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In rat or man,
increased temperature causes an exponential increase in blood perfusion. Increased
perfusion in humans has been associated with an increase in core body temperature as well
as in local skin temperature . Patel et al. studied the effect of temperature and pressure
on perfusion in fuzzy rats and found that there was a significant increase in perfusion
with increased temperature at surface pressures below 50 mmHg. This result was attributed
to a local autoregulatory mechanism . In addition, increased temperature caused skin to
become stiffer in response to increased surface pressure with resultant decreases in
deformation and creep. Thus, by warming the fluid (air or other viscous material) in
support surfaces by several degrees (1-5 C), the induced increase in skin stiffness may be
beneficial in preventing tissue breakdown. However, these beneficial temperature effects
must be balanced against the increasing metabolic requirements of the tissue. |