Can a patient make a movement and still meet criteria
for brain death?
Yes!
Spinally mediated reflexes and
automatisms can be present in the setting of brain death. These movements are
often misinterpreted by laypersons as signs of purposeful brain function. Careful
neurologic examination can differentiate between reflexive movements and
purposeful motor movements.
These are non-purposeful movements
released by lack of descending inhibition of primitive spinal motor reflex
pathways.
·
Deep-tendon
reflexes: For example, Achilles, patellar, and biceps are by definition
monosynaptic spinally mediated reflexes and hence often preserved despite brain
death.
·
Abdominal
reflexes: Deviation of the umbilicus toward a light stroking of the skin. Often
preserved in brain-dead patients, it may be absent in normal or obese patients.
·
Triple
flexion response or limb posturing: Stereotyped, non-purposeful flexion or
extension and internal rotation in response to noxious stimulus. (A movement
may be purposeful if the limb reliably moves away from, rather than toward, an
applied noxious stimulus.)
·
Lazarus
sign: Considered a variant of opisthotonus. It consists of extensor posturing
of the trunk, which may look like chest expansion, simulating a breath. It may
be accompanied by raising and crossing of the arms in front of the chest or
neck. This sign most often occurs in the setting of apnea testing or
disconnection from the ventilator. Hence it may be upsetting for family members
or health care providers to witness this reflex.
No comments:
Post a Comment