Volumetric fluid withdrawal system

• US 4,767,399 A
• Filed: 12/05/1986
• Issued: 08/30/1988
• Est. Priority Date: 12/05/1986
• Status: Expired due to Fees

• Current Assignee: ALARIS Medical Systems, Inc. (Becton, Dickinson & Co)
• Original Assignee: Fisher Scientific Group, Inc. (Thermo Fisher Scientific Incorporated)
• Inventors: Bollish, Stephen J.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Costantino, Mario
• Application Number:
  US06/938,622
• Time in Patent Office: 634 Days
• Field of Search: 604/4-6, 604/28, 604/29, 604/151, 604/152, 210/645-647, 210/416.1, 210/929, 210/651
• US Class Current: 604/6.06
• CPC Class Codes: A61M 1/34 Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
• CPC Class Codes: A61M 1/341 by measuring the filtrate rate or volume
• CPC Class Codes: Y10S 210/929 Hemoultrafiltrate volume measurement or control processes

Abstract

A system for withdrawing a predetermined volume of fluid from a patient comprises a filter assembly which is connected in line for fluid communication between an artery and a vein of the patient. A pump having a fluid chamber is connected in fluid communication with a filtrate port of the filter. Operation of the pump causes the withdrawal of fluid from the filter and into the pump chamber at a preselected volumetric rate. Periodically, the pump is cycled to expel the withdrawn fluid from the pump chamber. The system further comprises a fluid collection device for collecting the expelled fluids and may include means for replenishing fluids to the patient.

Claims

1. A system for volumetric withdrawal of fluid from a patient which comprises:

an assembly having a porous filter and formed with a venous port, an arterial port and a filtrate formed with a venous port, an arterial port and a filtrate port;

a volumetric pump having a fluid chamber of predetermined volume, said chamber having an inlet and an outlet with said inlet connected for fluid communication with said filtrate port to provide a direct effect on the filtering process by said pump and, said pump having a piston slidably received in said chamber to vary the volume of said chamber; and

control means operatively connected with said piston to alternatingly draw fluid from said filter into said chamber at a predetermined rate compatible with the capacity of said filter and empty fluid from said chamber through said outlet.

2. A system as cited in claim 1 wherein said control means empties fluid from said chamber at a faster rate than said means draws fluid from said assembly.

3. A system as cited in claim 2 further comprising a fluid collection device in fluid communication with said outlet.

4. A system as cited in claim 3 further comprising a venous line having a first end connected in fluidwise communication with said venous port of said filter and a second end adapted for insertion into a vein of a patient.

5. A system as cited in claim 4 further comprising an arterial line having a first end connected in fluidwise communication with said venous port of said filter and a second end adapted for insertion into an artery of a patient.

6. A system as cited in claim 5 further comprising a fluid source in fluid communication with said venous line.

7. A system as cited in claim 5 further comprising a fluid source in fluid communication with said arterial line.

8. A system as cited in claim 1 wherein said assembly comprises a hemofilter.

9. A system as cited in claim 1 wherein saId assembly comprises a plasmapheresis filter.

10. An apparatus useful for continuous arteriovenous hemofiltration which comprises:

a porous fiber bundle;

a filter housing formed as a hollow cylinder for receiving said fiber bundle therein, said housing having an arterial port, a venous port and a filtrate port;

a pump having an inlet and an outlet and having a chamber in fluid communication with said inlet and said outlet;

a connector fluid line connecting said filtrate port into fluid communication with said inlet;

a piston operatively associated with said pump and positioned thereon for reciprocal movement in said chamber between a first position and a second position for varying the effective volume of said chamber according to the position of said piston in said chamber;

a valve operatively associated with said chamber to alternatingly block fluid communication between said inlet and said chamber or between said outlet and said chamber;

means associated with said pump to synchronize operation of said valve with said piston to draw fluid from said filter housing through said connecting fluid line into said chamber and to expel fluid from said chamber through said outlet; and

means associated with said pump to alternatingly provide for controlled drawing of fluid into said chamber at a relatively slow volumetric flow rate and for relatively rapid expulsion of fluid from said chamber.

11. A method for setting up a system and drawing fluid from a patient at a predetermined volumetric rate for continuous arteriovenous hemofiltration which comprises the steps of:

(a) obtaining a filter assembly for holding a porous filter, said assembly having a venous port, an arterial port and a filtrate port;

(b) connecting a venous line between a vein of the patient and said venous port and an arterial line between an artery of the patient and said arterial port to establish a blood flow route through said filter;

(c) engaging a volumetric pump with said filtrate port of said filter assembly to provide a direct effect on the filtering process by said pump, said pump having a fluid chamber and a piston slidably disposed in said chamber to vary the volume thereof, said chamber formed with an inlet and an outlet with said inlet engaged in fluid communication with said filtrate port; and

(d) operating a control means connected with said pump to alternatingly draw fluid from said filter into said chamber at a predetermined rate and emptying fluid from said chamber through said outlet.