Patterns of Retrieval and Transplantation
As suggested by Figure 5 in the previous section, the majority of retrieved organs are transplanted. Figure 6 provides a more detailed breakdown of the percentage of organs transplanted among retrieved organs. In almost all cases (87%, n=5040), 100% of retrieved organs were transplanted. Because of the vast differences in magnitude between this category and the remaining percentages, a logarithmic scale is used to display the entire distribution. Among cases where not all organs were used, the vast majority used at least 50% or more of retrieved organs. Only a very small number of cases had a lower proportion of organs transplanted.
Trends in retrieval show two distinct patterns (Figure 7). The percentage of donors from which two or more organs were retrieved has been increasing, on average, between 1991 and 2004. This increase is largest among the four-organ donors. In contrast, single-organ retrieval has decreased considerably, from approximately 25% in 1991 to less than 15% in 2004. It is also worth noting that the yearly variation is actually quite small. Despite the apparent scattering of points, actual variation from each of the respective trend lines rarely exceeds five percent in any given year.
In Figure 8, trends in mean number of organs retrieved and the percentage of donors with at least one retrieved organ not transplanted are plotted together. The proportion of cases in which not all organs are transplanted never exceeds 30% in any given year. The apparent increase in non-use in the mid-1990 parallels the increase in the average number of organs retrieved, possibly an indication that more aggressive retrieval efforts did not always result in transplantation. Since that time, the number of retrieved organs has appeared to level off to approximately 2.4 per donor; however, non-use has also decreased to about 10%, suggesting that the increase in retrievals has been accompanied by better management and utilization of the organs.