System and method for non-invasive cardiovascular assessment from supra-systolic signals obtained with a wideband external pulse transducer in a blood pressure cuff
OwnerNigel Sharrock, Andrew Lowe +1inventors
InventorsNigel Sharrock, Andrew Lowe, Daniel Roldan
Life of this patent
Estimating the term…
Abstract
A method and apparatus are disclosed for non-invasively determining a cardiovascular status of a patient. Cardiac pulse waveforms associated with the peripheral artery are monitored during a plurality of cardiac ejection cycles, using a wideband external pulse transducer. The waveforms are analyzed to obtain information relating to the patient's Augmentation index (AI), cardiac performance, and/or cardiac stroke volume.
Claims64
A method for determining a cardiovascular status of a mammal having a cardiovascular system that includes a peripheral artery, comprising the steps of:
- (a) measuring a sequence of cardiac pulse waveforms associated with the peripheral artery and representing a plurality of cardiac ejection cycles;
- (b) analyzing the waveforms with respect to at least one parameter of the cardiovascular system, said parameter being selected from the group consisting of Augmentation index (AI), cardiac performance, and cardiac stroke volume;
- and
- (c) generating an output based on said analysis.
An apparatus for determining a cardiovascular status of a mammal having a cardiovascular system that includes a peripheral artery, said apparatus comprising:
- (a) a low frequency, wideband pressure transducer for measuring over time a sequence of cardiac pressure waveforms associated with a peripheral artery of a patient;
- and
- (b) a processor, receiving an output of said transducer, and analyzing the cardiac pressure waveform to with respect to a change in a parameter of a model representing the cardiovascular system of the mammal and generating an output bases on the analysis.
A blood pressure cuff comprising:
- (a) an elongate bladder suitable for wrapping around the arm of a patient;
- (b) an air pump adapted to be connected to the bladder for inflating the bladder to a desired pressure;
- and
- (c) a low frequency wideband external pulse transducer attached to the bladder in a position such that it is situated adjacent to the brachial artery when the bladder is in place on the arm of a patient.
A method of non-invasively obtaining information about heart stroke volume of a patient, said method comprising the steps of:
- i) obtaining a signal indicative of supra-systolic blood pressure amplitude with time from a peripheral artery of the patient with the peripheral artery's blood flow occluded;
- ii) measuring the area beneath a first major peak in the signal, or a function of this signal, and above a base line;
- and
- iii) determining, based on the measured area, at least one of the stroke volume of the patient and a change in stroke volume over time.
A method of non-invasively determining a change in blood volume in a patient comprising the steps of:
- i) obtaining a signal indicative of blood pressure from a peripheral artery of the patient over at least one inspiratory/expiratory breathing cycle of the patient, the signal containing a repeating sequence of groups of pulses including a first major peak in each group;
- ii) measuring a change in the amplitude of the first major peak between different groups of pulses;
- and
- iii) determining, based on the measured change in amplitude, the change in blood volume of the patient.
Apparatus for non-invasively determining stroke volume of a patient comprising:
- means for obtaining a signal indicative of supra-systolic blood pressure amplitude with time from a peripheral artery of the patient with the peripheral artery's blood flow occluded;
- measuring means for measuring the area beneath a first major peak in the signal or a function of the signal and above a base line;
- and
- determining means which, based upon the measured area, determines the stroke volume of the patient.
Apparatus for non-invasively determining a change in blood volume in a patient comprising:
- means for obtaining a signal indicative of blood pressure from a peripheral artery of the patient over at least one inspiratory/expiratory breathing cycle of the patient, the signal containing a repeating sequence of groups of pulses including a first major peak in each group;
- measuring means for measuring a change in the amplitude of the first major peak between different groups;
- and
- determining means which determines the change in blood volume of the patient based on the measured change in amplitude of the first major peak.
A method for diagnosing heart disease of a patient having a cardiovascular system that includes a peripheral artery, said method comprising the steps of:
- (a) measuring a signal indicative of supra-systolic blood pressure amplitude with time from the peripheral artery of the patient with the peripheral artery's blood flow occluded, said signal thereby indicating the presence and amplitude of heartbeats;
- (b) automatically determining, from the signal, any variation in at least one of beat-to-beat rate and beat-to-beat amplitude;
- and
- (c) producing a diagnosis of heart disease based on said variations, if any.
A method for diagnosing the propensity of heart failure in a patient having a cardiovascular system that includes a peripheral artery, said method comprising the steps of:
- (a) measuring a signal indicative of supra-systolic blood pressure amplitude with time from the peripheral artery of the patient with the peripheral artery's blood flow occluded, said signal thereby indicating each forward (SS1) and reflective (SS2) wave resulting from each heartbeat;
- (b) determining at least one of the amplitude of the SS2 wave and the delay time dt1-2 between the peak of the SS1 wave and an immediately following SS2 wave;
- and
- (c) producing a diagnosis of heart disease based on the information determined in step (b).
Dependencies are inferred from the claim text.