Administration and monitoring of nitric oxide in ex vivo fluids
Described are systems and methods for monitoring administration of nitric oxide (NO) to ex vivo fluids. Examples of such fluids include blood in extracorporeal membrane oxygenation (ECMO) circuits or perfusion fluids used for preserving ex vivo organs prior to transplanting in a recipient. The systems and methods described herein provide for administering nitric oxide to the fluid, monitoring nitric oxide or a nitric oxide marker in the fluid, and adjusting the nitric oxide administration.
1. A method of preserving an ex vivo liver for transplant comprising:
persufflating the liver with a persufflation gas comprising nitric oxide (NO);
monitoring one or more persufflation parameters in (i) the liver and/or (ii) a preservation fluid used to store the liver during persufflation; and
adjusting the amount of NO provided to the liver by the persufflation gas based on the monitoring of the one or more persufflation parameters,
wherein the one or more persufflation parameters includes an indicator of tissue damage, and
wherein the indicator of tissue damage includes aspartate aminotransferase (AST), alanine aminotransferase (ALT), or combinations thereof.
2. The method of claim 1 , wherein the concentration of NO in the persufflation gas is in the range from 0.1 ppm to 300 ppm.
3. The method of claim 1 , wherein the persufflation gas further comprises oxygen, air, and/or carrier gases.
4. The method of claim 3 , wherein the carrier gasses are nitrogen and/or helium.
5. The method of claim 1 , wherein the monitoring is performed continuously or intermittently.
6. The method of claim 1 , wherein the adjusting the amount of NO is performed continuously or intermittently.
7. The method of claim 1 , further comprising perfusing the liver with a perfusion fluid comprising NO and/or a NO donor.
8. The method of claim 7 , wherein the liver is perfused with the perfusion fluid before the liver is persufflated with the persufflation gas.
9. The method of claim 7 , further comprising:
monitoring one or more perfusion parameters in the perfusion fluid and/or in the liver itself; and
adjusting the amount of NO and/or NO donor provided to the liver by the perfusion fluid based on the monitoring of the one or more perfusion parameters.
10. The method of claim 9 , wherein the one or more perfusion parameters is selected from the group consisting of NO, a NO marker, an indicator of tissue damage, or combinations thereof.
11. The method of claim 9 , wherein adjusting one or more of (i) the amount of NO provided to the liver by the persufflation gas or (ii) the amount of NO provided to the liver by the perfusion fluid comprises adjusting the NO concentration in a flow of gas delivered to the persufflation gas or perfusion fluid, respectively and/or adjusting the flow rate of the gas delivered to the persufflation gas or perfusion fluid, respectively.
12. The method of claim 9 , wherein the perfusion fluid comprises red blood cells.
13. The method of claim 12 , further comprising oxygenating the perfusion fluid before perfusing the liver.
14. The method of claim 9 , wherein monitoring the NO marker in the perfusion fluid comprises monitoring methemoglobin.
15. The method of claim 9 , wherein the viability of the liver is increased by the persufflation and/or perfusion with NO and/or NO donor when the NO administration is adjusted based on the monitoring of the one or more persufflation parameters and/or the one or more perfusion parameters.