Flow impacts of hot/cold zone infection control procedures during the COVID-19 pandemic in the emergency department

Abstract

Background: The COVID-19 pandemic forced emergency departments (EDs) to change operations to minimize nosocomial infection risk. Many EDs cohort patients using provincial screening tools at triage. Despite cohorting, staff exposures occurred in the ‘cold zone’ due to lack of personal protective equipment (PPE) use with patients deemed low risk, resulting in staff quarantines. The cohorting strategy was perceived to lengthen time to physician initial assessment and ED length of stay times in our ED without protecting staff well enough due to varying PPE use. The objective of this study was to assess the impact of hot/cold zones for patient cohorting during a viral pandemic on ED length of stay. Methods: We conducted an interrupted time series analysis 3 weeks before and after the removal of hot/cold zone care space cohorting in our ED. In the before period, staff did not routinely wear full PPE to see cold zone patients. After removal, staff wore full PPE to see almost all patients. We collected data on ED length of stay, physician initial assessment times, arrival-to-room times, patient volumes, Canadian Triage Acuity Score (CTAS), admissions, staff hours of coverage, as well as proportions of patients on droplet/contact precautions and COVD-19 positive patients. The primary outcome was median ED length of stay. Results: After the removal of the hot/cold divisions, there was a decrease in the adjusted median ED length of stay by 24 min (95% CI 14; 33). PPE use increased in the after arm of the study. The interrupted time series analysis suggested a decrease in median ED length of stay after removal, although the change in slope and difference did not reach statistical significance. Conclusion: Cohorted waiting areas may provide a safety benefit without operational compromise, but cohorting staff and care spaces is likely to compromise efficiency and create delays.