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Original Research

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

  • Li-Heng Tsai1
  • Wei-Che Chien1
  • Chen-Bin Chen1,2
  • Shang-Li Tsai2,3
  • Chung-Hsien Chaou1
  • Yi-Ming Weng1,4
  • Chip-Jin Ng1
  • Chen-June Seak1,2
  • Shou-Yen Chen1
  • Chien-Hsiung Huang1
  • Shao-Yu Fang1
  • Chi-Chun Lin1,5
  • Cheng-Yu Chien1,5

1Department of Emergency Medicine, Chang Gung Memorial Hospital, Linkou branch and College of Medicine, Chang Gung University, Tao-Yuan, Taiwan

2Department of Emergency Medicine, New Taipei Municipal Tucheng Hospital, New Taipei City, Taiwan

3Department of Emergency Medicine, Chang Gung Memorial Hospital, Keelung Branch, Taiwan

4Department of Emergency Medicine, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan, Taiwan

5Department of Emergency Medicine, Ton-Yen General Hospital, Zhubei, Taiwan

DOI: 10.22514/sv.2021.029

Online publish date: 08 February 2021

*Corresponding Author(s): Cheng-Yu Chien E-mail:


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.


Emergency department; Cardiac arrest; Crowding; Nursing staff

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Li-Heng Tsai,Wei-Che Chien,Chen-Bin Chen,Shang-Li Tsai,Chung-Hsien Chaou,Yi-Ming Weng,Chip-Jin Ng,Chen-June Seak,Shou-Yen Chen,Chien-Hsiung Huang,Shao-Yu Fang,Chi-Chun Lin,Cheng-Yu Chien. Association of patient-to-emergency department staff ratio with the incidence of cardiac arrest: A retrospective cohort study. Signa Vitae. 2021.doi:10.22514/sv.2021.029.


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