DROWNING

Dr K.B.SuryakumarProf & HOD

Dept of Forensic MedicineKVG Medical CollegeSULLIA_- KARNATAKA

Drowning

-Death caused by suffocation when liquid interrupts body's absorption of oxygen from air leading to asphyxia .

..The primary cause of death is hypoxia and acidosis leading to cardiac arrest

Near drowning

-survival of a drowning -unconsciousness /water inhalation --can lead to serious complications, including death, after the event.

Secondary drowning --death due to chemical / biological changes in the lungs after a near drowning incident

Types

Most drowning occur in water, 90% in freshwater (rivers, lakes and

pools) 10% in sea water , drowning in other fluids are rare and

often industrial accidents.

Types

Dry drowning- type1 Wet –type2 Shallow water [alco. ,epileptics ,infants,

unconcious Immersion syndrome –vagal Secondary –near drowning –

infection ,edema ,acidosis

Believe it or not

People have drowned in as little as 30 ml of water lying face down, in one case in a wheel rut.

Children have drowned in baths, buckets and toilets;

inebriates or those under the influence of drugs have died in puddles

The pathophysiology of drowning The body's reaction to submersion Submerging the face in water colder than

about 21 °C (70 °F) triggers the mammalian diving reflex found in all mammals and especially in marine mammals such as whales and seals

This reflex protects the body by putting it into energy saving mode to maximize the time it can stay under water.

The strength of this reflex is greater in colder water and has three principal effects

symptoms Bradycardia --,- slowing of the heart rate of

up to 50% in humans. Peripheral vasoconstriction , -to extremities

to increase the blood and oxygen supply to the vital organs, especially the brain

Blood Shift, the shifting of blood to the thoracic cavity to avoid the collapse of the lungs under higher pressure during deeper dives.

The reaction to oxygen deprivation

try to access air, resulting in panic --rapid body movement.

uses up more oxygen in blood stream -reduces time to unconsciousness –

victim can voluntarily hold breath for some time, but breathing reflex will increase until victim will try to breathe, even when submerged.

The breathing reflex related to amount of oxygen in blood, to the

amount of carbon di oxide. During apnea, the oxygen in the body is

used by the cells, excreted as carbon dioxide. Thus, the level of oxygen in the blood

decreases, level of carbon dioxide increases. Leading to stronger breathing reflex, up to

the breath-hold breakpoint, when victim no longer voluntarily hold breath. typically occurs at arterial partial pressure of carbon dioxide of 55 mm Hg,

Reaction to water inhalation

If water enters airways of conscious victim --will try to cough up water or swallow ,thus inhaling more water involuntarily.

Upon water entering airways, both conscious and unconscious victims experience laryngospasm, prevents water from entering lungs ..

So, water enters stomach in initial phase of drowning and very little water enters lungs.

Reaction to water inhalation

Laryngospasm relaxes some time after unconsciousness and water can enter the lungs causing a "wet drowning".

However, about 10-15% of victims maintain this seal until cardiac arrest, this is called “ dry drowning " as no water enters the lungs.

autopsy

In forensic medicine water in the lungs indicates that the victim was still alive at the point of submersion;

the absence of water in the lungs may be either a dry drowning or indicates a death before submersion.

P.M findings External-fresh- cloths wet ,sand ,mud on

body Cutis anserina [goose skin ]-erector pilae

contraction Washer woman hand –sodden, wrinkle Cadaver spasm Fine lathery froth –churning of air in alveoli Congested conjunctiva P M staining –variable Aquatic animal bite marks Ante mortem injuries

Internal Mud in mouth ,esophagus Fine froth in larynx ,trachea .bronchus , Lung—voluminous ,edematous ,balloon

like ,rib indentation ,pit on pressure---- c/ s-frothy fluid

Paltauf’s hemorrhage— violent resp. effort>rupture alveoli>blood+air [emphysematous aquosum ]

Dry drowning Stomach –water, mud ,sand

Lab findings Diatoms –most dependable findings –in

remote organs –brain ,bone marrow Gettler’s test —chloride in all chambers of

heart is equal---in fresh water –haemodilution in Rt early >50%

Salt water drowning-heamoconcentration in left>increase to 30-40 %

R B C –decreased in fresh water-dilution Salt water – increased magnesium

Unconsciousness

A continued lack of oxygen to brain, (hypoxia ,) renders a victim unconscious at blood partial pressure of oxygen of 25-30mmHg.

An unconscious victim rescued with an airway still sealed from laryngospasm stands a good chance of a full recovery.

Artificial respiration

--more effective without water in the lungs.

victim stands good chance of recovery if attended to within minutes.

In most victims the laryngospasm relaxes some time after unconsciousness and water fills the lungs resulting in a wet drowning.

Cardiac arrest and death

The brain cannot survive long without oxygen and continued lack of oxygen in the blood combined with cardiac arrest will lead to deterioration of brain cells

This causes brain damage and eventually brain death from which recovery is generally considered impossible.

lack of oxygen

chemical changes in the lungs -cause heart to stop beating;

cardiac arrest stops the flow of blood and stops the transport of oxygen to the brain. Cardiac arrest used to be the traditional point of death but at this point there is still a chance of recovery.

The brain will die after approximately six minutes without oxygen but special conditions may prolong this

Exchange

. Freshwater contains less salt than blood and will therefore be absorbed into the blood stream by osmosis

.Sea water is much saltier than blood. Through osmosis water will leave the blood stream and enter the lungs thickening the blood...

After death rigor mortis will set in and remains for about two days, depending on many factors including water temperature

Secondary drowning

Water,, will damage the inside surface of the lung, collapse the alveoli and cause pulmonary edema-

-reduced ability to exchange air. This may cause death up to 72 hours after a

near drowning incident. called secondary drowning.

Freshwater can be more dangerous than saltwater in secondary drowning.

Hemolysis

When fresh water enters the lungs it is pulled into the pulmonary circulation via the alveoli because of the low capillary hydrostatic pressure and high colloid osmotic pressure.

Consequently, the plasma is diluted and the hypotonic environment causes red blood cells to burst (hemolysis).

The resulting elevation of plasma K+ level and depression of Na+ level, due to the hemolysis, alter the electrical activity of the heart.

Ventricular fibrillation

Ventricular fibrillation often occurs as a result of electrolyte changes.

Additionally, if drowning occurs in very cold water ( <10* C), the uptake of cold water into the vascular system can stop the heart.

In open heart surgery, the technique of pouring cold saline solution over the heart is used to prevent heart action.

If the victim is resuscitated death can occur hours later due to renal failure.

Hemolysis

During hemolysis, hemoglobin is also released into the plasma which can accumulate in the kidneys leading to acute renal failure.

In contrast, salt-water drowning does not lead to uptake of inspired water into the vascular system because it is isotonic to blood. Therefore, no red cell hemolysis occurs.