Hypo/Hyperthermia

Question 1

Define hypopthermia

Answer 1

Unintentional reduction of core body temperature below the normal physiological limits

Mild hypothermia: 32-35°C
Moderate or severe hypothermia: < 32°C

Question 2

What occurs physiologically in the initial stages of hypothermia?

Answer 2

Thermoreceptors cause vasoconstriction
Hypothalamus in turn releases TSH and ACTH
Stimulates heat production by promoting shivering

Question 3

What are some causes of hypothermia?

Answer 3

Exposure to cold in the environment is the major cause
Inadequate insulation in the operating room
Cardiopulmonary bypass
Newborn babie

Question 4

What are RFs for hypothermia?

Answer 4

General anaesthesia
Substance abuse
Hypothyroidism
Impaired mental status
Homelessness
Extremes of age

Question 5

What are the signs of hypothermia?

Answer 5

shivering

cold and pale skin (Frostbite occurs when the skin and subcutaneous tissue freeze, causing damage to cells)

slurred speech

tachypnoea, tachycardia and hypertension (if mild)

respiratory depression, bradycardia and hypothermia (if moderate)

confusion/ impaired mental state

Question 6

What investigations are done for hypothermia?

Answer 6

Temperature - special low reading thermometers
ECG - acute ST elevation and J or osborn waves
FBC - elevated Hb, platelets and wbcs low (sequester in spleen)
CXR

Question 7

What is the management for hypothermia?

Answer 7

Removing the patient from the cold environment and removing any wet/cold clothing

Warming the body with blankets

Securing the airway and monitoring breathing,

If not responding well to passive warming, you may consider maintaining circulation using warm IV fluids or applying forced warm air directly to the patient’s body

Question 8

What can rapid rewarming lead to?

Answer 8

peripheral vasodilation and shock

Question 9

What should not be done to someone with hypothermia for risk of cardiac arrest?

Answer 9

Don’t put the person into a hot bath
Don’t massage their limbs
Don’t use heating lamps
Don’t give them alcohol to drink

Question 10

What are key features of heat stroke?

Answer 10

core body temperature >40°C and central nervous system dysfunction

Question 11

What are presenting features of heat stroke?

Answer 11

Exposure to environmental heat or strenuous exercise
CNS dysfunction e.g. altered level of consciousness
>40 degrees
Anhidrosis (hot, dry skin) 
Intense thirst
Weakness
Dizziness
Headache 
N+V

Question 12

What investigations should be done in heatstroke?

Answer 12

Rectal temperature

Question 13

What is the management for acute heat stroke?

Answer 13

Assess and stabilise the patient using the ABC approach
Remove excess clothing
Rapid active cooling e.g. wetting/fanning skin, icepacks, iced water immersion