What are the criteria to confirm death?

Confirming Death: Clinical Criteria and Diagnostic Approach

Death is confirmed through one of three pathways: circulatory criteria (irreversible cessation of cardiopulmonary function), neurological criteria (brain death), or somatic criteria (visible signs of death on external inspection), with the appropriate pathway determined by clinical circumstances. 1

Circulatory Death Determination

For patients after cardiac arrest, death is declared following a "no-touch period" of continuous absent cardiopulmonary activity, with international protocols varying from 5 to 20 minutes. 2

Key Components:

• Absence of circulation must be documented 2
• Absence of spontaneous ventilation must be confirmed 2
• Absence of respiratory effort on observation 2
• No electrical activity on electrocardiogram 2
• No cardiac movement on focused echocardiography (when available) 2
• No pressure wave on arterial line tracing (if present) 2

The definition of refractory cardiac arrest typically requires 30 minutes of failed resuscitation before death determination can proceed 2. Following cessation of resuscitation, the mandatory hands-off observation period ensures irreversibility before declaring death.

Brain Death Determination (Neurological Criteria)

Brain death requires two complete neurological examinations by different attending physicians, separated by an observation period, to confirm irreversible cessation of all brain function. 3

Prerequisites (Must Be Corrected First):

• Establish a known, irreversible cause of coma 3
• Normalize blood pressure and core temperature above 35°C 3, 4
• Correct all metabolic disturbances 3
• Discontinue sedatives, analgesics, neuromuscular blockers, and anticonvulsants for appropriate time based on elimination half-life 3
• Ensure medication levels are in low to mid-therapeutic range 3

Clinical Examination Components:

Coma Assessment:

• Complete unresponsiveness to all stimuli must be documented 3
• No eye opening to verbal or painful stimuli 2

Brainstem Reflex Testing:

• Absent pupillary light reflexes (pupils fixed and dilated) 3, 5
• Absent corneal reflexes (no blink response to corneal stimulation) 3, 5
• Absent oculocephalic reflexes (doll's eyes) 3
• Absent oculovestibular reflexes (cold caloric testing) 3
• Absent gag and cough reflexes 3

Motor Response:

• No motor response to painful stimuli in cranial nerve distribution 3
• Spinal reflexes may be present and do not preclude brain death 6

Apnea Testing (Critical Component):

The apnea test confirms loss of brainstem respiratory drive and requires PaCO₂ to rise to ≥60 mmHg or ≥20 mmHg above baseline with no respiratory effort observed. 3, 4

Procedure:

• Pre-oxygenate with 100% oxygen for 5-10 minutes 3, 4
• Obtain baseline arterial blood gas 4
• Disconnect from ventilator while providing oxygen via catheter or T-piece 3, 4
• Monitor continuously for any respiratory effort 4
• Obtain serial ABGs to document PaCO₂ rise 4
• Reconnect to ventilator if oxygen saturation drops below 85% (test cannot be completed safely) 4

If the apnea test cannot be safely completed due to hypoxemia or hemodynamic instability, ancillary testing becomes necessary 3, 4.

Observation Periods:

For term newborns (37 weeks gestational age) to 30 days: 24-hour observation period between examinations 2

For infants and children (30 days to 18 years): 12-hour observation period 2

For adults: observation periods vary by institutional protocol, but two separate examinations are required 3

The first examination determines the patient meets brain death criteria; the second confirms an unchanged and irreversible condition 2.

Ancillary Testing (When Required):

Ancillary tests are NOT required for brain death determination but should be used when: 3, 7

• Components of examination or apnea testing cannot be completed safely 3
• Uncertainty exists about examination results 3
• Medication effects may be present 3
• Reduction of inter-examination observation period is desired 3

Accepted ancillary tests include:

• Electroencephalogram (EEG) showing electrocerebral silence 3, 8
• Cerebral blood flow studies (four-vessel angiography or radionuclide scan) 3, 8
• Transcranial Doppler (TCD) showing absent cerebral blood flow 8
• Somatosensory evoked potentials (SEP) showing absent responses 8

EEG has the highest completion rate (98%) with good sensitivity (83%) and specificity (97%) 8. When combined with SEP or TCD, specificity reaches 100% 8.

Declaration of Death:

Death is declared when all clinical criteria are fulfilled, including two complete examinations by different physicians and successful apnea testing (or ancillary studies if apnea test cannot be completed). 2, 3

Somatic Criteria (Traditional Death)

In most cases without artificial ventilation, permanent loss of cardiopulmonary function with visible signs of death on external inspection is sufficient. 1, 9

This includes obvious decomposition, rigor mortis, or dependent lividity in the context of absent vital signs 1.

Common Pitfalls to Avoid:

• Never declare brain death without correcting confounding factors (hypothermia, drugs, metabolic derangements) 3
• Spinal reflexes do not preclude brain death and should not delay declaration 6
• Do not attempt apnea testing in hemodynamically unstable patients without first stabilizing or plan for ancillary testing 4
• Ensure adequate observation periods are met based on patient age 2
• Document all examination findings meticulously, including both examinations and all test results 3