Perspective on Macroscale Complexity in the National Transplant System

Figure 2

Directed multiplex structure of information sharing within the OPTN during allocation. Each OPO (top layer) has authority in a geographical region that encapsulates several transplant hospitals (bottom layer). The two spatial dimensions of the layers correspond to geographical relationships, since physical distance influences organizational ties and authority. An ellipse covering multiple hospitals illustrates OPOs’ one-to-many relationship with transplant hospitals. Physically adjacent OPOs typically have emergent links arising from the geographic locality preference of policy. Transplant hospitals may develop links through personnel exchanges from recruitment, attrition, and residents who become physicians at the other transplant hospitals. The Organ Center (OC) facilitates bridging between disparate organizations during allocation. Note that the number of nodes illustrated in each layer is smaller than the actual system and is only to convey that transplant hospitals outnumber OPOs.