National Emergency Access Targets metrics of the emergency department-inpatient interface: Measures of patient flow and mortality for emergency admissions to hospital

Abstract

Background. Movement of emergency patients across the emergency department (ED)-inpatient ward interface influences compliance with National Emergency Access Targets (NEAT). Uncertainty exists as to how best measure patient flow, NEAT compliance and patient mortality across this interface. Objective. To compare the association of NEAT with new and traditional markers of patient flow across the ED-inpatient interface and to investigate new markers of mortality and NEAT compliance across this interface. Methods. Retrospective study of consecutive emergency admissions to a tertiary hospital (January 2012 to June 2014) using routinely collected hospital data. The practical access number for emergency (PANE) and inpatient cubicles in emergency (ICE) are new measures reflecting boarding of inpatients in ED; traditional markers were hospital bed occupancy and ED attendance numbers. The Hospital Standardised Mortality Ratio (HSMR) for patients admitted via ED (eHSMR) was correlated with inpatient NEAT compliance rates. Linear regression analyses assessed for statistically significant associations (expressed as Pearson R coefficient) between all measures and inpatient NEAT compliance rates. Results. PANE and ICE were inversely related to inpatient NEAT compliance rates (r=0.698 and 0.734 respectively, P<0.003 for both); no significant relation was seen with traditional patient flow markers. Inpatient NEAT compliance rates were inversely related to both eHSMR (r=0.914, P=0.0006) and all-patient HSMR (r=0.943, P=0.0001). Conclusions. Traditional markers of patient flow do not correlate with inpatient NEAT compliance in contrast to two new markers of inpatient boarding in ED (PANE and ICE). Standardised mortality rates for both emergency and all patients show a strong inverse relation with inpatient NEAT compliance. What is known about the topic? Impaired flow of emergency admissions across the interface between ED and inpatient wards retards achievement of NEAT-compliance rates and adversely affects patient outcomes. Uncertainty exists as to which measures of patient flow and mortality outcomes correlate closely with NEAT-compliance rates for patients admitted from emergency departments. What does this paper add? This study investigates the utility of two new markers of patient flow from ED to inpatient wards. The Practical Access Number for Emergency (PANE) is the number of patients in ED who have had their episode of ED care completed and are awaiting an inpatient bed at a particular point in time. The Inpatient Cubicles in Emergency (ICE) represents the theoretical number of ED cubicles blocked by boarding patients over a specified time interval (in this study 5 weekdays, Monday-Friday), based on the mean time boarders spent in ED during that interval. Both measures were shown to be significantly inversely related to inpatient NEAT compliance rates (i.e. as PANE and ICE increased, NEAT compliance decreased). In contrast, no relation was seen with traditional markers of patient flow (i.e. hospital bed occupancy and ED attendance numbers). HSMR for both all patients and emergency patients only demonstrated a strong inverse relation with inpatient NEAT compliance. What are the implications for practitioners? When pursuing higher NEAT compliance rates, traditional markers of patient flow across the ED-inpatient interface may be misleading and adversely impact bed-management strategies and patient safety. Identifying when hospitals may be at risk of developing, or already in, a state of reduced access to emergency care may be performed more accurately using new flow markers such as PANE and ICE. The inverse relationship between inpatient NEAT compliance and HSMR, whether calculated for all patients or for emergency patients only, underscores the dependence of inpatient mortality on the swift flow of large volumes of emergency admissions across the ED-inpatient interface. This flow may be compromised by imposing additional demands on a limited number of commissionable beds by way of increasing ED demand and/or use of more beds for elective admissions.