The use of cusum analysis in the early detection and management of hospital bed occupancy crises

Abstract

Objective: To assess the value of cusum analysis in hospital bed management. Design: Comparative analysis of medical patient flows, bed occupancy, and emergency department admission rates and access block over 2 years. Setting: Internal Medicine Services and Emergency Department in a teaching hospital. Interventions: Improvements in bed use and changes in the level of available beds. Main outcome measures: Average length of stay; percentage occupancy of available beds; number of patients waiting more than 8 hours for admission (access block); number of medical patients occupying beds in non‐medical wards; and number of elective surgical admissions. Results: Cusum analysis provided a simple means of revealing important trends in patient flows that were not obvious in conventional time‐series data. This prompted improvements in bed use that resulted in a decrease of 9500 occupied bed‐days over a year. Unfortunately and unexpectedly, after some initial improvement, the levels of access block, medical ward congestion and elective surgical admissions all then deteriorated significantly. This was probably caused by excessive bed closures in response to the initial improvement in bed use. Conclusion: Cusum analysis is a useful technique for the early detection of significant changes in patient flows and bed use, and in determining the appropriate number of beds required for a given rate of patient flow.

Access block and ED overcrowding

“…Historical and prospective data show that when bed occupancy rates are reduced towards 85%, this facilitates patient transfers to the wards, which in turn frees up space in the ED to see and process new patients. This then reduces ED length of stay, 2,20,23,30 ambulance diversion rate 21,25 and theatre cancellations 21 …”

“…The rate of ED presentations per 1000 population in Australia has increased from 202 in [2003][2004] [15][16][17] Bed occupancy rates in most hospitals exceed 85% as a result of the increased demand and bed shortages, a level which is considered the maximum for efficient care and surge capacity. 2,6,7,14,[18][19][20][21][22][23][24] Increased patient mortality associated with access block and overcrowding Access block and overcrowding are associated with increased patient mortality. Different authors have estimated that there is a 20-30% excess mortality rate…”

“…Multifaceted, multidisciplinary and hospital interventions are believed more likely to improve health outcomes than single-faceted and single hospital interventions. 13,14 However, 89% of the evidence reported in Table 2 derives from single hospital interventions [19][20][21][22][23][25][26][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]46,[49][50][51][52][53][54][55][56][57][58][59][60][61][62][63]65,[67][68][69][70][71] and only 11% from multicentre interventions. 27,45,...…”

Emergency department crowding

“…Cameron et al ,82 Burns et al 83 and Yancer et al 84 have demonstrated the potential efficacy of a broad strategy. Munro et al ,85 in a paper from the UK, described a multiplicity of temporary interventions used to bring EDs under the 4 h standard during a ‘monitoring week’.…”

The NHHRC final report: view from the hospital sector

“…In the United Kingdom's National Health Service (NHS), up to 75% of all elective operations have been converted into day‐only cases, 17 compared with 55% in Australia. Achieving a daily balance between acute and elective hospitalisations and between admissions and discharges by means of anticipatory monitoring of bed status and responsive bed management systems, 18 driven by dedicated patient flow directors and 7‐day‐a‐week discharges, can also help avoid bed crises that are slow to resolve.…”