Blood processing systems and methods using apparent hematocrit as a process of control parameter

• US 6,451,203 B2
• Filed: 02/23/2001
• Issued: 09/17/2002
• Est. Priority Date: 06/07/1995
• Status: Expired due to Term

• Current Assignee: Fenwal Incorporated (Fresenius SE & Co. KGaA)
• Original Assignee: Baxter International Inc.
• Inventors: Brown, Richard I.
• Primary Examiner(s): Drodge, Joseph W.
• Application Number:
  US09/793,801
• Publication Number:
  US 20010006810A1
• Time in Patent Office: 571 Days
• Field of Search: 210/85, 210/94, 210/96.1, 210/143, 210/512.1, 210/646, 210/739, 210/745, 210/787, 210/87, 210/97, 210/145, 494/1, 494/10, 494/37, 604/4.01, 604/5.01, 604/6.01
• US Class Current: 210/143
• CPC Class Codes: A61M 1/0209 Multiple bag systems for separating or storing blood components
• CPC Class Codes: A61M 1/0218 with filters
• CPC Class Codes: A61M 1/025 Means for agitating or shaking blood containers A61M1/0245 takes precedence; shaking in general B01F31/00
• 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• CPC Class Codes: A61M 1/302 having a reservoir for withdrawn untreated blood
• 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 1/3603 in the same direction
• CPC Class Codes: A61M 1/3624 Level detectors; Level control
• CPC Class Codes: A61M 1/3672 Means preventing coagulation
• CPC Class Codes: A61M 1/3693 using separation based on different densities of components, e.g. centrifuging
• 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 1/385 taking into account of the patient characteristics
• CPC Class Codes: A61M 2202/0071 product to be retained or harvested, e.g. by pheresis
• CPC Class Codes: A61M 2202/0092 starting product created by centrifuging
• CPC Class Codes: A61M 2202/0415 Plasma
• CPC Class Codes: A61M 2202/0427 Platelets; Thrombocytes
• CPC Class Codes: A61M 2205/331 used as turbidity change detectors, e.g. for priming-blood or plasma-hemoglubine-interface detection
• CPC Class Codes: A61M 2205/3344 Measuring or controlling pressure at the body treatment site
• CPC Class Codes: A61M 2205/3351 Controlling upstream pump pressure
• CPC Class Codes: A61M 2205/3355 : Controlling downstream pump pressure
• CPC Class Codes: A61M 2205/3393 : by weighing the reservoir
• CPC Class Codes: B01D 17/0217 : by centrifugal force
• CPC Class Codes: B01D 21/2405 : Feed mechanisms for settling tanks
• CPC Class Codes: B01D 21/245 : Discharge mechanisms for the sediments
• CPC Class Codes: B01D 21/26 : Separation of sediment aided by centrifugal force or centripetal forcecentrifuges B04B; cyclones B04C
• CPC Class Codes: B01D 21/262 : by using a centrifuge
• CPC Class Codes: B01D 21/34 : Controlling the feed distribution; Controlling the liquid level ; Control of process parameters
• CPC Class Codes: B01D 2221/10 : Separation devices for use in medical, pharmaceutical or laboratory applications, e.g. separating amalgam from dental treatment residues apparatus for dental treatment A61C17/065
• CPC Class Codes: B04B 13/00 : Control arrangements specially designed for centrifuges; Programme control of centrifuges control arrangements for feed, charge, or discharge B04B11/00
• CPC Class Codes: B04B 5/0442 : with means for adding or withdrawing liquid substances during the centrifugation, e.g. continuous centrifugation
• CPC Class Codes: B04B 7/08 : Rotary bowls centrifugal casting machines B22D

Abstract

Blood processing systems and methods separate whole blood into red blood cells and a plasma constituent within a rotating centrifugal separation device. The systems and methods convey whole blood into the separation device through an inlet path including a pump operable at a prescribed rate. The systems and methods remove plasma constituent from the separation device through an outlet path including a pump operable at a prescribed rate. The systems and methods derive a value H_b representing an apparent hematocrit of whole blood entering the separation device, where: $H_b=\frac{H_{\mathrm{rbc}}\left(Q_b-Q_p\right)}{Q_b}$

and where H_rbc is a value relating to hematocrit of red blood cells in the separation device. The systems and methods generate outputs and control commands based, at least in part, upon H_b.

Claims

1. A blood processing system comprising

a centrifugal separation device rotatable about a rotational axis,

an inlet path operable to convey whole blood into the separation device for separation into red blood cells and a plasma constituent, the whole blood in the inlet path having an actual whole blood hematocrit value,

an outlet path operable to remove plasma constituent from the separation device at least in part while whole blood is conveyed into the separation device,

an outlet path operable to remove red blood cells from the separation device at least in part while whole blood is conveyed into the separation device and plasma is removed from the separation device, and

a controller including a stage operable at least in part while whole blood is conveyed into the separation device and plasma and red blood cells are removed from the separation device, to generate a derived hematocrit value representing an apparent hematocrit of whole blood entering the separation device based, upon at least one operating condition and without sensing the actual whole blood hematocrit value.

2. A system according to claim 1

wherein the at least one operating condition includes at least one red blood cell dependent factor not including the actual whole blood hematocrit value.

6. A system according to claim 1 or 3

wherein the controller includes a stage operable to generate a control command at least in part while whole blood is conveyed into the separation device and plasma and red blood cells are removed from the separation device, based, at least in part, upon the derived hematocrit value.

7. A system according to claim 1 or 3

wherein the at least one operating condition includes a rate of rotation of the separation device.

8. A system according to claim 1 or 3

wherein the at least one operating condition includes a flow rate of whole blood in the inlet path.

9. A system according to claim 1 or 3

wherein the at least one operating condition includes a flow rate of plasma constituent in the outlet path.

10. A system according to claim 1 or 3

wherein the separation device has an area, and

wherein the at least one operating condition includes the area of the separation device.

11. A system according to claim 1 or 3

wherein the separation device is rotatable at a controlled rate of rotation, and

wherein the at least one operating condition includes a centrifugal acceleration factor based upon the controlled rate of rotation.

3. A blood processing system comprising

a centrifugal separation device rotatable about a rotational axis,

an inlet path operable to convey whole blood into the separation device for separation into red blood cells and a plasma constituent, the red blood cells in the separation device having an actual red blood cell hematocrit value,

an outlet path operable to remove plasma constituent from the separation device at least in part while whole blood is conveyed into the separation device,

an outlet path operable to remove red blood cells from the separation device at least in part while whole blood is conveyed into the separation device and plasma is removed from the separation device, and

a controller including a stage operable, at least in part while whole blood is conveyed into the separation device and plasma and red blood cells are removed from the separation device, to generate a derived hematocrit value representing an apparent hematocrit of red blood cells within the separation device based upon at least one operating condition without sensing the actual red blood cell hematocrit value.

4. A system according to claim 3

wherein the whole blood in the inlet path has an actual whole blood hematocrit value, and

wherein the controller includes a stage operable, at least in part while whole blood is conveyed into the separation device and plasma and red blood cells are removed from the separation device, to generate a derived hematocrit value representing an apparent hematocrit of whole blood entering the separation device based upon at least one operating condition and without sensing the actual whole blood hematocrit value.

5. A system according to claim 3

wherein the whole blood in the inlet path has an actual whole blood hematocrit value, and

wherein the controller includes a stage operable, at least in part while whole blood is conveyed into the separation device and plasma and red blood cells are removed from the separation device, to generate a derived hematocrit value representing an apparent hematocrit of whole blood entering the separation device based upon the derived hematocrit value representing the apparent hematocrit of red blood cells within the separation device and without sensing the actual whole blood hematocrit value.

12. A system according to claim 3

wherein the at least one operating condition includes at least one red blood cell dependent factor not including the actual red blood cell hematocrit value.