Medical valve

1. A valve for use in an endoscope, the valve comprising:

a proximal valve stem member having a first lumen extending from a proximal opening at a proximalmost end of the proximal valve stem member to a distal opening at a distalmost end of the proximal valve stem member, wherein a membrane within the first lumen forms a fluid-tight barrier between the proximal opening and the distal opening; and

a distal valve stem member having a second lumen with a proximal opening at a proximalmost end of the distal valve stem member;

wherein the proximalmost end of distal valve stem member is received within the distal opening of the first lumen, and wherein the distal valve stem is movable relative to the proximal valve stem member;

wherein the valve has a first configuration for delivering air to an air channel of the endoscope, a second configuration for delivering water to a water channel of the endoscope, and a third configuration for delivering water to the air channel of the endoscope, and wherein, in the first and second configurations, the proximalmost end of the distal valve stem member is distal to an original location of the membrane, and, wherein transitioning from the second configuration to the third configuration includes puncturing the membrane and moving the proximalmost end of the distal valve stem to a position proximal to the original location of the membrane.

2. The valve of claim 1 , wherein the distal valve stem member has a shoulder that is contacted by the distalmost end of the proximal valve stem member in the third configuration.

3. The valve of claim 1 , wherein the proximal valve stem member includes a first aperture formed through a wall of the proximal valve stem member, and wherein the first aperture is in fluid communication with the first lumen.

4. The valve of claim 3 , wherein the proximal valve stem member includes a second aperture formed through the wall of the proximal valve stem member, and wherein the second aperture is in fluid communication with the first lumen.

5. The valve of claim 1 , wherein the second lumen is closed at a distalmost end of the second lumen.

6. The valve of claim 5 , wherein the distal valve stem member has a third aperture formed through a wall of the distal valve stem member, and wherein the third aperture is in fluid communication with the second lumen.

7. The valve of claim 1 , wherein the proximal valve stem member includes a button configured to be contacted by a finger of an operator.

8. The valve of claim 7 , wherein a proximal surface of the button is at the proximalmost end of the proximal valve stem member.

9. The valve of claim 7 , wherein the proximal valve stem member includes at least one tab on a distal surface of the button.

10. The valve of claim 1 , wherein at least one seal is disposed on an external surface of the distal valve stem member.

11. The valve of claim 1 , wherein at least one O-ring seal is disposed on an external surface of the proximal valve stem member.

12. The valve of claim 1 , wherein a one-way seal is disposed on an external surface of the proximal valve stem member.

13. A valve for use in an endoscope, the valve comprising:

a proximal valve stem member having a first lumen extending from a proximal opening at a proximalmost end of the proximal valve stem member to a distal opening at a distalmost end of the proximal valve stem member, wherein a membrane within the first lumen forms a fluid-tight barrier between the proximal opening and the distal opening; and

a distal valve stem member received within the distal opening of the first lumen;

wherein, in a first configuration of the valve, the valve is capable of delivering air to an air channel of the endoscope, in a second configuration of the valve, the valve is capable of delivering water to a water channel of the endoscope, and, in a third configuration of the valve, the valve is capable of delivering water to the air channel of the endoscope, wherein, in the first and second configurations, the proximalmost end of the distal valve stem member is distal to an original location of the membrane, and, in the third configuration, the membrane is punctured and the proximalmost end of the distal valve stem is proximal to the original location of the membrane.

14. The valve of claim 13 , wherein the distal valve stem member has a second lumen with a proximal opening at a proximalmost end of the distal valve stem member, wherein, in the first configuration, the first lumen and the second lumen are not in fluid communication, and wherein, in the second configuration, the first lumen and the second lumen are in fluid communication.

15. The valve of claim 14 , wherein the second lumen is closed at a distalmost end of the second lumen, wherein the distal valve stem member has an aperture formed through a wall of the distal valve stem member, and wherein the aperture is in fluid communication with the second lumen.

16. The valve of claim 13 , wherein the proximal valve stem member includes first and second apertures through a wall of the proximal valve stem member, and wherein each of the first and second aperture is in fluid communication with the first lumen.

17. A method of delivering air and water, the method comprising:

via a valve in a first configuration, delivering air to an air channel of a medical device;

transitioning the valve from the first configuration to a second configuration to deliver water to a water channel of the medical device; and

transitioning the valve from the second configuration to a third configuration to deliver the water to the air channel of the medical device,

wherein the valve includes:

a proximal valve stem member having a first lumen extending from a proximal opening at a proximalmost end of the proximal valve stem member to a distal opening at a distalmost end of the proximal valve stem member, wherein a membrane within the first lumen forms a fluid-tight barrier between the proximal opening and the distal opening; and

a distal valve stem member received within the distal opening of the first lumen:

wherein, in the first and second configurations, the proximalmost end of the distal valve stem member is distal to an original location of the membrane, and, wherein transitioning from the second configuration to the third configuration includes puncturing the membrane and moving the proximalmost end of the distal valve stem to a position proximal to the original location of the membrane.

18. The method of claim 17 , further comprising transitioning the valve to the first configuration by covering a proximal hole of the valve; and wherein

transitioning the valve to the second configuration includes depressing the valve part-way; and

transitioning the valve to a third configuration includes fully depressing the valve.

19. The valve of claim 13 , wherein, in the first configuration, a proximal hole of the valve is covered, in the second configuration the valve is depressed part-way, and in the third configuration, the valve is fully depressed.

20. The valve of claim 13 , wherein the proximal valve stem member includes a button configured to be contacted by a finger of an operator.