Reperfusion protection in resuscitation

• US 20070169779A1
• Filed: 01/24/2006
• Published: 07/26/2007
• Est. Priority Date: 01/24/2006
• Status: Abandoned Application

• Current Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Original Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Inventors: Freeman, Gary
• Application Number:
  US11/339,307
• Publication Number:
  US 20070169779A1
• Time in Patent Office: Days
• US Class Current: 128/204.180
• CPC Class Codes: A61M 16/0081 Bag or bellow in a bottle
• CPC Class Codes: A61M 16/12 by mixing different gases
• CPC Class Codes: A61M 16/202 electrically actuated
• 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 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/202 partial carbon oxide pressure, e.g. partial dioxide pressure (P-CO2)
• CPC Class Codes: A61M 2230/208 pH-value
• CPC Class Codes: A61M 2230/40 Respiratory characteristics

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. Resuscitation apparatus for resuscitating a patient suffering from cardiac arrest or another condition in which normal circulation has been interrupted, the apparatus comprising:

a ventilator for delivering a gas mixture to the patient,

wherein the ventilator includes apparatus 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.

2. The apparatus of claim 1 wherein the partial pressure of CO₂ is adjusted to be higher than ambient CO₂ partial pressure during the period of time.

3. The apparatus of claim 1 wherein adjustment of the partial pressure of CO₂ includes adding CO₂ to the gas inspired by the patient.

4. The apparatus of claim 1 further comprising a sensor and associated processing for measuring a physiological status of the patient, wherein the partial pressure of CO₂ is adjusted at least in part in response to the output of the sensor.

5. The apparatus of claim 4 wherein the sensor and associated processing are configured to detect return of spontaneous circulation, and wherein the partial pressure of CO₂ is changed in response to detection of return of spontaneous circulation.

6. The apparatus of claim 1 wherein the period of time is greater than 30 seconds.

7. The apparatus of claim 6 wherein the period of time is greater than 3 minutes.

8. The apparatus of claim 5 wherein the sensor comprises a CO₂ sensor.

9. The apparatus of claim 1 wherein adjustment of the partial pressure of CO₂ has the effect of maintaining the pH of the patient'"'"'s tissues below 7.0 for the period of time following return of spontaneous circulation.

10. The apparatus of claim 9 wherein the pH of the patient'"'"'s tissues is maintained below 6.8.

11. The apparatus of claim 10 wherein the pH of the patient'"'"'s tissues is maintained below 6.5.

12. The apparatus of claim 1 further comprising a defibrillator.

13. The apparatus of claim 1 further comprising a chest compressor.

14. The apparatus of claim 1 further comprising an infuser.

15. The apparatus of claim 1 further comprising a sensor and associated processing for determining the pH of the patient'"'"'s tissue, wherein the partial pressure of CO₂ is adjusted at least in part in response to the pH of the patient'"'"'s tissue.

16. The apparatus of claim 15 wherein the partial pressure of CO₂ is adjusted to maintain tissue pH below 6.8 for a period of time following return of spontaneous circulation.

17. The apparatus of claim 1 wherein the partial pressure of CO₂ is gradually lowered over at least a portion of the period of time so as to gradually raise the pH of the patient'"'"'s tissues.

18. The apparatus of claim 1 further comprising processing using a mathematical model of the relationship between CO₂ retention in the patient and the pH of the patient'"'"'s tissues.

19. The apparatus of claim 18 wherein the mathematical model comprises processing using the Henderson-Hasselbalch equations.

20. The apparatus of claim 1 further comprising apparatus and processing for measuring the inspired volume and expired volume of CO₂ in the ventilation cycle, and using the inspired and expired volumes to adjust the partial pressure of CO₂.

21. The apparatus of claim 1 further comprising apparatus and processing for monitoring an E_tCO₂ level, and wherein the partial pressure of CO₂ is adjusted to maintain the E_tCO₂ level above a level found in the arrest victim prior to the arrest.

22. The apparatus of claim 21 wherein the adjustment of the partial pressure of CO₂ is accomplished by adjusting the partial pressure between a lower level in a first cycle and a higher level in a second cycle, wherein in the first cycle the partial pressure of CO₂ is lower than a previously measured E_tCO₂ level, and wherein in the second cycle the partial pressure of CO₂ is higher than the previously measured E_tCO₂ level, and wherein the lower and higher levels are adjusted to maintain E_tCO₂ at a desired level.

23. The apparatus of claim 13 wherein the ventilator and chest compressor are controlled so that a ratio of chest compression rate to ventilation rate is less than 15:

2 during at least a portion of the period of time following return of spontaneous circulation.

24. The apparatus of claim 23 wherein the ratio is less than 5:

1.

25. The apparatus of claim 24 wherein the ratio is about 6:

2.

26. The apparatus of claim 1 further comprising a fluid infusion device.

27. The apparatus of claim 26 wherein the fluid infusion device is configured to infuse fluids containing metabolic substances during reperfusion.

28. The apparatus of claim 27 wherein the metabolic substances comprise amino acids.

29. The apparatus of claim 28 wherein the amino acids comprise aspartate, dihydroxyacetone phosphate or glutamate.

30. The apparatus of claim 1 further comprising a defibrillator, compressor, and infuser.

31. The apparatus of claim 30 wherein the defibrillator, compressor, ventilator, and infuserare separate devices and are linked by a communications link.

32. The apparatus of claim 31 wherein an additional computing device is used to synchronize all of the separate devices.

33. The apparatus of claim 1 wherein there are both negative and positive pressures available from the ventilator.

34. The apparatus of claim 1 wherein the ventilator is configured to elevate oxygen levels to greater than 40%.

35. The apparatus of claim 1 wherein the period of time begins prior to the return of spontaneous circulation.

36. The apparatus of claim 35 wherein the period of time begins immediately prior to the return of spontaneous circulation.

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

applying a ventilator to the patient;

delivering a gas mixture to the patient using the ventilator,

wherein 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.

38. The method of claim 37 wherein the partial pressure of CO₂ is adjusted to be higher than ambient CO₂ partial pressure during the period of time.

39. The method of claim 37 wherein adjustment of the partial pressure of CO₂ includes adding CO₂ to the gas inspired by the patient.

40. The method of claim 37 further comprising providing a sensor and associated processing for measuring a physiological status of the patient, wherein the partial pressure of CO₂ is adjusted at least in part in response to the output of the sensor.

41. The method of claim 40 wherein the sensor and associated processing are configured to detect return of spontaneous circulation, and wherein the partial pressure of CO₂ is changed in response to detection of return of spontaneous circulation.

42. The method of claim 37 wherein adjustment of the partial pressure of CO₂ has the effect of maintaining the pH of the patient'"'"'s tissues below 7.0 for the period of time following return of spontaneous circulation.

43. The method of claim 37 further comprising using a sensor and associated processing for determining the pH of the patient'"'"'s tissue, and adjusting the partial pressure of CO₂ at least in part in response to the pH of the patient'"'"'s tissue.

44. The method of claim 37 wherein the period of time begins prior to the return of spontaneous circulation.