SYSTEMS AND METHODS FOR EX VIVO LUNG CARE

• US 20090197324A1
• Filed: 04/08/2008
• Published: 08/06/2009
• Est. Priority Date: 01/31/2008
• Status: Active Grant

• Current Assignee: TransMedics, Inc. (TransMedics Group, Inc.)
• Original Assignee: TransMedics, Inc. (TransMedics Group, Inc.)
• Inventors: Hassanein, Waleed, SULLIVAN, John, FATTAH, Ihab Abdel, BRINGHAM, Richard, BISHOP, Tom, KYI, Stanley, VAN DRIEL, Michael, NEWELL, Scott, ABDELAZIM, Anas, DE REMER, Matthew, HARRIOTT, Doug, MURRAY, Paul, KHAYAL, Tamer, HAVENER, Robert, ANDERSON, Mark, FISHMAN, Robert, TAYLOR, Ron
• Granted Patent: US 9,462,802 B2
• Time in Patent Office: Days
• US Class Current: 435/284.1
• 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 including at least one housing drain, and walls;

a support surface for supporting a lung, the support surface defining a drain and drainage channels leading to the drain for draining a perfusion fluid exiting the lung;

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

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

a second interface for allowing ventilation of the lung; and

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

2. The assembly of claim 1, wherein the housing includes a drain system for carrying the flow of the perfusion fluid away from the lung, the drain system comprising a measurement drain for directing a part of the perfusion fluid flow to a sensor of a perfusion fluid gas content and a main drain for receiving a remaining part of perfusion fluid flow.

3. The assembly of claim 2, wherein the drain system further comprises a region for collecting the flow of perfusion fluid away from the lung into a pool that feeds the measurement drain, the measurement drain having a drainage capacity 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 region flows to the main drain.

5. The assembly of claim 2, wherein the drain system further comprises a wall 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 above the measurement drain.

6. The assembly of claim 1, wherein the first 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, wherein the second interface includes a tracheal cannula having a distal insertion portion for insertion into the trachea, 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 third 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 third 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 atrial 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.