Devices, systems and methods for reducing the concentration of carbon dioxide in blood

Patent metadata

Field	Value
Publication number	US-9814821-B2
Application number	US-201314405038-A
Country	US
Kind code	B2
Filing date	Jun 15, 2013
Priority date	Jun 15, 2012
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

A method for removal of at least a portion of carbon dioxide from an aqueous fluid such as a blood fluid includes placing a first surface of at least one membrane through which carbon dioxide and at least one acid gas other than carbon dioxide can pass in fluid in contact with the fluid. The membrane limits or prevent passage of the fluid therethrough. A carrier or sweep gas including the acid gas other than carbon dioxide is passed over a second surface (which is typically opposite the first surface) of the membrane so that the acid gas other than carbon dioxide can pass through the membrane into the fluid, and carbon dioxide from the fluid can pass from the liquid, through the membrane, and into the sweep gas.

First claim

What is claimed is:

1. A method for removal of at least a portion of carbon dioxide from blood fluid, comprising: placing a first surface of at least one membrane through which carbon dioxide and at least one acid gas other than carbon dioxide can pass in fluid in contact with the fluid, passing a sweep gas including oxygen and the at least one acid gas other than carbon dioxide over a second surface of the at least one membrane so that the at least one acid gas other than carbon dioxide can pass through the at least one membrane into the fluid, and carbon dioxide from the aqueous fluid can pass from the liquid through the at least one membrane and into the sweep gas, the at least one membrane being adapted to limit or prevent passage of the fluid therethrough, wherein the concentration of the acid gas other than carbon dioxide in the sweep gas is sufficient to decrease pH in the boundary layer adjacent to the at least one membrane while maintaining bulk blood fluid pH within a physiological range, the at least one membrane comprising immobilized carbonic anhydrase on or in the vicinity of the first surface thereof such that the immobilized carbonic anhydrase comes into contact with the blood fluid, wherein the acid gas other than carbon dioxide and the carbonic anhydrase function synergistically in the removal of carbon dioxide.

2. The method of claim 1 wherein the fluid is blood.

3. The method of claim 1 wherein the carbonic anhydrase is immobilized on the first surface and the first surface exhibits a carbonic anhydrase activity of at least 20% of maximum theoretical activity of the first surface of the at least one membrane based on monolayer surface coverage of carbonic anhydrase surface.

4. The method of claim 1 wherein the carbonic anhydrase is immobilized on the first surface and the first surface exhibits a carbonic anhydrase activity of at least 40% of maximum theoretical activity of the first surface of the at least one membrane based on monolayer surface coverage of carbonic anhydrase.

5. The method of claim 1 wherein the carbonic anhydrase is immobilized on the first surface and the first surface exhibits a carbonic anhydrase activity of at least 60% of maximum theoretical activity of the first surface of the at least one membrane based on monolayer surface coverage of carbonic anhydrase.

6. The method of claim 1 wherein the carbonic anhydrase is immobilized on the first surface and the first surface exhibits a carbonic anhydrase activity of at least 80% of maximum theoretical activity of the first surface of the at least one membrane based on monolayer surface coverage of carbonic anhydrase.

7. The method of claim 1 wherein the carbonic anhydrase is immobilized on the first surface and the first surface exhibits a carbonic anhydrase activity which exceeds the maximum theoretical activity of the first surface of the at least one membrane based on monolayer surface coverage of carbonic anhydrase.

8. The method of claim 1 wherein the at least one membrane comprises a polymeric material.

9. The method of claim 8 wherein the carbonic anhydrase is immobilized on the at least one membrane via adsorption, covalent bonding, ionic bonding or chelation.

10. The method of claim 8 wherein the carbonic anhydrase is covalently attached to the polymeric material.

11. The method of claim 8 wherein the polymeric material is microporous or permeable such that CO 2 and the at least one acid gas other than CO 2 can pass therethrough.

12. The method of claim 11 wherein the polymeric material is microporous and sufficiently hydrophobic so that its pores remain gas filled after contacting the blood fluid.

13. The method of claim 12 wherein the polymeric material is an olefinic polymeric material.

14. The method of claim 11 wherein the carbonic anhydrase is covalently attached to the first surface of a microporous polymeric hollow fiber.

15. The method of claim 14 wherein the first surface is an outer surface of the microporous polymeric hollow fiber and an interior lumen of the microporous polymeric hollow fiber receive the sweep gas therethrough, the sweep gas further comprising oxygen and the microporous polymeric hollow fiber being adapted to pass oxygen and the at least one acid gas other than carbon dioxide into the blood fluid while carbon dioxide passes from the blood fluid to the interior lumen of the microporous polymeric hollow fiber.

16. The method of claim 15 wherein the carbonic anhydrase is covalently attached to a permeable, nonporous polymeric layer positioned on an exterior surface of the microporous polymeric hollow fiber.

17. The method of claim 16 wherein the permeable, nonporous polymeric layer comprises CO 2 -permeable silicone.

18. The method of claim 15 wherein the at least one membrane comprises a plurality of membranes formed by a plurality of the microporous polymeric hollow fibers.

19. The method of claim 1 wherein the at least one membrane comprises a porous layer and a gas permeable, nonporous layer adjacent the porous layer.

20. The method of claim 1 further comprising contacting the blood fluid with free carbonic anhydrase.

21. The method of claim 1 wherein carbon dioxide is present in the fluid in the form of bicarbonate ion.

22. The method of claim 1 wherein the at least one acid gas other than CO 2 is sulfur dioxide, hydrogen sulfide, nitrogen dioxide, nitric oxide, or hydrogen iodide.

23. The method of claim 1 wherein the at least one acid gas other than CO 2 is sulfur dioxide or nitrogen dioxide.

24. The method of claim 1 wherein the at least one acid gas other than CO 2 is sulfur dioxide.

25. A system for removal of at least a portion of carbon dioxide from a blood
fluid blood, comprising: at least one
membrane comprising a first surface and a second surface, the at least one membrane being adapted to pass carbon dioxide and at least one acid gas other than carbon dioxide from a sweep gas therethrough, the at least one membrane being further adapted to limit or prevent passage of the fluid therethrough, the at least one source of the sweep gas, adapted to be placed in fluid connection with the second surface of the at least one membrane to pass the sweep gas over the second surface of the at least one membrane so that the at least one acid gas other than carbon dioxide can pass through the at least one membrane into the fluid and carbon dioxide from the fluid can pass from the aqueous fluid through the at least one membrane and into the sweep gas, wherein the concentration of the acid gas other than carbon dioxide in the sweep gas is sufficient to decrease pH in the boundary layer adjacent to the at least one membrane while maintaining bulk blood pH in a physiological range, the at least one membrane comprising immobilized carbonic anhydrase on or in the vicinity of the first surface thereof such that the immobilized carbonic anhydrase comes into contact with the blood fluid, wherein the acid gas other than carbon dioxide and the carbonic anhydrase function synergistically in the removal of carbon dioxide.

26. The system of claim 25 wherein the fluid is blood.

27. A respiratory assist system for removal of at least a portion of carbon dioxide from a blood fluid, comprising: a plurality of hollow fiber membranes, each of the plurality of hollow fiber membrane comprising a first or inner surface and a second or outer surface, each of th

Assignees

• Univ Of Pittsburgh—Of The Commonwealth System Of Higher Education

Inventors

• Federspiel William J
• Arazawa David T
• Kimmel Jeremy D

Classifications

• B01D67/0093

  Chemical modification · CPC title

• A61M2202/0283

  Nitrous oxide (N2O) · CPC title

• A61M1/1698

  Blood oxygenators with or without heat-exchangers (intracorporal A61M1/1678; manufacturing of membranes therefor B01D67/00; semi-permeable membranes for separation processes characterised by their properties B01D69/00; semi-permeable membranes characterised by their material B01D71/00) · CPC title

• B01D63/04

  comprising multiple hollow fibre assemblies · CPC title

• A61M1/3687

  Chemical treatment (A61M1/3675 takes precedence) · CPC title