"Take care of hydrocution! Vagal Inhibition due to Submersion (Immersion Syndrome), also known as Hydrocution in Europe.
Hydrocution accident is attributed to cardiac arrest due to vagal inhibition, which results from stimulation of vagal nerve endings and in case of drowning, this may be brought about a main way: a sudden entry into cold water! "
Article by: Hydrocution
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Survival beyond 24 hours after the victim is removed from the aqueous environment has been considered as ‘near drowning’. The victim may survive or die later. Injury to the central nervous system (CNS) has been reported to be the major determinant of subsequent survival and long-term morbidity. Hypothermia and decrease in oxygen delivery to vital tissues, especially the brain, are the most important contributing factors towards morbidity and mortality resulting from ‘near drowning’. In such cases, the pulmonary and CNS findings at autopsy will depend mainly upon the amount of initial insult to the lungs and brain by the aspirated water/vomitus and hypoxaemia coupled with oxygen and other therapy. Kvittingen and Naess (1963) recorded recovery of a child after submersion for 20 minutes. Artificial respiration, therefore, need not be abandoned readily.
Drowning literally means, ‘suffer death by submersion in water or any other liquid because of being unable to breathe’. While ‘submersion’ or ‘immersion’ means ‘putting or plunging the person under water’, differentiation is obvious, i.e. ‘drowning’ denotes a confined concept where death is suffered due to submersion in water or any other liquid and the word immersion/submersion conveys a broader concept where death might have been due to drowning or some other cause, though the body had been recovered from water. Therefore, during autopsy, one must focus attention to distinguish between changes that are due to drowning and those that are otherwise, i.e. those that occur in bodies immersed/submerged/disposed in water after death from causes other than drowning. As pointed out already, while considering the circumstances of production of mechanical asphyxia, deaths due to drowning are attended by a series of physiologic and biochemical disturbances and to regard it as a straightforward ‘asphyxial death’ will appear to be oversimplification of the events. However, ‘asphyxial’ phenomena do constitute a significant portion of the fatal course of events; hence, deaths from drowning are usually considered under ‘asphyxial deaths’. (Here, the respiratory passage is occupied by the fluid, i.e. water or any other fluid, due to submersion and inhalation of the fluid. This creates physical impediment to the process of respiration.) Three major factors influencing the human reactions to the drowning process include: pre-existing state of the body of the victim, chemical components of water and the amount of solution inhaled. Complete submersion of the body is not necessary. Death due to drowning can take place when nostrils and the mouth are occluded by water or any other fluid. To put it otherwise, one can drown in a sea/river or in a bath tub a few inches deep.
When a non-swimmer in possession of his/her senses falls into water, he/she immediately tends to sink to the depth proportionate to the momentum accrued during the fall, weight and specific gravity of the body and to some extent the nature of clothing. The victim at this stage may die at once, either from concussion following head injuries by fall from a height or from heart failure due to old coronary artery disease or from sudden cardiac arrest because of vagal inhibition, specifically if the fluid happens to be cold, and the victim happens to be under influence of alcohol or drug, etc.
Usually, however, the victim rises up to water surface, owing to natural buoyancy of the body and air locked in the clothing, accompanied by struggling movements of his/her limbs. On reaching water surface, the victim cries for help and in an effort to breathe is likely to inhale water. While some air is inhaled into the lungs, some water also passes into the mouth and some of it may be aspirated into the air passages, inducing coughing. Out of fatigue or difficulty, the victim tends to make clutching movements with arms and legs and lay hold of anything within his/her reach and alternately sinks and rises.
Each time when his head dips beneath water, some fluid is drawn into the respiratory passage. This ingoing water irritates the mucous membrane of the air passages and provokes the secretion of mucus. This mucus when mixed with water and possibly some surfactant from the lungs is whipped into tenacious foam by the violent respiratory efforts made by the victim. Its amount and consistence soon becomes sufficient to act like a ‘check valve’. The more powerful inspiratory efforts carry air past the obstruction but expiratory efforts are insufficient to expel air, water and foam. The struggle for life may continue for sometime according to the prior status of the individual but eventually exhaustion ensues and the victim sinks beneath the surface, opens the mouth, tries to draw in air but only water enters. There usually occur some convulsive movements prior to coma or suspended animation and death. The body eventually sinks until it floats because of development of sufficient gases of decomposition.