Under drowning should be understood a separate type of violent death, which is caused by a complex of external influences on the human body when its body is immersed in liquid. At a certain stage of development of a complex pathophysiological process of dying, phenomena determined by the aspiration of a fluid are added.
The most common drowning in water. By the nature of death, this is usually an accident, rarely - suicide and even less often - murder.
An indispensable condition for drowning is immersion of the body in a liquid. The closure of the respiratory tract and cavities with a fluid and the subsequent asphyctic condition should be considered as a special case of obstructive asphyxia. For example, immersing only a person in a shallow stream or puddle can be fatal due to aspiration asphyxiation, but not drowning.
When a person is suddenly and quickly submerged in water or another liquid, which is accompanied by the closure of the respiratory tract, a complex and not always unambiguous complex of pathophysiological changes develops in the body. This complex is based on several factors: low (compared to the body and ambient air) water temperature, hydrostatic pressure, varying from the depth of immersion, and psycho-emotional stress caused by fear. The latter can deprive a person (even a swimmer) of the opportunity to stay on the surface of the water.Go
The genesis of death when drowning may be different:
1) water at a temperature of about 20 ° C, getting into the upper respiratory tract, can cause irritation of the mucous membranes and endings of the vertebral nerve, which leads to a spasm of the vocal cords and reflex cardiac arrest. This mechanism of death has been called asphyctic (or dry) drowning;
2) penetrating the upper respiratory tract, water closes them. This type of drowning was called “true” or “wet” drowning. There is a typical asphyxia from the closure of the upper respiratory tract, proceeding, like mechanical asphyxia, in several phases.
Originally observed reflex delay (stop) breathing, lasting 30-60 s. After this comes the phase of inspiratory dyspnea (up to 1 min), the water begins to penetrate into the respiratory tract and lungs. The inspiratory dyspnea is replaced by an expiratory one, at the beginning of which consciousness is lost, convulsions develop, reflexes are lost. Water continues to penetrate into the lungs and into the vessels of the small, and then the great circle of blood circulation, significantly diluting the blood (hemodilution) and hemolyzing it.
It has been established that water can penetrate into the blood in a volume approximately equal to the volume of circulating blood. After expiratory dyspnea, breathing stops for a short time, after which there are several deep breathing movements (terminal breathing), during which water continues to penetrate the lungs. Then, persistent respiratory arrest occurs due to paralysis of the respiratory center and, after 5–10 min, persistent cardiac arrest. Death comes. It is not uncommon for drowning to develop first in the asphyctic type, and end in the type of true drowning (laryngism is resolved, water enters the airways and lungs);
3) under the action of cold water on the body, a spasm of the vessels of the skin and lungs develops, a contraction of the respiratory muscles occurs, resulting in sharp disturbances in breathing and cardiac activity, brain hypoxia, leading to a rapid onset of death, even before the development of proper drowning.
The different genesis of death determines the difference in the severity and nature of the morphological changes found in the forensic examination of the corpses.
The whole period of drowning lasts 5-6 minutes. The rate of development of asphyxia when drowning is affected by water temperature. In cold water, the onset of death from drowning is accelerating due to the cold effect on the reflex zones. When drowning, water is usually swallowed, enters the stomach and the initial part of the small intestine.
The mechanism of death from drowning in other fluids is essentially no different from drowning in water.