Brain Death Flashcards
(34 cards)
Organ Donation is ___________ & tissue donation is .____________
lifesaving
life-enhancing
In organ donation the donor patient must be:
Whereas in tissue donation the patient is:
Patient must be maintained by a mechanical ventilator
Donation occurs after death
How long does organ donation vs tissue donation take?
The process is lengthy from referral to procurement 24-72 hours
Ocular Donation process takes about 8 hours.
TIssue donation occurs:
after death.
True or false: organ donation occurs while the individual is still alive
False
organ donation process must begin while the individual has a beating heart so that their organs are still being perfused. Only after death donation occurs.
Criteria for Organ Donation
GIVE
- Grave Prognosis
- Injured brain/non-recoverable illness
- Ventilated
- End of Life Discussion Plan
2 Types of Death
- Death Determination by. Neurological Criteria (DNC - brain death)
- Death Determination by Circulatory Criteria (DCC - cardio-pulmonary death)
Define DNC
irreversible loss of the capacity for consciousness combined with the irreversible loss of all brainstem functions, including the capacity to breathe
Spinal cord reflexes may still be intact
Define DCC
determination of physical death by circulatory based, still has blood flow to brainstem.
There is severe but incomplete brain damage where there is no chance of recovery or meaningful recovery. There is still blood flow to the vital brain centres.
Explain patho of DNC
Known/Definitive Cause of Injury to brain
- arrest of blood flow due to catastrophic intracranial HTN
- brain injury/edema/mass increasing ICP
- Impaired cerebral blood flow
- pressure related ischemia; continued rise in ICP
- Brain herniates through path of least resistance (brainstem/cerebellum)
6 Physiological Criteria of DNC
- Complete and irreversible – stopping of all brain function
- Unresponsive & Irreversible coma
- Definitive cause
- Absent centrally mediated motor responses.
- Absent brainstem reflexes.
- Apnea
DNC Organ Donor patients will always be cared for in the _____ and transferred to the OR for organ recovery still on ______________
ICU
Life support measures
Clinical Manifestation of DNC
- Conning
- Period of instability characterized by HTN, Bradycardia, irregular respirations
AKA
Cushing triad is, unfortunately, a late sign of increasing ICP and indicative that brainstem herniation is imminent.
o Widening pulse pressure
o Bradycardia
o Cheyne Stokes
Prerequisites required before DNC can be determined:
- Clinical imaging showing evidence of a acute catastrophic injury, that supports a diagnosis of brain death.
- No severe electrolyte imbalances.
- No drastic acid base disturbance.
- No endocrine abnormalities.
- No drugs intoxication. Including medications given at hospital. (neuro blockade agents, sedation ect)
- Appropriate core temp
7 Determinants of Brain Death (DNC)
- Definitive cause of death must be identified
- Deep unresponsive Coma: GCS 3
- Body temperature: >36 for Infants-adults
- All sedation, narcotics and neuro-blockade agents stopped
- Absence of spontaneous movements & elicited movements (seizures/posturing)
- Absent brain stem reflex
- DNC is determined by 2 attending physicians with skill and knowledge of patients with severe brain injury and DNC. The clinical assessment can be done concurrently.
How is absence of cortical functions clinically determined in DNC
No spontaneous movements, eye opening or movement after auditory, verbal or visual commands.
Cerebral motor response to pain:
>Nail beds, traps, supraorbital ridge.
> Do not count spinal reflexes – can be intact.
How is absence of brain function clinically determined in DNC
Cannot have:
o Gag
o Cough
o Corneal response
o Bilateral pupillary response to light & >3mm
o Bilateral Vestibulo-ocular response (caloric reflex)
o Suck reflex (neonates)
o Oculo-cephalic reflex has been removed (doll’s eyes)
How is absence of gag reflex clinically determined in DNC?
Gag and cough reflexes are not present in brain death.
> Gag reflex can be encouraged by stimulating the posterior pharynx.
> Cough reflex can be elicited by the ETT suction.
How is absence of corneal response clinically determined in DNC?
A corneal response will be absent with brain death.
o Tested by directly touching
How and what pupillary response is present in the clinical determination of DNC?
- Pupils can be midsize to all the way dilated.
- Absent light reflex.
- Pupils will be fixed and unresponsive
How is bilateral vestibulo-ocular response clinically determined in DNC?
Tested by putting 50ml of ice water into the ear canal, ensuring ice water reaches tympanic membrane.
o Normal response will have eye move towards painful stimuli. Absent movement after 3 min support a Dx of brain death.
Describe the apnea test used in determination of DNC?
Attempt to achieve normal ABG
- Pre-Oxygenate with 100% Oxygen for 10 minutes
- Change ventilator setting to spontaneous
- Observe chest and abdomen for respiratory effort
- Measure ABGs 5 min, 8 min, and 10 min (if needed)
- Apnea test confirms brain death if at 8 min or 10 min
- PaC02 ≥ 60 mmHg
- PaC02 ≥ 20 mmHg above baseline
- PH ≤ 7.28
Brain death is determined if there is an Absent Respiratory Effort
- Driving up PaC02 to elicit a respiratory response
- If patients is not tolerating this test – BP dropping test is stopped
Describe ancillary testing in determination of DNC
Testing Brain Blood Flow
> Radionuclide Cerebral Blood Flow Study
> CT Angiography
> MR Angiography
When is DCC donation a possibility?
- plan to withdraw life sustaining therapy after health care team determined there is no long term prognosis for recovery
- DNC not met
- May have catastrophic brain injury but do not meet DNC criteria
- Wihtdrawal of support is planned
