The rise in UK births has placed maternity units under strain and high occupancy may lead to sub-standard care or service.
The Erlang equation helps planners in many industries to calculate the number of service points (for example, check-outs, telephones or beds) where the arrival rate (admissions) and average service time (length of stay) are known. It also calculates turn-away – the time that the service (a bed) will not be available for the next arriving client (mother).
Figure 1 shows available beds and occupancy levels in maternity units across England for the last quarter (January to March) of 2010/11 and the first quarter (April to June) of 2011/12.
Superimposed are lines of constant turn-away, as calculated by the Erlang equation. A maternity unit will have sufficient beds when it is operating below 0.1% turn-away, although below 1% is tolerable. A figure of 0.1% implies that, on one in 1000 occasions, a bed is not available. As turn-away rises, so does operational inefficiency, as the unit increasingly operates at 100% occupancy.
Most maternity units appear to be operating below 0.1% turn-away and, on the face of it, some could even operate safely with slightly fewer beds.
However, the 35 hospitals operating above 1% turn-away are a potential concern. A further 30 hospitals lie between 0.1% and 1%, so are in danger of providing poor service should births rise. The large maternity units (>100 beds) are generally operating with a comfortable occupancy margin; the problem appears to lie with units with fewer than 60 beds.
All the hospitals operating above 1% turn-away need to increase available beds to bring occupancy to an acceptable level.
The next point of relevance is the flawed assumption behind the
one-price-for-all sized units represented by the Healthcare Resource
Group (HRG) tariff. Figure 1 demonstrates how larger maternity units can
operate at higher average occupancy. The tariff is calculated at the
national average, so the point at which the average costs for maternity
HRG will be determined is for units with 59 beds and 61% average
occupancy, such as roughly at 0.1% turn-away for 59 available beds.
However, as smaller units can not make economies of scale, they will
experience cost pressures.
One-size-fits-all solutions just do not work in the real world of health care and especially not in the case of maternity.
Dr Rod Jones is a statistical adviser at Healthcare Analysis and Forecasting, in Camberley
Data was obtained from
http://bit.ly/DHstats.
If you would like to contact Dr Rod Jones, email:
hcaf_rod@yahoo.co.uk
References
Jones R. (2009a) Limitations of the HRG tariff: local adjustments.
British Journal of Healthcare Management 15(3): 144-7.
Jones R. (2009b) Emergency admissions and hospital beds.
British Journal of Healthcare Management 15(6): 289-96.
Jones R. (2011a) Hospital bed occupancy demystified and why hospitals of different size and complexity must operate at different average occupancy.
British Journal of Healthcare Management 17(6): 242-8.
Jones R. (2011b) A&E performance and inpatient bed occupancy.
British Journal of Healthcare Management 17(6): 256-7.
