BOOKS OF RtfiDIfGS - PAHO/WHO

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Once thc planning phase is completed, hospitais are assigned to delivery routes.
These delivery routes are constrained lo provide for deliveries lo aill hospitals at a fixed
time each delivery day. Delivery day intevals are cither one, two, or four days,
dclpendiíng on ihe size of lhe hospital alid special requirements or strong preferences
expressed. Froni these assigniments "regional distribution sumniaries" per delivcry day
are prepare(l for eval:uation. Thlcsc ae revised as needed to equalize the amnount of blood
distributed cach day as far as possible. Individual hospital "sumnmaries of delivery
schcdules" anid of 'desired inventory levels" are then prepared and sent lo all HBB's.
After discussions during which the above distribution schedules are confirmed or
modified as required andtl extensive educational sessions with the HBB's' management
and operational personnel take place, thle operation is ready to start. The final step is the
preparation of packing documents which are prepared in the order in which deliveries are
to be made.
Once operational, da¡ I'files or dislribution schedules are modified by one of two
meanis. As new hospitais are added, as hospitals are removed, as changes in usage occur,
such as those from incrcased bed capacity, or as chlilages in us;age are deleccd by hle
control procedutire, i¡e tl;al; I'iles ae muodilied. 'I'he olicy selectiomn tables are revised
eacl tiIme tilere ale revisiois ii usage estimates. The revised tables are then nmanually
evaluated lo determine if the changes are substantial enough to require a change in
targets. A change in targets may also be required if a substantial increaise or decrease iii
the blood supply is anticipated froni othler iniformation. If such changes are required, then
the regional distribution forecasting procedure is performed again as described above.
Scheduling deliíveries
A major advaintage of PBDS, both to the RBC and to the HBB's, is the ability to
preschedule most deliveries. Prior to PBDS being implemented, a number of delivery
vehicles were dispatched as orders came in. For urgent orders, vehicles were dispatched
immediately, while for more routine orders an attenipt wa.vs made to hold vehicles back
until several deliveries in the samne geographical area could be combined. This procedure
was expensive and, perhaps more importantly, resulted in situations where even urgent
orders were delayed, since delivery vehicles were not always available.during peak
delivery hours.
With the PBDS inost deliveries are prescheduled, and take advantage of known
traffic patterns in order to mininiize delivery time. An interactive, comiputer-aided
procedure was dcvised which assigns HBB's to delivery routes so as to meet their time
and frequency of delivery requirenients. The twelve delivery day planning cycle is split
into three groups of four delivery days, after which the delivery cycle repeats. In each
four-delivery-day cycle each HBB receives either one, two, or four deliveries. Thíc
procedure tries lo satisfy the delivery requircmenis without leaving gaps in consecutive
time siots, since an emnpty time sloi indicates idle time.
An opportunity to test the flexibility of this delivery schene occurred recently when
the LIBS Blood Center was mnoved from one location to ainoiher several muiles away. 11
was found that the delivcry roules couid be adjusted rapidly and the required reassign.
ment of the HBB's was determined conveniently.
INTERFACES November 1979