Method and means for monitoring cardiac output
First Claim
1. Cardiac output apparatus for connection to an intra-aortic balloon pumping system including a balloon located in a patient'"'"'s aorta which is alternatively inflated and deflated in synchronism with the heart to improve blood flow therefrom, said apparatus displaying the quantity of blood flow in the patient'"'"'s heart in response to a signal representing blood pressure in an artery and including:
- A. pressure signal means for transmitting an input pressure signal in response to the blood pressure signal from the system,B. means for transmitting a balloon deflation signal representing a pressure excursion at the time the balloon is deflated in response to the input pressure signal,C. means for transmitting a ventricle ejection pressure signal representing the pressure excursion during a ventricle ejection pulse in response to the input pressure signal,D. means responsive to the balloon deflation pressure and the ventricle ejection pressure signals for transmitting an output signal representing blood flow from the aorta, andE. means for utilizing the output signal.
1 Assignment
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Accused Products
Abstract
A cardiac output monitor. The monitor receives signals representing radial arterial pressure, balloon pressure, balloon drive and balloon volume from an intra-aortic balloon pumping system. These signals are processed to define balloon depletion pressure (P1), ventricle ejection pressure (P2), balloon volume (BV) and heart rate (HR). The monitor displays the cardiac output according to
Cardiac output = (P.sub.2 /P.sub.1) (BV) (HR)
the monitor also indicates certain improper pumping system operations and can provide a continuous display.
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Citations
23 Claims
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1. Cardiac output apparatus for connection to an intra-aortic balloon pumping system including a balloon located in a patient'"'"'s aorta which is alternatively inflated and deflated in synchronism with the heart to improve blood flow therefrom, said apparatus displaying the quantity of blood flow in the patient'"'"'s heart in response to a signal representing blood pressure in an artery and including:
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A. pressure signal means for transmitting an input pressure signal in response to the blood pressure signal from the system, B. means for transmitting a balloon deflation signal representing a pressure excursion at the time the balloon is deflated in response to the input pressure signal, C. means for transmitting a ventricle ejection pressure signal representing the pressure excursion during a ventricle ejection pulse in response to the input pressure signal, D. means responsive to the balloon deflation pressure and the ventricle ejection pressure signals for transmitting an output signal representing blood flow from the aorta, and E. means for utilizing the output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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6. Cardiac output apparatus as recited in claim 5 wherein said means for transmitting the balloon deflation pressure and ventricle ejection pressure transmit a new set of said signals for each heart beat, and said cardiac output transmitting means includes means for transmitting a final ratio signal based upon the ratios of said pressure signals for each heart beat.
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7. Cardiac output apparatus as recited in claim 5 additionally comprising input pressure analysis means for indicating abnormal conditions in response to predetermined characteristics of the input pressure signal.
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8. Cardiac output apparatus as recited in claim 5 wherein the input pressure signal is characterized by a plateau region in the vicinity of point of balloon deflation, said cardiac output apparatus additionally comprising plateau analysis means connected to said output means for indicating abnormal conditions in response to predetermined characteristics of the input pressure signal in the plateau region.
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9. Cardiac output apparatus as recited in claim 8 wherein said plateau analysis means is responsive to a signal representing the magnitude of the input pressure signal in the plateau region.
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10. Cardiac output apparatus as recited in claim 8 wherein said plateau analysis means is responsive to a signal representing the slope of the input signal in the plateau region.
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11. Cardiac output apparatus as recited in claim 8 wherein said plateau analysis apparatus is responsive to a signal representing the width of the plateau region normalized with respect to the patient'"'"'s heart rate.
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12. A method for displaying on a display means the cardiac output of a patient undergoing treatment with an intra-aortic balloon pumping system which icludes an intra-arortic balloon and controller which transmits balloon drive signals for controlling the inflation and deflation of the balloon and arterial pressure signals representing arterial pressure in a patient, the cardiac output display method comprising the steps of:
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A. transmitting a signal representing the arterial pressure excursion of a ventricle ejection pulse in response to the arterial pressure signal, B. transmitting a signal representing the arterial pressure change resulting from balloon deflation in response to the arterial pressure signal, C. transmitting a signal representing cardiac output in response to the ventricle ejection pulse signal and the balloon deflation signal, D. energizing the display means with the cardiac output signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification