Terminal states are the sequential stages of the extinction of vital body functions preceding biological death. Understanding these stages is critical for determining the reversibility of processes and performing effective resuscitation.
Clinical deathLasts 3–6 minutes at normothermia, and up to 15–25 minutes during hypothermia.
Limiting factorThe duration of resuscitation is limited by the degree of hypoxia in the cerebral cortex neurons.
Stages of dyingPreagony, terminal pause, agony, clinical death, and biological death.
Post-resuscitationAn unstable state of the organism after revival with a risk of multiple organ dysfunction syndrome.
Dynamics of Dying
The dying process is not an instantaneous event, but a sequence of stages:
Preagony — initial depression of functions.
Terminal pause.
Agony.
Clinical death — a reversible stage characterized by the complete cessation of respiration and circulation.
Biological death — irreversible cessation of all physiological processes in cells and tissues.
The first four stages are potentially reversible with timely intervention.
Resuscitation Measures
The goal of resuscitation is to restore the integrity of the organism. The main tasks include:
Mechanical ventilation to restore gas exchange.
Resumption of circulation (chest compressions, defibrillation).
Correction of metabolic disorders: elimination of acidosis, normalization of ion balance and hemostasis.
Resuscitation efficacy significantly increases with the use of hypothermia and hyperbaric oxygenation.
Post-Resuscitation Disease
After successful resuscitation, the body enters a state of instability that goes through three stages:
Temporary stabilization.
Transient destabilization caused by the development of multiple organ dysfunction syndrome.
Normalization of functions or recovery.
Mnemonic
PTAD-B: Preagony, Terminal pause, Agony, Death (clinical), Biological death.
Frequently asked questions
What clinical symptoms and hemodynamic changes are characteristic of the preagonal state?
The preagonal state is characterized by central nervous system depression, as well as pronounced respiratory and hemodynamic disorders.
CNS — the patient is lethargic, with progressive depression of consciousness, brain electrical activity, and reflexes.
Respiration — marked dyspnea (initially tachypnea, then bradypnea).
Skin — pale, cyanotic, or mottled.
Hemodynamics — low blood pressure (60–70 mm Hg) or undetectable; pulse is rapid, weak (thready), or absent entirely; initial tachycardia is followed by bradycardia.
What early and late reliable signs confirm the onset of biological death?
Biological death is confirmed by reliable signs and cadaveric changes.
Reliable signs: absence of cardiac activity, absence of spontaneous breathing, maximal pupil dilation with no reaction to light, absence of the corneal reflex, presence of postmortem hypostasis in dependent parts of the body; at standard ambient temperature, absence of cardiac activity for more than 25 minutes.
Early signs: drying and clouding of the cornea, cat's eye symptom (Beloglazov's sign).
Late signs: lividity (postmortem lividity), rigor mortis, putrefaction.
What are the clinical and pathophysiological characteristics of the terminal pause stage?
The terminal pause serves as a transitional link between preagony and agony, manifesting as respiratory arrest and a sharp drop in cardiac activity.
Pathophysiology — cessation of the bioelectrical activity of the brain.
Respiration — arrest and breath-holding.
Hemodynamics — slowing of the heart leading to asystole, drop in heart rate.
Reflexes and temperature — extinction of corneal reflexes and drop in body temperature to 33–34 °C.
What is the respiratory pattern upon entering the agony stage?
When agony begins, respiration becomes pathological because it is regulated by bulbar centers. It becomes shallow, rapid, convulsive, or significantly slowed. This stage features the first breath after a pause and gasping respiration (terminal rare breathing). The patient appears to grasp for air, making deep, convulsive, short inspirations and expirations with long intervals between them, after which respiration stops entirely.
Why does the duration of clinical death increase during hypothermia?
Low temperature slows down tissue metabolism, which reduces the oxygen demand of neurons and delays the development of irreversible damage to the cerebral cortex.
Can a person be revived after the onset of biological death?
Restoring the organism as an integrated system is impossible. However, the functions of individual organs may be preserved for transplantation purposes.
What is the main criterion for the duration of clinical death?
The primary limiting factor is the degree of hypoxia in the cerebral cortex neurons, as they are most sensitive to oxygen deprivation.
Go deeper
Pathophysiological mechanisms of acidosis development in terminal states.
The effect of hyperbaric oxygenation on the metabolism of ischemic tissues.
Differential diagnosis of the stages of agony.
Mechanisms of multiple organ dysfunction syndrome formation in the post-resuscitation period.