Most scenarios of catastrophic MCEs [Mass Casualty Events] would create sudden large numbers of fatally injured or critically ill short-term survivors that are at least a few orders of magnitude larger than the existing vulnerable populations. Depending on the event, some victims will last only a few weeks (e.g., pulmonary injury from airborne chemicals) and some may last for months (e.g., pandemic influenza). In many cases, those who survive the onset usually will live for some time - days to months - but will not be expected to survive due to the event itself or to the ensuring resource scarcities it creates. Initial identification of those who might fit into the not expected to survive category following a catastrophic MCE may include: (1) Those exposed to the event who are expected to die over the course of weeks (e.g., those with radiation exposure) (2) The already existing palliative care population (e.g., those already enrolled in hospice or receiving palliative care in acute care settings) (3) Vulnerable patients (e.g., advanced illness patients in long-term care facilities) whose situation will be worsened due to scarcities associated with the event (4) Patients who are triaged as a result of scarce resources. (AHRQ/HHS, Mass Medical Care..., 2007, p. 103)