Theoretical Evaluation Of Selective Brain Cooling Control Through A Simplified Thermal Model

Cl inical and experimental trails demonstrated that brain hypothermia is neural protective for brain injury therapy. It’s a challenge to cool the brain temperature to proper extent in proper duration. In this research, theoretical evaluation of thermal distributions and selective brain cooling control method based on a brain thermal model was studied. A simplified thermal model based on the Pennes’Equation was established to evaluate the contributions of heat conduction of brain temperature distributions under selective brain cooling method. Temperature distributions was evaluated in situations when scalp temperature were at6℃,16℃,26℃and model parameters were different. System identification method was used to achieve the approximate process model of the mechanistic model, and based on which a PI controller with K=0.8and Ti=2was adopted to achieve the setting brain cooling and rewarming process. Because perfusion rate and heat conduct contribute the most to the difference of the thermal model outcome, take individual differences into account, two parameter estimation method were implemented to estimate the parameters of the model. The PSO (Particle Swarm Optimization) estimated parameters in the stationary condition and the EKF (Extended Kalman Filter) in the time dependent condition to make the thermal model closer to reality situation. Thus the solutions of this research can make clinical therapy more reasonable.