Fig 1.
System architecture for the proposed model.
It shows the centralised-decentralised approach to PPE supply chain.
Table 1.
Notations and associated definitions.
Fig 2.
Total and peak occupied hospital beds with illness related to COVID-19 in the seven regions of NHS England up to and including 01 Aug 2020.
Data to produce the background map in Fig 2 is from the UK Office of National Statistics, 2019 licensed under the Open Government License [39].
Table 2.
Storage capacities of the seven NHS England regions.
Fig 3.
Millions of PPE sets required daily nationally (dotted line), ordered daily nationally (bold line) according to the game, and stored in each of the seven regions of NHS England (coloured areas).
Here, stockpiling started on 28 Feb, standard storage capacity was multiplied by five and the peak of the second wave is expected to happen in mid October. Stored PPE sets for each region is stacked on top of each other in order to show the cumulative PPE stock of all regions to illustrate the game mechanism. Note that the areas are scaled down by a factor of five in order to make the figure more readable.
Fig 4.
Comparison between the outcome of three different scenarios, a reference scenario (without scheduling), when stockpiling starts on 11 Mar and when it starts on 07 Feb and storage capacities are multiplied by 10.
This shows that cumulative cost saving can represent the challenge level of securing PPE supply. A colour grading is applied to represent the level of this challenge, where dark red is used for the highest challenge level and green for the lowest.
Fig 5.
Challenge in terms of fulfilling PPE demand delivery according to the amount of available storage capacity (x-axis), the stockpiling starting date in 2020 (y-axis), and the peak date of a putative second wave of COVID-19 (each cell in the grid is divided in five stripes corresponding, from top to bottom, to peak dates in October, November, December 2020, January and February 2021).
Fig 6.
Challenge in terms of fulfilling PPE demand delivery according to the amount of available storage capacity (x-axis) and the peak date of a putative second wave of COVID-19 (y-axis).
Fig 7.
Effect of increasing storage capacity on the outcome of the game in terms of aggregate PPE demand.
These results are for a second wave where PPE demand peaks in mid November.