Biomedical Engineering Reference
In-Depth Information
With the development of modern respirators, however, the medical profession encoun-
tered an increasing number of situations in which a patient with irreversible brain damage
could be maintained almost indefinitely. Once again, a new technological advance created
the need to reexamine the definition of death.
The movement toward redefining death received considerable impetus with the publica-
tion of a report sponsored by the Ad Hoc Committee of the Harvard Medical School in
1968, in which the committee offered an alternative definition of death based on the func-
tioning of the brain. The report of this committee was considered a landmark attempt to
deal with death in light of technology.
In summary, the criteria for death established by this committee included the following:
(1) the patient must be unreceptive and unresponsive—that is, in a state of irreversible
coma; (2) the patient must have no movements of breathing when the mechanical respirator
is turned off; (3) the patient must not demonstrate any reflexes; and (4) the patient must
have a flat EEG for at least 24 hours, indicating no electrical brain activity. When these
criteria are satisfied, then death may be declared.
At the time, the committee also strongly recommended that the decision to declare the
person dead and then to turn off the respirator should not be made by physicians involved
in any later efforts to transplant organs or tissues from the deceased individual. In this way,
a prospective donor's death would not be hastened merely for the purpose of transplanta-
tion. Thus, complete separation of authority and responsibility for the care of the recipient
from the physician or group of physicians who are responsible for the care of the prospec-
tive donor is essential.
The shift to a brain-oriented concept involved deciding that much more than just
biological life is necessary to be a human person. The brain death concept was essentially
a statement that mere vegetative human life is not personal human life. In other words,
an otherwise intact and alive but brain-dead person is not a human person. Many of us
have taken for granted the assertion that being truly alive in this world requires an “intact
functioning brain.” Yet, precisely this issue was at stake in the gradual movement from
using heartbeat and respiration as indices of life to using brain-oriented indices instead.
Indeed, total and irreparable loss of brain function, referred to as “brainstemdeath,” “whole
brain death,” or, simply, “brain death,” has been widely accepted as the legal standard for
death. By this standard, an individual in a state of brain death is legally indistinguishable from
a corpse and may be legally treated as one even though respiratory and circulatory functions
may be sustained through the intervention of technology. Many take this legal standard to
be the morally appropriate one, noting that once destruction of the brainstem has occurred,
the brain cannot function at all, and the body's regulatory mechanisms will fail unless artifi-
cially sustained. Thus mechanical sustenance of an individual in a state of brain death is
merely postponement of the inevitable and sustains nothing of the personality, character, or
consciousness of the individual. It is simply the mechanical intervention that differentiates
such an individual from a corpse, and a mechanically ventilated corpse is a corpse nonetheless.
Even with a consensus that brainstem death is death, and thus that an individual in such
a state is indeed a corpse, difficult cases remain. Consider the case of an individual in a per-
sistent vegetative state, the condition known as “neocortical death.” Although severe brain
injury has been suffered, enough brain function remains to make mechanical sustenance of
respiration and circulation unnecessary. In a persistent vegetative state, an individual exhi-
bits no purposeful response to external stimuli and no evidence of self-awareness. The eyes
