# US 9,039,629 B2 · Carbon dioxide monitoring system

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- Number: US 9,039,629 B2
- Document ID: US9039629B2
- Status: Granted
- Kind: B2
- Application number: 13/126,033
- Filed: 2009-10-27
- Published: 2011-08-18
- Granted: 2015-05-26
- Earliest claimed: 2008-11-07
- Assignees: Koninklijke Philips N.V.
- Applicants: Sophia Zhou; Eric Helfenbein; John Cadigan; William Grube; James Russell; Saeed Babaeizadeh
- Inventors: Sophia Zhou; Eric Helfenbein; John Cadigan; William Grube; James Russell; Saeed Babaeizadeh
- Web page: https://patentgrep.com/patent/US9039629B2

## CPC

- A61B 5/0836: {Measuring rate of CO2 production}
- A61M 16/0051: {with alarm devices}
- A61M 16/0084: {self-reinflatable by elasticity, e.g. resuscitation squeeze bags}
- A61M 16/021: {operated by electrical means (A61M16/202 – A61M16/205 take precedence)}
- A61B 2560/0431: Portable apparatus, e.g. comprising a handle or case
- A61H 2230/205: partial CO2-value
- A61M 16/04: Tracheal tubes (catheters in general A61M25/00)
- A61M 2016/0413: {with detectors of CO2 in exhaled gases}
- A61M 2230/432: partial CO2 pressure (P-CO2)
- A61N 1/3925: {Monitoring; Protecting}
- 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)}
- A61H: PHYSICAL THERAPY APPARATUS, e.g. DEVICES FOR LOCATING OR STIMULATING REFLEX POINTS IN THE BODY; ARTIFICIAL RESPIRATION; MASSAGE; BATHING DEVICES FOR SPECIAL THERAPEUTIC OR HYGIENIC PURPOSES OR SPECIFIC PARTS OF THE BODY (electrotherapy, magnetotherapy, radiation therapy or ultrasound therapy A61N)
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)

## Abstract

A CO2 monitoring system (20) is described which is operable to monitor the CO2 content of respiratory gases during intubation, CPR, or ventilation treatment of a patient. The patient's respiratory gases are sensed for CO2 content (17) and characteristics of a CO2 waveform are detected (30), such as waveform baseline, waveform amplitude, waveform frequency, waveform slope, waveform rhythm, and waveform corners. One or more of the waveform characteristics are analyzed in consideration of the type of respiration treatment being performed to identify an abnormal respiratory condition. These abnormal conditions may include the intubation tube located in the esophagus, ineffective CPR, or an airway obstruction, for example. When an abnormal condition is identified (34) a visual or audible alarm (40) is issued to alert a caregiver to tend to the patient.

## Claims

### Claim 1

A carbon dioxide (CO2) monitoring system for use with patients undergoing intubation, cardiopulmonary resuscitation (CPR), or ventilation comprising:
a CO2 sensor which receives respiratory gases from a patient and senses the CO2 content of the gases to produce CO2 measurement signals;
a recorder which records samples of the CO2 measurement signals;
a waveform detector responsive to the CO2 signal samples which identifies characteristics of a CO2 waveform;
a monitor operable to identify which of an intubation mode, a CPR mode, and a ventilation mode is the use mode of the monitoring system;
a waveform analyzer responsive to identified characteristics of the CO2 waveform and the use mode which analyzes the waveform characteristics in consideration of the use mode; and
an alarm which produces an alarm output in response to the indication of an abnormal condition by the waveform analyzer.

### Claim 2 (depends on 1)

The CO2 monitoring system of claim 1, wherein the samples of the CO2 measurement signals comprise digital signals.

### Claim 3 (depends on 2)

The CO2 monitoring system of claim 2, wherein the identified characteristics of a CO2 waveform comprise at least one of waveform baseline, waveform amplitude, waveform frequency, waveform slope, waveform rhythm, and waveform corners.

### Claim 4 (depends on 3)

The CO2 monitoring system of claim 3, wherein the monitor further comprises a manually settable user control which is operable to identify the use mode.

### Claim 5 (depends on 3)

The CO2 monitoring system of claim 3, wherein the monitor is operable to identify the use mode by sensing a connection to a respiration treatment device used with a patient.

### Claim 6 (depends on 1)

The CO2 monitoring system of claim 1, wherein the use mode is intubation, and further wherein the alarm is responsive to an abnormal condition comprising one of no respiration received or erratic CO2 waveform.

### Claim 7 (depends on 6)

The CO2 monitoring system of claim 6, wherein the alarm output comprises a visual or audio advisory to check the intubation tube.

### Claim 8 (depends on 1)

The CO2 monitoring system of claim 1, wherein the use mode is CPR, and further wherein the alarm is responsive to an abnormal condition comprising a downward trend of the CO2 waveform amplitude.

### Claim 9 (depends on 8)

The CO2 monitoring system of claim 8, wherein the alarm output comprises a visual or audio advisory of the effectiveness of the CPR.

### Claim 10 (depends on 1)

The CO2 monitoring system of claim 1, wherein the use mode is ventilation, and further wherein the alarm is responsive to an abnormal condition comprising one of airway obstruction, apnea, or undesirable rate of ventilation.

### Claim 11 (depends on 10)

The CO2 monitoring system of claim 10, wherein the alarm output comprises one of check patient or adjust ventilator settings.

### Claim 12 (depends on 1)

The CO2 monitoring system of claim 1, wherein the alarm is further operable to produce an output signal in response to normal respiration.

### Claim 13 (depends on 12)

The CO2 monitoring system of claim 12, wherein the output signal produced during CPR comprises an indication that CPR is effective.

### Claim 14 (depends on 1)

The CO2 monitoring system of claim 1, further comprising a display responsive to the waveform detector which displays a detected CO2 waveform in real time.

### Claim 15 (depends on 1)

The CO2 monitoring system of claim 1, further comprising a noise analyzer which analyzes the noise content of CO2 signal samples.