Death and Dying Flashcards
What are the three different definitions of death used in the medical community
Traditional heart-lung failure
Whole brain death
Higher brain death-Not including brain death
What is the historical view of heart and lung failure
When there is no heart beat and no breathing the person is dead and nature has run its course
What is the current view of heart and lung failure
We can use pharamacological and mechanical means of support forcing the heart and lungs to continue functioning when they will not work on their own
Whole Brain Death
A person with whole brain death will not appear any different than those who are under the traditional definition of death
They do not move purposefully, they do not breath on their own, but they still may have a heartbeat
If the organs are forced to keep working people can continue to digest food, excrete waste and bear children
this is the type of death that is being referred to with brain death, and there is no chance of survival for the patient
Higher brain death
the higher brain is the part of the brain that is responisble for self-awareness and the ability to reason
Everything taht makes an individal a unique person is believed to be part of the higher brain
Even though the person part may be gone the body may still be functioning. This can be disocncerning to the family as someone is dead but their body is functioning
Misconceptions about Brain Death
- Family may think their love one is still alive with brain death because they have a heartbeat
- stopping pharamacological and mechanical support may then be seen as allowing the patient to die
- they may also think that their love one will get better with treatment
- Confusion as to when death should be recorded in the pt chart
- Brain death is recorded as the time death is pronounced on the basis of neurological criteria (different from cardiopulmonary criteria)
- Ideally death should not be recorded at the time when the vent is disconnected
Neurological Criteria
In most patients with brain death, neuro-imaging studies show abnormalities consistent with loss of brain and brain stem function.
- Cerebral blood flow and MRI Study
- No cerebral perfuaion as measured by radionuclide cerebral angiography and brain perfusion studies
- EEG
- patient who are brain dead there is no electrical activity during a period of at least 30 min of EEG recording
Occasionally patients with ischemic-anoxic cerebral injury and resultant brain death have normal neuro-imaging findings.
Bedside Testing for Neuological Criteria
- Determining brain death in comatose patients can be accomplished through prolonged observation and confirmation that the patient’s condition fits clinical and diagnostic criteria.
- In the case of ischemic-anoxic insult causing brain death, imaging can appear normal at first. When the imaging is repeated the next day this is when the irregularities show up.
- Normally there will not be huge damage until after 24 hours with a noxic brain injury so they will do a CT upon arrival and the repeat one 24 hours later
Common Causes of Brain Death
- Massive head trauma
- Intracranial hemorrhage
- Hypoxic Ischemic Damage during CPR
- Rapid and marked brain edema which increases brain volume, which can come from 2 morbid events
- Herniation and infarction of the brain stem as it is forcibly displaced from its original location “coning”
- Loss of cerebral perfusion pressure as intracranial pressure exceeds mean arterial blood pressur
Because we are getting better at treating TBI we are seeing the rates of brain death decrease
Testing the Brain Stem Reflexes
- Pupillary Signs
- Ocular Movements
- Oculocephalic reflex
- Vestibulo-ocular reflex
- Facial Sensory and Motor Responses
- Pharyngeal and Tracheal Reflexes
Pupillary Signs
Round, oval, or irregularly shaped pupils are compatible with brain death, and most pupils are midsize(4-6 mm) and fixed.
The pupillary light reflex must be absent in brain death.
Ocular Movements
Oculocephalic Reflex
- Oculocephalic Reflex: Elicited by rapidly and vigorously turning the head 90° laterally on both sides. “gently”
- The normal repsonse is the deviation of the eyes to the opposite side of the head turning
- When a person is brain dead the oculocephalic reflex and no eye movement (i.e. Dolls Eyes)
- An individual with dysfunction of the brainstem, the doll’s eye effect will be absent.
- In this situation, the eyes will remain fixed in the mid position while the head is turned from sides to sides.
- The eyes do not move laterally towards the side opposites to the direction which the head is turned.
- Any injury to the midbrain or pons which involves the eighth cranial nerve, sixth cranial nerve and third cranial nerve may lead to an absence of the doll’s eye signs.
Ocular Movements
Oculovestibular Reflex
Oculovestibular (aka caloric test) reflex is elicited by elevating the head 30° and irrigating both tympanic membranes with at least 20 mL of icedsaline or water.
In a normal response, the eyes will turn towards the irrigated ear
In brain death, vestibulo-ocular reflexes are absent, and no deviation of the eyes occurs in response to ear irrigations.
The patient should be observed for up to 1 minute after each ear irrigation, with a 5-minute wait between testing of each ear.
Facial Sensory and Motor Responses
Corneal and jaw reflexes will be absent in brain death
Cerebrally modulated motor responses of all extremities are absent in brain death.
These motor responses are tested and should be absent after painful stimulation with pressure to the supra-orbital ridge and the nail beds.
Corneal reflexes (also called blink reflex) should be tested by using a cotton-tipped swab.
Grimacing in response to pain can be tested by applying deep pressure to the nail beds, supraorbital ridge, or temporomandibular joint
Pharyngeal and Tracheal Reflexes
Both gag and cough reflexes are absent in patients with brain death.
The gag reflex can be evaluated by stimulating the posterior part of the pharynx with a tongue blade, but the results can be difficult to evaluate in orally intubated patients.
The cough reflex can be tested by using bronchial suctioning.
This is something that we test daily and report out in rounds. Very important to report changes as this will effect the plan for the patient.
