Methods and systems that use implanted posture sensor to monitor pulmonary edema

1. A method to monitor pulmonary edema of a patient, comprising:

(a) detecting, using an implanted posture sensor, when a posture of the patient changes from a first predetermined posture to a second predetermined posture;

(b) determining, based on an impedance signal, an amount of time it takes the impedance signal to achieve a steady state after the posture of the patient changes from the first predetermined posture to the second predetermined posture,

where the impedance signal is obtained using implanted electrodes and is indicative of at least one of left atrial pressure or intra-thoracic fluid volume of the patient, and

where the amount of time it takes the impedance signal to achieve a steady state, after the posture of the patient changes from the first predetermined posture to the second predetermined posture, is indicative of a degree of pulmonary edema; and

(c) monitoring the pulmonary edema of the patient based on the determined amount of time it takes the impedance signal to achieve the steady state after the posture of the patient changes from the first predetermined posture to the second predetermined posture.

2. The method of claim 1 wherein the first predetermined posture is an upright posture and the second predetermined posture is a supine posture.

3. The method of claim 1 wherein the first predetermined posture is a supine posture and the second predetermined posture is an upright posture.

4. The method of claim 1 , wherein:

steps (a) and (b) are repeated a period of time thereafter; and

step (c) includes

identifying when a degree of the pulmonary edema of the patient, or a change therein, exceeds a threshold; and

one or both of triggering an alert and adjusting therapy administered to the patient in response to identifying that the degree of the pulmonary edema, or change therein, exceeds the threshold.

5. The method of claim 4 , wherein steps (a), (b) and (c) are performed by an implanted system including the implanted posture sensor and implanted electrodes; and wherein when an alert is triggered, the method further comprises:

(d) transmitting the alert from the implanted system to a non-implanted system; and

(e) at least one of displaying a visual warning or issuing an audible warning by way of the non-implanted system in response to the alert.

6. The method of claim 4 , wherein steps (a), (b) and (c) are performed by an implanted system including the implanted posture sensor and implanted electrodes; and wherein when therapy administered to the patient is adjusted, the method further comprises:

(d) adjusting medication based on a physician pre-determined formula; and

(e) displaying a visual indication of the medication adjustment to the patient.

7. The method of claim 4 , wherein steps (a), (b) and (c) are performed by an implanted system including the implanted posture sensor and implanted electrodes; and wherein when therapy administered to the patient is adjusted, the method further comprises:

(d) adjusting electrical therapy administered by an implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D).

8. The method of claim 1 ,

further comprising, after step (a), transmitting the impedance signal, or data indicative thereof, to a non-implanted system; and

wherein steps (b) and (c) are performed by the non-implanted system.

9. A system to monitor pulmonary edema of a patient comprising:

an implantable posture sensor adapted to determine a posture of the patient;

an implantable impedance sensor adapted to obtain, using implanted electrodes, an impedance signal indicative of at least one of left atrial pressure or intra-thoracic fluid volume of the patient; and

a pulmonary edema monitor adapted to

determine, based on the impedance signal, an amount of time it takes the impedance signal to achieve a steady state after the posture of the patient changes from a first predetermined posture to a second predetermined posture, where the amount of time it takes the impedance signal to achieve a steady state, after the posture of the patient changes from the first predetermined posture to the second predetermined posture, is indicative of a degree of pulmonary edema; and

monitor the pulmonary edema of the patient based on the determined amount of time it takes the impedance signal to achieve the steady state after the posture of the patient changes from the first predetermined posture to the second predetermined posture.

10. The system of claim 9 , wherein the first predetermined posture is an upright posture and the second predetermined posture is a supine posture.

11. The system of claim 9 , wherein the first predetermined posture is a supine posture and the second predetermined posture is an upright posture.

12. The system of claim 9 , wherein:

the pulmonary edema monitor is adapted to trigger an alert in response to a degree of the pulmonary edema of the patient, or a change therein, exceeding a threshold.

13. The system of claim 9 , wherein:

the pulmonary edema monitor is associated with a non-implanted system that is adapted to at least one of display a visual warning or issue an audible warning in response to the alert; and

the implantable impedance sensor is associated with an implantable device adapted to communicate with the non-implanted system.

14. The system of claim 9 ,

wherein the implantable pulmonary edema monitor is associated with an implantable device; and

further comprising a non-implanted device adapted to communicate with the implantable device and at least one of display a visual warning or issue an audible warning in response to an alert received from the implantable device.