Ivac Corporation

Alaris Medical Systems, Inc.

Kenneth J Pytel

Robert Dwaine Butterfield

Stephen A Martin

Charles R Holdaway

William R Ewing

A system for noninvasively continuously monitoring arterial blood pressure includes a tissue stress sensor that has a continuous diaphragm for sensing stress within tissue adjacent a preselected artery caused by arterial pulsations within that artery. The stress sensitive diaphragm is coupled with electromechanical means for producing electrical signals that represent the stress within the tissue that is communicated to the sensor. These signals are then processed electronically in order to yield an output that is indicative of the arterial blood pressure of the preselected artery. The disclosed system includes methods of operation for determining blood pressure while maintaining a preselected artery in an optimum applanation state and an off-optimum applanation state.

Tonometry system for monitoring blood pressure

A tissue contact stress sensing system incorporates a semiconductor assembly and a continuous diaphragm to noninvasively determine the intra-arterial blood pressure of a patient. The system comprises a continuous diaphragm placed against a patient's tissue which covers an underlying artery. The semiconductor assembly is placed in close proximity to and spaced apart from the diaphragm for directly irradiating the diaphragm with electromagnetic radiation and receiving a portion of the electromagnetic radiation which is reflected from the continuous diaphragm. The disclosed system also utilizes a technique for minimizing the system errors associated with temperature drift and aging of the sensor.

Tonometry system for determining blood pressure

An artery applanation actuator for use in a system for noninvasively determining the intra-arterial blood pressure of a user incorporates a fluid actuator to effect movement of a sensor. The movement of the sensor is effective for applanating an artery of interest and measuring the stress of the tissue overlaying the artery of interest. Alternative embodiments of the artery applanation actuator are presented wherein an electric motor is used to activate a rotating arm which has a sensor located thereon. The rotation of the arm causes the sensor to contact and press against the tissue overlying the artery of interest. The artery applanation actuator is presented having a protective sheath surrounding the sensor to protect the sensor against inadvertent contact.

Apparatus and method for moving a tissue stress sensor for applanating

A calibration apparatus for use in calibrating a tissue stress sensor used in a blood pressure monitoring system. The calibration apparatus includes a calibration head which is adapted to be retained in close proximity to a tissue stress sensor. The calibration head includes means for heating the tissue stress sensor. A calibration system is also disclosed for calibrating a blood pressure monitoring system, the blood pressure monitoring system employing a stress sensor for generating an electric output signal representative of tissue stress data. The calibration system comprises a tissue stress sensor having a displaceable diaphragm and a sealed chamber. The chamber has a continuous wall defining an inner volume and an outer volume. The displaceable diaphragm comprises a portion of the continuous wall, whereby the displaceable diaphragm is responsive to a pressure differential between the inner chamber volume and the outer chamber volume. The vacuum means is fluidly coupled to the inner volume of the sealed chamber for applying a controlled vacuum to the inner volume of the chamber whereby the diaphragm is displaced in response to the application of the vacuum. Calibration means is provided for detecting the sensors response to heating and displacing of the sensor diaphragm and for generating corrective data for use in correcting the effects of sensor temperture on the data generated by the sensor.

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San Diego, CA, United States of America

Kenneth J Pytel