Apparatus and computer program for determining a patient's volemic status represented by cardiopulmonary blood volume

• US 20080045845A1
• Filed: 06/20/2007
• Published: 02/21/2008
• Est. Priority Date: 06/21/2006
• Status: Abandoned Application

• Current Assignee: Edwards Lifesciences IPRM AG (Edwards Lifesciences Corporation)
• Original Assignee: IPRM Intellectual Property Rights Management
• Inventors: Knoll, Reinhold, Pfeiffer, Ulrich, Michard, Frederic
• Application Number:
  US11/820,785
• Publication Number:
  US 20080045845A1
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61M 16/021 operated by electrical means A61M16/202 – A61M16/205 take precedence
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

An apparatus for determining a patient'"'"'s volemic status can make use of a physiological heart-lung interaction during spontaneous breathing or mechanical ventilation. Further, a computer program for determining the patient'"'"'s volemic status has instructions for carrying out the steps of generating data of a physiological heart-lung interaction during spontaneous breathing or mechanical ventilation, and determining the patient'"'"'s volemic status when making use of the data of the physiological heart-lung interaction, when run on a computer.

Claims

1. An apparatus for determining a patient'"'"'s or mammalian animal'"'"'s volemic status comprising:

a device for determining the volemic status as a function of a physiological heart-lung interaction during spontaneous breathing or mechanical ventilation.

2. The apparatus according to claim 1, wherein the device is adapted to provide an envelope of the arterial pulse pressure or a surrogate and is capable to determine the physiological heart-lung interaction as a function of the arterial pulse pressure.

3. The apparatus according to claim 2, wherein the device is capable of deriving expiratory cardiopulmonary blood volume (CPBVex) by making use of the equation

CPBVex=CO*TTcp,ex,

wherein CO is the cardiac output and TTcp,ex is the cardiopulmonary transit time of blood in the hemodynamic status of expiration being derived from the envelope of the arterial pulse pressure.

4. The apparatus according to claim 2, wherein the device is capable of deriving the inspiratory left heart volume (LHVin) by making use of the equation

LHVin=CO*TTlh,in,

wherein CO is the cardiac output and TTlh,in is the inspiratory transit time of blood through the left heart being derived from the envelope of the arterial pulse pressure.

5. The apparatus according to claim 2, wherein the apparatus is capable of deriving a middle expiratory cardiopulmonary blood volume (CPBV) by making use of the equation

6. The apparatus according to claim 1, wherein the apparatus is capable of deriving an expiratory cardiopulmonary blood volume and a cardiopulmonary transit time of blood in the hemodynamic status of expiration (TTcp,ex) by making use of the equation

TTcp,ex=t(B)−

t(I−

E),

wherein t(I−

E) is the time point of end-inspiration and start of expiration, and t(B) is the time point where the envelope of arterial pressure reaches the same level as at the time point of end-expiration and start of inspiration.

7. The apparatus according to claim 1, wherein the apparatus is capable of deriving an inspiratory transit time (TTlh,in) by making use of the equation

TTlh,in=t(E−

I)−

t(A),

wherein t(E−

I) is the time point of end-expiration and start of inspiration, and t(A) is the time point where the envelope of arterial pressure starts to rise.

8. The apparatus according to claim 1, wherein the apparatus is capable of obtaining the cardiac output (CO) from any continuous real time cardiac output measurement method like arterial pulse contour analysis, esophageal Doppler, transthoracic or esophageal echo Doppler, transthoracic or esophageal electrical Bioimpedance, continuous heating right heart catheter, or CO2-rebreathing.

9. The apparatus according to claim 1, wherein the apparatus is capable of initially checking the equilibrium in the cardiopulmonary vascular system by a single extended breathing cycle in investigating as to whether a constant plateau of pulse pressure for expiration is reached in order to necessarily adjust the breathing cycle to a degree with approximate equilibrium.

10. The apparatus according to claim 9, wherein the apparatus is capable of applying the checking of equilibrium in a pressure controlled ventilation mode or in a volume controlled ventilation mode.

11. The apparatus according to claim 2, wherein the apparatus is capable of using prolonged step changes of the level of Positive End-Expiratory Pressure (PEEP).

12. The apparatus according to claim 2, wherein the apparatus is capable of using prolonged step changes of the level of Positive End-Expiratory Pressure (PEEP) by breathing on three different mean airway pressure levels (MPaw).

13. The apparatus according to claim 12, wherein the apparatus is adapted to compose a phase of low PEEP level, a phase of high PEEP level, and a phase of intermediate PEEP level.

14. The apparatus according to claim 13, wherein the apparatus is adapted to compose the phase of intermediate PEEP level corresponding to the mean airway pressure (Paw mean) before a testing phase.

15. The apparatus according to claim 13, wherein the apparatus is capable of deriving the mean cardiopulmonary blood volume (CPBVmean) by making use of the equation

CPBVmean=COmean*TTcp mean,

wherein COmean is the mean cardiac output (CO) in the mean positive airway pressure phase after stabilization and TTcp mean is the mean cardiopulmonary transit time of blood being derived from the envelope of the arterial pulse pressure.

16. The apparatus according to claim 15, wherein the apparatus is capable of deriving the mean cardiopulmonary transit time of blood (TTcp mean) by making use of the equations

TTcp mean=t(D)−

t(3−

2), or
TTcp mean=t(F)−

t(1−

2),

wherein t(3−

2) is the moment of change from the highest level of PEEP or MPaw to mean positive airway pressure level or the intermediate level of PEEP or MPaw, t(1−

2) is the moment of change from the lowest level of PEEP or MPaw to average positive airway pressure level or the intermediate level of PEEP or MPaw, t(D) is the time point where the envelope of arterial pulse pressure curve has adapted to intermediate PEEP or MPaw level, and t(F) is the time point where the envelope of arterial pulse pressure curve has adapted to intermediate PEEP or MPaw level.

17. The apparatus according to claim 13, wherein the apparatus is capable of deriving the mean left heart volume (LHVmean) by making use of the equation

LHVmean=COmean*TTlh,mean,

wherein COmean is the mean cardiac output (CO) in the mean positive airway pressure phase after stabilization and TTlh,mean is the mean transit time of blood being derived from the envelope of the arterial pulse pressure.

18. The apparatus according to claim 17, wherein the apparatus is capable of deriving the mean transit time of blood (TTlh,mean) by making use of the equation

TTlh,mean=t(1−

2)−

t(E)

wherein t(E) is the time point where envelope curve of arterial pulse pressure starts to rise.

19. The apparatus according to claim 15, wherein the apparatus is capable of deriving the slope of Starling curve during TriPAP for the total heart by making use of the difference quotient built from

delta SV over delta CPBV on 3 PEEP or MPaw levels, and

for the left heart by making use of the difference quotient built from

delta SV over delta LHV on 3 PEEP or MPaw levels.

20. A computer program for determining a patient'"'"'s volemic status, having instructions adapted to carry out the following steps:

generating data of a physiological heart-lung interaction during spontaneous breathing or mechanical ventilation,

determining the patient'"'"'s volemic status as a function of data of the physiological heart-lung interaction,

when run on a computer.

21. The computer program according to claim 20, having instructions adapted to carry out the steps:

providing an envelope of the arterial pulse pressure or a surrogate,

determining the physiological heart-lung interaction as a function of the envelope of the arterial pulse pressure.

22. The computer program according to claim 21, having instructions adapted to carry out the step:

deriving the expiratory cardiopulmonary blood volume (CPBVex) by making use of the equation

CPBVex=CO*TTcp,ex,

wherein CO is the cardiac output and TTcp,ex is the cardiopulmonary transit time of blood in the hemodynamic status of expiration being derived from the envelope of the arterial pulse pressure.

23. The computer program according to claim 21, having instructions adapted to carry out the step:

deriving the inspiratory left heart volume (LHVin) by making use of the equation

LHVin=CO*TTlh,in,

wherein CO is the cardiac output and TTlh,in is the inspiratory transit time of blood through the left heart being derived from the envelope of the arterial pulse pressure.

24. The computer program according to claim 21, having instructions adapted to carry out the step:

deriving a middle expiratory cardiopulmonary blood volume (CPBV) by making use of the equation

CPBV=CO*TTcp,

wherein CO is the cardiac output and TTcp is middle cardiopulmonary transit time ranging between the cardiopulmonary transit time of blood (TTcp,ex) in the hemodynamic status of expiration, and the inspiratory transit time (TTlh,in) of blood through the left heart, both being derived from the envelope of the arterial pulse pressure.

25. The computer program according to claim 21, having instructions adapted to carry out the step:

deriving the cardiopulmonary transit time of blood in the hemodynamic status of expiration (TTcp,ex) by making use of the equation

TTcp,ex=t(B)−

t(I−

E),

wherein t(I−

E) is the time point of end-inspiration and start of expiration, and t(B) is the time point where the envelope of arterial pressure reaches the same level as at the time point of end-expiration and start of inspiration.

26. The computer program according to claim 21, having instructions adapted to carry out the step:

deriving the inspiratory transit time (TTlh,in) by making use of the equation

TTlh,in=t(E−

I)−

t(A),

wherein t(E−

I) is the time point of end-expiration and start of inspiration, and t(A) is the time point where the envelope of arterial pressure starts to rise.

27. The computer program according to claim 21, having instructions adapted to carry out the step:

obtaining the cardiac output (CO) from a continuous real time cardiac output measurement method like arterial pulse contour analysis, esophageal Doppler, transthoracic or esophageal echo Doppler, transthoracic or esophageal electrical Bioimpedance.

28. The computer program according to claim 21, having instructions adapted to carry out the step:

initially checking the equilibrium in the cardiopulmonary vascular system by a single extended breathing cycle in investigating as to whether a constant plateau of pulse pressure for expiration is reached in order to necessarily adjust the breathing cycle to a degree with approximate equilibrium.

29. The computer program according to claim 28, having instructions adapted to carry out the step:

applying the checking of equilibrium in a pressure controlled ventilation mode or in a volume controlled ventilation mode.

30. The computer program according to claim 21, having instructions adapted to carry out the step:

using prolonged step changes of the level of Positive End-Expiratory Pressure (PEEP).

31. The computer program according to claim 21, having instructions adapted to carry out the step:

using prolonged step changes of the level of Positive End-Expiratory Pressure (PEEP) by breathing on three different mean airway pressure levels (MPaw).

32. The computer program according to claim 31, having instructions adapted to carry out the step:

composing a phase of low PEEP level, a phase of high PEEP level, and a phase of intermediate PEEP level.

33. The computer program according to claim 32, having instructions adapted to carry out the step:

composing the phase of intermediate PEEP level corresponding to the mean airway pressure (Paw mean) before a testing phase.

34. The computer program according to claim 32, having instructions adapted to carry out the step:

deriving the mean cardiopulmonary blood volume (CPBVmean) by making use of the equation

CPBVmean=COmean*TTcp mean,

wherein COmean is the mean cardiac output (CO) in the mean positive airway pressure phase after stabilization and TTcp mean is the mean cardiopulmonary transit time of blood being derived from the envelope of the arterial pulse pressure (5).

35. The computer program according to claim 34, having instructions adapted to carry out the step:

deriving the mean cardiopulmonary transit time of blood (TTcp mean) by making use of the equations

TTcp mean=t(D)−

t(3−

2), or
TTcp mean=t(F)−

t(1−

2),

wherein t(3−

2) is the moment of change from the highest level of PEEP or MPaw to mean positive airway pressure level or the intermediate level of PEEP or MPaw, t(1−

2) is the moment of change from the lowest level of PEEP or MPaw (PEEP 1) to average positive airway pressure level or the intermediate level of PEEP or MPaw (PEEP 2), t(D) is the time point where the envelope of arterial pulse pressure curve has adapted to intermediate PEEP or MPaw level, and t(F) is the time point where the envelope of arterial pulse pressure curve has adapted to intermediate PEEP or MPaw level.

36. The computer program according to claim 32, having instructions adapted to carry out the step:

deriving the mean left heart volume (LHVmean) by making use of the equation

LHVmean=COmean*TTlh,mean,

wherein COmean is the mean cardiac output (CO) in the mean positive airway pressure phase after stabilization and TTlh,mean is the mean transit time of blood being derived from the envelope of the arterial pulse pressure.

37. The computer program according to claim 36, having instructions adapted to carry out the step:

deriving the mean transit time of blood (TTlh,mean) by making use of the equation

TTlh,mean=t(1−

2)−

t(E)

wherein t(E) is the time point where envelope curve of arterial pulse pressure starts to rise.

38. The computer program according to claim 34, having instructions adapted to carry out the step:

deriving the slope of Starling curve during TriPAP for the total heart by making use of the difference quotient built from

delta SV over delta CPBV on at least two PEEP or MPaw levels, and

for the left heart by making use of the difference quotient built from

delta SV over delta LHV on at least two PEEP or MPaw levels.

39. A method for determining a patient'"'"'s volemic status comprising:

generating data of a physiological heart-lung interaction during spontaneous breathing or mechanical ventilation,

determining on a computer the patient'"'"'s volemic status as a function of data of the physiological heart-lung interaction.