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 — the 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:
- Artificial pulmonary ventilation to restore gas exchange.
- Restoration of circulation (chest compressions, defibrillation).
- Correction of metabolic disorders: elimination of acidosis, normalization of ion balance and hemostasis.
The effectiveness of resuscitation significantly increases with the use of hypothermia and hyperbaric oxygenation.
Post-resuscitation disease
After successful revival, 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.
Briefly: answers to topical 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.
- Central nervous system — the patient is lethargic, with progressive depression of consciousness, brain electrical activity, and reflexes.
- Respiration — pronounced dyspnea (initially tachypnea, then bradypnea).
- Skin — pale, cyanotic, or mottled.
- Hemodynamics — blood pressure is low (60–70 mm Hg) or undetectable; pulse is rapid, weak (thready), or completely undetectable; initially tachycardia is observed, followed by bradycardia.
What early and late reliable signs are used to establish the onset of biological death?
Biological death is established based on reliable signs and cadaveric changes.
- Reliable signs: absence of cardiac activity, absence of spontaneous breathing, maximum pupillary dilation and absence of light reflex, absence of corneal reflex, presence of postmortem hypostasis in dependent body parts; at normal 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 phenomenon).
- Late signs: cadaveric spots, rigor mortis, putrefaction.
What are the clinical and pathophysiological characteristics of the terminal pause stage?
The terminal pause is a transitional link between preagony and agony, manifested by respiratory arrest and a sharp depression of cardiac activity.
- Pathophysiology — cessation of the brain's bioelectrical activity.
- Respiration — arrest and cessation of breathing.
- Hemodynamics — slowing of the heart down to asystole, drop in heart rate.
- Reflexes and temperature — extinction of corneal reflexes and drop in body temperature to 33–34 degrees.
What is the pattern of breathing at the onset of the agony stage?
Upon entering agony, breathing becomes pathological as it is regulated by the bulbar centers. It becomes shallow, rapid, convulsive, or significantly slowed. In this stage, the first breath after a pause and gasping respiration (terminal rare breathing) are observed. The person begins to gasp for air, making deep, short, convulsive breaths and expirations with long intervals between them, after which breathing stops completely.
PTAK-B: Preagony, Terminal pause, Agony, Clinical death, Biological death.
Class and exam questions
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.
Is it possible to revive a person after the onset of biological death?
Restoration of the organism as an integral system is impossible. However, the functions of individual organs can be preserved for transplantology purposes.
What is the main criterion for the duration of clinical death?
The main limiting factor is the degree of hypoxia in the cerebral cortex neurons, as they are most sensitive to oxygen deprivation.
What else to study on this topic
- Pathophysiological mechanisms of acidosis development in terminal states.
- The effect of hyperbaric oxygenation on the metabolism of ischemic tissues.
- Differential diagnosis of agony stages.
- Mechanisms of multiple organ dysfunction syndrome formation in the post-resuscitation period.
- Etiology and pathogenesis of the terminal pause.
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