Criteria for Declaring Medical Death
Medical death is determined by either irreversible cessation of circulatory and respiratory functions or irreversible cessation of all brain functions, including the brainstem, with specific clinical criteria and observation periods required for each determination method. 1
Circulatory Death Criteria
Clinical Examination
- Absence of circulation (no pulse, no heart sounds, no blood pressure)
- Absence of respiratory effort
- Unresponsiveness to all stimuli
- Fixed and dilated pupils
- Absence of corneal and other brainstem reflexes 1
Observation Period
- Minimum 2-5 minutes of absent circulation is required to declare death 2
- The American Thoracic Society supports a 2-minute standard for declaring death after circulatory cessation 2
- Any return of cardiac or respiratory activity during this period requires restarting the observation period 1
Brain Death Criteria
Clinical Examination
- Complete unresponsiveness to all stimuli (coma)
- Absence of all brainstem reflexes:
- Pupillary light reflex
- Corneal reflex
- Oculocephalic reflex (doll's eyes)
- Oculovestibular reflex (cold caloric)
- Gag and cough reflexes 1
Apnea Testing
- Must demonstrate absence of respiratory effort with adequate CO₂ stimulus
- PaCO₂ must reach ≥60 mmHg AND ≥20 mmHg above baseline
- Testing requires preoxygenation with 100% oxygen and continuous monitoring 1, 2
- If apnea testing cannot be completed due to medical contraindications or hemodynamic instability, ancillary testing is required 2
Observation Period
- For adults: typically 6 hours between examinations
- For term newborns (37 weeks to 30 days): 24 hours between examinations
- For infants and children (30 days to 18 years): 12 hours between examinations 1, 2
- Defer assessment for 24-48 hours after cardiopulmonary resuscitation or severe acute brain injuries 1
Prerequisites for Death Determination
Rule Out Reversible Conditions
- Core temperature >35°C (hypothermia must be corrected)
- Normal blood pressure (hypotension must be corrected)
- Corrected metabolic disturbances
- No sedatives, analgesics, or neuromuscular blockers that could confound examination
- Neuromuscular blocking agents must be discontinued with Train of Four (TOF) of 4/4 confirmed 1
Ancillary Testing (When Required)
Cerebral Blood Flow Studies
- Four-vessel cerebral angiography (gold standard)
- Radionuclide cerebral blood flow studies
- Transcranial Doppler ultrasonography 1
Electrophysiological Studies
- Electroencephalography (EEG) - absence of electrical activity 1
Documentation Requirements
- Clinical examination findings
- Results of apnea testing
- Results of ancillary testing (if performed)
- Determination of irreversibility
- Two examinations by different physicians (for brain death) 1
Common Pitfalls to Avoid
- Misinterpreting spinal reflexes as signs of brain function
- Inadequate observation time
- False detection of respiratory effort
- Performing testing too early after injury
- Failing to correct reversible conditions 1
Special Considerations
Organ Donation After Circulatory Death
- Death must be declared before organ procurement can proceed (dead donor rule)
- The timing of death declaration is critical for organ viability
- In controlled donation after circulatory death (DCDD), death is typically declared after 2-5 minutes of absent circulation 2
- Different countries have varying protocols for the required observation period 2
Pediatric Considerations
- More stringent criteria and longer observation periods are required for infants and children
- Two separate examinations with age-specific observation periods are mandatory 2
By following these established criteria and protocols, clinicians can accurately determine medical death while avoiding potential errors in this critical determination.