Drowning Flashcards
What is drowning?
Process resulting in primary respiratory impairment from submersion or immersion into a liquid medium
So you airway gets blocked, from being completely underwater or on top.
Whether the victim lives or dies, they have still drowned. If they do not survive, they have fatally drowned.
Immersion
Being covered in a liquid medium, the airway is above the surface of the liquid. Hypothermia, cardiovascular collapse - hydrostatic pressure (pressure given off by the water).
What is Submersion
Entire body including airways goes below the water
Asphyxia and hypoxia
Physiological process of drowning/what happens
- water enters airway,
- voluntary spat out or swallow a little bit.
- Conscious response is to hold breathe
- Reflex response is to breathe and cough (larynx epiglottis)
- Aspiration (water starts to enter the lungs) takes place
- Laryngospasm (when water touches vocal cords, they shut tight). This shuts off air and you don’t know how long this will last.
- Sooner or later it will open up, Continued aspiration
- Hypoxemia (low oxygen in blood) leading to loss of consciousness
- Apnoea
- Cardiac arrest
Immersion and submersion drowning
Sudden immersion into cold water can cause a sudden intake of breath
Panic breathing as a result
Frequent submersion occurs
Compounding respiratory distress.
Casualty buoyancy is compromised as losing air out of the body
Begin to sink
At the same time they are swallowing large volumes of water
Can’t coordinate breathing and muscular action of swimming, even in strong swimmers
What are the five types of drowning
Near drowning Dry drowning Fresh water drowning Salt water drowning Secondary drowning
What is dry drowning
As unconsciousness deepens the patient will try and breath. Water enters the pharynx triggers reflex causing laryngospasm.
Water never reaches the lungs. Instead breathing in causes vocal cords to spasm and close up.
What is near drowning
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What is fresh water drowning?
Inhalation of water goes into respiratory tract.
Causing interference with external respiration, preventing gas exchange.
Water absorbed into circulation causing gross haemodilution. Fresh water is hypotonic compared to lung tissue. (Dilutes your blood, red blood cells to burst, release potassium ions)
Electrolyte imbalance. Disrupts ph balance of blood
Cerebral anoxia.
Cardiac arrest
What is secondary drowning
Usually occurs within 4 hours of near drowning
Can be fatal
If water has entered the body rapid absorption takes place from stomach to blood
Salt water drowning
Salt water entering the lungs is more solute than blood (hypertonic)
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Immersion in cold water
Rapid reduction in skin temp leads to cold shock
Mix of sympathetic (speeds things up except digestion) and parasympathetic (slows things down except digestion) responses and so the body doesn’t know what to do, gets conflicting messages.
This autonomic conflict leads to life threatening arrhythmias
Sympathetic
Hyperventilation Hypocapnia (co2 diffusion between cells and blood isn’t happening) can’t get co2 out of cells and into the blood Tachycardia Hypertension Peripheral vasoconstriction
Parasympathetic
Profound bradycardia
Vagal stimulation in the pharynx and larynx (so slows breathing down)
Mammalian diving reflex
Set of reflexes triggered by cold water coming into contact with the face - trigeminal nerve
Clever physiological mechanism that enables the body to manage and tolerate a lower level of oxygen
Rapid fall in core temp
Bradycardia
Peripheral vasoconstriction
Blood shift to lower metabolism and oxygenation consumption
Rewarming must take place slowly
