Blood processing systems and methods which monitor citrate return to the donor

• US 5,676,841 A
• Filed: 06/07/1995
• Issued: 10/14/1997
• 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): Drodge, Joseph W.
• Application Number:
  US08/472,439
• Time in Patent Office: 860 Days
• Field of Search: 210/85, 210/87, 210/96.1, 210/96.2, 210/97, 210/143, 210/645, 210/739, 210/782, 210/787, 210/257.1, 210/512.1, 210/789, 210/167, 210/194, 210/805, 604/4, 604/5, 604/6, 422/44, 364/554, 364/555, 364/564, 364/567, 364/569, 364/413.09, 128/760, 128/771
• US Class Current: 210/739
• CPC Class Codes: A61M 1/02 Blood transfusion apparatus blood infusion by syringes A61M5/14
• 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 1/30 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• CPC Class Codes: A61M 1/302 having a reservoir for withdrawn untreated blood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 2202/0427 Platelets; Thrombocytes
• 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: 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 collection systems and methods minimize citrate toxicity in donors. The systems and methods convey whole blood at a prescribed rate Q_b into a separation device for separation into red blood cells and a plasma constituent. The systems and methods add anticoagulant including citrate to the whole blood. The systems and methods control Qb (in ml/min or equivalent) based upon a citrate equivalent blood flow rate EqQB_CIR, where: ##EQU1## where: CIR is a selected nominal a-symptomatic citrate infusion rate (in mg/kg/min or equivalent),

AC is a selected anticoagulant ratio,

Wgt is the donor'"'"'s weight (in kg or equivalent), and

CitrateConc is the citrate concentration in the anticoagulant (in mg/ml or equivalent).

Claims

1. A blood processing system comprising

a separation device,

an inlet path including a pump operable at a prescribed rate Q_b constructed and arranged to convey whole blood from an individual donor into the separation device for separation into components including red blood cells and a plasma constituent,

an anticoagulant including a citrate concentration added to the whole blood,

a controller coupled to the inlet path pump operative to control Q_b (in ml/min or equivalent) based at least in part upon a citrate equivalent blood flow rate EqQb_CIR, where:

##EQU33## where;

CIR is a nominal a-symptomatic citrate infusion rate (in mg/kg/min or equivalent), empirically selected based upon citrate reactions in a population of different donors,

AC is a selected anticoagulant ratio,

Wgt is the individual donor'"'"'s weight (in kg or equivalent), and

CitrateConc is the citrate concentration in the anticoagulant (in mg/ml or equivalent), and

an outlet path constructed and arranged to return at least a portion of component containing anticoagulant from the separation device to the individual donor.

2. A system according to claim 1

wherein CIR is about 1.25 mg/kg/min.

3. A system according to claim 1

wherein the separation device comprises a centrifugation chamber.

4. A blood processing system comprising

a separation device,

an inlet path including a pump operable at a prescribed rate Q_b constructed and arranged to convey whole blood from an individual donor into the separation device for separation into components including red blood cells and a plasma constituent,

an anticoagulant including a concentration of citrate added to the whole blood,

a controller coupled to the inlet path pump to control Q_b (in ml/min or equivalent), where:

##EQU34## and where;

H_b is a value reflecting anticoagulated hematocrit of the whole blood conveyed into the separation device,

Vb_Rem is a value reflecting a remaining volume of whole blood to be processed,

PPP_Goal is a value reflecting a plasma constituent volume collection goal (in ml or equivalent),

PPP_Current is a value reflecting a current collected plasma constituent volume (in ml or equivalent), and

EqQb_CIR is a value reflecting citrate equivalent blood flow rate (in ml/min or equivalent), calculated as follows;

##EQU35## where;

CIR is a nominal a-symptomatic citrate infusion rate (in mg/kg/min or equivalent), empirically selected based upon citrate reactions in a population of different donors,

AC is a selected anticoagulant ratio,

Wgt is the individual donor'"'"'s weight (in kg or equivalent), and

CitrateConc is the citrate concentration in the selected anticoagulant (in mg/ml or equivalent), and

an outlet path constructed and arranged to return at least a portion of component containing anticoagulant from the separation device to the individual donor.

5. A system according to claim 4

wherein CIR is about 1.25 mg/kg/min.

6. A system according to claim 4

wherein the separation device comprises a centrifugation chamber.

7. A system according to claim 4

and further including an outlet path including a pump operable at a prescribed rate Q_p to remove plasma constituent from the separation device, and

wherein the value H_b represents an apparent hematocrit of whole blood entering the separation device, where:

##EQU36## and where H_rbc is a value relating to hematocrit of red blood cells in the separation device.

8. A system according to claim 7 wherein the separation device comprises a centrifugation chamber having an area, a radius and an operable rate of rotation

wherein the value H_rbc represents apparent hematocrit of red blood cells in the separation device, where:

##EQU37## where;

q_b is inlet blood flow rate (cm³ /sec), which when converted to ml/min, corresponds with Q_b,

q_p is measured plasma flow rate (in cm³ /sec), which, when converted to ml/min corresponds with Q_p,

β

is a shear rate dependent term, and S_Y is a red blood cell sedimentation coefficient (sec) and β

/S_Y =15.8×

10⁶ sec^-1,

A is the area of the separation device (cm²),

g is the centrifugal acceleration (cm/sec²), which is the radius of the separation device multiplied by the rate of rotation squared Ω

² (rad/sec²), and

k is a viscosity constant=0.625, and κ

is a viscosity constant based upon k and another viscosity constant α

=4.5, where;

##EQU38##

9. A blood processing method comprising the steps of

conveying whole blood at a prescribed rate Q_b from an individual donor into a separation device for separation into red blood cells and a plasma constituent,

adding anticoagulant including a concentration of citrate to the whole blood,

controlling Q_b in ml/min or equivalent) based upon a citrate equivalent blood flow rate EqQb_CIR where:

##EQU39## where;

CIR is a nominal a-symptomatic citrate infusion rate (in mg/kg/min or equivalent), empirically selected based upon citrate reactions in a population of different donors,

AC is a selected anticoagulant ratio,

Wgt is the individual donor'"'"'s weight (in kg or equivalent), and

CitrateConc is the citrate concentration in the anticoagulant (in mg/ml or equivalent), and

returning at least a portion of component containing anticoagulant from the separation device to the donor.

10. A method according to claim 9

wherein CIR is about 1.25 mg/kg/min.

11. A blood processing method comprising the steps of

conveying whole blood at a prescribed rate Q_b from an individual donor into the separation device for separation into red blood cells and a plasma constituent,

adding an anticoagulant including a concentration of citrate to the whole blood,

controlling Q_b (in ml/min or equivalent), where:

##EQU40## and where;

H_b is a value reflecting anticoagulated hematocrit of the whole blood conveyed into the separation device,

Vb_Rem is a value reflecting a remaining volume of whole blood to be processed,

PPP_Goal is a value reflecting a plasma constituent volume collection goal (in ml or equivalent),

PPP_Current is a value reflecting a current collected plasma constituent volume (in ml or equivalent), and

EqQb_CIR is a value reflecting citrate equivalent blood flow rate (in ml/min or equivalent), calculated as follows;

##EQU41## where;

CIR is a nominal a-symptomatic citrate infusion rate (in mg/kg/min or equivalent), empirically selected based upon citrate reactions in a population of different donors,

AC is a selected anticoagulant ratio,

Wgt is the individual donor'"'"'s weight (in kg or equivalent), and

CitrateConc is the citrate concentration in the selected anticoagulant (in mg/ml or equivalent), and

returning at least a portion of component containing anticoagulant from the separation device to the donor.

12. A method according to claim 11

wherein CIR is about 1.25 mg/kg/min.

13. A method according to claim 11

and further including the step of removing plasma constituent at a prescribed rate Q_p from the separation device, and

wherein the value H_b represents an apparent hematocrit of whole blood entering the separation device, where:

##EQU42## and where H_rbc is a value relating to hematocrit of red blood cells in the separation device.

14. A method according to claim 13 wherein the separation device comprises a centrifugation chamber having an area, a radius and an operable rate of rotation

wherein the value H_rbc represents apparent hematocrit of red blood cells in the separation device, where:

##EQU43## where;

q_b is inlet blood flow rate (cm³ /sec), which when converted to ml/min, corresponds with Q_b,

q_p is measured plasma flow rate (in hcm³ /sec), which, when converted to ml/min corresponds with Q_p,

β

is a shear rate dependent term, and S_Y is a red blood cell sedimentation coefficient (sec) and β

/S_Y =15.8×

10⁶ sec^-1,

A is the area of the separation device (cm²),

g is the centrifugal acceleration (cm/sec²), which is the radius of the separation device multiplied by the rate of rotation squared Ω

² (rad/sec²), and

k is a viscosity constant=0.625, and κ

is a viscosity constant based upon k and another viscosity constant α

=4.5, where;

##EQU44##