Applying traditional Jewish law to PVS

Jewish law allows removal of life-support systems that are impeding the natural process of dying in a terminally ill patient, but it forbids hastening that process. The tradition measures death primarily in terms of cessation of respiration and, for some, cessation of heartbeat as well. Nevertheless, most, but not all, rabbis writing on bioethics permit the use of full brain death (including the brain stem) to determine death, either because the apnea test now used in consort with other neurological criteria to determine brain death fulfills the tradition's demand for cessation of respiration, or because brain death amounts to decapitation, another traditional sign of death. Since PVS patients fulfill none of these criteria, most rabbis consider them alive, but some would permit withholding or withdrawing artificial nutrition and hydration.