Systems and methods for obtaining a platelet suspension having a reduced number of leukocytes

• US 6,071,421 A
• Filed: 11/25/1997
• Issued: 06/06/2000
• Est. Priority Date: 12/23/1991
• 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): KIM, SUN U
• Application Number:
  US08/977,305
• Time in Patent Office: 924 Days
• Field of Search: 210/767, 210/739, 210/744, 210/745, 210/782, 210/787, 210/789, 210/85, 210/86, 210/97, 210/109, 210/205, 210/435, 210/446, 604/4, 604/5, 604/6, 494/2, 494/3, 494/10, 494/37
• US Class Current: 210/782
• 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• CPC Class Codes: A61M 1/302 having a reservoir for withdrawn untreated blood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 2202/0071 product to be retained or harvested, e.g. by pheresis
• 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 2221/08 : Mobile separation devices
• CPC Class Codes: B01D 2221/10 : Separation devices for use in medical, pharmaceutical or laboratory applications, e.g. separating amalgam from dental treatment residues
• 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 2005/045 : having annular separation channels
• 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

Systems and methods obtain a platelet suspension with reduced number of leukocytes by centrifugally separating whole blood into red blood cells, a suspension of platelets, and an intermediate layer comprising leukocytes. The systems and methods convey the suspension of platelets from the centrifugal separation chamber to a filter, while maintaining the intermediate layer containing leukocytes inside the centrifugal separation chamber. The systems and methods filter remaining leukocytes from the platelet suspension in the filter.

Claims

1. A system for obtaining a platelet suspension having a reduced number of leukocytes comprising

a separation chamber having an entry region to receive whole blood containing leukocytes to centrifugally separate the whole blood into a first layer comprising red blood cells, a second layer comprising a platelet suspension which includes a number of leukocytes, and an interface between the first and second layers which includes a number of leukocytes, the separation chamber including a collection region to collect the platelet suspension and an outlet communicating with the collection region,

an inlet path communicating with the entry region of the separation chamber to convey whole blood into the entry region,

an outlet path communicating with the outlet of the separation chamber to convey platelet suspension from the collection region,

a filter in the outlet path for removing leukocytes from the platelet suspension,

a monitoring element monitoring location of the interface within the collection region and transmitting location signals, and

a controller coupled to the monitoring element and the outlet path and operating to continuously maintain the location of the interface at a substantially constant location in the collection region spaced from the outlet, whereby the number of leukocytes in the interface are retained in the separation chamber to reduce the number of leukocytes present in the platelet suspension, while platelet suspension is conveyed in the outlet path from the collection region through the filter, whereby the number of leukocytes in the platelet suspension is additionally reduced.

2. A system according to claim 1

wherein the separation chamber rotates about an axis in a rotational field, and

wherein the filter is located outside the rotational field.

3. A system for obtaining a platelet-rich concentrate having a reduced number of leukocytes comprising

a separation chamber having a first portion to receive whole blood containing leukocytes to centrifugally separate the whole blood into a first layer comprising red blood cells, a second layer comprising a platelet suspension including a number of leukocytes, and a third layer comprising a number of leukocytes between the first and second layers, the separation chamber including a second portion to separate the platelet suspension into a platelet-rich concentrate and a platelet-poor plasma constituent,

a whole blood path to convey whole blood into the first portion of the separation chamber,

a platelet suspension path for conveying the platelet suspension from the first portion to the second portion of the separation chamber through an outlet, the platelet suspension path including a filter which removes leukocytes from the platelet suspension to provide a leukocyte-reduced platelet suspension for separation in the second portion of the separation chamber, thereby providing a platelet-rich concentrate having a reduced number of leukocytes, and

a controller to continuously maintain the location of the third layer at a substantially constant location in the first portion of the separation chamber spaced from the outlet, while separation of the leukocyte-reduced platelet suspension occurs in the second portion of the separation chamber, whereby the number of platelets in the leukocyte-reduced platelet suspension is additionally reduced before separation of the leukocyte-reduced platelet suspension occurs in the second portion of the separation chamber.

4. A system according to claim 3

wherein the separation chamber rotates about an axis in a rotational field, and

wherein the filter is located outside the rotational field.

5. A method for obtaining a platelet suspension with reduced number of leukocytes comprising the steps of

conveying whole blood containing leukocytes into a centrifugal separation chamber for separation into a first layer comprising red blood cells, a second layer comprising a platelet suspension including a number of leukocytes, and a third layer comprising a number of leukocytes between the first and second layers,

at least partially while conveying whole blood into the centrifugal separation chamber, conveying the platelet suspension from the centrifugal separation chamber through an outlet to a filter, while continuously maintaining the third layer containing the number of leukocytes at a substantially constant location inside the centrifugal separation chamber spaced from the outlet, whereby the number of leukocytes in the platelet suspension is reduced, and

filtering leukocytes from the platelet suspension in the filter, whereby the number of leukocytes in the platelet suspension is further reduced.

6. A method for obtaining a platelet suspension with reduced number of leukocytes comprising the steps of

conveying whole blood containing leukocytes into a rotational field comprising a centrifugal separation chamber for separation into a first layer comprising red blood cells, a second layer comprising a platelet suspension including a number of leukocytes, and a third layer comprising a number of leukocytes between the first and second layers,

conveying the platelet suspension from the centrifugal separation chamber outside the rotational field through an outlet to a filter, while continuously maintaining the third layer containing the number of leukocytes at a substantially constant location inside the rotational field within the centrifugal separation chamber spaced from the outlet, whereby the number of leukocytes in the platelet suspension is reduced, and

filtering leukocytes from the platelet suspension in the filter outside the rotational field, whereby the number of leukocytes in the platelet suspension is further reduced.

7. A method for obtaining a platelet-rich concentrate with reduced number of leukocytes comprising the steps of

conveying whole blood containing leukocytes into a centrifugal separation chamber for separation into a first layer comprising red blood cells, a second layer comprising a platelet suspension including a number of leukocytes, and a third layer comprising a number of leukocytes between the first and second layers,

at least partially while conveying whole blood into the centrifugal separation chamber, conveying the platelet suspension from the centrifugal separation chamber through an outlet to a filter, while continuously maintaining the third layer containing the number of leukocytes at a substantially constant location inside the centrifugal separation chamber spaced from the outlet, whereby the number of leukocytes in the platelet suspension is reduced,

filtering leukocytes from the platelet suspension in the filter, whereby the number of leukocytes in the platelet suspension is further reduced, and

conveying the leukocyte-reduced platelet suspension from the filter to a second centrifugal separation chamber for separation into a platelet-rich concentrate and platelet-poor plasma.

8. A method for obtaining a platelet-rich concentrate with reduced number of leukocytes comprising the steps of

conveying whole blood containing leukocytes into a rotational field comprising a centrifugal separation chamber for separation into a first layer comprising red blood cells, a second layer comprising a platelet suspension including a number of leukocytes, and a third layer comprising a number of leukocytes between the first and second layers,

conveying the platelet suspension from the centrifugal separation chamber outside the rotational field through an outlet to a filter, while continuously maintaining the third layer containing the number of leukocytes inside the rotational field at a substantially constant location within the centrifugal separation chamber spaced from the outlet, whereby the number of leukocytes in the platelet suspension is reduced,

filtering leukocytes from the platelet suspension in the filter outside the centrifugal field, whereby the number of leukocytes in the platelet suspension is further reduced, and

conveying the leukocyte-reduced platelet suspension from the filter back into the rotational field to a second centrifugal separation chamber for separation into a platelet-rich concentrate and platelet-poor plasma.