# US 11,439,321 B2 · Monitoring system for identifying an end-exhalation carbon dioxide value of enhanced clinical utility

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- Number: US 11,439,321 B2
- Document ID: US11439321B2
- Status: Granted
- Kind: B2
- Application number: 16/047,276
- Filed: 2018-07-27
- Published: 2019-05-23
- Granted: 2022-09-13
- Earliest claimed: 2006-02-10
- Applicants: Lawrence A. Lynn
- Inventors: Lawrence A. Lynn
- Web page: https://patentgrep.com/patent/US11439321B2

## CPC

- A61B 5/0836: {Measuring rate of CO2 production}
- A61B 5/00: Measuring for diagnostic purposes (radiation diagnosis A61B6/00; diagnosis by ultrasonic, sonic or infrasonic waves A61B8/00); Identification of persons
- A61B 5/087: Measuring breath flow
- A61B 5/0871: {Peak expiratory flowmeters}
- A61B 5/145: Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value {; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue} (non-radiation detecting or locating of foreign bodies in blood A61B5/06)
- A61B 5/14551: {for measuring blood gases}
- A61B 5/412: {Detecting or monitoring sepsis}
- A61B 5/4818: {Sleep apnoea}
- 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}
- A61B 5/746: {Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms}
- A61B 7/003: {Detecting lung or respiration noise}
- A61M 16/0051: {with alarm devices}
- 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}
- A61M 16/085: {Gas sampling}
- G16H 50/20: for computer-aided diagnosis, e.g. based on medical expert systems
- G16H 50/30: for calculating health indices; for individual health risk assessment
- G16H 50/70: for mining of medical data, e.g. analysing previous cases of other patients
- A61B 5/0205: Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
- A61B 5/7257: {using Fourier transforms}
- A61B 5/726: {using Wavelet transforms}
- A61B 5/7267: {involving training the classification device}
- A61M 16/0858: {Pressure sampling ports}
- A61M 2016/0027: {pressure meter}
- A61M 2016/0042: {in the expiratory circuit}
- A61M 2205/50: with microprocessors or computers
- A61M 2205/502: User interfaces, e.g. screens or keyboards
- A61M 2205/8206: battery-operated
- A61M 2230/205: partial oxygen pressure (P-O2)
- A61M 2230/432: partial CO2 pressure (P-CO2)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- 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)}
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA

## Abstract

A medical monitoring system for identifying an end-exhalation carbon dioxide value of enhanced clinical utility is described herein. The medical monitoring system can include a capnometer for generating an output corresponding to a time-series of exhaled carbon dioxide values from a patient during an exhalation and a processor programmed to analyze the exhalation. In some examples, the processor can also be programmed to identify a peak carbon dioxide value at an end of the exhalation, determine if the peak carbon dioxide value may have been higher if the exhalation had been prolonged, and provide an output responsive to said determination.

## Claims

### Claim 1

A patient monitor for real-time assessment of the reliability of a carbon dioxide value at the end of exhalation as a guide for cardiopulmonary resuscitation comprising: a capnometer in connection with a flow tube for flow connection with the patient's airway and configured for generating an output comprising a time-series of exhaled carbon dioxide values from the patient during exhalation; a processor integrated with the capnometer and programmed to: determine in real-time the slope of the exhaled carbon dioxide values; identify a carbon dioxide value at an end of the exhalation; determine if the identified carbon dioxide value occurred when the slope of the exhaled carbon dioxide values was positive [greater than about zero]; and provide an output in real-time responsive to said determination so that the healthcare worker is notified of the reliability of the identified carbon dioxide value as an indication to terminate cardiopulmonary resuscitation.

### Claim 2 (depends on 1)

The medical monitor of claim 1, wherein the processor is programmed to determine the slope at the end of a plateau of the carbon dioxide values during exhalation.

### Claim 3 (depends on 2)

The medical monitor of claim 2, wherein the processor is programmed to determine the carbon dioxide value at the end of exhalation and to provide a warning if the carbon dioxide value is below a threshold and the slope at the end of the plateau is positive.

### Claim 4 (depends on 3)

The medical monitor of claim 3, wherein the threshold is about 12-15 mmHg.

### Claim 5 (depends on 1)

The medical monitor of claim 1, wherein the system includes a sensor for indicating a presence of exhaled flow of gas and for generating a time series of exhaled flow of gas values, the processor being programmed to determine the reliability of the identified carbon dioxide value at the end of exhalation as a guide for cardiopulmonary resuscitation by determining if the exhalation flow of gas was still continuing [exceeds about zero] at the end of exhalation and before an onset of a next inhalation.