospective cohort study

Abstract

Background: Emergency department (ED) overcrowding and overuse are global healthcare problems. Despite that substantial pieces of literature have explored quality parameters to monitor the patients’ safety and quality of care in the ED, to the best of our knowledge, no reasonable patient-to-ED staff ratios were established. Objectives: This study aimed to find the association between unexpected emergency department cardiac arrest (EDCA) and the patient-to-ED staff ratio. Methods: A retrospective cohort study was conducted in a medical center in Taiwan. Non-trauma patients (age > 18) who visited the ED from January 1, 2016 to November 30, 2018 were included. The total number of patients in ED, number of patients waiting for boarding, length of stay over 48 hours, and physician/nurse number in ED were collected and analyzed. The primary outcome was the association of each parameter with the incidence of EDCA. Results: A total of 508 patients were included. The total number of patients in ED (> 361, RR: 1.54; 95% CI {1.239-1.917}), ED occupancy rate (> 280, RR: 1.54; 95% CI {1.245-1.898}), ED bed occupancy rate (> 184, RR: 1.63; 95% CI {1.308-2.034}), number of patients waiting for boarding (> 134, RR: 1.45; 95% CI {1.164-1.805}), number of patients in ED with length of stay over 48 hours (> 36, RR: 1.27; 95% CI {1.029-1.558}) and patient-to-nurse ratio (> 8.5, adjusted RR: 1.33; 95% CI {1.054-1.672}) had significant associations with higher incidence of EDCA. However, the patient-to-physician ratio was not associated with EDCA incidence. Discussions: Regarding loading parameters, the patient-to-nurse ratio is more representative than the patient-to-physician ratio as regards association with higher EDCA incidence. Conclusions: A higher patient-to-nurse ratio (> 8.5) was associated with an increment in the incidence of EDCA. Our findings provide a basis for setting different thresholds for different ED settings to adjust ED staff and develop individually tailored approaches corresponding to the level of ED overcrowding.