Local control of temperature in a theoretical human model of selective brain cooling.

A method of feedback control of local brain temperature during therapeutic intracarotid cold saline infusion is presented and tested on a theoretical cerebral heat transfer model based on the Pennes bioheat equation. In this temperature control method, the infusion rate of cold saline is varied based on the rate of temperature change, and the deviation of temperature to a target, within a voxel in the treated region of brain. This control method is tested in cases where the head is exposed to ambient room temperature, and where the head is packed in ice. In both the ice and non-ice cases, target temperature (33 degrees C) is achieved in the voxel according to the desired time constant (2 minutes). Two hours of treatment decreased the required inflow of ice-cold saline from 30 ml/min to 21 and 7 ml/min in the non-ice and ice cases, respectively. Intracarotid hematocrit had higher values in the non-ice case.