Systems and methods for ex vivo lung care
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.
1. A method of measuring reoxygenation time of an ex-vivo human lung, the method comprising:
circulating a perfusion fluid through the ex-vivo lung, the perfusion fluid entering the ex-vivo lung through a pulmonary artery interface and leaving the ex-vivo lung through a left atrial interface;
ventilating the ex-vivo lung by flowing a ventilation gas through a tracheal interface;
deoxygenating the perfusion fluid until a predetermined first value of oxygen content in the perfusion fluid is reached;
holding the perfusion fluid at the predetermined first value of the oxygen content;
halting ventilation or initiating a purge cycle;
reoxygenating the perfusion fluid by ventilating the ex-vivo lung with an oxygenation gas until a predetermined second value of the oxygen content in the perfusion fluid is reached; and
measuring an ex-vivo lung reoxygenation time as a time taken for the ex-vivo lung to cause the oxygen content in the perfusion fluid to change from the predetermined first value of the oxygen content to the predetermined second value of the oxygen content.
2. The method of claim 1 , wherein the deoxygenating perfusion fluid comprises ventilating the ex-vivo lung with a deoxygenation gas comprising CO 2 .
3. The method of claim 2 wherein the deoxygenation gas comprises approximately 6% CO 2 .
4. The method of claim 1 , wherein the deoxygenating the perfusion fluid comprises circulating the perfusion fluid through a gas exchange device, the gas exchange device being in fluid communication with a deoxygenation gas comprising CO 2 and N 2 , the gas exchange device removing oxygen from the perfusion fluid by gas exchange between the deoxygenation gas and the perfusion fluid.
5. The method of claim 4 , wherein the deoxygenation gas comprises approximately 6% CO 2 and approximately 94% N 2 .
6. The method of claim 1 , wherein the deoxygenating the perfusion fluid comprises ventilating the ex-vivo lung with a deoxygenation gas comprising CO 2 and N 2 .
7. The method of claim 1 , wherein the oxygenation gas is air.
8. The method of claim 1 , wherein the oxygenation gas contains between approximately 25% and 100% oxygen.
9. The method of claim 1 , wherein the perfusion fluid flows through a perfusion circuit at a rate of approximately 1.5 liters per minute.
10. The method of claim 1 , further comprising evaluating the ex-vivo lung while the ex-vivo lung is being transported.
11. The method of claim 1 , further comprising maintaining the perfusion fluid at a near physiologic temperature.
12. The method of claim 1 , wherein the perfusion fluid comprises a blood product.
13. The method of claim 12 , wherein the perfusion fluid is at least partially depleted of leukocytes.
14. The method of claim 12 , wherein the perfusion fluid is at least partially depleted of platelets.
15. The method of claim 1 , wherein the perfusion fluid comprises whole blood.
16. The method of claim 1 , comprising delivering one or more therapeutics to the ex-vivo lung during perfusion of the ex-vivo lung.
17. The method of claim 16 , wherein the one or more therapeutics are selected from antimicrobials, vasodilators, and anti-inflammatory drugs.
18. The method of claim 16 , wherein the one or more therapeutics are selected from a group consisting of prostaglandins, prostacyline, dextran, isuprel, flolan, and nitric oxide donors.
19. The method of claim 16 , wherein the one or more therapeutics are delivered through the tracheal interface through one of a nebulizer and a bronchoscope.