Circulatory assist method and apparatus
First Claim
1. A method for providing circulatory assistance to a patient, comprising the steps of:
- detecting the onset of ventricular ejection in the cardiac cycle of the patient,continuously or periodically monitoring the patient'"'"'s cardiac output on a breath by breath basis and providing output signals indicative thereof,selectively increasing intrathoracic pressure of the patient by injecting a respiratory fluid into the patient'"'"'s lungs in relative phase with respect to said ventricular ejection, andrepeatedly in response to said output signals adjusting said relative phase of pressure increase to ventricular ejection to maximize cardiac output by reducing ventricular afterload and maintaining ventricular preload.
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Accused Products
Abstract
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.
212 Citations
25 Claims
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1. A method for providing circulatory assistance to a patient, comprising the steps of:
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detecting the onset of ventricular ejection in the cardiac cycle of the patient, continuously or periodically monitoring the patient'"'"'s cardiac output on a breath by breath basis and providing output signals indicative thereof, selectively increasing intrathoracic pressure of the patient by injecting a respiratory fluid into the patient'"'"'s lungs in relative phase with respect to said ventricular ejection, and repeatedly in response to said output signals adjusting said relative phase of pressure increase to ventricular ejection to maximize cardiac output by reducing ventricular afterload and maintaining ventricular preload. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for improving the cardiac output of a patient said apparatus comprising:
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detection means for detecting the onset of ventricular ejection in the cardiac cycle of the patient; pressure increasing means including means for injecting a respiratory fluid into the patient'"'"'s lungs for selectively increasing intrathoracic pressure of the patient; control means responsive to said detection means for activating said pressure increasing means in relative phase with respect to said ventricular ejection; cardiocirculatory monitoring means for continuously or periodically monitoring the patient'"'"'s cardiac output on a breath by breath basis and for providing output signals indicative thereof; and delay means responsive to said output signals for delaying activation of said control means in response to said detecting means and for thereby repeatedly adjusting said relative phase of pressure increase to ventricular ejection so that said cardiac output is maximized by reducing ventricular afterload and maintaining ventricular preload. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An apparatus for improving the cardiac output of a patient, said apparatus comprising:
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detection means for detecting the onset of ventricular ejection in the cardiac cycle of the patient; continuously or periodically monitoring means for monitoring the patient'"'"'s cardiac output on a breath by breath basis, pressure increasing means including means for injecting a respiratory fluid into the patient'"'"'s lungs for selectively increasing intrathoracic pressure of the patient; and control means responsive to said detection means for activating said pressure increasing means in relative phase with respect to said ventricular ejection and for repeatedly adjusting said relative phase of pressure increase to ventricular ejection to maximize cardiac output by reducing ventricular afterload and maintaining ventricular preload.
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21. An apparatus for improving the cardiac output of a patient, said apparatus comprising:
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detection means for detecting the onset of ventricular ejection in the cardiac cycle of the patient; pressure increasing means for selectively increasing, intrathoracic pressure of the patient; control means responsive to said detection means for activating said pressure increasing means in relative phase with respect to said ventricular ejection; cardiocirculatory monitoring means for ascertaining the extent of cardiac output improvement and for providing an output signal indicative thereof, said cardiocirculatory monitoring means including oxygen consumption monitoring means for determining the rate of oxygen consumption of the patient, and said oxygen consumption monitoring means comprising (i) means for supplying an oxygen stream to the patient, (ii) first concentration measuring means for measuring concentration of oxygen in said oxygen stream, (iii) second concentration measuring means for measuring concentration of oxygen in said stream at a point including gases exhausted by the patient, and (iv) flow measuring means for measuring the flow rate of gases in said stream, said cardiocirculatory monitoring means including calculating means responsive to said means (i)-(iv) for producing said output signal, and delay means responsive to said output signal, said delay means being for delaying activation of said control means in response to said detecting means so that said cardiac output is maximized. - View Dependent Claims (22, 23, 24, 25)
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Specification