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• Flows through beds not occupancy
  Matthew W Cooke
  Published on: 29 April 2016

• Published on: 29 April 2016

  Flows through beds not occupancy

  • Matthew W Cooke
  • Other Contributors:
    • Stephen Black, Adrian Fletcher, Mark Jennings

  Dear Editor

  The article by Cooke et al. [1] on the relationship between A&E performance and average bed occupancy is based on data collected in 2002. Other have recognised an association between occupancy and delays in emergency care in USA[2] and Australia[3]. Recently there have been significant advances in our understanding of that relationship and we believe some of the recent results are worth repo...

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  Dear Editor

  The article by Cooke et al. [1] on the relationship between A&E performance and average bed occupancy is based on data collected in 2002. Other have recognised an association between occupancy and delays in emergency care in USA[2] and Australia[3]. Recently there have been significant advances in our understanding of that relationship and we believe some of the recent results are worth reporting. In 2003 and 2004 the Department of Health conducted a number of detailed surveys of Acute trusts' operations (some focussing on A&E activity, most recently focussing on flows into and out of beds). The A&E surveys revealed that two of the major causes of delay were related to the process of getting patients into beds, thus providing more direct evidence that the state of beds affects A&E performance. We also observed that these delays were concentrated at certain times and on certain days. However, we were prompted to get more detailed evidence about the flows through beds because the observed correlation with A&E performance was so weak. Surely we should be seeing a stronger effect if beds are such the major cause of A&E delay?

  Our survey of bed flows explained much of this paradox. We asked trusts to record the timing of all arrivals and departures from their beds (classified by some simple categories such as elective or emergency admissions) over the course of a week. For those trusts who provided reasonably consistent data (many were unable to do so) we were able to calculate an hourly bed availability. This hourly position generated major insights, some of which we describe below.

  Key insights:

  * The reported weekly bed occupancy (which is measured at midnight Thursday) is unrepresentative of the actual occupancy across the week. For there to be no delays, sufficient beds need to be available 168 hours every week, not just in the 1 hour sampled for the national returns.

  * Hourly occupancy can vary greatly across a single day (sometimes moving from the 70%s to the high 90%s or more). The highest peaks tend to occur in the middle of the day but are often cleared by the evening (see graph).

  * Different days (and weeks) may show very different peaks in occupancy. Often only one or two days in a week show extremes of occupancy likely to result in knock-on effects in A&E.

  * The fluctuations in bed occupancy are not primarily the result of the randomness of A&E admissions (which are predictable within bounds). The dominant driver is the variability and unpredictability of elective arrivals (which, in many trusts, occur at the worst possible time of day or day of week) and the lack of coordination of the controllable flows (discharges and elective arrivals) with emergencies and with each other. It is not uncommon to observe very low levels of discharge over a weekend. Emergencies continue to arrive, therefore using up beds. Then, first thing on Monday morning, the peak arrival of elective patients occurs (coinciding with the daily emergency peak and perhaps 4 or 5 hours before any discharges). The result is very poor bed availability by lunchtime on Monday.

  A separate analysis of changes in performance over a six month period showed no correlation between this and change in bed occupancy (as collected in national data in Cooke's study, using same methodology, correlation coefficient r2=0.097, p=0.24). This reinforced our belief that to gain useful insight into the relationship between bed occupancy and performance we need to study the detailed hourly flows across the week.

  Our observations explain both why bed availability is such a big issue for A&E and why the reported statistics do not reflect the strength of the relationship. Also, we can see from our datasets that relatively small variations in any flow can have large consequences for peak bed occupancy so shortages may appear to be quite sporadic (perhaps occurring one week in 4 rather than all the time).

  But the most important message from our work is that big improvements are possible if trusts are prepared to manage their beds actively. The extreme peaks we observed in bed use were always the result of a failure to coordinate different flows. While there is little trusts can do to manage emergency flows into beds, these are relatively predictable. Discharges and Elective admissions are-or should be-mostly within the control of trusts. Improved coordination (eg more morning discharges and more afternoon arrivals) can reduce or eliminate extreme peaks in bed occupancy.

  The nationally reported point availability of beds does not provide adequate information for the operational management of beds through the week. Hospital Trusts need a complete picture at least hour by hour if they are to manage beds so that beds are available when needed. The benefits of better coordination will reduce the frequency of both A&E delays and cancelled elective activity (even though these have often been seen as opposing goals). The goal of policy now needs to move beyond the improved supply of beds to the improved management of the flows through beds.

  References

  1. Cooke MW, Wilson S, Halsall J, Roalfe A. Total time in English accident and emergency departments is related to bed occupancy. Emerg Med J. 2004 Sep;21(5):575-6.

  2. Alan J. Forster, Ian Stiell, George Wells, Alexander J. Lee, and Carl van Walraven The Effect of Hospital Occupancy on Emergency Department Length of Stay and Patient Disposition Acad Emerg Med 2003 10: 127-133.

  3. Dunn R. Reduced access block causes shorter emergency department waiting times: An historical control observational study. Emerg Med (Fremantle). 2003 Jun;15(3):232-8

  Declaration: All the authors are either employed by or partially funded by the Dept of Health.

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  Conflict of Interest:
  None declared.

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