Though declaring a
person dead is a simple routine, but undoubtedly a critical moment for a doctor.
It is an organized step-wise process of patient’s examination to assess the
brain functions. Death must be declared by a medical doctor or medical professional.
Check the Video Below ↓
No Pulse
The dead person is always pulse-less. You cannot
feel any radial pulse in both fore-arms or any pulse anywhere in the body. The
heart pumps blood out into the body through vessels producing a pressure onto
their walls. This pressure produces and amplitude in the vessel wall that is
felt as a “Pulse”. If the heart is not functioning, no pulse can be felt. However,
only pulselessness does not confirm that the patient is dead. In several
conditions, pulse may not be recordable. In other words, a working heart may be
too weak to produce pulse. Carotid pulses are better to be examined.
No Blood Pressure
No blood pressure can be recorded in
both upper limbs or anywhere in a dead person. In a dead person, heart stops
working! The heart pumps blood out into the body through vessels producing a
pressure onto their walls. This pressure is named as “Blood Pressure”. If the
heart is not working, no blood pressure can be recorded. However, only B.P.
lessness does not confirm the patient is dead. In several conditions, blood
pressure may not be recordable. In other words, a working heart may be too weak
to produce enough power to give a recordable blood pressure.
Blood Pressure (Source: www.drelaine.com) |
No Heart Sounds
No heart sounds can be heard over the
chest of a dead person at least for one minute. Simply, when the heart is dead,
no sound will be produced. If you are in doubt, ask to your colleague to hear
the patient’s heart (auscultate).
Heart Sounds |
No Respiratory Sounds
No respiratory or other breathing sounds
can be heard over chest. No respiratory movements are observed. When the brain
is dead, breathing movements and sounds stop.
Breath Sounds |
No Response to Deep Painful Stimulus
The dead person does
not respond to any deep painful stimulus. Deep painful stimulus can be applied
by sharply pushing or rubbing against the sternum (central bone of chest).
Painful Stimulus/ Pressing the Sternum |
Absent Pupillary Light Reflex
It refers to the change in the
diameter of pupil in response to light. The pupil dilates in dim light (darkness)
while constricts in high or intense light, regulating the light entering the
eye. It assesses the brain function (mid-brain) whether it is functioning or
not. In a dead patient, pupillary light reflex is absent. It means the both pupils
do not respond to light and the pupils are seen as bilaterally fixed dilated.
However, some drugs (e.g. mydriatic eye drops, anticholinergic drugs, tricyclic
antidepressant overdose) and third nerve palsy may dilate the pupils so that
they fail to respond to light. So, other signs must be considered along with
papillary light reflex. Afferent limb (sensory limb) of this reflex is made by
first cranial nerve (optic nerve, CN-I) while efferent limb (motor limb) is
made by third cranial nerve (Oculomotor nerve, CN-III).
Pupillary Light Reflex |
Absent Corneal Reflex
Corneal reflex or blink reflex refers
to the blinking of eyelids by the stimulation of cornea. Corneal reflex can be
checked by brushing something like cotton swab against the corneal surface. It
is also mediated by brain (a centre located in pons of midbrain). It is absent too
in a dead person. Afferent limb (sensory limb) of this reflex is made by the
first branch (ophthalmic nerve, V1) of the fifth cranial nerve (Trigeminal
nerve, CN-V) while efferent limb (motor limb) is made by branches (temporal and
zygomatic nerves) of seventh cranial nerve (Facial nerve, CN-VII).
Corneal Reflex |
Straight-Lined Electrocardiograph (ECG)
The ECG of a dead person shows
straight line. Straight line refers to absent electric signals in the heart. However,
sometimes ECG shows some irregular and abnormal drawings that may be due to
injected drugs like atropine and adrenaline. So, clinician should wait till the
ECG is straight before declaring the patient is dead.
ECG (Straight-line) |
Absent Oculocephalic Reflex
Oculocephalic reflex or vestibulo-ocular reflex refers to the conjugate but opposite movements of eyeballs when the head is rotated to one side. For instance, if the head is moved to the right, the eyeballs will move to the left. These are the reflex eye movements meant for the stabilization of the image on retina. In other words, when an examiner moves or rotates the head of the patient side to side, the eyes remain fixated on the examiner's face. Sensory signals of oculocephalic reflex are carried through vestibular system (semi-circular canals) to the eighth cranial nerve (vestibular nerve, CN-VIII), from where the signals reach the brain stem. From the brain stem, motor signals reach the ocular muscles through sixth cranial nerve (abducens nerve, CN-VI ) and third cranial nerve (oculomotor nerve, CN-III). In the dead, this reflex is absent. It is also called as "doll's eye reflex" or "doll's eye movements". Doll's eye maneuver is contraindicated in the patients with brain-stem injury.Oculocephalic reflex (Source: www.wikilectures.eu) |
Absent Gag Reflex (Pharyngeal Reflex)
In this test, the back of the throat (i.e. the posterior wall of pharynx) is touched with a cotton swab or a suction tube. It causes the back of the throat to contract (i.e. contraction of pharyngeal muscles) producing cough or gag. The sensory fibers of the gag reflex are carried by glossophaygeal nerve (CN-IX) while the motor fibers by vagus nerve (CN-X). Gag reflex is absent in brain dead person. Pharyngeal reflex is usually done in patients who present with deep coma or who have been on ventilator or when the doctor is not sure about "the brain is dead".Gag Reflex (Source: www.clinicalexams.co.uk) |
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