METHOD FOR DETERMINING HEMODYNAMIC EFFECTS

• US 20130338514A1
• Filed: 08/20/2013
• Published: 12/19/2013
• Est. Priority Date: 09/17/2008
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Karst, Edward, Vandine, Joseph Douglas, Porges, Charles E., Baker, Clark R. Jr.
• Granted Patent: US 9,414,769 B2
• Time in Patent Office: Days
• US Class Current: 600/484
• 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 5/0806 by whole-body plethysmography measuring blood flow using plethysmography A61B5/0295; impedance plethysmography A61B5/053; measuring volume of the body or parts thereof A61B5/1073
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system

Abstract

The present disclosure relates, in some embodiments, to devices, systems, and/or methods for collecting, processing, and/or displaying stroke volume and/or cardiac output data. For example, a device for assessing changes in cardiac output and/or stroke volume of a subject receiving airway support may comprise a processor; an airway sensor in communication with the processor, wherein the airway sensor is configured and arranged to sense pressure in the subject'"'"'s airway, lungs, and/or intrapleural space over time; a blood volume sensor in communication with the processor, wherein the blood volume sensor is configured and arranged to sense pulsatile volume of blood in a tissue of the subject over time; and a display configured and arranged to display a representative of an airway pressure, a pulsatile blood volume, a photoplethysmogram, a photoplethysmogram ratio, the determined cardiac output and/or stroke volume, or combinations thereof. A method of assessing changes in cardiac output or stroke volume of a subject receiving airway support from a breathing assistance system may comprise sensing pressure in the subject'"'"'s airway as a function of time, sensing pulsatile volume of blood in a tissue of the subject as a function of time, producing a photoplethysmogram from the sensed pulsatile volume, determining the ratio of the amplitude of the photoplethysmogram during inhalation to the amplitude of the photoplethysmogram during exhalation, and determining the change in cardiac output or stroke volume of the subject using the determined ratio.

Claims

1-25. -25. (canceled)

26. A method of predicting the effect of changes in ventilation settings on stroke volume of a ventilated subject, the method comprising:

sensing pressure in the subject'"'"'s airway during at least one breathing cycle comprising an inhalation and an exhalation;

producing a photoplethysmogram spanning the at least one breathing cycle;

determining the ratio of the amplitude of the photoplethysmogram during inhalation to the amplitude of the photoplethysmogram during exhalation; and

determining a change in cardiac output or stroke volume of the subject using the determined ratio.

27. The method of according to claim 29, wherein the change in ventilation settings comprises a change in a setting selected from the group consisting of positive end-expiratory pressure (PEEP), continuous positive airway pressure, inspiratory pressure target, inspiratory volume target, I:

E ratio, and combinations thereof.

29. The method of according to claim 26, further comprising:

referencing the stroke volume to current active ventilation settings of the breathing assistance system; and

comparing changes in ventilation settings to the current active ventilation settings.

30. The method of according to claim 29, further comprising:

displaying a representative parameter of the sensed airway pressure, a sensed pulsatile blood volume, the produced photoplethysmogram, the determined photoplethysmogram ratio, the cardiac output and/or the stroke volume, the determined change in the cardiac output and/or the stroke volume or combinations thereof.

31. The method of according to claim 29, wherein the representative parameter is a graphical representation of the actual parameter value.

32. The method of according to claim 29, wherein the representative of a parameter is the actual parameter value.

33. The method of according to claim 29, further comprising:

sensing a pulse rate of the subject.

34. The method of according to claim 33, further comprising:

calculating the cardiac output by multiplying the stroke volume by the pulse rate.

35. The method of according to claim 26, further comprising:

referencing the stroke volume to a parameter selected from a group consisting of zero end-expiratory pressure, current active breathing assistance system control settings, and combinations thereof.

45. The method of according to claim 29, further comprising:

changing the current active ventilator settings based on the step of comparing the changes in ventilation settings to the current active ventilation settings,

wherein the current ventilator settings include at least one of positive-end expiratory pressure (PEEP), ratio of inspiratory time to expiratory time (I;

E ratio), peak inspiratory pressure, volume delivered, and percent support

28. A method of assessing the relative strength of an autonomic neural response of a subject connected to a breathing assistance system, the method comprising:

determining the cardiac output of the subject at a first airway pressure;

changing the subject'"'"'s airway pressure to a second airway pressure;

monitoring the cardiac output of the subject at the second airway pressure;

comparing the cardiac output of the subject at the second airway pressure with the cardiac output of the subject at the first airway pressure;

measuring the time required for the cardiac output of the subject at the second airway pressure to return to the cardiac output of the subject at a first airway pressure; and

comparing the required time to a reference time to determine the relative strength of an autonomic neural response of the subject.

36. The method of according to claim 28, further comprising:

displaying a representative parameter of the sensed airway pressure, a pulsatile blood volume, a cardiac output and/or the stroke volume, or combinations thereof.

37. The method of according to claim 28, further comprising:

displaying the required time and/or the reference time.

38. The method of according to claim 28, further comprising:

displaying the determined relative strength of the autonomic neural response of the subject.

39. A processor including a device for executing logic instruction, the logic instructions comprising:

instructions to produce a photoplethysmogram spanning the at least one breathing cycle;

instructions to determine the ratio of the amplitude of the photoplethysmogram during inhalation to the amplitude of the photoplethysmogram during exhalation; and

instructions to determine a change in cardiac output or stroke volume of the subject using the determined ratio.

40. The processor of claim 39, wherein the logic instructions further comprise:

instructions to monitor pressure in the subject'"'"'s airway during at least one breathing cycle comprising an inhalation and an exhalation; and

instruction to monitor pulsatile volume of blood in a tissue of the subject as a function of time.

41. The processor of claim 39, wherein the logic instructions further comprise:

instructions to display a representative parameter of an airway pressure, a pulsatile blood volume, the produced photoplethysmogram, the determined photoplethysmogram ratio, the cardiac output and/or the stroke volume, the determined change in the cardiac output and/or the stroke volume or combinations thereof.

42. The method of according to claim 41, wherein the representative parameter is a graphical representation of the actual parameter value.

43. The method of according to claim 39, wherein the logic instructions further comprise:

instructions to sense a pulse rate of the subject.

44. The method of according to claim 43, wherein the logic instructions further comprise:

instructions to calculate the cardiac output by multiplying the stroke volume by the pulse rate.