# US 11,389,069 B2 · Hemodynamic reserve monitor and hemodialysis control

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- Number: US 11,389,069 B2
- Document ID: US11389069B2
- Status: Granted
- Kind: B2
- Application number: 15/649,411
- Filed: 2017-07-13
- Published: 2017-10-26
- Granted: 2022-07-19
- Earliest claimed: 2011-07-22
- Assignees: Flashback Technologies, Inc.; The Regents of the University of Colorado
- Applicants: Flashback Technologies, Inc.; The Regents of the University of Colorado
- Inventors: Gregory Zlatko Grudic; Steven L. Moulton; Isobel Jane Mulligan
- Web page: https://patentgrep.com/patent/US11389069B2

## CPC

- A61B 5/02028: {Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction}
- A61B 5/02042: {Determining blood loss or bleeding, e.g. during a surgical procedure}
- A61B 5/021: Measuring pressure in heart or blood vessels
- A61B 5/7275: {Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor}
- G16H 40/60: for the operation of medical equipment or devices
- G16H 50/30: for calculating health indices; for individual health risk assessment
- A61B 5/029: Measuring blood output from the heart, e.g. minute volume
- A61B 5/14551: {for measuring blood gases}
- Y02A 90/10: Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

## Abstract

Tools and techniques for estimating a probability that a patient is bleeding or has sustained intravascular volume loss (e.g., due to hemodialysis or dehydration) and/or to estimate a patient's current hemodynamic reserve index, track the patient's hemodynamic reserve index over time, and/or predict a patient's hemodynamic reserve index in the future. Tools and techniques for estimating and/or predicting a patient's dehydration state. Tools and techniques for controlling a hemodialysis machine based on the patient's estimated and/or predicted hemodynamic reserve index.

## Claims

### Claim 1

A system, comprising:
one or more sensors to obtain physiological data from a patient, wherein the physiological data is cardiovascular data of the patient; and
a computer system in communication with the one or more sensors, the computer system comprising:
one or more processors; and
a non-transitory computer readable medium in communication with the one or more processors, the non-transitory computer readable medium having encoded thereon a set of instructions executable by the computer system to perform one or more operations, the set of instructions comprising:
instructions for receiving the physiological data from the one or more sensors;
instructions for analyzing the physiological data, wherein analyzing the physiological data further comprises:
comparing the physiological data against a pre-existing model, the pre-existing model comprising a plurality of waveforms of reference data, each waveform of the plurality of waveforms corresponding to a respective hemodynamic reserve index value determined by the following formula:
HDRI
⁡
(
t
)
=
1
-
BLV
⁡
(
t
)
BLV
HDD
where HDRI(t) is the hemodynamic reserve at time t, BLV(t) is an intravascular volume loss of the patient at time t, and BLVHDD is an intravascular volume loss of the patient at a point of hemodynamic decompensation, and
wherein the physiological data includes waveform data of the patient, wherein waveform data of the patient includes one or more patient waveforms, wherein comparing the physiological data against the pre-existing model comprises comparing waveform data of the patient against the plurality of waveforms of reference data, and
determining a similarity between a respective patient waveform of the one or more patient waveforms and each of one or more waveforms of the plurality of waveforms of reference data individually;
instructions for estimating the hemodynamic reserve index value of the patient, based at least in part on the respective similarities of the respective patient waveform to each of the one or more waveforms of the plurality of waveforms of reference data individually; and
instructions for taking one or more actions based on the estimated hemodynamic reserve index value of the patient.

### Claim 2

A method, comprising:
monitoring, with one or more sensors, physiological data of a patient, wherein the physiological data is cardiovascular data of the patient;
analyzing, with a computer system, the physiological data, wherein analyzing the physiological data further comprises:
comparing the physiological data against a pre-existing model, the pre-existing model comprising a plurality of waveforms of reference data, each waveform of the plurality of waveforms corresponding to a respective hemodynamic reserve index value determined by the following formula:
HDRI
⁡
(
t
)
=
1
-
BLV
⁡
(
t
)
BLV
HDD
where HDRI(t) is the hemodynamic reserve at time t, BLV(t) is an intravascular volume loss of the patient at time t, and BLVHDD is an intravascular volume loss of the patient at a point of hemodynamic decompensation, and
wherein the physiological data includes waveform data of the patient, wherein waveform data of the patient includes one or more patient waveforms, wherein comparing the physiological data against the pre-existing model comprises comparing waveform data of the patient against the plurality of waveforms of reference data, and
determining a similarity between a respective patient waveform of the one or more patient waveforms and each of one or more waveforms of the plurality of waveforms of reference data individually;
estimating, with the computer system, the hemodynamic reserve index value of the patient, based at least in part on respective similarities of the respective patient waveforms to each of the one or more waveforms of the plurality of waveforms of reference data individually; and
taking, with the computer system, one or more actions based on the estimated hemodynamic reserve index value of the patient.

### Claim 3 (depends on 2)

The method of claim 2, further comprising:
estimating, based on the hemodynamic reserve index value of the patient, a dehydration state of the patient.

### Claim 4 (depends on 2)

The method of claim 2, further comprising:
predicting, with the computer system, the hemodynamic reserve index value of the patient at one or more time points in the future, based on the physiological data.

### Claim 5 (depends on 2)

The method of claim 2, wherein the estimate of the hemodynamic reserve index value of the patient is based on a fixed time history of monitoring the physiological data of the patient.

### Claim 6 (depends on 2)

The method of claim 2, wherein the estimate of the hemodynamic reserve index value of the patient is based on a dynamic time history of monitoring the physiological data of the patient.

### Claim 7 (depends on 2)

The method of claim 2, wherein the estimate of the hemodynamic reserve index value of the patient is based on a baseline estimate of the patient's hemodynamic reserve index value established when the patient is euvolemic.

### Claim 8 (depends on 2)

The method of claim 2, wherein the estimate of the hemodynamic reserve index value of the patient is not based on a baseline estimate of the patient's hemodynamic reserve index value established when the patient is euvolemic.

### Claim 9 (depends on 2)

The method of claim 2, wherein taking one or more actions comprises:
displaying, with a display, the estimated hemodynamic reserve index value of the patient.

### Claim 10 (depends on 2)

The method of claim 2, further comprising:
normalizing the estimate of the hemodynamic reserve index value of the patient relative to a first blood volume value corresponding to euvolemia and a second blood volume value corresponding to cardiovascular collapse.

### Claim 11 (depends on 10)

The method of claim 10, wherein the first blood volume value corresponding to euvolemia is 1 and the second blood volume value corresponding to cardiovascular collapse is 0.

### Claim 12 (depends on 10)

The method of claim 10, wherein taking one or more actions comprises displaying a graphical plot showing the normalized first blood volume value corresponding to euvolemia, the normalized second blood volume value corresponding to cardiovascular collapse, and the normalized estimate of the hemodynamic reserve index value relative to the normalized first blood volume value corresponding to euvolemia and the normalized second blood volume value corresponding to cardiovascular collapse.

### Claim 13 (depends on 2)

The method of claim 2, further comprising:
normalizing the estimate of the hemodynamic reserve index value of the patient relative to a first blood volume value corresponding to euvolemia, a second blood volume value corresponding to circulatory overload, and a third blood volume value corresponding to cardiovascular collapse.

### Claim 14 (depends on 13)

The method of claim 13, wherein the second blood volume value corresponding to circulatory overload is 1, the first blood volume value corresponding to euvolemia is 0, and the third blood volume value corresponding to cardiovascular collapse is −1.

### Claim 15 (depends on 13)

The method of claim 13, wherein the second blood volume value corresponding to circulatory overload is >1, the first blood volume value corresponding to euvolemia is 1, and the third blood volume value corresponding to cardiovascular collapse is 0.

### Claim 16 (depends on 13)

The method of claim 13, wherein taking one or more actions comprises:
displaying a graphical plot showing the normalized second blood volume value, the normalized first blood volume value, the normalized third blood volume value, and the normalized estimate of the hemodynamic reserve index value relative to the normalized second blood volume value, the normalized first blood volume value, the normalized third blood volume value.

### Claim 17 (depends on 2)

The method of claim 2, wherein taking one or more actions comprises:
determining a probability that the patient is bleeding.

### Claim 18 (depends on 2)

The method of claim 2, wherein taking one or more actions comprises:
selecting, with the computer system, a recommended treatment option for the patient.

### Claim 19 (depends on 18)

The method of claim 18, further comprising:
displaying, with a display, the recommended treatment option.

### Claim 20 (depends on 18)

The method of claim 18, wherein the recommended treatment option is selected from the group consisting of: optimizing hemodynamics of the patient, a ventilator adjustment, an intravenous fluid adjustment, transfusion of blood or blood products to the patient, infusion of volume expanders to the patient, a change in medication administered to the patient, a change in patient position, and surgical therapy.

### Claim 21 (depends on 2)

The method of claim 2, further comprising:
repeating the operations of monitoring physiological data of the patient, analyzing the physiological data, and estimating the hemodynamic reserve index value of the patient, to produce a new estimated hemodynamic reserve index value of the patient.

### Claim 22 (depends on 2)

The method of claim 2, wherein at least one of the one or more sensors is selected from the group consisting of a blood pressure sensor, an intracranial pressure monitor, a central venous pressure monitoring catheter, an arterial catheter, an electroencephalograph, a cardiac monitor, a transcranial Doppler sensor, a transthoracic impedance plethysmograph, a pulse oximeter, a near infrared spectrometer, a ventilator, an accelerometer, and an electronic stethoscope.

### Claim 23 (depends on 2)

The method of claim 2, wherein the one or more types of physiological data comprises blood pressure waveform data.

### Claim 24 (depends on 2)

The method of claim 2, wherein the one or more types of physiological data comprises plethysmograph waveform data.

### Claim 25 (depends on 2)

The method of claim 2, wherein the one or more types of physiological data comprises photoplethysmograph (PPG) waveform data.

### Claim 26 (depends on 2)

The method of claim 2, further comprising:
estimating a first value of the hemodynamic reserve index when the patient is in a first position;
estimating a second value of the hemodynamic reserve index when the patient is in a second position; and
estimating a sensitivity of the patient to volume loss based on a difference between the first value and the second value.

### Claim 27 (depends on 26)

The method of claim 26, wherein the first position is selected from the group consisting of lying prone and sitting, and wherein the second position is selected from the group consisting of sitting and standing.

### Claim 28 (depends on 2)

The method of claim 2, further comprising:
generating the pre-existing model.

### Claim 29 (depends on 28)

The method of claim 28, wherein the plurality of waveforms of reference data is generated by inducing one or more test subjects to enter one or more physiological states, and obtaining physiological data from one or more test subjects while the one or more test subjects is in a respective physiological state of the one or more physiological states.

### Claim 30 (depends on 29)

The method of claim 29, further comprising:
inducing the physiological state of reduced circulatory system volume in the one or more test subjects.

### Claim 31 (depends on 30)

The method of claim 30, wherein inducing the physiological state comprises subjecting the one or more test subjects to lower body negative pressure (“LBNP”).

### Claim 32 (depends on 30)

The method of claim 30, wherein inducing the physiological state comprises subjecting the one or more test subjects to dehydration.

### Claim 33 (depends on 29)

The method of claim 29, wherein the one or more physiological states comprises a state of cardiovascular collapse.

### Claim 34 (depends on 29)

The method of claim 29, wherein the one or more physiological states comprises a state of euvolemia.

### Claim 35 (depends on 29)

The method of claim 29, wherein the one or more physiological states comprises a state of hypervolemia.

### Claim 36 (depends on 29)

The method of claim 29, wherein the one or more physiological states comprises a state of dehydration.

### Claim 37 (depends on 29)

The method of claim 29, further comprising correlating the physiological data of the test subject to the respective physiological state, wherein correlating the physiological data of the one or more test subjects with the physiological state of the one or more test subjects comprises:
identifying a most predictive set of signals Sk out of a set of signals s1, s2, . . . , sD for each of one or more outcomes ok, wherein the most-predictive set of signals Sk corresponds to a first data set representing a first physiological parameter of the physiological data of the one or more test subjects, and wherein each of the one or more outcomes ok represents a physiological state measurement of the one or more physiological states respectively;
autonomously learning a set of probabilistic predictive models ôk=Mk(Sk), where ôk is a prediction of outcome ok derived from a model Mk that uses as inputs values obtained from the set of signals Sk; and
repeating the operation of autonomously learning incrementally from data that contains examples of values of signals s1, s2, . . . , sD and corresponding outcomes o1, o2, . . . , oK.

### Claim 38 (depends on 2)

The method of claim 2, wherein taking one or more actions comprises:
controlling operation of hemodialysis equipment, based at least in part on the estimate of the hemodynamic reserve index value of the patient.

### Claim 39 (depends on 38)

The method of claim 38, wherein controlling operation of the hemodialysis equipment comprises adjusting an ultra-filtration rate of the hemodialysis equipment.

### Claim 40 (depends on 2)

The method of claim 2, wherein determining the similarity between the respective patient waveform and each of the one or more waveforms of the plurality of waveforms of reference data individually further comprises:
producing one or more similarity coefficients, each similarity coefficient of the one or more similarity coefficients expressing a respective similarity between the respective patient waveform and individual waveforms of the one or more waveforms of the plurality of waveforms of reference data;
wherein estimating the hemodynamic reserve index value of the patient further comprises:
normalizing the one or more similarity coefficients of the one or more waveforms of the plurality of waveforms of reference data;
summing each respective hemodynamic reserve index value, corresponding to a respective individual waveform of the one or more waveforms of the plurality of waveforms of reference data, weighted by the normalized similarity coefficient corresponding to the respective individual waveform of the one or more waveforms of the plurality of waveforms of reference data, for each of the one or more waveforms of the plurality of waveforms of reference data; and
determining, for the respective patient waveform, an estimated hemodynamic reserve index value for the patient based on the sum of the hemoynamic reserve index values as weighted by the normalized similarity coefficients.

### Claim 41 (depends on 40)

The method of claim 40, wherein one or more of the plurality of sample waveforms are generated by exposing one or more test subjects to a state of hemodynamic decompensation, or a series of states progressing toward hemodynamic compensation, and monitoring physiological data of the one or more test subjects.

### Claim 42

An apparatus, comprising: a non-transitory computer readable medium having encoded thereon a set of instructions executable by one or more computers to perform one or more operations, the set of instructions comprising:
instructions for receiving physiological data from one or more sensors, wherein the physiological data is cardiovascular data of the patient;
instructions for analyzing the physiological data, wherein analyzing the physiological data further comprises:
comparing the physiological data against a pre-existing model, the pre-existing model comprising a plurality of waveforms of reference data, each waveform of the plurality of waveforms corresponding to a respective hemodynamic reserve index value determined by the following formula:
HDRI
⁡
(
t
)
=
1
-
BLV
⁡
(
t
)
BLV
HDD
where HDRI(t) is the hemodynamic reserve at time t, BLV(t) is an intravascular volume loss of the patient at time t, and BLVHDD is an intravascular volume loss of the patient at a point of hemodynamic decompensation, and
wherein the physiological data includes waveform data of the patient, wherein waveform data of the patient includes one or more patient waveforms, wherein comparing the physiological data against the pre-existing model comprises comparing waveform data of the patient against the plurality of waveforms of reference data, and
determining a similarity between a respective patient waveform of the one or more patient waveforms and each of one or more waveforms of the plurality of waveforms of reference data individually;
instructions for estimating, with the computer system, a hemodynamic reserve index value of the patient, based at least in part on respective similarities of the respective patient waveform to each of the one or more waveforms of the plurality of waveforms of reference data individually; and
instructions for instructions for taking one or more actions based on the estimated hemodynamic reserve index value of the patient.