🧠 Brain Death / Death by Neurologic Criteria (DNC) Determination
Work through the adult brain-death / death-by-neurologic-criteria determination: prerequisites, brainstem-reflex examination and the apnea test. Instant, browser-side.
Clinical takeaway
Confounders (drugs, severe metabolic/electrolyte derangement, neuromuscular blockade, hypothermia) must be corrected/excluded before determination.
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When to use
Structured clinical determination of brain death (BD/DNC) per the AAN/AAP/CNS/SCCM 2023 consensus.
How it works
All three must hold: prerequisites (irreversible cause, confounders excluded, core temp ≥ 36℃, SBP ≥ 100 / adequate MAP, no hypoxia) + all brainstem reflexes absent in a comatose patient with no induced movement + a positive apnea test (PaCO₂ ≥ 60 and ↑ ≥ 20 over baseline). Ancillary testing only when the exam/apnea test cannot be completed.
Key points
- Confounders (drugs, severe metabolic/electrolyte derangement, neuromuscular blockade, hypothermia) must be corrected/excluded before determination.
- The apnea test is positive only with no respiratory effort AND PaCO₂ ≥ 60 AND a ≥ 20 mmHg rise over baseline.
- EEG assesses the cerebral hemispheres, not the brainstem; cerebral-blood-flow studies (CTA/DSA/TCD/nuclear) are the ancillary options.
- Spinally mediated movements do not exclude brain death; follow hospital/regional policy on examiner qualifications and documentation.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Prerequisites | All met (known irreversible cause + confounders excluded [drug intoxication / severe metabolic-electrolyte-acid-base / neuromuscular blockade] + core temp ≥ 36℃ + SBP ≥ 100 or adequate MAP + no hypoxia) |
|---|---|
| Clinical examination | Coma with no induced movement + pupillary/corneal/oculocephalic/oculovestibular/pharyngeal/cough reflexes all absent |
| Apnea test | Positive: no spontaneous breathing AND PaCO₂ ≥ 60 AND ↑ ≥ 20 mmHg over baseline |
→Brain-death determinationMeets clinical brain-death criteria
- Conclusion：Prerequisites + all brainstem reflexes absent + positive apnea test are all satisfied. Time of death is recorded as the moment of the final apnea-test blood-gas report (PaCO₂/pH meeting criteria). Spinally mediated movements do not exclude brain death. Follow hospital/regional policy (examiner qualifications, documentation, whether ancillary testing or repeat determination is required).
- Examination items (all must be absent)：Unresponsiveness/no induced movement, pupillary light reflex, corneal reflex, oculocephalic reflex (OCR), oculovestibular reflex (OVR), pharyngeal (gag) reflex, cough reflex (add sucking/rooting reflexes if < 6 months old)
- Positive apnea test：No spontaneous respiratory effort AND PaCO₂ ≥ 60 mmHg AND ↑ ≥ 20 mmHg over baseline (adults ≥ 1 time after the final examination)
| Prerequisites | Not all met / confounders present |
|---|---|
| Clinical examination | Any reflex/motor response present, or a reflex cannot be assessed |
| Apnea test | Not yet performed |
→Brain-death determinationCannot determine yet (prerequisites not met)
- Conclusion：Confounders must first be corrected/excluded: core temp ≥ 36℃ (if it was ≤ 35.5℃, rewarm to ≥ 36℃ and wait ≥ 24 h, an observation period that ancillary testing cannot replace), stop sedatives/paralytics and exclude drug intoxication, correct severe metabolic/electrolyte/acid-base derangement, maintain SBP ≥ 100 or adequate MAP, PaCO₂ 35–45, no hypoxia.
- Examination items (all must be absent)：Unresponsiveness/no induced movement, pupillary light reflex, corneal reflex, oculocephalic reflex (OCR), oculovestibular reflex (OVR), pharyngeal (gag) reflex, cough reflex (add sucking/rooting reflexes if < 6 months old)
- Positive apnea test：No spontaneous respiratory effort AND PaCO₂ ≥ 60 mmHg AND ↑ ≥ 20 mmHg over baseline (adults ≥ 1 time after the final examination)
Frequently asked questions
- What is Brain Death / Death by Neurologic Criteria (DNC) Determination?
- Work through the adult brain-death / death-by-neurologic-criteria determination: prerequisites, brainstem-reflex examination and the apnea test. Instant, browser-side.
- How is Brain Death / Death by Neurologic Criteria (DNC) Determination calculated? What is the core formula?
- All three must hold: prerequisites (irreversible cause, confounders excluded, core temp ≥ 36℃, SBP ≥ 100 / adequate MAP, no hypoxia) + all brainstem reflexes absent in a comatose patient with no induced movement + a positive apnea test (PaCO₂ ≥ 60 and ↑ ≥ 20 over baseline). Ancillary testing only when the exam/apnea test cannot be completed.
- When is Brain Death / Death by Neurologic Criteria (DNC) Determination used?
- Structured clinical determination of brain death (BD/DNC) per the AAN/AAP/CNS/SCCM 2023 consensus.
- What are the key clinical points for Brain Death / Death by Neurologic Criteria (DNC) Determination?
- Confounders (drugs, severe metabolic/electrolyte derangement, neuromuscular blockade, hypothermia) must be corrected/excluded before determination. The apnea test is positive only with no respiratory effort AND PaCO₂ ≥ 60 AND a ≥ 20 mmHg rise over baseline. EEG assesses the cerebral hemispheres, not the brainstem; cerebral-blood-flow studies (CTA/DSA/TCD/nuclear) are the ancillary options. Spinally mediated movements do not exclude brain death; follow hospital/regional policy on examiner qualifications and documentation.
- What are the limits and cautions when using Brain Death / Death by Neurologic Criteria (DNC) Determination?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Brain Death / Death by Neurologic Criteria (DNC) Determination calculated in practice? Can you show a worked example?
- Inputs: Prerequisites All met (known irreversible cause + confounders excluded [drug intoxication / severe metabolic-electrolyte-acid-base / neuromuscular blockade] + core temp ≥ 36℃ + SBP ≥ 100 or adequate MAP + no hypoxia), Clinical examination Coma with no induced movement + pupillary/corneal/oculocephalic/oculovestibular/pharyngeal/cough reflexes all absent, Apnea test Positive: no spontaneous breathing AND PaCO₂ ≥ 60 AND ↑ ≥ 20 mmHg over baseline → Result: Brain-death determination Meets clinical brain-death criteria（Conclusion: Prerequisites + all brainstem reflexes absent + positive apnea test are all satisfied. Time of death is recorded as the moment of the final apnea-test blood-gas report (PaCO₂/pH meeting criteria). Spinally mediated movements do not exclude brain death. Follow hospital/regional policy (examiner qualifications, documentation, whether ancillary testing or repeat determination is required)., Examination items (all must be absent): Unresponsiveness/no induced movement, pupillary light reflex, corneal reflex, oculocephalic reflex (OCR), oculovestibular reflex (OVR), pharyngeal (gag) reflex, cough reflex (add sucking/rooting reflexes if < 6 months old), Positive apnea test: No spontaneous respiratory effort AND PaCO₂ ≥ 60 mmHg AND ↑ ≥ 20 mmHg over baseline (adults ≥ 1 time after the final examination)） Inputs: Prerequisites Not all met / confounders present, Clinical examination Any reflex/motor response present, or a reflex cannot be assessed, Apnea test Not yet performed → Result: Brain-death determination Cannot determine yet (prerequisites not met)（Conclusion: Confounders must first be corrected/excluded: core temp ≥ 36℃ (if it was ≤ 35.5℃, rewarm to ≥ 36℃ and wait ≥ 24 h, an observation period that ancillary testing cannot replace), stop sedatives/paralytics and exclude drug intoxication, correct severe metabolic/electrolyte/acid-base derangement, maintain SBP ≥ 100 or adequate MAP, PaCO₂ 35–45, no hypoxia., Examination items (all must be absent): Unresponsiveness/no induced movement, pupillary light reflex, corneal reflex, oculocephalic reflex (OCR), oculovestibular reflex (OVR), pharyngeal (gag) reflex, cough reflex (add sucking/rooting reflexes if < 6 months old), Positive apnea test: No spontaneous respiratory effort AND PaCO₂ ≥ 60 mmHg AND ↑ ≥ 20 mmHg over baseline (adults ≥ 1 time after the final examination)）