Influences of hypothermia and tissue perfusion on temperature distributions in simulated cranial surgery

We applied the bioheat transfer (FEM) equation to the analysis of intracranial temperature distributions. The brain was isothermal at steady state, for perfusion rates of 1.0 and 0.1 ml/gm/min but not at 0.01 ml/gm/min. The largest temperature gradients were observed in the naso-pharyngeal (N-P) region. Altering surface heat transfer coefficient had little influence on brain temperature, even in regions of surgical exposure. Transient analysis demonstrated prompt reductions in cerebral temperature, with slower fall in N-P temperature. Maintaining normal tissue perfusion throughout the cooling period ensures uniform temperature within the cerebral tissues and avoids inadequate local cooling arising out of ischemic insult.