ZOLL Thermogard XP IVTM Physician Manual - Manual (Page 13)

ZOLL IVTM™ System Physicians' Manual
600248-001 Rev 3 12
surface of the body can lose heat to the environment, yet all the cubes generate
heat.
The larger the patient, the less surface area there is per unit of volume by which to
lose heat. Smaller people heat more quickly for a given energy expenditure and lose
heat to a colder environment more quickly than a larger person starting from the
same body temperature.
When the IVTM System is active, heat is removed from the patient. In a febrile
patient, the amount of excess heat is the product of the temperature increase and the
thermal mass of the patient, unless the patient has as yet untapped reserves for heat
generation. The higher the temperature the patient is allowed to reach prior to
starting therapy, the longer it will take to return the patient to a normal temperature.
For a given patient, the stronger the endogenous drive to heat production, the longer
it will take to cool that patient. Larger patients will take longer to cool than smaller
patients because they have more thermal mass.
In some cases, the IVTM System may not have sufficient power to reduce the
patient’s temperature to normal levels. The use of the IVTM System does not
preclude the use of other antipyretic measures. For example, pharmacological agents
that can reduce the endogenous drive to increased temperature or any mechanisms
for increasing heat loss from the skin will still be of benefit.
1. It is important to use the IVTM System in conjunction with conventional
antipyretic measures.
2. Whenever possible, for antipyretic therapy, it is best to precool the IVTM
System prior to connection to the patient to optimize performance. This can
be done, for example, at the time that the patient is being prepared for
insertion of the central line.