# US 7,608,053 B2 · Extracorporeal blood processing methods with return-flow alarm

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- Number: US 7,608,053 B2
- Document ID: US7608053B2
- Status: Granted
- Kind: B2
- Application number: 11/530,122
- Filed: 2006-09-08
- Published: 2007-04-05
- Granted: 2009-10-27
- Earliest claimed: 2000-01-10
- Assignees: Caridianbct, Inc.
- Inventors: Thomas J. Felt; Marlene Adele Bainbridge
- Web page: https://patentgrep.com/patent/US7608053B2

## CPC

- A61M 1/30: Single needle dialysis {; Reciprocating systems, alternately withdrawing blood from and returning it to the patient, e.g. single-lumen-needle dialysis or single needle systems for hemofiltration or pheresis}
- A61M 1/303: {having a reservoir for treated blood to be returned}
- A61M 1/308: {Volume control, e.g. with open or flexible containers, by counting the number of pump revolutions, weighing}
- A61M 1/36222: {Details related to the interface between cassette and machine}
- A61M 1/36224: {with sensing means or components thereof}
- A61M 1/36225: {with blood pumping means or components thereof}
- A61M 1/36226: {Constructional details of cassettes, e.g. specific details on material or shape}
- A61M 1/362262: {Details of incorporated reservoirs}
- A61M 1/362265: {Details of valves}
- A61M 1/362266: {Means for adding solutions or substances to the blood}
- A61M 1/3639: {Blood pressure control, pressure transducers specially adapted therefor}
- A61M 1/3641: {Pressure isolators}
- A61M 1/3656: {Monitoring patency or flow at connection sites; Detecting disconnections}
- A61M 1/3696: {with means for adding or withdrawing liquid substances during the centrifugation, e.g. continuous centrifugation}
- A61M 1/3496: {Plasmapheresis; Leucopheresis; Lymphopheresis (A61M1/3472 takes precedence)}
- A61M 1/362263: {Details of incorporated filters}
- A61M 2205/123: with incorporated reservoirs
- A61M 2205/17: with redundant control systems
- A61M 2205/18: with alarm
- A61M 2205/3331: Pressure; Flow
- 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

This invention provides a method for controlling a fluid separation system, preferably a blood apheresis system having a leukocyte reduction chamber. The method utilizes a return-flow alarm system. A return-flow alarm-triggering pressure is specified, and when pressure of the return flow in the system is higher than or equal to the specified pressure, a return-flow alarm is triggered.

## Claims

### Claim 1

A method for controlling flow rate of return of fluid to a fluid source in a fluid separation process wherein components have been separated from said fluid, said method comprising:
specifying a system return-flow alarm-triggering pressure, and when pressure of said return flow in the system is higher than or equal to said specified pressure, triggering a return-flow alarm wherein said specified system return flow alarm-triggering pressure is used to calculate a specified sensor pressure which triggers said return-flow alarm by modifying the specified sensor pressure in the system using the specified system return-flow alarm-triggering pressure and selected system parameters and wherein said system is a single-needle blood apheresis system, and said selected system parameters include the flow rate in the inlet tubing line, the hematocrit in the inlet tubing line, the flow rate in the needle, and the hematocrit in the needle.

### Claim 2 (depends on 1)

The method of claim 1 wherein said return-flow alarm comprises stopping of said return fluid.

### Claim 3 (depends on 2)

The method of claim 2 wherein said return-flow alarm comprises sounding an audible alarm and/or displaying a visible alarm.

### Claim 4 (depends on 2)

The method of claim 2 wherein said specified system return-flow alarm-triggering pressure is between about 100 and about 310 mmHg.

### Claim 5 (depends on 1)

The method of claim 1 wherein the specified sensor pressure that triggers the return-flow alarm condition is calculated using the formula:
Specified Sensor Pressure=Config−50−0.3309*QIN/(1−HIN)−0.3026*QN/(1−HN)
wherein Config is a configuration-specified system pressure (mmHg), QIN is the flow rate in the inlet tubing line (ml/min), HIN is the hematocrit in the inlet tubing line, QN is the flow rate in the needle (ml/min), and HN is the hematocrit in the needle.