Of the various inventories maintained in a hospital, that of blood has received particular attention. This focus is perhaps justified by the critical nature of the commodity, vitally necessary in so many medical episodes. A critical analysis of the literature must examine the approaches suggested for the control of such inventories by their adaption to the particular but important peculiarities of blood banking: expiration, assigned/unassigned inventories, and blood types. In the United States, law prohibits the use of whole blood more than 21 days after being drawn. Therefore, units age in inventory, and even though it may be assumed that little change will be experienced in its utility for the first 21 days, one must account for its perishability. It follows that the major appropriate criteria in the analysis of such systems are the probability of (or expected) shortage and expected outdates. Only recently has there been development of theory concerning the control of perishable inventories1). Secondly, in preparation for certain surgical procedures or other expected need for blood, “units” are crossmatched (checked for compatibility) with the patients’ blood and “assigned” to the proposed recipient.
Unable to display preview. Download preview PDF.