Extracorporeal blood processing methods with return-flow alarm

• US 7,608,053 B2
• Filed: 09/08/2006
• Issued: 10/27/2009
• Est. Priority Date: 01/10/2000
• Status: Expired due to Fees

• Current Assignee: Terumo BCT, Inc. (Terumo Corporation)
• Original Assignee: Caridianbct Biotechnologies LLC (Baxter International Inc.)
• Inventors: Bainbridge, Marlene Adele, Felt, Thomas J.
• Primary Examiner(s): Deak; Leslie R
• Application Number:
  US11/530,122
• Publication Number:
  US 20070078368A1
• Time in Patent Office: 1,145 Days
• Field of Search: 604/4.01, 604/5.01, 604/6.01, 604/6.03, 604/6.11, 604/6.15, 604 65- 67, 604/151, 210/600, 210/634, 210/645, 210/781, 210/782, 210/739, 210/741
• US Class Current: 604/6.05
• CPC Class Codes: 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
• CPC Class Codes: A61M 1/303 having a reservoir for treated blood to be returned
• CPC Class Codes: A61M 1/308 Volume control, e.g. with open or flexible containers, by counting the number of pump revolutions, weighing
• CPC Class Codes: A61M 1/3496 Plasmapheresis; Leucopheresis; Lymphopheresis A61M1/3472 takes precedence
• CPC Class Codes: A61M 1/36222 Details related to the interface between cassette and machine
• CPC Class Codes: A61M 1/36224 with sensing means or components thereof
• CPC Class Codes: A61M 1/36225 with blood pumping means or components thereof
• CPC Class Codes: A61M 1/36226 Constructional details of cassettes, e.g. specific details on material or shape
• CPC Class Codes: A61M 1/362262 Details of incorporated reservoirs
• CPC Class Codes: A61M 1/362263 Details of incorporated filters
• CPC Class Codes: A61M 1/362265 Details of valves
• CPC Class Codes: A61M 1/362266 Means for adding solutions or substances to the blood
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 1/3641 Pressure isolators
• CPC Class Codes: A61M 1/3656 Monitoring patency or flow at connection sites; Detecting disconnections
• CPC Class Codes: A61M 1/3696 with means for adding or withdrawing liquid substances during the centrifugation, e.g. continuous centrifugation
• CPC Class Codes: A61M 2205/123 with incorporated reservoirs
• CPC Class Codes: A61M 2205/17 with redundant control systems
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/3331 Pressure; Flow

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

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.

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

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

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

5. 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*Q_IN/(1−

H_IN)−

0.3026*Q_N/(1−

H_N)

wherein Config is a configuration-specified system pressure (mmHg), Q_IN is the flow rate in the inlet tubing line (ml/min), H_IN is the hematocrit in the inlet tubing line, Q_N is the flow rate in the needle (ml/min), and H_N is the hematocrit in the needle.