Method and apparatus for controlling the inner temperature of a patient

An apparatus for controlling an inner temperature of a human patient that is subjected to whole body hyperthermia, the apparatus comprising:

• two catheters for creating a fluid circuit external to the human patient, wherein one catheter is for exiting a fluid from the human patient and the other catheter is for returning said fluid to the human patient, wherein said fluid is blood;
• at least two temperature sensors for measuring a temperature of said human patient on multiple locations on the body of the human patient, wherein the temperature sensors are not located in the brain;
• a pump in association with said catheters, for pumping said fluid through said fluid circuit and the human patient;
• a heat exchanger through which said fluid circuit flows for influencing the temperature of said fluid;
• a controller arranged to estimate an organ temperature of the human patient, wherein the organ is the brain, and control the power supplied to the heat exchanger based on the estimated organ temperature of the human patient such that the estimated organ temperature of the human patient remains below an upper threshold organ temperature of the human patient, wherein the organ temperature of the human patient is estimated by a model comprising a parametric correlation function of the temperature of the organ and a number of input parameters, said input parameters including the body mass of the human patient and temperature measurements on multiple locations on the body based on signals from said two temperature sensors, wherein the parametric correlation function, including the calibration of the parameters of the correction function, has been obtained on an animal other than the human patient, by:
• creating a fluid circuit that comprises the animal and a heat exchanger, the power supply thereto being controlled by a controller;
• controlling the heat exchanger to set a temperature profile;
• subjecting at least a portion of the fluid in said fluid circuit to the heat exchanger;
• directing the subjected fluid to and into the animal to change the temperature of the animal;
• measuring corresponding input parameters comprising the temperature of at least one body part of the animal at a time t, and the power supplied to the heat exchanger prior to time t;
• measuring the organ temperature of the animal at the time t, wherein the organ is the brain;
• establishing a parametric correlation function between an estimated organ temperature of the animal and the input parameters measured on the animal, wherein the estimated organ temperature of the animal is an estimated brain temperature of the animal, and
• determining the model parameters of the parametric correlation function such that the difference between the estimated organ temperature of the animal calculated with the correction function and the measured organ temperature of the animal is minimized.