Systems and methods for ex vivo lung care

• US 9,462,802 B2
• Filed: 04/08/2008
• Issued: 10/11/2016
• Est. Priority Date: 01/31/2008
• Status: Active Grant

• Current Assignee: TransMedics, Inc. (TransMedics Group, Inc.)
• Original Assignee: TransMedics, Inc. (TransMedics Group, Inc.)
• Inventors: Fishman, Robert, Havener, Robert, Fattah, Ihab Abdel, Abdelazim, Anas, Newell, Scott, Bishop, Tom, Khayal, Tamer, Kyi, Stanley, Taylor, Ron, Harriott, Doug, De Remer, Matthew, Murray, Paul, Sullivan, John, Anderson, Mark, Bringham, Richard, Van Driel, Michael, Hassanein, Waleed
• Primary Examiner(s): HURST, JONATHAN M
• Application Number:
  US12/099,725
• Publication Number:
  US 20090197324A1
• Time in Patent Office: 3,108 Days
• Field of Search: 435/284.1
• US Class Current: 1/1
• CPC Class Codes: A01N 1/02 Preservation of living parts
• CPC Class Codes: A01N 1/021 Preservation or perfusion media, liquids, solids or gases used in the preservation of cells, tissue, organs or bodily fluids
• CPC Class Codes: A01N 1/0247 for perfusion, i.e. for circulating fluid through organs, blood vessels or other living parts

Abstract

Methods and systems of maintaining, evaluating, and providing therapy to a lung ex vivo. The methods and systems involve positioning the lung in an ex vivo perfusion circuit; circulating a perfusion fluid through the lung, the fluid entering the lung through a pulmonary artery interface and leaving the lung through a left atrial interface; and ventilating the lung by flowing a ventilation gas through a tracheal interface. Maintaining the lung for extended periods involves causing the lung to rebreath a captive volume of air, and reaching an equilibrium state between the perfusion fluid and the ventilation gas. Evaluating the gas exchange capability of the lung involves deoxygenating the perfusion fluid and measuring a time taken to reoxygenate the perfusion fluid by ventilating the lung with an oxygenation gas.

Claims

1. A lung chamber assembly comprising:

a housing having a bottom surface defining a first housing drain, and walls,

wherein the bottom surface defines a pooling region proximate to the first housing drain to collect perfusion fluid draining from a lung, and

wherein the bottom surface defines an overflow region proximate to the pooling region to collect overflow perfusion fluid from the pooling region;

a support surface for supporting a lung, the support surface defining a support surface drain for draining a perfusion fluid exiting the lung to the first housing drain;

a flexible wrap configured to wrap around the lung and maintain the lung in a physiologic configuration, the flexible wrap comprising one or more holes for draining perfusate from the lung to the support surface;

an openable lid that provides a sealable connection to the walls of the housing;

a first perfusion interface for allowing a flow of the perfusion fluid into the lung;

a ventilation interface that allows for ventilation of the lung by a ventilator device; and

a second perfusion interface for allowing a flow of the perfusion fluid away from the lung.

2. The assembly of claim 1, wherein:

the bottom surface of the housing defines a second housing drain;

the first drain is a measurement drain that is in fluid communication with a sensor configured to sense a gas content of the perfusion fluid; and

the second drain is a main drain that is in fluid communication with a reservoir.

3. The assembly of claim 2, wherein the pooling region is configured to collect perfusion that feeds the measurement drain, the measurement drain having a drainage flow rate less than a flow rate of the perfusion fluid away from the lung.

4. The assembly of claim 3, wherein a flow of perfusion fluid overflowing the pooling region flows toward the overflow region and main drain.

5. The assembly of claim 2, wherein the housing further comprises a wall extending from the bottom surface and partially surrounding the measurement drain, the wall partially blocking a flow of perfusion fluid from the measurement drain to the main drain, the wall promoting formation of a pool of perfusion fluid proximate the measurement drain.

6. The assembly of claim 1, wherein the first perfusion interface includes a pulmonary artery cannula, a proximal portion of the cannula being connected to a perfusion fluid circuit and a distal portion of the cannula being connected to a pulmonary artery of the lung.

7. The assembly of claim 6, wherein a wall of the housing defines an opening for sealably engaging an outer surface of the pulmonary cannula with the housing.

8. The assembly of claim 6, wherein the pulmonary artery cannula further includes a pressure transducer connector, the pressure transducer connector defining an opening into a lumen of the cannula near the distal end of the cannula.

9. The assembly of claim 8, wherein the pressure transducer connector provides a channel for a pressure transducer within the cannula to be remotely vented.

10. The assembly of claim 8, further including a pressure transducer positioned near a point of entry of the perfusion fluid into the pulmonary artery, the pressure transducer being connected to an external controller by a pressure transducer cable, the cable passing through the pressure transducer connector and a pressure transducer conduit.

11. The assembly of claim 10, wherein a wall of the housing defines an opening for sealably engaging an external surface of the pressure transducer conduit.

12. The assembly of claim 1, further comprising a second ventilation interface that includes a tracheal cannula having a distal insertion portion for insertion into a trachea of the lungs, a proximal connector portion for connecting to a gas circuit for ventilating the lung, and a locking mechanism adjacent to the connector portion.

13. The assembly of claim 12, wherein a wall of the housing defines an opening for sealably engaging the tracheal cannula locking mechanism with the housing.

14. The assembly of claim 12, wherein the tracheal insertion portion has a diameter of about 0.65 inches to 0.95 inches.

15. The assembly of claim 12, wherein the insertion portion is bounded at a distal end and a proximal end by a rib, the rib having a diameter about 0.2 greater than a diameter of the insertion portion.

16. The assembly of claim 1, wherein the second perfusion interface includes a left atrial cuff exposed to the lung chamber assembly for allowing the perfusion fluid to flow from the lung to support surface drain.

17. The assembly of claim 1, wherein the second perfusion interface includes a connection between a left atrial cuff and a cannula.

18. The assembly of claim 17, wherein the cannula is in fluid communication with a conduit that directs the perfusion fluid to a perfusion gas content sensor and to a reservoir.

19. The assembly of claim 17, wherein the cannula directs the perfusion fluid to the support surface drain.

20. The assembly of claim 17, wherein the cannula has a cage-like structure for achieving a low contact area between the cannula and the left atrial cuff.

21. The assembly of claim 17, wherein the cannula is configured to hold open the left trial cuff.

22. The assembly of claim 17, wherein the cannula further includes a lumen and a connector for connecting to a pressure transducer positioned inside the cannula.

23. A lung chamber assembly comprising:

a housing having a bottom surface including at least one housing drain, and walls;

a support surface for supporting a lung, the support surface defining a drain for draining a perfusion fluid exiting the lung to the first housing drain;

a flexible wrap configured to wrap around the lung and maintain the lung in a physiologic configuration, the flexible wrap comprising one or more holes for draining perfusate from the lung to the support surface;

an openable lid that provides a sealable connection to the walls of the housing;

a first perfusion interface for allowing a flow of the perfusion fluid into the lung;

a ventilation interface that allows ventilation of the lung by a ventilator; and

a second perfusion interface for allowing a flow of the perfusion fluid away from the lung;

wherein the first perfusion interface includes at least one connector portion, and at least one insertion tube attached to a distal end of the connector portion and disposed at an angle relative to the connection portion, and wherein the insertion tube is made of a bio inert material having a hardness between about 50 Shore A and 90 Shore A for suturing the insertion tube to a pulmonary artery.