Control and operation
HICO-VARIOTHERM 550
36
Heat transfer:
The heat transfer (heat supply or heat withdrawal) between
patient and the water pad will only takes place if the temperature
of the water pad is higher or lower than the skin temperature of
the patient at the contact surface.
The measure of heat transfer is proportional
•
to the temperature difference of the skin temperature and the
water pad temperature
•
to the size of the contact area.
Intermediate layers impair heat transfer (e. g. surgical cloths or
gel pads).
Example of temperature difference:
The heat transfer from the pad to the patient doubles if the temperature
difference between the water pad and the patient is doubled. If the patient's
skin has a temperature of 34 °C at the contact area and the water pad
temperature is raised from 36 °C to 38 °C, then the heat transfer will double
because the temperature difference is doubled from 2 °C to 4 °C.
Due to the thermoregulation of the patient, this is only approximately true.
