# US 11,298,447 B2 · Gasless extra-corporeal carbon dioxide removal

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- Number: US 11,298,447 B2
- Document ID: US11298447B2
- Status: Granted
- Kind: B2
- Application number: 16/266,193
- Filed: 2019-02-04
- Published: 2020-08-06
- Granted: 2022-04-12
- Earliest claimed: 2019-02-04
- Assignees: The United States of America as represented by the Secretary of the Air Force
- Applicants: Government of the United States as represented by the Secretary of the Air Force
- Inventors: Ian J. Stewart; Jeremy W. Cannon
- Web page: https://patentgrep.com/patent/US11298447B2

## CPC

- A61M 1/3486: {Biological, chemical treatment, e.g. chemical precipitation; treatment by absorbents}
- A61M 1/1698: {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)}
- A61M 1/3479: {by dialysing the filtrate}
- A61M 1/3627: {Degassing devices; Buffer reservoirs; Drip chambers; Blood filters}
- A61M 1/3679: {by absorption (A61M1/3675 takes precedence)}
- B01D 63/031: {Two or more types of hollow fibres within one bundle or within one potting or tube-sheet}
- B01D 69/08: Hollow fibre membranes (manufacture of hollow fibres D01D5/24, D01F1/08)
- B01D 69/081: {characterised by the fibre diameter}
- B01D 71/16: Cellulose acetate
- B01D 71/421: {Polyacrylonitrile}
- B01D 71/68: Polysulfones; Polyethersulfones
- A61M 2202/0225: Carbon oxides, e.g. Carbon dioxide
- A61M 2205/3334: Measuring or controlling the flow rate
- A61M 2205/3337: Controlling, regulating pressure or flow by means of a valve by-passing a pump
- B01D 71/56: Polyamides, e.g. polyester-amides
- B01D 2311/2626: Absorption or adsorption
- B01D 2313/40: Adsorbents within the flow path
- B01D 2313/44: Cartridge types
- B01D 2315/12: Feed-and-bleed systems
- B01D 2315/22: Membrane contactor
- B01D 2325/20: Specific permeability or cut-off range
- A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)}
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## Abstract

A carbon dioxide absorption medium. The absorption medium includes a plurality of hollow fibers and a plurality of binder particles. The hollow fibers have walls comprising a selectively permeable membrane that is configured to permit passage of gaseous carbon dioxide but not liquids. The plurality bind particles are dispersed between the hollow fibers and comprise an absorbent material configured to absorb gaseous carbon dioxide and to bind the carbon dioxide in a solid state.

## Claims

### Claim 1

A carbon dioxide absorption medium comprising:
a plurality of hollow fibers, each hollow fiber of the plurality having a proximal end, a distal end, a lumen extending between the proximal and distal ends, and a wall surrounding the lumen, the wall of each hollow fiber of the plurality comprising a membrane selectively permeable to gaseous carbon dioxide; and
a plurality of binder particles dispersed between hollow fibers of the plurality, each binder particle of the plurality being configured to absorb gaseous carbon dioxide and to bind and to retain the carbon dioxide in a solid state.

### Claim 2 (depends on 1)

The carbon dioxide absorption medium of claim 1, wherein the membrane comprising the wall of each hollow fiber of the plurality comprises at least one polymer selected from the group consisting of cellulose acetate, cellulose triacetate, polyamide, polysulfone, polyethersulfone (PES), polyacrylonitrile (PAN), sulfonated polyacrylonitrile, polymethylmethacrylate (PmmA), and polymethylpentene (PMP).

### Claim 3 (depends on 1)

The carbon dioxide absorption medium of claim 1, wherein the wall of each hollow fiber of the plurality has an outer thickness ranging from about 5 μm to about 50 μm.

### Claim 4 (depends on 1)

The carbon dioxide absorption medium of claim 1, wherein the binder particles of the plurality have a maximum dimension ranging from about 100 μm to about 10,000 μm.

### Claim 5 (depends on 1)

The carbon dioxide absorption medium of claim 1, wherein the plurality of binder particles comprise at least one absorbent material selected from the group consisting of sodium oxide, sodium hydroxide, calcium oxide, calcium hydroxide, potassium hydroxide, lithium hydroxide, lithium peroxide, lithium carbonate, and lithium chloride.

### Claim 6 (depends on 1)

A carbon dioxide absorption cartridge for removing carbon dioxide from the blood of a patient, the cartridge comprising:
a housing having an inlet port and an outlet port and an internal cavity therebetween, the inlet port configured to fluidically receive blood from the patient and the outlet port configured to fluidically return filtered blood to the patient; and
the carbon dioxide absorption medium of claim 1 disposed within the internal cavity of the housing.

### Claim 7 (depends on 6)

The cartridge of claim 6, wherein the membrane comprising the wall of each hollow fiber of the plurality comprises at least one polymer selected from the group consisting of cellulose acetate, cellulose triacetate, polyamide, polysulfone, polyethersulfone (PES), polyacrylonitrile (PAN), sulfonated polyacrylonitrile, polymethylmethacrylate (PmmA), and polymethylpentene (PMP).

### Claim 8 (depends on 6)

The cartridge of claim 6, wherein the wall of each hollow fiber of the plurality has an outer thickness ranging from about 5 μm to about 50 μm.

### Claim 9 (depends on 6)

The cartridge of claim 6, wherein the binder particles of the plurality have a maximum dimension ranging from about 100 μm to about 10,000 μm.

### Claim 10 (depends on 6)

The cartridge of claim 6, wherein the plurality of binder particles comprise at least one absorbent material selected from the group consisting of sodium oxide, sodium hydroxide, calcium oxide, calcium hydroxide, potassium hydroxide, lithium hydroxide, lithium peroxide, lithium carbonate, and lithium chloride.

### Claim 11 (depends on 6)

The cartridge of claim 6, wherein the internal cavity of the housing comprising a first partition and a second partition fluidically isolated from the first partition, wherein the proximal ends of the hollow fibers of the plurality extend into the first partition while the distal ends of the hollow fibers of the plurality and the plurality of binder particles reside within the second partition such that flow of blood through the housing is restricted to flow through the plurality of hollow fibers.

### Claim 12 (depends on 6)

The cartridge of claim 6, wherein the absorption medium removes carbon dioxide from the blood at a rate ranging from about 50 mL/min to about 100 mL/min as measured at about atmospheric pressure and at a temperature from about 35° C. to about 39° C.

### Claim 13 (depends on 6)

The cartridge of claim 6, wherein the blood flows through the absorption medium at a rates ranging from about 0.2 L/min to about 0.5 L/min.

### Claim 14 (depends on 6)

A blood treatment system comprising:
the carbon dioxide absorption cartridge of claim 6;
a first blood flow pathway extending between a patient and the inlet port of the housing of the carbon dioxide absorption cartridge; and
a second blood flow pathway extending between the outlet port of the housing of the carbon dioxide absorption cartridge and the patient.

### Claim 15 (depends on 14)

The blood treatment system of claim 14, further comprising:
a pump configured to pump blood between the patient and the carbon dioxide absorption cartridge along the first and second blood flow pathways.

### Claim 16 (depends on 14)

The blood treatment system of claim 14, further comprising:
a dialyzer along the first blood flow pathway or the second blood flow pathway and configured to perform hemodialysis.

### Claim 17

A method for removing carbon dioxide from blood, the method comprising:
transporting blood from a patient to a carbon dioxide absorption cartridge, the carbon dioxide absorption cartridge comprising:
a housing having an internal cavity therein; and
a carbon dioxide absorption medium disposed within the internal cavity of the housing, the carbon dioxide absorption medium comprising a plurality of hollow fibers, each hollow fiber of the plurality having a proximal end, a distal end, a lumen extending between the proximal and distal ends, and a wall surrounding the lumen, the wall of each hollow fiber of the plurality comprising a membrane selectively permeable to gaseous carbon dioxide and a plurality of binder particles dispersed between hollow fibers of the plurality, each binder particle of the plurality being configured to absorb gaseous carbon dioxide and bind the carbon dioxide in a solid state;
moving the blood through the carbon dioxide absorption cartridge, thereby removing carbon dioxide from the blood; and
transporting the blood from the carbon dioxide absorption cartridge to the patient,
wherein neither a carrier fluid flow nor a sweep fluid flow is required for removing carbon dioxide from the blood of the patient.

### Claim 18 (depends on 17)

The method of claim 17, wherein the membrane comprising the wall of each hollow fiber of the plurality comprises at least one polymer selected from the group consisting of cellulose acetate, cellulose triacetate, polyamide, polysulfone, polyethersulfone (PES), polyacrylonitrile (PAN), sulfonated polyacrylonitrile, polymethylmethacrylate (PmmA), and polymethylpentene (PMP).

### Claim 19 (depends on 17)

The method of claim 17, wherein the wall of each hollow fiber of the plurality has an outer thickness ranging from about 5 μm to about 50 μm and the binder particles of the plurality have a maximum dimension ranging from about 100 μm to about 10,000 μm.

### Claim 20 (depends on 17)

The method of claim 17, wherein the plurality of binder particles comprise at least one absorbent material selected from the group consisting of sodium oxide, sodium hydroxide, calcium oxide, calcium hydroxide, potassium hydroxide, lithium hydroxide, lithium peroxide, lithium carbonate, and lithium chloride.

### Claim 21 (depends on 17)

The method of claim 17, wherein carbon dioxide is removed from the blood at a rate ranging from about 50 mL/min to about 100 mL/min.

### Claim 22 (depends on 17)

The method of claim 17, wherein blood flows through carbon dioxide absorption cartridge at a range ranging from about 0.2 L/min to about 0.5 L/min.

### Claim 23 (depends on 6)

The cartridge of claim 6, wherein neither a carrier fluid flow nor a sweep fluid flow is required for removing carbon dioxide from the blood of the patient.