# US 10,864,337 B2 · Systems and methods for tracking spontaneous breathing in a mechanically ventilated patient

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- Number: US 10,864,337 B2
- Document ID: US10864337B2
- Status: Granted
- Kind: B2
- Application number: 16/000,922
- Filed: 2018-06-06
- Published: 2019-03-21
- Granted: 2020-12-15
- Earliest claimed: 2017-09-20
- Assignees: ART MEDICAL Ltd.
- Applicants: ART Medical Ltd.
- Inventors: Liron Elia; Gavriel J. Iddan
- Web page: https://patentgrep.com/patent/US10864337B2

## CPC

- A61M 16/024: {including calculation means, e.g. using a processor}
- A61B 5/037: {Measuring oesophageal pressure}
- A61B 5/1107: {Measuring contraction of parts of the body, e.g. organ or muscle}
- A61B 5/113: occurring during breathing
- A61B 5/4836: {Diagnosis combined with treatment in closed-loop systems or methods (A61B5/0036 takes precedence)}
- A61B 5/7257: {using Fourier transforms}
- A61J 15/0003: {Nasal or oral feeding-tubes, e.g. tube entering body through nose or mouth}
- A61J 15/0084: {for sensing parameters related to the patient}
- A61M 16/0003: {Accessories therefor, e.g. sensors, vibrators, negative pressure}
- A61M 16/021: {operated by electrical means (A61M16/202 – A61M16/205 take precedence)}
- A61M 16/022: {Control means therefor}
- 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}
- G16H 20/40: relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
- G16H 50/20: for computer-aided diagnosis, e.g. based on medical expert systems
- A61B 5/6847: {mounted on an invasive device}
- A61J 15/0049: {Inflatable Balloons (balloon catheters A61M25/10)}
- A61J 15/0069: {Tubes feeding directly to the intestines, e.g. to the jejunum}
- A61M 16/0069: {the speed thereof being controlled by respiratory parameters, e.g. by inhalation}
- A61M 16/0434: {Cuffs}
- A61M 16/0463: {combined with suction tubes, catheters or the like; Outside connections}
- A61M 2016/0015: {inhalation detectors}
- A61M 2016/0018: {electrical}
- A61M 2016/0027: {pressure meter}
- A61M 2016/0033: {electrical}
- A61M 2039/085: {external enteral feeding tubes}
- A61M 2202/0482: Enteral feeding product
- A61M 2205/33: Controlling, regulating or measuring
- A61M 2205/3317: Electromagnetic, inductive or dielectric measuring means
- A61M 2205/3331: Pressure; Flow
- A61M 2205/3334: Measuring or controlling the flow rate
- A61M 2205/3344: Measuring or controlling pressure at the body treatment site
- A61M 2205/3375: Acoustical, e.g. ultrasonic, measuring means
- A61M 2205/3553: remote, e.g. between patient's home and doctor's office
- A61M 2205/3561: local, e.g. within room or hospital
- A61M 2205/502: User interfaces, e.g. screens or keyboards
- A61M 2205/52: with memories providing a history of measured variating parameters of apparatus or patient
- A61M 2210/1014: Diaphragm
- A61M 2210/1025: Respiratory system (A61M2210/0618 take precedence)
- A61M 2210/105: Oesophagus
- A61M 2210/1053: Stomach
- A61M 2230/08: Other bio-electrical signals
- A61M 2230/40: Respiratory characteristics
- A61M 2230/42: Rate
- A61M 2230/65: Impedance, e.g. conductivity, capacity
- 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)
- A61J: CONTAINERS SPECIALLY ADAPTED FOR MEDICAL OR PHARMACEUTICAL PURPOSES; DEVICES OR METHODS SPECIALLY ADAPTED FOR BRINGING PHARMACEUTICAL PRODUCTS INTO PARTICULAR PHYSICAL OR ADMINISTERING FORMS; DEVICES FOR ADMINISTERING FOOD OR MEDICINES ORALLY; BABY COMFORTERS; DEVICES FOR RECEIVING SPITTLE
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA

## Abstract

There is provided system for monitoring spontaneous breathing of a mechanically ventilated target individual, comprising: a feeding tube for insertion into a distal end of an esophagus of the individual, sensor(s) disposed on the feeding tube at a location such that the sensor(s) is located at the distal end of the esophagus of the individual when the feeding tube is in use, wherein the sensor(s) is positioned for sensing values by contact with the tissue of the esophagus including a lower esophageal sphincter (LES) and/or tissue in proximity to the LES, and code for computing an indication of a frequency band of diaphragm movement of the individual according to an analysis of values sensed by the sensor(s), and for adjustment of parameter(s) of a mechanical ventilator for mechanically ventilating the individual, wherein the instructions for adjustment are computed while the feeding tube is in use.

## Claims

### Claim 1

A system for mechanically ventilating a target individual, the system comprising:
a feeding tube for insertion into a distal end of an esophagus of the mechanically ventilated target individual;
at least one sensor comprising at least one electrode for sensing impedance values disposed near a distal end of the feeding tube at a location such that the at least one electrode is located at the distal end of the esophagus of the target individual when the feeding tube is located within the esophagus and in use, wherein the at least one electrode is positioned for sensing impedance values when contacting tissue of the esophagus including at least one of a lower esophageal sphincter (LES) and tissue in proximity to the LES;
and
a non-transitory memory having stored thereon a code that in response to execution by at least one hardware processor of a computing device, causes the computing device to extract a frequency band of diaphragm movement and a phase of the diaphragm movement of the mechanically ventilated target individual from the impedance values sensed by the at least one electrode that include much larger amplitude signals generated based on a mechanical ventilator, and compute instructions to adjust ventilation frequencies and ventilation phases of the mechanical ventilator for mechanically ventilating the target individual by synchronizing to a waveform of the diaphragm movement in frequency band and phase of diaphragm movement for matching a waveform of the ventilator to the waveform of the diaphragm movement;
wherein the instructions to adjust the ventilation frequencies and the ventilation phases of the waveform of the mechanical ventilator are computed while the feeding tube is in use for feeding the individual and while the at least one electrode senses impedance values by contacting the tissue of the esophagus including at least one of the LES and tissue in proximity to the LES.

### Claim 2 (depends on 1)

The system according to claim 1, wherein the at least one electrode is mounted on an inflatable balloon located at the distal end of the feeding tube, wherein when the inflatable balloon is inflated the at least one electrode contacts the tissue of the esophagus.

### Claim 3 (depends on 1)

The system according to claim 1, further comprising:
at least one esophageal body having a pressure dependent volume, coupled to a distal portion of the feeding tube, wherein the at least one esophageal body is adapted to contact the tissue of the esophagus when inflated; and
wherein the at least one sensor comprises a pressure sensor that senses the pressure in the at least one esophageal body when inflated.

### Claim 4 (depends on 1)

The system according to claim 1, wherein the at least one sensor adapted to contact at least one of the LES and tissue in proximity to the LES comprises a pressure sensor that senses pressure changes created by the movement of the diaphragm.

### Claim 5 (depends on 1)

The system according to claim 1, further comprising code that in response to execution by at least one hardware processor of the computing device, causes the computing device to compute a Fourier transform of a current signal indicative of current values sensed by the at least one sensor, identify a maximum value of the Fourier transform, and compute the frequency band of diaphragm movement according to a frequency and amplitude corresponding to the maximum value.

### Claim 6 (depends on 5)

The system according to claim 5, wherein the maximum value of the Fourier transform is identified within the range of about 0.2 to 0.5 hertz (Hz).

### Claim 7 (depends on 5)

The system according to claim 5, further comprising code that in response to execution by at least one hardware processor of the computing device, causes the computing device to compute a band pass filter based on values sensed by the at least one sensor during a historical time interval, the band pass filter computed according to a frequency and phase corresponding to a maximum value computed from a Fourier transform of pressure values obtained during a historical time interval, and according to a frequency bandwidth based on the maximum value, and apply the filter to the current signal indicative of pressure values to compute the frequency band and phase of diaphragm movement.

### Claim 8 (depends on 7)

The system according to claim 7, wherein the frequency bandwidth is computed according to a frequency range in which values of the Fourier transform are at least half of the maximum value.

### Claim 9 (depends on 7)

The system according to claim 7, wherein the band pass filter comprises a cascade of a low pass filter followed by a high pass filter.

### Claim 10 (depends on 1)

The system according to claim 1, further comprising code that in response to execution by at least one hardware processor of the computing device, causes the computing device to compute a band reject filter according to a spectrum band of the mechanical ventilator, and removing interference signals of the mechanical ventilator from the values sensed by the at least one sensor by applying the band reject filter to the values sensed by the at least one sensor.

### Claim 11 (depends on 1)

The system according to claim 1, wherein the at least one sensor is located within about 0-5 centimeters from the lower esophageal sphincter when contacting the tissue of the esophagus, when the system is in use.

### Claim 12 (depends on 1)

The system according to claim 1, further comprising:
code that in response to execution by at least one hardware processor of the computing device, causes the computing device to compute a trend curve according to a plurality of diaphragm movement frequencies measured over a plurality of time intervals; and
predict a future frequency of diaphragm movement at a future time interval according to the trend curve.

### Claim 13 (depends on 12)

The system according to claim 12, further comprising:
code that in response to execution by at least one hardware processor of the computing device, causes the computing device to generate an alert for presentation on a display of a client terminal when the future frequency of diaphragm movement at the future time interval is predicted to meet a requirement.

### Claim 14 (depends on 1)

The system according to claim 1, wherein the mechanical ventilator is a conventional mechanical ventilator that ventilates the target individual at a frequency within a normal respiratory rate.

### Claim 15 (depends on 1)

The system according to claim 1, further comprising code for computing a filter for filtering of neural signals, and for applying the filter to values sensed by the at least one sensor.

### Claim 16

A method for mechanically ventilating a target individual, the method comprising:
providing a feeding tube for insertion into a distal end of an esophagus of the mechanically ventilated target individual, the feeding tube including at least one sensor comprising at least one electrode for sensing impedance values disposed near a distal portion thereof;
sensing impedance values by the at least one sensor, when the at least one electrode is located at the distal end of the esophagus of the target individual when the feeding tube is located within the esophagus and in use, wherein the at least one electrode senses impedance values when contacting tissue of the esophagus including at least one of a lower esophageal sphincter (LES) and tissue in proximity to the LES;
extracting a frequency band of diaphragm movement and phase of diaphragm movement of the mechanically ventilated target individual from the impedance values sensed by the at least one electrode that include much larger amplitude signals generated based on a mechanical ventilator; and
computing instructions to adjust ventilation frequencies and ventilation phases of the mechanical ventilator for mechanically ventilating the target individual by synchronizing to a waveform of the diaphragm movement in frequency band and phase of diaphragm movement for matching a waveform of the ventilator to the waveform of the diaphragm movement;
wherein the instructions to adjust the ventilation frequencies and the ventilation phases of the waveform of the mechanical ventilator are computed while the feeding tube is in use for feeding the individual and while the at least one electrode senses impedance values by contacting the tissue of the esophagus including at least one of the LES and tissue in proximity to the LES.

### Claim 17 (depends on 16)

The method of claim 16, wherein the frequency band of diaphragm movement of the mechanically ventilated target individual is within the range having a lower cutoff of greater than 0.2 Hz and a higher cutoff of about 0.5 Hz.

### Claim 18 (depends on 16)

The method of claim 16, wherein the frequency band of diaphragm movement of the mechanically ventilated target individual is within the range having a lower cutoff of over 12 breathes per minute and a higher cutoff of about 40 breathes per minute.

### Claim 19 (depends on 16)

The method of claim 16, further comprising creating a phase locked loop between the extracted frequency band and phase of diaphragm movement and the mechanical ventilator.

### Claim 20 (depends on 16)

The method of claim 16, wherein the frequency band and phase of the diaphragm movement of the mechanically ventilated target individual are different than motion of the lungs of the target individual corresponding to a frequency setting of the mechanical ventilator that forces air in and out of the target individual.

### Claim 21 (depends on 16)

The method of claim 16, wherein the frequency band and phase of the diaphragm are extracted using a Fourier transform of the impedance values, and by applying a bandpass reject filter designed to exclude the signals associated with the mechanical ventilator and include signals associated with movement of the diaphragm.