REPERFUSION PROTECTION IN RESUSCITATION

• US 20150157816A1
• Filed: 10/29/2014
• Published: 06/11/2015
• Est. Priority Date: 01/24/2006
• Status: Active Grant

• Current Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Original Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Inventors: Freeman, Gary A., Silver, Annemarie
• Granted Patent: US 10,071,218 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61M 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 16/12 by mixing different gases
• CPC Class Codes: A61M 2016/0413 with detectors of CO2 in exhaled gases
• CPC Class Codes: A61M 2202/0007 introduced into the body
• CPC Class Codes: A61M 2202/0225 Carbon oxides, e.g. Carbon dioxide
• CPC Class Codes: A61M 2205/3313 used specific wavelengths
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2230/04 Heartbeat characteristics, e.g. ECG, blood pressure modulation
• CPC Class Codes: A61M 2230/202 partial carbon oxide pressure, e.g. partial dioxide pressure (P-CO2)
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)
• CPC Class Codes: A61M 2230/208 pH-value
• CPC Class Codes: A61M 2230/432 partial CO2 pressure (P-CO2)

Abstract

An apparatus and method for resuscitating a patient suffering from cardiac arrest or another condition in which normal circulation has been interrupted. A ventilator is used for delivering a gas mixture to the patient. The ventilator is configured to adjust the partial pressure of CO2 to one or more partial pressures high enough to slow expiration of CO2 from the patient'"'"'s lungs and thereby maintain a reduced pH in the patient'"'"'s tissues for a period of time following return of spontaneous circulation.

Claims

1. A medical system comprising:

at least one sensor configured to monitor a partial pressure of carbon dioxide (PCO₂) of a tissue of a patient and to generate a signal representing the tissue PCO₂ level; and

a processor communicably coupled to the at least one sensor, the processor configured to receive the signal and generate an instruction configured to result in a ventilator delivering a gas mixture to a patient, wherein the instruction is configured to result in the ventilator adjusting a partial gas pressure of CO₂ in the gas mixture to one or more partial pressures high enough to slow expiration of CO₂ from the patient'"'"'s lungs and thereby maintain an increased PCO₂ in the patient'"'"'s tissues for a period of time following return of spontaneous circulation.

2. The medical system of claim 1, further comprising a ventilator, wherein the processor is communicably coupled to the ventilator and is configured to provide the instruction to the ventilator.

3. The medical system of claim 1, wherein the processor is further configured to cause the instruction to be displayed to a clinician.

4. The medical system of claim 1, wherein the at least one sensor comprises an optical sensor used to perform near infrared spectroscopy (NIRS).

5. The medical system of claim 1, wherein the at least one sensor is configured to determine the pH of the patient'"'"'s tissue, and wherein the processor is further configured to receive the pH, wherein the instruction is configured to result in the ventilator adjusting the partial gas pressure of CO₂ in the gas mixture at least in part in response to the pH.

6. The medical system of claim 5, wherein the instruction is configured to result in the ventilator adjusting the partial gas pressure of CO₂ in the gas mixture so as to maintain the pH at a constant level for a first portion of the period of time.

7. The medical system of claim 6, wherein the instruction is configured to result in the ventilator adjusting the partial gas pressure of CO₂ in the gas mixture so as to cause the pH to increase at a first rate during a second portion of the period of time.

8. The medical system of claim 7, wherein the first rate comprises no more than 0.4 pH units/minute.

9. The medical system of claim 7, wherein the instruction is configured to result in the pH increasing during the second portion of the period of time such that the absolute value of the pH at the end of the second portion of the period of time is no more than 6.8.

10. The medical system of claim 7, wherein the instruction is configured to result in the ventilator adjusting the partial gas pressure of CO₂ in the gas mixture so as to cause the pH to increase at a second rate during a third portion of the period of time.

11. The medical system of claim 10, wherein the sensor is configured to determine the pH of the patient'"'"'s tissue during the third portion of the period of time, and wherein:

if the pH during the third portion of the period of time is less than 6.8, the second rate comprises approximately 0.4 pH units/minute or less; and

if the pH during the third portion of the period of time is greater than 7, the second rate comprises approximately 0.2 pH units/minutes or less.

12. The medical system of claim 10, wherein each of the first, second, and third portions of the period of time comprises up to approximately five minutes.

13. A method of resuscitating a patient suffering from cardiac arrest or another condition in which normal circulation has been interrupted, the method comprising:

determining, using near infrared spectroscopy (NIRS), a partial pressure of carbon dioxide of a tissue (tissue PCO₂) of a patient who is undergoing cardiac arrest; and

delivering, using a ventilator, a gas mixture to the patient, wherein the ventilator is configured to adjust a partial gas pressure of CO₂ in the gas mixture to one or more partial pressures high enough to slow expiration of CO₂ from the patient'"'"'s lungs and thereby maintain an increased tissue PCO₂ for a period of time following return of spontaneous circulation.

14. The method of claim 13, further comprising providing, to the ventilator, a signal representing the tissue PCO₂.

15. The method of claim 13, further comprising:

determining the pH of a tissue of the patient; and

adjusting, using the ventilator, the partial gas pressure of CO₂ in the gas mixture at least in part in response to the pH.

16. The method of claim 15, wherein the partial gas pressure of CO₂ in the gas mixture is adjusted so as to maintain the pH at a constant level for a first portion of the period of time.

17. The method of claim 16, wherein the partial gas pressure of CO₂ in the gas mixture is adjusted so as to cause the pH to increase at a first rate during a second portion of the period of time.

18. The method of claim 16, wherein the first rate comprises no more than 0.4 pH units/minute.

19. The method of claim 17, wherein the partial gas pressure of CO₂ in the gas mixture is adjusted so as to cause the pH to increase during the second portion of the period of time such that the absolute value of the pH at the end of the second portion of the period of time is no more than 6.8.

20. The method of claim 17, wherein the partial gas pressure of CO₂ in the gas mixture is adjusted so as to cause the pH to increase at a second rate during a third portion of the period of time.

21. The method of claim 20, further comprising determining the pH of the patient'"'"'s tissue during the third portion of the period of time, wherein:

if the pH during the third portion of the period of time is less than 6.8, the second rate comprises approximately 0.4 pH units/minute; and

if the pH during the third portion of the period of time is greater than 7, the second rate comprises 0.2 pH units/minute.

22. The method of claim 20, wherein each of the first, second, and third portions of the period of time comprises five minutes.

23. A medical system comprising:

at least one sensor configured to monitor, using near infrared spectroscopy (NIRS), a tissue pH of a patient and to generate a signal representing the tissue pH; and

a processor communicably coupled to the at least one sensor, the processor configured to generate an instruction configured to result in a ventilator adjusting a partial gas pressure of CO₂ in the gas mixture at least in part in response to the tissue pH.