# US 12,214,127 B2 · Calibration method for oxygen sensor, medical ventilation system, anesthetic machine, and ventilator

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- Number: US 12,214,127 B2
- Document ID: US12214127B2
- Status: Granted
- Kind: B2
- Application number: 17/854,093
- Filed: 2022-06-30
- Published: 2022-10-20
- Granted: 2025-02-04
- Earliest claimed: 2019-12-30
- Assignees: Shenzhen Mindray Bio-Medical Electronics Co., Ltd.
- Applicants: Shenzhen Mindray Bio-Medical Electronics Co., Ltd.
- Inventors: Congying Wan; Guangtao Chen; Wei Ling; Chao Wang; Dongsheng Liang
- Web page: https://patentgrep.com/patent/US12214127B2

## CPC

- A61M 16/024: {including calculation means, e.g. using a processor}
- A61M 16/01: specially adapted for anaesthetising {(A61M16/104, A61M16/18 take precedence)}
- A61M 16/12: by mixing different gases
- G01N 27/409: Oxygen concentration cells
- G01N 27/4175: {Calibrating or checking the analyser}
- A61M 2016/0027: {pressure meter}
- A61M 2016/003: {with a flowmeter}
- A61M 2016/1025: {the O2 concentration}
- A61M 2202/0208: Oxygen
- A61M 2205/3317: Electromagnetic, inductive or dielectric measuring means
- A61M 2205/3334: Measuring or controlling the flow rate
- A61M 2205/502: User interfaces, e.g. screens or keyboards
- A61M 2205/70: with testing or calibration facilities
- A61M 2205/702: automatically during use
- G01N 2201/127: Calibration; base line adjustment; drift compensation
- 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)}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A calibration method for an oxygen sensor and a medical ventilation system are disclosed. At least two electrical signals are acquired at two time points within a preset time period, when the oxygen sensor is in a preset oxygen concentration. A response function of the oxygen sensor which corresponds to the preset oxygen concentration, is determined according to the at least two time points and the at least two electrical signals. A steady-state output value of the oxygen sensor in the preset oxygen concentration is determined, according to the response function and a characteristic curve of the oxygen sensor is determined, according to the steady-state output value of the oxygen sensor in the preset oxygen concentration. The described method reduces the time waiting for the oxygen sensor to respond, thus improving calibration efficiency, and facilitating the improvement of the oxygen concentration monitoring accuracy of a ventilation device in daily use.

## Claims

### Claim 1

A calibration method for an oxygen sensor electrically connected to a gas control device of a medical ventilation system, comprising:
detecting, by a detection circuit connected to the oxygen sensor, at least two electrical signals, which are correspondingly outputted by the oxygen sensor at at least two time points within a preset time period, when the oxygen sensor is in a preset oxygen concentration;
determining a response function of the oxygen sensor which corresponds to the preset oxygen concentration, according to the at least two time points and the at least two electrical signals, wherein the response function represents a relationship between the electrical signals outputted by the oxygen sensor and the time points;
determining a steady-state output value of the oxygen sensor in the preset oxygen concentration, according to the response function;
determining a characteristic curve of the oxygen sensor, according to the steady-state output value of the oxygen sensor in the preset oxygen concentration; and
controlling, by the gas control device, a gas supply in the medical ventilation system according to an actual oxygen concentration determined based on the characteristic curve of the oxygen sensor.

### Claim 2 (depends on 1)

The calibration method according to claim 1, wherein acquiring the at least two electrical signals, which are correspondingly outputted by the oxygen sensor at at least two time points within a preset time period, when the oxygen sensor is in a preset oxygen concentration, comprises:
placing the oxygen sensor inside an environment of the preset oxygen concentration to acquire the at least two electrical signals, which are correspondingly outputted by the oxygen sensor at the at least two time points within the preset time period; or
filling a space where the oxygen sensor is located with a gas of the preset oxygen concentration to acquire the at least two electrical signals, which are correspondingly outputted by the oxygen sensor at the at least two time points within the preset time period.

### Claim 3 (depends on 1)

The calibration method according to claim 1, wherein the oxygen sensor is arranged at an inspiratory branch of a medical ventilation system; and
acquiring the at least two electrical signals, which are correspondingly outputted by the oxygen sensor at at least two time points within a preset time period, when the oxygen sensor is in a preset oxygen concentration, comprises:
filling the inspiratory branch with a gas of the preset oxygen concentration, and acquiring the at least two electrical signals, which are correspondingly outputted by the oxygen sensor at the at least two time points within the preset time period.

### Claim 4 (depends on 1)

The calibration method according to claim 1, wherein a time duration of the preset time period is no more than two minutes.

### Claim 5 (depends on 1)

The calibration method according to claim 1, wherein determining the response function of the oxygen sensor which corresponds to the preset oxygen concentration, according to the at least two time points and the at least two electrical signals, comprises:
determining a model parameter of the response function of the oxygen sensor which corresponds to the preset oxygen concentration, according to the at least two time points and the at least two electrical signals; and
obtaining the response function of the oxygen sensor which corresponds to the preset oxygen concentration, according to the determined model parameter.

### Claim 6 (depends on 5)

The calibration method according to claim 5, wherein the response function approaches a fixed value when the time approaches positive infinity; or
the response function comprises a step response function, an exponential function, or a polynomial function.

### Claim 7 (depends on 5)

The calibration method according to claim 5, wherein determining the steady-state output value of the oxygen sensor in the preset oxygen concentration, according to the response function, comprises:
determining a function value of the response function, which approaches a steady state, as the steady-state output value of the oxygen sensor in the preset oxygen concentration.

### Claim 8 (depends on 1)

The calibration method according to claim 1, wherein determining the characteristic curve of the oxygen sensor, according to the steady-state output value of the oxygen sensor in the preset oxygen concentration, comprises;
acquiring a characteristic curve of the oxygen sensor which is to be calibrated; and
correcting the characteristic curve of the oxygen sensor which is to be calibrated, according to the steady-state output value of the oxygen sensor in the preset oxygen concentration.

### Claim 9 (depends on 8)

The calibration method according to claim 8, wherein correcting the characteristic curve of the oxygen sensor which is to be calibrated, according to the steady-state output value of the oxygen sensor in the preset oxygen concentration, comprises:
correcting the characteristic curve which is to be calibrated to enable the corrected characteristic curve to cover at least one calibration point, wherein the calibration point is determined by a corresponding preset oxygen concentration and the steady-state output value which corresponds to the corresponding preset oxygen concentration.

### Claim 10 (depends on 9)

The calibration method according to claim 9, wherein the preset oxygen concentration comprises at least two preset oxygen concentrations, and correcting the characteristic curve of the oxygen sensor which is to be calibrated, according to the steady-state output value of the oxygen sensor in the preset oxygen concentration, further comprises:
determining the characteristic curve of the oxygen sensor according to at least two calibration points, wherein the at least two calibration points are respectively determined by the steady-state output values which correspond to the at least two preset oxygen concentrations, respectively.

### Claim 11 (depends on 10)

The calibration method according to claim 10, wherein determining the characteristic curve of the oxygen sensor according to at least two calibration points, comprises:
determining the characteristic curve of the oxygen sensor according to the at least two calibration points by linear interpolation.