Futile' medical treatment is indeed ordinarily not wanted, but useful treatment is wanted ... except that 'useful' treatment is interpreted in such a broad fashion that it is often wanted even when its utility is highly marginal, and when the quality of life it provides is slight to vanishing. For practical purposes, it is this desire for useful treatment, however slight in value, that is most important, not the rejection of futile treatment.... Given the growing effectiveness of medical therapies at the margin of life and death, and the increased ...