Thermal Technologies, Inc.

Other

William H Newman

Harry Frederick Bowman

Michael G Curley

A cardiac output measurement device volumetrically heating a predefined quantity of blood flowing through a heart by arbitrarily applying a containable energy field to the blood using a thermodilution catheter having an emitter that uniformly emits electromagnetic radiation. Blood temperature is measured at the pulmonary artery by a sensor that provides a signal representing the temperature of the mixed blood to a controller. The controller determines the flow rate, or cardiac output, by performing a heat balance analysis based upon the applied power and resultant blood temperature. The cardiac output measurement device includes a catheter having an emitter and, preferably, a temperature sensor located at its distal end. The catheter is coupled to a laser or other energy source capable of generating containable electromagnetic radiation, such as an ultraviolet or microwave energy source. Significantly, for the preferred laser source, the emitter is a diffuser that uniformly emits the laser-generated energy into a predetermined volume of flowing blood. A temperature measuring system of the controller receives temperature signals from the sensor and generates a resultant temporal temperature profile used by a flow estimator to determine the flow rate and generate a power excitation function to control the energy source. The resultant measured flow may also be presented though a user interface.

Method and apparatus for invasively measuring cardiac output by

A device for heating a medium with which the device is in thermal contact for use in determining the thermal or flow properties of the medium. The device has a heater for supplying heat to the medium at an interface of the device with the medium and a temperature sensor for sensing the temperature at such interface.

Thermal probe for measuring thermal properties of a flowing medium

A method for determining the properties of a medium by activating temperature changing means to change the temperature of the medium from a first unperturbed temperature to a second different temperature during a first time period and permitting the temperature to relax to a final unperturbed temperature during a second time period. In a particular embodiment, for example, the intrinsic thermal conductivity and diffusivity of the medium are calculated during a selected portion of the first time period assuming an arbitrary value for the perfusion, and the perfusion of the medium is calculated during a selected portion of the second time period using the calculated intrinsic thermal conductivity and diffusivity. The calculated perfusion is then used to recalculate the intrinsic thermal conductivity and diffusivity during the selected portion of the first time period and the perfusion is then recalculated using such recalculated intrinsic thermal conductivity and diffusivity. The recalculation steps are repeated until each of the recalculated values converge to a substantially non-changing value.

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Jamaica Plain, MA, United States of America

William H Newman