Baxter International Inc.

Invensys Systems, Inc.

Jeffrey A Norris

Ajay P Mishra

David C Rasmussen

Gary D Carlson

Matthew C Meyer

A continuous cardiac output monitor includes a general-purpose monitoring console with local display and communication facilities, and a module removably interfacing with the console to configure the latter for performing continuous cardiac output monitoring. The module includes a switch-mode high efficiency power amplifier for providing electrical heating power at a selected voltage, frequency, and wave form to a heating element of a continuous cardiac output monitoring catheter, which catheter at a distal end portion thereof is immersed in the blood flow of a patient. The catheter effects a temperature transient in the patient's blood flow by the controlled application of electrical resistance heating utilizing electrical power from the power amplifier, and this temperature transient is sensed and used to derive a value for the patient's cardiac output.

Selectively programmable variable-voltage direct-current voltage source

Electrical power amplifier for continuous cardiac output monitoring

A system for monitoring and controlling the temperature of a heating element in a thermodilution catheter to maintain it within safe physiological limits includes, in the preferred embodiment, a thermodilution catheter having a resistive heating element with a known temperature coefficient of resistance and system elements which (1) supply and control power to the heating element, (2) monitor the temperature of the heating element by monitoring its resistance, (3) determine the rate of change of the temperature of the heating element, and (4) respond to the rate of temperature change measurement by removing power from the heating element. In an alternate, preferred embodiment, the system further comprises a calibration circuit or resistor and circuit elements which (1) control the supply of power to the system, (2) switch power between the calibration circuit or the heating element, (3) determine whether power has been supplied to the calibration circuit, and (4) respond to the power determination to remove power from the system. The system also includes methods of operation for each of the above-referenced system embodiments.

System and method for monitoring and controlling the temperature of a

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Lake Forest, CA, United States of America

Jeffrey A Norris