APPARATUS AND METHODS FOR COMPUTING CARDIAC OUTPUT OF A LIVING SUBJECT

• US 20140276071A1
• Filed: 03/14/2013
• Published: 09/18/2014
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Zhejiang Shanshi Biological Medical Devices Company Limited
• Original Assignee: HighDim GmbH
• Inventors: Hunziker, Patrick, Morozov, Oleksii, Friedrich, Felix
• Granted Patent: US 9,345,436 B2
• Time in Patent Office: Days
• US Class Current: 600/453
• CPC Class Codes: A61B 3/165 Non-contacting tonometers
• CPC Class Codes: A61B 5/02 Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 8/02 Measuring pulse or heart rate
• CPC Class Codes: A61B 8/065 to determine blood output from the heart in general A61B5/029
• CPC Class Codes: A61B 8/481 involving the use of contrast agent, e.g. microbubbles introduced into the bloodstream analysis of echo signal exploiting properties of a contrast enhancer in devices for short-range imaging with acoustic waves G01S7/52039
• CPC Class Codes: A61B 8/488 involving Doppler signals

Abstract

Apparatus and methods for calculating cardiac output (CO) of a living subject. In one embodiment, the apparatus and methods build a nonlinear mathematical model to correlate physiologic source data vectors to target CO values. The source data vectors include one or more measurable or derivable parameters such as: systolic and diastolic pressure, pulse pressure, beat-to-beat interval, mean arterial pressure, maximal slope of the pressure rise during systole, the area under systolic part of the pulse pressure wave, gender (male or female), age, height and weight. The target CO values are acquired using various methods, across a plurality of individuals. Multidimensional nonlinear optimization is then used to find a mathematical model which transforms the source data to the target CO data. The model is then applied to an individual by acquiring physiologic data for the individual and applying the model to the collected data.

Claims

1. A method of computing cardiac output (CO) of a living subject, comprising:

obtaining a plurality of target CO values;

generating an mathematical model based at least in part on said target CO values;

obtaining a plurality of physiologic input source data from said living subject;

transforming said plurality of physiologic input source data using at least said mathematical model; and

expressing a result of said transformation as a CO value in physiologic units.

2. The method of claim 1, wherein said target CO values are obtained by performing at least one of:

waveform-based methods;

Doppler echocardiography-based methods;

or

thermodilution-based methods.

3. The method of claim 1, wherein said optimization module comprises a multi-dimensional non-linear optimization algorithm.

4. The method of claim 1, wherein said plurality of physiologic input source data comprises at least one of:

systolic pressure of said living subject;

diastolic pressure of said living subject; and

pulse pressure of said living subject.

5. The method of claim 1, wherein said plurality of physiologic input source data comprises at least one of:

beat-to-beat interval;

mean arterial pressure;

maximal slope of pressure rise during systole; and

area under a systolic portion of a pulse pressure wave.

6. The method of claim 1, wherein said plurality of physiologic input source data comprises at least one of:

age of said living subject;

gender of said living subject;

height of said living subject; and

weight of said living subject.

7. The method of claim 1, wherein said act of transforming comprises fitting said physiologic input data into said target CO data in a least-square optimal fashion.

8. A computer readable apparatus configured to store at least one computer program thereon, said computer program comprising a plurality of instructions which are configured to when executed by a processor:

receive a plurality of first data, individual ones of said plurality of first data each comprising cardiac output (CO) values representative of living subjects having a respective plurality of physiologic parameters;

generate a mathematical model to correlate said plurality of CO values to said respective plurality of physiologic parameters;

receive second data, said second data comprising one or more measured physiologic parameters of a particular living subject;

link, in a mathematically optimal way, said second data to one of said plurality of CO values; and

cause a display of said one of said plurality of CO values.

9. The apparatus of claim 8, wherein said plurality of instructions are further configured to process said one or more measured physiologic parameters to a format which a physiologic parameter of said first data is expressed.

10. The apparatus of claim 9, wherein said format said first data is expressed as comprises pulse pressure variation;

said second data comprises pulse pressure of said particular living subject; and

said plurality of instructions configured to process do so via estimation of an average pulse pressure of said particular living subject over one or more respiratory cycles.

11. The apparatus of claim 9, wherein said format said first data is expressed as comprises stroke volume variation;

said second data comprises stroke volume of said particular living subject; and

said plurality of instructions configured to process do so via estimation of an average stroke volume of said particular living subject over one or more respiratory cycles.

12. The apparatus of claim 8, wherein said plurality of instructions are further configured to link, in a mathematically optimal way, said second data to one of said plurality of CO values via:

detection of one or more specific data points within continuous bio-signals received from said particular living subject;

selection of a data vector representative of said continuous bio-signals based at least in part on said detected one or more specific data points; and

application of a mathematical transformation to said selected data vector to arrive at said one of said plurality of CO values.