Brain Death
Anna Berry
Background
- Brain death = complete and permanent loss of brain function. Defined by coma with loss of capacity for consciousness, brainstem reflexes, and the ability to breathe independently
Checklist for determination of brain death (American Academy of Neurology)
1. Prerequisites (all must be checked)
- Coma, irreversible and cause known
- Neuroimaging explains coma – usually CT or MRI
- Absence of CNS depressing drugs
- No evidence of residual paralytics (electrical stimulation if paralytics used)
- Absence of severe acid-base, electrolyte, endocrine abnormality
- Normothermia or mild hypothermia (core temp >36°C)
- SBP ≥100 mmHg
- No spontaneous respirations
2. Examination (all must be checked) – Attending MUST Be Present For Brain Death Exam
Test | Regions Tested | Indications of Brain Death | Cautions |
|---|---|---|---|
| Consciousness | Rostral brainstem, thalamus, bilateral cerebral hemispheres | No response to noxious auditory, visual, or tactile stimulation | Use of adequate stimulation is important, including noxious tactile stimulus of the cranium (supra-orbital notch and temporomandibular joint, intra-nasal stimulation) as well as the torso and limbs |
| Pupillary reflex | Upper brainstem | No response to bright light | Use of medications may affect pupillary reactivity; History of corneal trauma or ophthalmic surgery may affect reactivity Quantitative pupillometry may be a useful adjunct for detection of subtle reactivity |
| Corneal reflex | Middle-to-upper brainstem | No eyelid response when pressure is applied at the border of iris with a cotton swab on a stick | Use of adequate pressure should be ensured; the lateral conjunctiva, which is less sensitive than the proximal conjunctiva, should be avoided |
| Oculocephalic reflex ("doll's eye" maneuver) | Middle brainstem | No eye movement with head turning | Use of this approach should be avoided when the integrity of the cervical spine is questionable |
| Oculovestibular reflex ("cold caloric" reflex test) | Middle brainstem | No eye movement within 60 seconds of instillation of ice water | Clear pathway to intact tympanic membrane should be ensured; head should be elevated to an angle of 30 degrees; wait 5 minutes between testing of each ear |
| Gag reflex | Lower brainstem | No gag reflex in response to bilateral stimulation of the posterior pharynx with a tongue depressor or suction catheter | Avoid manipulation of endotracheal tube, if present |
| Cough reflex | Lower brainstem | No cough in response to deep bronchial suctioning | May be absent in patients with phrenic nerve palsy resulting from injury to the cervical cord |
| Motor response | Brainstem, cerebral hemispheres | No cerebrally mediated response to deep nail-bed pressure or proximal stimulation of trunk or arms and legs | May be difficult to distinguish spinally mediated responses from cerebrally mediated responses; expertise and, in some instances, ancillary testing may be required |
Greer DM, Determination of Brain Death. NEJM. 2021;385;2554-61. doi: 10.1056/NEJMcp2025326
3. Apnea Testing (all must be checked) – Attending MUST Be Present
- Pt is hemodynamically stable
- Ventilator adjusted to provide normocarbia (PaCO2 35–45 mmHg)
- Preoxygenate with 100% FiO2 and PEEP of 5 cmH2O for >10 min to PaO2 >200 mmHg
- Provide oxygen via a suction catheter to the level of the carina at 6 L/min or attach T-piece with continuous positive airway pressure (CPAP) at 10 cmH2O
- Disconnect ventilator
- Spontaneous respirations absent
- Arterial blood gas drawn at 8–10 minutes, pt reconnected to ventilator
- PCO2 ≥60 mmHg, or 20 mmHg rise from normal baseline value; OR:
- Apnea test aborted due to spontaneous respirations present, hemodynamic instability, or hypoxia
4. Ancillary testing (Order one test if clinical examination cannot be fully performed due to pt factors or if apnea testing inconclusive/aborted)
- Cerebral angiogram
- HMPAO SPECT (Single photon emission computed tomography)
- EEG & TCD (transcranial Doppler)
Organ Donation Caveats
- Discussions about organ donation should take place between Tennessee Donor Services (TDS) and the surrogate. You SHOULD NOT be having conversations with the surrogate about donation. Direct questions to TDS