Stages of terminal state
The dying process does not occur instantaneously. Three consecutive types of terminal states are distinguished, each characterized by progressive decompensation:
- Preagonal state. At this stage, the central nervous system (CNS) is depressed, and the patient becomes lethargic. Marked dyspnea develops, and the skin turns pale or acquires a cyanotic (bluish) tint. Hemodynamics are critically impaired: blood pressure (BP) drops to 60–70 mm Hg or is not detectable at all. The pulse is rapid, becomes very weak (thready), or disappears completely.
- Agony (deep stage of dying). Characterized by a complete lack of consciousness. Hemodynamic parameters continue to deteriorate — BP is undetectable, the pulse remains thready or disappears. The breathing pattern is severely impaired: breaths can be shallow, frequent, spasmodic, or, conversely, significantly slowed.
- Clinical death. Occurs immediately after complete circulatory and respiratory arrest. This is a specific transitional state from life to biological death when resuscitation is still possible.
Clinical death and survival mechanisms
In a state of clinical death, metabolic processes in the body sharply decrease. Since oxygen supply ceases, its absence is temporarily compensated by anaerobic glycolysis mechanisms.
This period lasts only 3–5 minutes. If effective resuscitation measures are not started on time, deep, irreversible changes develop after 5–6 minutes. The central nervous system suffers from oxygen deprivation first. As soon as the cerebral cortex neurons die, true or biological death occurs.
Resuscitation (revival) is a set of emergency measures aimed at restoring cardiac activity, respiration, and metabolism. Its efficacy directly depends on the patient's baseline condition:
- High efficacy is observed in sudden cardiac arrest if the body's compensatory mechanisms are preserved.
- Low efficacy or inefficacy is noted when cardiac arrest occurs against the background of a severe, incurable disease that has led to complete exhaustion of reserves.
Cardiac arrest: types and causes
Cardiac arrest can develop according to two scenarios:
- Gradually. Develops against the background of chronic and debilitating diseases. In this case, the arrest is necessarily preceded by prolonged periods of pre-agony and agony.
- Suddenly. Occurs abruptly, against the background of relative well-being or acute conditions.
The main causes of sudden cardiac arrest include:
- Acute myocardial infarction.
- Reflex cardiac arrest.
- Mechanical obstruction (blockage) of the upper airway by foreign bodies.
- Anaphylactic shock.
- Direct cardiac trauma.
- Drowning and electrical injury.
- Severe metabolic shifts in the body (e.g., hyperkalemia or pronounced metabolic acidosis).
Diagnosis of clinical death
The time to diagnose clinical death must be extremely short, as every second counts. The main criterion for the immediate start of resuscitation is the absolute diagnostic triad:
- Absence of pulse in a major (carotid) artery.
- Respiratory arrest (apnea).
- Persistent pupil dilation (mydriasis) with a complete lack of light reflex.
In addition to the triad, the clinical picture of a terminal state is complemented by the following signs:
- Complete lack of consciousness.
- Pallor, less often pronounced skin cyanosis.
- Absence of pulse in peripheral arteries.
- Zero blood pressure.
- Absence of audible heart sounds.
Important to remember: the presence of absolute signs from the diagnostic triad requires an immediate transition to cardiopulmonary resuscitation.
Briefly: answers to topical questions
What types of cardiac arrest are distinguished by electrocardiographic (ECG) mechanisms?
- Ventricular fibrillation.
- Pulseless ventricular tachycardia.
- Asystole.
- Pulseless electrical activity (PEA).
For a quick decision on starting resuscitation, use the APM rule (diagnostic triad): Apnea (no breathing) + Pulse (absent on the carotid artery) + Mydriasis (wide pupils with no light reaction).
Class and exam questions
How much time does a physician have to diagnose clinical death?
The time to establish a diagnosis must be kept to an absolute minimum. Clinical death itself lasts only 3–5 minutes, after which (in 5–6 minutes) irreversible CNS changes and biological death ensue.
In which cases is resuscitation most likely to be ineffective?
Resuscitation has a poor prognosis if cardiac arrest occurred gradually against the background of a severe incurable disease, when the body's compensatory reserves are fully exhausted.
What compensates for oxygen deprivation in the first minutes of clinical death?
During clinical death, metabolic processes sharply decrease, and acute hypoxia is temporarily compensated for by tissue anaerobic glycolysis reactions.
What else to study on this topic
- Pathophysiological mechanisms of anaerobic glycolysis during hypoxia
- Differences between reflex cardiac arrest and arrest in myocardial infarction
- Diagnostic algorithms for metabolic acidosis and hyperkalemia
- Tactics for restoring airway patency in obstruction
- Assessment of vital functions during the gradual development of a terminal state
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