Novametrix Medical Systems, Inc.

American Home Products Corporation

Cardiopulmonary Corporation

Richard A Mentelos

James W Biondi

Charles A Reynolds

Richard S Burwen

Donald E Lewis

Normand C Herbert

Improved cardiocirculatory assistance is provided to a patient by detecting the onset of ventricular ejection in the cardiac cycle of the patient and selectively increasing intrathoracic pressure of the patient in relative phase with respect to the onset of ventricular ejection. Cardiocirculatory output may be monitored and the relative phase of the increase in intrathoracic pressure with respect to the onset of ventricular ejection adjusted to maximize cardiac output. The intrathoracic pressure is increased once every N cardiac cycles where N is a positive integer. The patient interface may include apparatus for supplying high frequency respiration pulses in synchronism with the cardiac cycle. Alternately, or in addition, the pulses may be used to inflate a bladder in contact with the thorax.

Circulatory assist method and apparatus

An improved apparatus for non-invasive measurement of transcutaneous carbon dioxide pressure employs a skin engaging sensor including pH and reference electrodes and a temperature sensor. The temperature sensor produces an output signal voltage having a characteristic which can be the same as or the complement of the voltage-temperature characteristic of the deviation voltage component of the pH-reference electrode voltage attributable to temperature deviation effects on the sensor as well as on the skin. An error signal voltage produced at the output of the temperature sensor is combined with the voltage measured across the pH and reference electrodes to provide a corrected voltage having a magnitude indicative of transcutaneous carbon dioxide pressure at a predetermined reference temperature without need to heat the skin or electrode or otherwise control their temperatures.

Apparatus and method for temperature compensated transcutaneous carbon

An apparatus and method for measuring and monitoring blood oxygen content and local perfusion factor. A transcutaneous gas measurement probe is heated by application of an electric current to a semi-conductor device housed therein. The heat developed in a semi-conductor device heats the probe to a constant temperature under the control of a temperature monitoring and regulating circuit and the amount of power applied to the semi-conductor device is measured by multiplying the current conducted through the semiconductor device by the voltage across it to provide a measurement of local perfusion factor. An alerting device is provided to signal when blood oxygen content and local perfusion factor are outside a predetermined acceptable range.

Transcutaneous oxygen and local perfusion measurement

Apparatus and a method for determining the onset of an interarterial blood pressure pulse and measuring the time delay preceding the onset from the corresponding electrical heartbeart triggering signal wherein the blood pressure pulse is converted to an electrical input signal which is split into two identical components, one being delayed in time, inverted and amplified after which it is added to the other. A timer measures the duration between the electrical heartbeat actuating signal and the point at which the sum of the blood pressure component signals reaches a peak and subtracts from that result the time delay applied to the one component to yield the electromechanical interval between the electrical heartbeat signal and onset of the blood pressure pulse.

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Hamden, CT, United States of America

Richard A Mentelos