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1. WO2020223587 - CALCULATING CARDIAC OUTPUT OF A PATIENT UNDERGOING VENO-VENOUS EXTRACORPOREAL BLOOD OXYGENATION

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[ EN ]

CLAIMS

1. A method for calculating cardiac output of a patient undergoing veno-venous extracorporeal blood oxygenation, the method comprising:

(a) establishing a blood flow rate from an extracorporeal blood oxygenation circuit into a venous portion of a circulatory system of a patient;

(b) measuring the blood flow rate of the extracorporeal blood oxygenation circuit;

(c) establishing a first removal rate of carbon dioxide from the blood in an oxygenator in the extracorporeal blood oxygenation circuit;

(d) determining through at least one of a representative parameter or a surrogate of each of (i) a first arterial carbon dioxide content and (ii) a first carbon dioxide content of the blood delivered to the patient after passing the oxygenator corresponding to the first removal rate of carbon dioxide from the blood;

(e) establishing a second removal rate of carbon dioxide from the blood in the oxygenator in the extracorporeal blood oxygenation circuit;

(f) determining through at least one of a representative parameter or a surrogate each of (i) a second arterial carbon dioxide content and (ii) a second carbon dioxide content of the blood delivered to the patient after passing the oxygenator corresponding to the second removal rate of carbon dioxide from the blood; and

(g) calculating a cardiac output of the patient corresponding to the blood flow rate, the first arterial carbon dioxide content and the first carbon dioxide content in the blood delivered to the patient after passing the oxygenator corresponding to the first removal rate of carbon dioxide from the blood, and the second arterial carbon dioxide content and the second carbon dioxide content in the blood delivered to the patient after passing the oxygenator corresponding to the second removal rate of carbon dioxide from the blood.

2. The method of Claim 1, wherein the first removal rate of carbon dioxide from the blood in the oxygenator in the extracorporeal blood oxygenation circuit includes establishing a first sweep gas flow rate through the oxygenator.

3. The method of Claim 1, further comprising measuring a recirculation in the extracorporeal blood oxygenation circuit and adjusting the calculated cardiac output

corresponding to the measured recirculation.

4. The method of Claim 1, wherein measuring the blood flow rate is provided by a pump in the extracorporeal blood oxygenation circuit.

5. The method of Claim 1, further comprising operably connecting a first dilution sensor to a venous line of the extracorporeal blood oxygenation circuit and a second dilution sensor to an arterial line of the extracorporeal blood oxygenation circuit.

6. The method of Claim 5, further comprising measuring a recirculation including introducing an indicator into the extracorporeal blood oxygenation circuit upstream of the second dilution sensor and downstream of the first dilution sensor.

7. The method of Claim 6, wherein measuring the recirculation includes sensing a dilution indicator with the first dilution sensor.

8. A method for calculating cardiac output of a patient undergoing veno-venous extracorporeal blood oxygenation, the method comprising:

(a) establishing a blood flow rate from an extracorporeal blood oxygenation circuit into a venous portion of a circulatory system of a patient;

(b) measuring the blood flow rate of the extracorporeal blood oxygenation circuit;

(c) establishing a first exchange rate of a gas with the blood in the extracorporeal blood oxygenation circuit;

(d) measuring a first value of a blood parameter in an arterial portion of the patient circulatory system corresponding to the first exchange rate;

(e) measuring a first value of the blood parameter of the blood delivered to the patient corresponding to the first exchange rate;

(f) establishing a second exchange rate of the gas with the blood in the extracorporeal blood oxygenation circuit;

(g) measuring a second value of the blood parameter in the arterial portion of the patient circulatory system corresponding to the second exchange rate;

(h) measuring a second value of the blood parameter of the blood delivered to the patient corresponding to the second exchange rate; and

(i) calculating a cardiac output of the patient corresponding to the blood flow rate, the first value of a blood parameter in an arterial portion of the patient circulatory system

corresponding to the first exchange rate, the first value of the blood parameter of the blood delivered to the patient corresponding to the first exchange rate, the second value of the blood parameter in the arterial portion of the patient circulatory system corresponding to the second exchange rate, and the second value of the blood parameter of the blood delivered to the patient corresponding to the second exchange rate.

9. The method of Claim 8, wherein the gas is carbon dioxide.

10. The method of Claim 8, further comprising measuring a recirculation in the extracorporeal blood oxygenation circuit and adjusting the calculated cardiac output

corresponding to the measured recirculation.

11. The method of Claim 8, wherein measuring the blood flow rate is provided by a pump in the extracorporeal blood oxygenation circuit.

12. The method of Claim 8, further comprising connecting a first dilution sensor to a venous line of the extracorporeal blood oxygenation circuit and a second dilution sensor to an arterial line of the extracorporeal blood oxygenation circuit.

13. The method of Claim 12, further comprising measuring a recirculation, wherein measuring the recirculation includes introducing an indicator into the extracorporeal blood oxygenation circuit upstream of the second dilution sensor and downstream of the first dilution sensor.

14. The method of Claim 8, wherein measuring the first value of the blood parameter of the blood delivered to the patient corresponding to the first exchange rate includes measuring the first value of the blood parameter of the blood prior to the blood entering the patient circulatory system.

15. The method of Claim 8, wherein measuring the second value of the blood parameter of the blood delivered to the patient corresponding to the second exchange rate includes

measuring the second value of the blood parameter of the blood prior to the blood entering the patient circulatory system.

16. An apparatus for quantifying a cardiac output of a patient operably connected to an extracorporeal blood oxygenation circuit, the extracorporeal blood oxygenation circuit having a venous line withdrawing blood from a circulatory system of the patient, a blood oxygenator, a pump and an arterial line returning oxygenated blood to a venous portion of the circulatory system, the apparatus comprising:

(a) a controller configured to connect to one of the blood oxygenator and the pump, the controller configured to calculate a cardiac output of the patient based on a measured flow rate of oxygenated blood from the extracorporeal blood oxygenation circuit, a first arterial carbon dioxide content and a first carbon dioxide content of the blood delivered to the patient circulatory system corresponding to a first gas removal rate in the blood oxygenator in the extracorporeal blood oxygenation circuit; and a second arterial carbon dioxide content and a second carbon dioxide content of the blood delivered to the patient circulatory system corresponding to a second gas removal rate in the oxygenator in the extracorporeal blood oxygenation circuit.

17. The apparatus of Claim 16, further comprising an indicator injection port in the venous line.

18. The apparatus of Claim 16, wherein the controller is further configured to calculate a recirculation.

19. The apparatus of Claim 16, wherein the first gas removal rate in the blood oxygenator corresponds to a first flow rate of sweep gas though the blood oxygenator.