# US 10,864,336 B2 · Methods and systems for breath delivery synchronization

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- Number: US 10,864,336 B2
- Document ID: US10864336B2
- Status: Granted
- Kind: B2
- Application number: 15/713,951
- Filed: 2017-09-25
- Published: 2018-02-08
- Granted: 2020-12-15
- Earliest claimed: 2014-08-15
- Assignees: Covidien LP
- Applicants: Covidien LP
- Inventors: Farhad Esmaeil-zadeh-azar
- Web page: https://patentgrep.com/patent/US10864336B2

## CPC

- A61M 16/0069: {the speed thereof being controlled by respiratory parameters, e.g. by inhalation}
- A61B 5/08: Measuring devices for evaluating the respiratory organs
- A61B 5/4538: {Evaluating a particular part of the muscoloskeletal system or a particular medical condition}
- A61B 5/4836: {Diagnosis combined with treatment in closed-loop systems or methods (A61B5/0036 takes precedence)}
- A61B 5/7203: {for noise prevention, reduction or removal}
- A61B 5/7239: {using differentiation including higher order derivatives}
- A61B 5/7246: {using correlation, e.g. template matching or determination of similarity}
- A61B 5/7289: {Retrospective gating, i.e. associating measured signals or images with a physiological event after the actual measurement or image acquisition, e.g. by simultaneously recording an additional physiological signal during the measurement or image acquisition}
- A61M 16/026: {specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis}
- A61B 5/113: occurring during breathing
- A61B 5/7278: {Artificial waveform generation or derivation, e.g. synthesizing signals from measured signals}
- A61M 2016/0021: {with a proportional output signal, e.g. from a thermistor}
- A61M 2016/0027: {pressure meter}
- A61M 2016/0039: {in the inspiratory circuit}
- A61M 2016/0042: {in the expiratory circuit}
- A61M 2205/3303: Using a biosensor
- A61M 2205/502: User interfaces, e.g. screens or keyboards
- A61M 2230/40: Respiratory characteristics
- A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

Systems and methods for triggering inspiration and/or cycling exhalation with a ventilator are described herein. In particular, systems and methods for synchronizing ventilator breath delivery with patient breath demand utilizing a digital sample counting trigger mode are described herein. The digital sample counting triggering mode characterizes digital samples taken from a measured or estimated parameter during the patient inhalation/exhalation period to synchronize breath delivery with patient breath demand.

## Claims

### Claim 1

A method for ventilating a patient with a ventilator, comprising:
monitoring a physiological parameter of the patient based on one or more received sensor measurements;
calculating a first derivative of the physiological parameter for a first sample period;
updating a sample count to form a first updated sample count for the first sample period based on first comparison results from at least one of the following:
comparing a first trigger count threshold to a previous trigger count threshold selected in a previous sample period,
comparing the first derivative to a previous first derivative calculated for the previous sample period, and
comparing the first derivative to a first level;
comparing the first updated sample count to the first trigger count threshold; and
triggering inspiration based on a first result of the comparing of the first updated sample count to the first trigger count threshold.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first result is that the first updated sample count is equal to the first trigger count threshold.

### Claim 3 (depends on 1)

The method of claim 1, wherein the first derivative is amplified.

### Claim 4 (depends on 1)

The method of claim 1, wherein the first trigger count threshold is selected from a count of 2 or 4 passing samples.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first level is selected from one of the following groups:
−3 cm of H2O per second and −8 cm of H2O per second;
−4 cm of H2O per second and −9 cm of H2O per second;
−5 cm of H2O per second and −10 cm of H2O per second;
−10 cm of H2O per second and −15 cm of H2O per second; and
−15 cm of H2O per second and −20 cm of H2O per second.

### Claim 6 (depends on 1)

The method of claim 1, wherein the updating the sample count for the first sample period further comprises:
determining that the first trigger count threshold is equal to the previous trigger count threshold based on the comparing of the first trigger count threshold to the previous trigger count threshold;
determining that the first derivative is less than the previous first derivative calculated for the previous sample period based on the comparing the first derivative to the previous first derivative calculated for the previous sample period;
determining that the first derivative is less than or equal to the first level based on the comparing of the first derivative to the first level; and
updating a previous sample count by +1 passing samples to form the first updated sample count.

### Claim 7 (depends on 1)

The method of claim 1, wherein the updating the sample count for the first sample period further comprises at least one of the following:
determining that the first trigger count threshold is not equal to the previous trigger count threshold based on the comparing of the first trigger count threshold to the previous trigger count threshold,
determining that the first derivative is equal to or more than the previous first derivative based on the comparing of the first derivative to the previous first derivative and,
determining that the first derivative is more than the first level based on the comparing of the first derivative to the first level, and
wherein the updating the sample count for the first sample period further comprises setting the first updated sample count to zero passing samples.

### Claim 8 (depends on 1)

The method of claim 1, wherein the physiological parameter is an estimated patient effort.

### Claim 9 (depends on 1)

The method of claim 1, wherein the physiological parameter is one of the following: a direct measurement of patient effort, a pressure, a flow, a net flow, a rate of change of flow, a rate of change of pressure, an estimated pressure, or an estimated flow.

### Claim 10 (depends on 1)

The method of claim 1, wherein the comparing of the first updated sample count to the first trigger count threshold has a second result, wherein the second result is that the first updated sample count is not equal to the first trigger count threshold.

### Claim 11 (depends on 10)

The method of claim 10, further comprising:
calculating a next first derivative of the physiological parameter for a second sample period;
updating the first updated sample count to form a second updated sample count for the second sample period based on second comparison results from at least one of the following:
comparing a second trigger count threshold to the first trigger count threshold,
comparing the next first derivative to the first derivative for the first sample period, and
comparing the first derivative to a second level;
comparing the second updated sample count to the second trigger count threshold;
determining that the second updated sample count is equal to the second trigger count threshold based on the comparison of the second updated sample count to the second trigger count threshold; and
triggering inspiration based on the determining that the second updated sample count is equal to the second trigger count threshold.

### Claim 12 (depends on 1)

The method of claim 1, wherein the first trigger count threshold and the first level are selected based on the first derivative by:
determining a signal to noise ratio of the first derivative; and
comparing the signal to noise ratio of the first derivative to a ratio threshold.

### Claim 13 (depends on 12)

The method of claim 12, wherein the first trigger count threshold and the first level are selected based on the first derivative further by:
determining that the signal to noise ratio for the first derivative is greater than the ratio threshold based on the comparing the signal to noise ratio for the first derivative to the ratio threshold; and
selecting a small trigger count threshold for the first trigger count threshold and selecting a large level for the first level based on the determining that the signal to noise ratio for the first derivative is greater than the ratio threshold.

### Claim 14 (depends on 12)

The method of claim 12, wherein the first trigger count threshold and the first level are selected based on the first derivative further by:
determining that the signal to noise ratio for the first derivative is less than or equal to the ratio threshold based on the comparing the signal to noise ratio for the first derivative to the ratio threshold; and
selecting a large trigger count threshold for the first trigger count threshold and selecting a small level for the first level based on the determining that the signal to noise ratio for the first derivative is less than or equal to the ratio threshold.