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# Brain death: clinical testing (Colombia)

- Assessment

Brain death means the whole brain, including the brainstem, has stopped for good; doctors confirm it with careful bedside tests.

Updated Nov 13, 2026

## Key points

- Prerequisites: a known irreversible cause, no drug, metabolic or temperature confounder, and adequate blood pressure.
- Examination: coma, absent brainstem reflexes (pupillary, corneal, oculocephalic, oculovestibular, gag, cough) and no breathing on the apnoea test.
- Apnoea test: no respiratory movement while arterial CO2 rises to at least 60 mmHg and 20 mmHg above baseline.
- Spinal reflexes (withdrawal of a limb, even complex movements) can persist and do not exclude brain death.
- Colombia, Decree 2493 of 2004: two or more doctors outside the transplant programme, one a neurologist; a confirmatory test if a sign cannot be confirmed.

## What it is

Brain death is the irreversible loss of all brain function, including the brainstem, and it is legally the death of the person even while a ventilator keeps the heart beating and the organs perfused. It follows a catastrophic brain injury of known cause, most often trauma, haemorrhage or hypoxic-ischaemic injury after cardiac arrest. The determination is a clinical examination with three parts. First, prerequisites: imaging consistent with the cause, and the exclusion of conditions that can mimic it, such as sedative or neuromuscular-blocking drugs, severe electrolyte, acid-base or endocrine disturbance, hypothermia and hypotension. Second, the examination: deep coma with no response to a painful stimulus in the head, and absence of every brainstem reflex (pupillary light, corneal, oculocephalic, oculovestibular, gag and cough). Third, the apnoea test, which shows that a high arterial carbon dioxide does not trigger any breath. When a part of the examination or the apnoea test cannot be done safely, an ancillary test such as a cerebral blood flow study or an EEG is used. In Colombia the diagnosis is regulated by Decree 2493 of 2004: it is made by two or more doctors who are not part of the transplant programme, one of them a neurologist, using the clinical signs set out in the decree, with a confirmatory test when a sign cannot be confirmed, and separate rules for children under two (see the Ethics page on the legal criteria).

## What to assess

- The cause: a catastrophic brain injury seen on imaging and consistent with the loss of all brain function.
- Confounders: sedatives, opioids and neuromuscular blockers (check a train-of-four), alcohol and poisons, enough time for drugs to clear.
- Physiology: core temperature above 36 °C, systolic blood pressure at least 100 mmHg or the target the protocol sets, and no severe electrolyte, glucose or acid-base disturbance.
- The neck: the oculocephalic test is not done until a cervical spine injury is excluded.
- Who examines: doctors trained in the determination, independent of any organ donation team.

## How it is done (and why)

- Confirm a known, irreversible, catastrophic cause on imaging — brain death cannot be diagnosed without one.
- Exclude confounders: drugs, neuromuscular blockade, hypothermia, hypotension, metabolic disturbance — each can mimic absent brain function.
- Apply a painful stimulus in the cranial nerve territory and to the limbs — no cerebral motor or facial response is allowed.
- Test pupils, corneal, oculocephalic and oculovestibular reflexes — each tests a different level of the brainstem.
- Test gag and cough with tracheal suction — these are the lowest brainstem reflexes, in the medulla.
- Preoxygenate, then disconnect and observe for breathing while CO2 rises, confirmed by a blood gas — tests the medullary respiratory centre.
- Stop the apnoea test if hypotension, desaturation or arrhythmia occur, and use an ancillary test — safety comes first.
- Use an ancillary test (cerebral blood flow study or EEG) when any part cannot be completed — confirms the absence of brain function.
- Document every prerequisite, finding, time and examiner — the time of death is when the determination is complete.

## Findings that change the plan

- Movements of the limbs to stimulation, sweating or tachycardia can come from the spinal cord and do not exclude brain death.
- Diabetes insipidus, hypotension and hypothermia are common after brainstem death: treat them to allow testing and organ care.
- A vegetative state, locked-in syndrome or deep sedation are not brain death: the brainstem still works in all three.
- Do not start the examination while a confounder is present; wait or use an ancillary test.
- In children under two, Colombian law and paediatric guidelines require age-specific observation periods and repeated examinations.

## Next step

- Follow the hospital protocol and the Colombian rules for the number and independence of examiners and the confirmatory tests.
- Notify the organ and tissue donation network in line with local rules once brain death is suspected, without involving the transplant team in the diagnosis.
- Tell the family clearly that the person has died, with time, privacy and support.
- Continue organ support only for donation or as the law and protocol allow, and record the time of death in the clinical record.

## Test yourself

Think of the answer, then tap the question to see it.

## Which conditions must be excluded before testing for brain death?

Sedative, opioid or neuromuscular-blocking drugs, poisoning, hypothermia, hypotension, and severe electrolyte, glucose, acid-base or endocrine disturbances.

## What makes an apnoea test consistent with brain death?

No respiratory movement after disconnection while arterial CO2 rises to at least 60 mmHg and 20 mmHg above baseline.

## Do spinal reflexes such as limb withdrawal exclude brain death?

No. Reflexes mediated by the spinal cord can persist after the brain has died and do not exclude the diagnosis.

## When is an ancillary test such as a cerebral blood flow study needed?

When part of the clinical examination or the apnoea test cannot be performed or interpreted, for example with facial injuries or instability.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anaesthesia/brain-death-clinical-testing/)

## Elsewhere in DurgiPedia

- [Brain death: the ethical and legal criteria in Colombia](https://durgical.com/en/medical-ethics/brain-death-the-ethical-and-legal-criteria-in-colombia/)
- [Ley 1805 de 2016: presumed consent for organ donation](https://durgical.com/en/medical-ethics/ley-1805-de-2016-presumed-consent-for-organ-donation/)
- [Limiting life-sustaining treatment: withholding and withdrawing](https://durgical.com/en/medical-ethics/limiting-life-sustaining-treatment-withholding-and-withdrawing/)
- [Diagnosing death: the signs of death](https://durgical.com/en/forensic-medicine/diagnosing-death-the-signs-of-death/)
- [Pupils: light reflex and abnormal pupils (Marcus Gunn, Horner, Argyll Robertson)](https://durgical.com/en/clinical-exam/pupils-light-reflex-and-abnormal-pupils/)

## Connections

## Related 5

- [The comatose patient in the ICU](https://durgical.com/en/anaesthesia/the-comatose-patient-in-the-icu/)
- [Care after cardiac arrest](https://durgical.com/en/anaesthesia/care-after-cardiac-arrest/)
- [Neurosurgery and raised intracranial pressure](https://durgical.com/en/anaesthesia/neurosurgery-and-raised-intracranial-pressure/)
- [Vasopressors and inotropes by receptor and mechanism](https://durgical.com/en/anaesthesia/vasopressors-and-inotropes-by-receptor-and-mechanism/)
- [Analgesia and sedation in the ICU: targets and scales](https://durgical.com/en/anaesthesia/analgesia-and-sedation-in-the-icu-targets-and-scales/)

## Related conditions 6

- [Coma and brain death](https://durgical.com/en/conditions/coma-and-brain-death/)
- [Traumatic brain injury](https://durgical.com/en/conditions/traumatic-brain-injury/)
- [Subarachnoid haemorrhage](https://durgical.com/en/conditions/subarachnoid-haemorrhage/)
- [Intracerebral haemorrhage](https://durgical.com/en/conditions/intracerebral-haemorrhage/)
- [Perinatal asphyxia and hypoxic-ischaemic encephalopathy](https://durgical.com/en/conditions/perinatal-asphyxia-and-hypoxic-ischaemic-encephalopathy/)
- [Diabetes insipidus (central and nephrogenic)](https://durgical.com/en/conditions/diabetes-insipidus/)

## In Pharmacology 2

- [Neuromuscular blockers](https://durgical.com/en/pharmacology/classes/neuromuscular-blockers/)
- [Benzodiazepines](https://durgical.com/en/pharmacology/classes/benzodiazepines/)

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Educational content; it does not replace supervised training, your institution's protocols or the anaesthetist's or intensivist's decision. It contains no doses and no ventilator or infusion settings.

Sources: [Brain Death](https://www.ncbi.nlm.nih.gov/books/NBK538159/) (StatPearls (NCBI Bookshelf), 2024).

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anaesthesia/brain-death-clinical-testing/