Hypothermia

Question 1

Name 4 methods of heat loss

Answer 1

-Evaporation: through resp tract, skin and sweat
-Radiation: From the warm body to cooler surrounding air
-Convection: Warm air around the body rises and is replaced by cooler air
-Conduction: Heat loss to a cold surface in direct contact with the body

Question 2

What are some responses to cold?

Answer 2

-Inc muscle activity: Voluntary movement or shivering
-Horripilation: Contraction of the erector pilli muscles at the base of the hairs causing them to rise and trap air for insulation
-Vasoconstriction: Reduces blood flow to extremeties
-Beh changes: rolling into a ball, huddling with others

Question 3

What factors promote hypothermia under GA?

Answer 3

inability to move, air conditioned theatre, reduced gut activity, clipped hair, prep solutions, contact with cold surfaces

Question 4

What effect does hypothermia have on the CVS?

Answer 4

Can cause a depression of the heart rate and cardiac output which can not be treated by atropine/other anticholinergics

Question 5

What effect does hypothermia have on the respiratory system?

Answer 5

Shivering which may be harmful post op as it increases o2 consumption

Question 6

What are some methods of reducing heat loss under GA?

Answer 6

Warming fluids, insulation, reducing evaporative losses, warming devices, keeping the environmental temp warm