⚖️ Chapter 65: Brain Death Criteria

Coma · Absence of brainstem reflexes · Apnoea (PaCO2 >60 or >20 above baseline) · Prerequisites (normothermia, no sedation, normal BP) · Observation periods (infants 24h, children 12h) · Two examinations by two physicians · Ancillary studies (EEG, cerebral blood flow) · Declaration of death

🔍 Core Concepts: Brain Death Criteria

📌 Definition (Uniform Determination of Death Act)
Irreversible cessation of all functions of the entire brain, including the brainstem. Legal and clinical death. Also defined by irreversible circulatory/respiratory arrest.
🧠 Three Essential Findings
1. Coma (no awareness, no response to pain). 2. Absence of all brainstem reflexes (pupils, corneal, gag, cough, oculovestibular). 3. Apnoea (no respiratory effort with PaCO2 ≥60 or >20 above baseline).
✅ Prerequisites
Normothermia (≥35°C), normal BP for age, no sedatives/neuromuscular blockers (adequate washout), no metabolic derangements. Defer evaluation for 24-48h after CPR or severe acute injury.
⏱️ Observation Periods
Neonates (term to 30 days): 24 hours. Infants/children (30 days to 18 years): 12 hours. Two examinations by two different attending physicians. Apnoea test may be performed by same physician.
📊 Apnoea Test
Preoxygenate with 100% O2, disconnect ventilator, observe for respiratory effort. PaCO2 must rise ≥60 mmHg or >20 above baseline. If unstable (desaturation <85%, hypotension), abort and use ancillary study.
🖥️ Ancillary Studies (if exam incomplete)
EEG (electrocerebral silence) or radionuclide cerebral blood flow (no flow). Four-vessel angiography gold standard. Not required if clinical exam complete.

🩺 Stepwise Approach: Brain Death Determination

1
Establish preconditions
Irreversible, identifiable cause of coma (massive brain injury, anoxia). Exclude confounders: normothermia (≥35°C), normal BP, no sedative/neuromuscular blocker effect (adequate washout period). Defer 24-48h after CPR or severe acute injury.
2
First neurological examination (by attending physician)
Coma: no response to pain, no vocalisation. Brainstem reflexes: pupils (midposition/fixed), corneal (absent), gag/cough (absent), oculovestibular (cold caloric — no eye movement). Spine-mediated reflexes may persist.
3
Apnoea test
Preoxygenate with 100% O2 for 10 min. Disconnect ventilator, provide O2 via tracheal cannula. Observe for respiratory effort. Draw ABG at 5-8 min. Positive (consistent with brain death) if PaCO2 ≥60 or ≥20 above baseline with no respiratory effort. If unstable (SpO2 <85%, hypotension), abort and use ancillary study.
4
Observation period
Neonates (term to 30 days): 24 hours. Infants/children (30d-18y): 12 hours. Adults: 6 hours.
5
Second examination (by different attending physician)
Repeat full neurological examination and apnoea test (or use ancillary study if apnoea test contraindicated). Both examinations must be consistent with brain death.
6
Declaration of death & family communication
Document findings. Declare death legally. Explain to family using clear, simple language. If organ donation planned, maintain somatic support. No person from transplant team can certify brain death.