The Cold Flashcards
What happens in mild hypothermia?
36 C Increased metabolic rate due to increased activation of skeletal muscles 35 C Maximum shivering thermogenesis 34-33 C Amnesia Judgement problems
What happens in moderate hypothermia?
Reduction in O2 consumption Oxidative enzymes start to become denatured Shivering stops at 31 C and risk of cardiac arrhythmias CO falls 29 C Conciousness decreases Pupils dont react to light 27 C Loss of voluntary motion and reflexes
What happens in severe hypothermia?
Acid base problems
Unresponsive to pain
18 C
Heart stops
Factors that affect heat loss
Subcutaneous fat Body shape Sex - females have greater % of fat Cold source - water = rapid decline in body temp compared to air Wind chill
Performance in the cold
Impaired muscle function
Power loss of sarcomere contraction
Central regulation of temperature
Decrease in temp Decrease in body temp Detected by central and peripheral thermoreceptors Sent to hypothalamus Sweat glands decrease sweat Arterioles vasoconstrict Brown fat metabolism Erector pili Skeletal muscle shiver
Can you atenuate the cold shock response
If people immersed in cold water repeatedly hyper ventilatory response reduce by 50% and HR response by 30%
Changes occur centrally rather than peripherally eg. Hypothalamus
What is the likelihood of circulatory resuscitation following cardiac arrest
Without cooling, if go into circulatory arrest very small chance of survival
The more you are cooled, the higher the likelihood of resuscitation and survival when you come back to normal body temp
What is heat loss like in water compared to air
Heat loss in water is much faster that in air because cold water is constantly in contact with you
What kind of injuries can the cold cause and how to treat
Freezing cold- Frostbite Treat by amputation Non- freezing cold - Trench foot - caused by prolonged exposure to wet environment. Damage to superficial skin layer Treat by skin graft
What is the difference between drowning and near drowning
Drowning: death caused by inspiration of cold water
Water enters lungs and prevents gas exchange
Water will cool blood and heart
Salt water will change osmotic gradient- draw water out of blood
Near drowning:
Post resuscitation survival following water aspiration
What is the differences in drowning survivals
People who drown in cold water more likely to survive that those that drown in warm water
If person is young and small in cold water they will survive for longer
