# US 12,766,235 B2 · Flow rate dependent blood leak detection systems and methods

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,766,235 B2
- Document ID: US12766235B2
- Status: Granted
- Kind: B2
- Application number: 17/283,746
- Filed: 2019-10-04
- Published: 2021-12-09
- Granted: 2026-10-20
- Earliest claimed: 2018-10-10
- Assignees: Gambro Lundia AB
- Applicants: Gambro Lundia AB
- Inventors: Daniel Ruhland
- Web page: https://patentgrep.com/patent/US12766235B2

## CPC

- A61M 1/3656: {Monitoring patency or flow at connection sites; Detecting disconnections}
- A61M 1/1623: {Disposition or location of membranes relative to fluids}
- A61M 2205/18: with alarm
- A61M 2205/3306: Optical measuring means
- A61M 2205/3334: Measuring or controlling the flow rate
- A61M 2230/207: hematocrit
- 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)}

## Abstract

Systems and methods used to detect blood leaks (in, for example, extracorporeal blood treatment apparatus) by detecting the presence of blood in liquid above a selected threshold amount based on the flow rate of the liquid flowing through a passage (for example, a tube, etc.) are described.

## Claims

### Claim 1

An extracorporeal blood treatment system comprising:
a filtration unit comprising a primary chamber and a secondary chamber separated by a semi-permeable membrane;
a blood withdrawal line connected to an inlet of the primary chamber and a blood return line connected to an outlet of the primary chamber, the blood withdrawal line and the blood return line being configured for connection to a patient cardiovascular system;
a blood pump configured to control the flow of blood through the primary chamber;
an effluent line connected to an outlet of the secondary chamber, wherein the effluent line is configured to remove effluent liquid from the secondary chamber;
an optical source configured to emit light along an optical path;
an optical detector configured to receive the light emitted by the optical source;
a tube retainer configured to retain a tube such that the optical path passes through a liquid passing through the tube positioned in the tube retainer, wherein the effluent line comprises the tube positioned in the tube retainer; and
a controller operably connected to the optical detector, the controller configured to:
receive a flow rate signal representative of a flow rate of liquid passing through the tube in the tube retainer;
receive a detection signal from the optical detector, the detection signal being indicative of a percent transmission of the light emitted by the optical source along the optical path that is received by the optical detector, the detection signal representative of an amount of blood in liquid passing through the tube in the tube retainer;
when the flow rate signal indicates that the flow rate is below a selected flow rate, determine existence of a blood leak when the percent transmission of the light emitted by the optical source along the optical path that is received by the optical detector as indicated by the detection signal from the optical detector is below a first value; and
when the flow rate signal indicates that the flow rate is above the selected flow rate after the flow rate signal indicates that the flow rate is below the selected flow rate, determine existence of a blood leak when the percent transmission of the light emitted by the optical source along the optical path that is received by the optical detector as indicated by the detection signal from the optical detector is below a second value, wherein the second value is greater than the first value;
wherein the first value comprises a constant value when the flow rate is below the elected flow rate.

### Claim 2 (depends on 1)

A system according to claim 1, wherein the second value increases as the flow rate increases.

### Claim 3 (depends on 1)

A system according to claim 1, wherein the second value is directly proportional to the flow rate when the flow rate is above the selected flow rate.

### Claim 4 (depends on 1)

A system according to claim 1, wherein the second value is constant.

### Claim 5 (depends on 4)

A system according to claim 4, wherein the selected flow rate comprises a first selected flow rate and wherein, when the flow rate signal indicates that the flow rate is above a second selected flow rate, determine existence of a blood leak when the percent transmission of the light emitted by the optical source along the optical path that is received by the optical detector as indicated by the detection signal from the optical detector is below a third value, wherein the second selected flow rate is greater than the first selected flow rate and the third value is greater than the second value.

### Claim 6 (depends on 5)

A system according to claim 5, wherein the third value is constant.

### Claim 7 (depends on 1)

A system according to claim 1, wherein the detection signal is representative of an amount of hematocrit in the liquid passing through the tube in the tube retainer.

### Claim 8 (depends on 1)

A system according to claim 1, wherein the first value and the second value are equivalent to a blood leak rate of 0.35 milliliters per minute or less.

### Claim 9 (depends on 1)

A system according to claim 1, wherein the controller is operably connected to an alarm and wherein the controller is configured to activate the alarm after identifying the existence of a blood leak.

### Claim 10 (depends on 1)

A system according to claim 1, wherein the optical source and optical detector are on a same side of the tube retainer.

### Claim 11 (depends on 1)

A system according to claim 1, wherein when the flow rate signal indicates that the flow rate is below the selected flow rate, the controller is configured to determine the existence of a blood leak only when the percent transmission of the light emitted by the optical source along the optical path that is received by the optical detector as indicated by the detection signal from the optical detector is below the first value for a selected delay period.

### Claim 12 (depends on 1)

A system according to claim 1, wherein when the flow rate signal indicates that the flow rate is above the selected flow rate, the controller is configured to determine existence of a blood leak only when the percent transmission of the light emitted by the optical source along the optical path that is received by the optical detector as indicated by the detection signal from the optical detector is below the second value for at least a selected delay period.

### Claim 13

A method of detecting an existence of a blood leak in an extracorporeal treatment apparatus, the method comprising:
emitting light from an optical source, the light traveling along an optical path passing through liquid flowing through a passage;
detecting the light emitted by the optical source after the light has traveled through the liquid, wherein only a portion of the light passing through the liquid is transmitted to a detector when the liquid contains blood;
first identifying existence of a blood leak into the liquid flowing through the passage when the portion of the light transmitted to the detector through the liquid is below a first value when the flow rate is below a selected flow rate; and
then identifying existence of a blood leak into the liquid flowing through the passage when the portion of the light transmitted to the detector through the liquid is below a second value when the flow rate is above the selected flow rate after the first identifying, wherein the second value is greater than the first value:
wherein the first value comprises a constant value when the flow rate is below the selected flow rate.

### Claim 14 (depends on 13)

A method according to claim 13, wherein the second value increases as the flow rate increases.

### Claim 15 (depends on 13)

A method according to claim 13, wherein the second value is directly proportional to the flow rate when the flow rate is above the selected flow rate.

### Claim 16 (depends on 13)

A method according to claim 13, wherein the second value is constant.

### Claim 17 (depends on 16)

A method according to claim 16, wherein the selected flow rate comprises a first selected flow rate and wherein, when the flow rate is above a second selected flow rate, identifying the existence of a blood leak when the portion of light transmitted to the detector through the liquid is below a third value, wherein the second selected flow rate is greater than the first selected flow rate and the third value is greater than the second value.

### Claim 18 (depends on 17)

A method according to claim 17, wherein the third value is constant.

### Claim 19 (depends on 13)

A method according to claim 13, wherein the portion of the light transmitted to the detector is representative of an amount of hematocrit in the liquid flowing through the passage.

### Claim 20 (depends on 19)

A method according to claim 19, wherein the first value and the second value are equivalent to a blood leak rate of 0.35 milliliters per minute or less.

### Claim 21 (depends on 13)

A method according to claim 13, wherein the method comprises activating an alarm after identifying the existence of a blood leak.

### Claim 22 (depends on 13)

A method according to claim 13, wherein the method comprises an extracorporeal blood treatment method, and wherein the liquid flowing through the passage comprises effluent liquid containing one or more constituents removed from blood.

### Claim 23 (depends on 13)

A method according to claim 13, wherein the detecting light emitted by the optical source is done with an optical detector, and wherein the optical source and optical detector are on a same side of the passage.