Death and Post-Mortem Changes

Study Notes

Nature and Definition of Death

Death is the irreversible cessation of life in a previously viable organism.
A dead person is an individual who has sustained irreversible cessation of:
- Circulatory and respiratory functions, or
- All functions of the entire brain (cortex and brain-stem)

Phases of Death

Somatic death: a person irreversibly loses their personality, becoming unconscious, unable to communicate with their environment, and unable to receive sensory stimuli or initiate voluntary movement, but reflexes and circulatory/respiratory functions may persist.
Cellular or molecular death: cessation of respiration and metabolism of body tissues and their constituent cells, followed by autolysis and decay.
Brain death:
- Cortical death: irreversible coma and failure of spontaneous breathing, leading to hypoxic cardiac arrest and cellular death.
- Brainstem death: irreversible damage to the brainstem, marking the end of somatic life, but not yet cellular death.

Diagnosis of Somatic or Clinical Death

Cessation of circulation:
- Absent pulsations in big arteries (carotid or femoral).
- Undetected blood pressure.
- Absent heart beats.
- Flat ECG on all leads.
Cessation of respiration:
- Apnea as checked by careful auscultation.
- Severe hypoxia and hypercapnea inconsistent with life in Arterial Blood Gas Analysis.

Diagnosis of Brain Stem Death

Clinical tests:
- Absent pupilary response to light.
- Absent corneal reflex.
- Oculocephalic reflex (doll's eye) is absent.
- Vestibulo-ocular reflex is negative when icewater is introduced into the ears.
- Pharyngeal and tracheal reflexes are absent (gagging and coughing).
- Testing for apnea (failure of spontaneous respiration) if all previous clinical tests are lost.
Exclusions:
- All reversible causes.
- Primary hypothermia.

Description

This quiz covers the definition and stages of death, including somatic death and cellular or molecular death. Learn about the irreversible cessation of life in a previously viable organism. Understand the differences between antemortem and postmortem phases of death.