Relation local skin temperature and perfusion

Perfusion is coherently related tot body temperature distribution. From
literature, and from earlier obtained measurements, from patients who underwent
an open heart surgery, it is concluded that there exists a strong relation
between local temeprature and local skin perfusion. However, it is not clear if
the relations that are used in literature are valid, because they are not based
on fysiological measurements. Moreover, it is not clear if the
temperature/perfusion relations found in literature also hold for people that
are under anesthesia.
In this study, perfusion and temperature relations are studied in healthy
volunteers. It will be investigated in what way the relations depend on the
measurement loation. With the help of the obtained measurement data, the
validity of the relations, found in literature, will be tested. Moreover, the
temperature/perfusion relations will be compared to the relations found in
anesthetized patients during cardiac surgery. In this way the effect of
anesthesia on the temeprature/perfusion relation can be studied.

Collecting temperature/perfusion data on a number of sites on the body during a
warming/cooling cycle in order to obtain a relation that describes the
connection between perfusion and temperature, depending on the measurement
site. The obtained measurement data will also be used for analyzing the
temperature/perfusion relations, obtained in a previous study fom patients who
underwent an open heart surgery.

The volunteers start the study by performing a light exercise on a bicycle
ergometer, till vasodilation is reached (forearm-fingertip temperature gradient
of 0 oC). Subsequently the subjects undergo a warming/cooling cycle. The cycle
starts by entering a climate room, regulated at a temperature of 30oC. The room
will be kept at this temperature during 90 minutes. Subsequently, the
temperature of the climate room will be set to 20oC during 120 minutes. The
volunteers stay in a reclining position during the whole period (90 minutes+120
minutes).
During the warming/cooling cycle, perfusion and temperature are recorded with
the help of 4 Laser Doppler Flowmetry sensors, 1 pletysmography device and 15
temperature sensors. Core temperature will be recorded with the help of a
rectal temperature sensor. Heart rate variability will be determined with the
help of an ECG device.

All measurements can be undergone without any problem. No risks are involved in
the experiments. The measurement methods are painless, and non-invasive.

Burden: a visit to Maastricht University during 4-4.5 hours (subjects will
spend 90 minutes in a climate room with a temperature of 30oC, and
subsequesntly 120 minutes in the climate room with the temperature set to
20oC). During the measurements, several non-invasive sensors will be used.