2. What is hyperthermia?
It is an acute heat injury disease resulting from
prolonged exposure to high environmental
temperature which causes a dysfunction of the
temperature-regulating mechanism and
excessive loss of water-electrolyte of the body.
3. Causitive Factors
high temperature climate
dry-heat working condition and high humid-warm
environment
dysfunction of the temperature-regulating mechanism
• increased heat production
• poor heat adaptation
• impedient heat dissipation
9. Regulation of heat production and
dissipation
Radiation
•the major way of heat dissipation
•depends on the difference between the body surface and
environmental temperature( 15-25℃ →60%, 33℃ →0% )
the most heat dissipation part of the body is head(50%),
then hands and feet
Convection
Conduction
•depends on the air flow rates
•the conduction power of water is 240 times than the air
Evaporation
•1g water evaporation for 2.4kj(0.58kcal)heat dissipation
•more humidity less evaporation
&
11. central nervous system
inhibiting effect
• inattention
• slow in reacting
• decreased accuracy and Coordination of action
dysfunction
• delirium、 mania
• coma
17. Prodrome
High temperature environment
Thirsty、fatigue、 excessive sweating、 dizziness、
headache、palpitation、nausea…
The body temperature is about normal or slightly high
18. Mild Hyperthermia
The exacerbation of premonitory hyperthermia
The early stage of dysfunction of the circulation:
flushed face or pale complexion、 dysphoria or
apathia 、nausea and vomiting 、 sweating 、
clammy skin, 、thin and rapid pulse、
hypotension 、 increased heart rate
The body temperature is slightly increased
20. high temperature
sweating a lot
excessive loss of water and salinity
supply more water but less salinity
hyponatremia and hypochloremia
muscle cramp、pain(water loss > salinity loss)
heat
cramps
22. body temperature>42℃ → protein denaturation
body temperature>50℃ → all cell death a few
minutes later
during the autopsy, pathological change can be
seen in the brain、 neurocyte 、 cardiomyocytes
、lung、liver、kidney and hemorrhagic spots can
be found in the pleura、 peritoneum 、small
intestine,etc
heat
stroke
24. Heat cramps
it refers to a severe muscle cramp and contraction pain
(the muscle of four limbs and abdomen)
it happens at the beginning of the hot season and before
the heat adaptation of the body
young people who do manual work under the high
temperature circumstance and sweat a lot
25. Heat exhaustion
acute onset
dizziness, headache, suddenly faint , pale complexion ,
cold sweat in the skin, weak or slow pulse, hypotension
but with normal pulse pressure
awake after lie on the back or leave the high temperature
environment
old people or individuals with heat intolerance
26. Heat stroke
typical symptoms:hyperpyrexia , anidrosis ,
disturbance of consciousness
prodrome:fatigue, dizziness, headache, nausea,
sweat reduced
body temperature increases rapidly(>41℃) →
somnolence, apathy, coma
hot and dry skin ,no sweat, flushed or pale skin ,
or even cyanosis
34. Heat cramps or exhaustion
exposure history to high temperature environment
symptoms:sweat a lot, muscle cramps, postural
syncope , transient fall of blood pressure
laboratory examination
35. Heat stroke
three characteristics
• hyperpyrexial fever
• dry and hot skin
• severe central nervous system symptoms
acute onset
causitive factors
36. Differential diagnosis
diseases cause high fever and coma
• cerebral malaria
• Japanese encephalitis
• meningitis
• acute cerebrovascular disease
• organic phosphorus pesticide poisoning
• …
37. Evaluation of vital signs
1
causes
duration of the
injury
start time of
rescue
2
severity
body temperature
disturbance of
water and
electrolyte
3
consciousness
pulse
respiratory
bloodpressure
muscular tension
urine volume
evaluate evaluate observation
39. On-site treatment
leave the high temperature environment immediately
have a quiet rest in a shelter, loosen the clothing
drink some cold salty water
NS、GS、KCL ivgtt (for a circulatory failure patient)
no massage for the muscle cramp and contraction pain
electrolyte supplement
a positive rescue for a heat sroke patient
41. lower the temperature of
environment
cool and ventilated place
indoor temperature <20 oC
42. lower the temperature of the body
surface
rub the body surface
put the ice bag on the main artery(head, bilateral
carotid artery, armpit, groin)
avoid shivering
cold bath
43. lower the temperature of the central
body temperature
5%GS 1000~2000mlivgtt (4-10oC)
10%GNS 1000ml enema (4-10oC)
inject cold NS into the gastric tube
51. symptomatic treatment
respiratory function
circulatory function
cerebral edema
renal dysfunction
hepatic dysfunction
DIC
water-electrolyte and acid-base balance
intensive nursing
52. prevention and treatment of
multiple organs failure
lower the central body temperature as soon as
possible
decrease the metabolic rate
complication treatment
53. Prognosis
mortality:20% -70%
the worst type:heat stroke
sequela
• mild neural dysfunction
• several weeks of muscular weakness
• permanent brain damage