The Risk of Cross Infection in the Emergency Department: A Simulation Study

Abstract

OBJECTIVESThe risk of cross infection in a busy emergency department (ED) is a serious public health concern, especially in times of pandemic threats. We simulated cross infections due to respiratory diseases spread by large droplets using empirical data on contacts (ie, close-proximity interactions of ≤1m) in an ED to quantify risks due to contact and to examine factors with differential risks associated with them.DESIGNProspective study.PARTICIPANTSHealth workers (HCWs) and patients.SETTINGA busy ED.METHODSData on contacts between participants were collected over 6 months by observing two 12-hour shifts per week using a radiofrequency identification proximity detection system. We simulated cross infection due to a novel agent across these contacts to determine risks associated with HCW role, chief complaint category, arrival mode, and ED disposition status.RESULTSCross-infection risk between HCWs was substantially greater than between patients or between patients and HCWs. Providers had the least risk, followed by nurses, and nonpatient care staff had the most risk. There were no differences by patient chief complaint category. We detected differential risk patterns by arrival mode and by HCW role. Although no differential risk was associated with ED disposition status, 0.1 infections were expected per shift among patients admitted to hospital.CONCLUSIONThese simulations demonstrate that, on average, 11 patients who were infected in the ED will be admitted to the hospital over the course of an 8-week local influenza outbreak. These patients are a source of further cross-infection risk once in the hospital.Infect Control Hosp Epidemiol 2018;39:688-693.

FIGURE 1

Risk of cross infection from infectious patient or infectious healthcare worker (HCW). Number of other participants infected (column) by 1 infectious person present in the emergency department (ED) (row), according to participant role (patient or HCW), over 10,000 simulations. Middle line indicates median; open diamond symbol is mean; upper and lower edges are placed at the 75th and 25th percentiles, respectively. Whiskers are placed at 1.5 times interquartile range beyond the 75th and 25th percentiles. Open circles indicate observations beyond the whisker values.

FIGURE 2

Average number of other participants infected by participant type, healthcare worker (HCW) role expanded. Number of other participants (column) infected by infectious person present in the emergency department (ED) (row), according to participant role (patient or HCW) with HCW role classified as provider, nurse, or staff. Middle line indicates median; open diamond symbol is mean; upper and lower edges are placed at the 75th and 25th percentiles, respectively. Whiskers are placed at 1.5 times the interquartile range beyond the 75th and 25th percentiles. Open circles indicate observations beyond the whisker values.