Active Implantable Medical Device Capable of Distinguishing Between a Local Infection and a Systemic Infection

Abstract

An active implantable medical device (IMD) which, in operation: repeatedly senses a body temperature of a person having the IMD implanted therein; stores the sensed body temperature values; repeatedly senses a cardiac physiologic parameter of the person; stores the sensed cardiac physiologic parameter values; determines whether one of the body temperature values exceeds a predefined body temperature threshold; if an excess is determined, the IMD: determines whether one of the cardiac physiologic parameter values exceeds a predefined cardiac physiologic parameter threshold, wherein the one cardiac physiologic parameter value is determined in the same time period as the one body temperature value exceeding the body temperature threshold; classifies an infection of the person as a local infection if the one cardiac physiologic parameter value does not exceed the threshold; or classifies an infection of the person as a systemic infection if the one cardiac physiologic parameter value exceeds the threshold.

Claims

1. Active implantable medical device, comprising a processor, a memory unit, a detection unit configured to detect a cardiac physiologic parameter, and a temperature sensor for sensing a body temperature, wherein the memory unit comprises a computer-readable program that causes the processor to perform the following steps when executed on the processor: a) causing the temperature sensor to repeatedly sense a body temperature of a person to whom the active implantable medical device is implanted; b) storing body temperature values obtained in step a) in the memory unit; c) causing the detection unit to repeatedly sense a cardiac physiologic parameter of the person; d) storing cardiac physiologic parameter values obtained in step c) in the memory unit; e) determining whether at least one of the body temperature values exceeds a predefined body temperature threshold; f) if an excess of the predefined body temperature threshold has been determined, determining whether at least one of the cardiac physiologic parameter values exceeds a predefined cardiac physiologic parameter threshold, wherein the at least one of the cardiac physiologic parameter values has been determined in the same time period as the at least one of the body temperature values exceeding the body temperature threshold; g) i) classifying an infection of the person as a local infection if the at least one of the body temperature values exceeds the body temperature threshold and if the at least one of the cardiac physiologic parameter values does not exceed the cardiac physiologic parameter threshold; or ii) classifying an infection of the person as a systemic infection if the at least one of the body temperature values exceeds the body temperature threshold and if the at least one of the cardiac physiologic parameter values exceeds the cardiac physiologic parameter threshold, wherein the cardiac physiologic parameter is a heart rate or a heart rate at rest, wherein the computer-readable program causes the processor to determine an excess of the cardiac physiologic parameter threshold if the heart rate or the heart rate at rest is at least 110% of a mean heart rate or a mean heart rate at rest, respectively, over a first number of last days prior to the determining, wherein the first number is a number chosen from a range between 3 and 400.

2. Active implantable medical device according to claim 1, wherein the active implantable medical device is an implantable pulse generator, an implantable cardioverter-defibrillator, a cardiac resynchronization therapy device, a neurostimulator, or an implantable cardiac monitor.

3. Active implantable medical device according to claim 1, wherein the cardiac physiologic parameter is at least one chosen from the group consisting of a heart rate, a heart rate at rest, a respiratory rate, a respiratory rate at rest, and a cardiac impedance, cardiac contractility, cardiac output, heart rate variability, respiratory arrhythmia, oxygen saturation, blood flow velocity, heart sounds.

4. Active implantable medical device according to claim 1, wherein the cardiac physiologic parameter is a heart rate or a heart rate at rest, wherein the cardiac physiologic parameter threshold is a heart rate in a range of 80 to 110 beats per minute.

5. Active implantable medical device according to claim 1, wherein the body temperature threshold is a temperature lying in a range from 37.5° C. to 38.5° C.

6. Active implantable medical device according to claim 1, wherein the computer-readable program causes the processor to sense the body temperature multiple times per day.

7. Active implantable medical device according to claim 1, wherein the computer-readable program causes the processor to sense the body temperature for multiple days.

8. Active implantable medical device according to claim 1, wherein the computer-readable program causes the processor to output an alert if the actual body temperature value exceeds the body temperature threshold and if optionally also the cardiac physiologic parameter value exceeds the cardiac physiologic parameter threshold.

9. Arrangement, comprising an active implantable medical device and an evaluation unit separate from the active implantable medical device, wherein the active implantable medical device comprises a first processor, a first memory unit, a detection unit configured to detect a cardiac physiologic parameter, a temperature sensor for sensing a body temperature, and a data communication unit, wherein the first memory unit comprises a first computer-readable program that causes the first processor to perform the following steps when executed on the first processor: a) causing the temperature sensor to repeatedly sense a body temperature of a person to whom the active implantable medical device is implanted; b) causing the detection unit to repeatedly sense a cardiac physiologic parameter of the person; c) transmitting body temperature values obtained in step a) and cardiac physiologic parameters obtained in step b) via the data communication unit to the evaluation unit located outside a body of the person; and in that the evaluation unit comprises a second processor and a second memory unit, wherein the second memory unit comprises a second computer-readable program that causes the second processor to perform the following steps when executed on the second processor: d) storing the transmitted body temperature values and the transmitted cardiac physiologic parameter values in the second memory unit; e) determining whether at least one of the body temperature values exceeds a predefined body temperature threshold; f) if an excess of the predefined body temperature threshold has been determined, determining whether at least one of the cardiac physiologic parameter values exceeds a predefined cardiac physiologic parameter threshold, wherein the at least one of the cardiac physiologic parameter values has been determined in the same time period as the at least one of the body temperature values exceeding the body temperature threshold; g) i) classifying an infection of the person as a local infection if the at least one of the body temperature values exceeds the body temperature threshold and if the at least one of the cardiac physiologic parameter values does not exceed the cardiac physiologic parameter threshold; or ii) classifying an infection of the person as a systemic infection if the at least one of the body temperature values exceeds the body temperature threshold and if the at least one of the cardiac physiologic parameter values exceeds the cardiac physiologic parameter threshold, wherein the cardiac physiologic parameter is a heart rate or a heart rate at rest, wherein the computer-readable program causes the processor to determine an excess of the cardiac physiologic parameter threshold if the heart rate or the heart rate at rest is at least 110% of a mean heart rate or a mean heart rate at rest, respectively, over a first number of last days prior to the determining, wherein the first number is a number chosen from a range between 3 and 400.

10. Arrangement according to claim 9, wherein the data communication unit is arranged and designed to transfer data to the evaluation unit in a wireless manner.

11. Arrangement according to claim 9, wherein the first computer-readable program causes the first processor to transmit the body temperature values and the cardiac physiologic parameter values at least once a day.

12. Computer program product comprising computer-readable code that causes a processor to perform the following steps when executed on the processor: a) storing body temperature values obtained from a temperature sensor of an active implantable medical device and cardiac physiologic parameter values obtained from a detection unit of the same active implantable medical device in a memory unit of the implantable medical device or of an evaluation unit located outside a body of a person to whom the active implantable medical device is implanted; b) determining whether at least one of the body temperature values exceeds a predefined body temperature threshold; c) if an excess of the predefined body temperature threshold has been determined, determining whether at least one of the cardiac physiologic parameter values exceeds a predefined cardiac physiologic parameter threshold, wherein the at least one of the cardiac physiologic parameter values has been determined in the same time period as the at least one of the body temperature values exceeding the body temperature threshold; d) i) classifying an infection of the person as a local infection if the at least one of the body temperature values exceeds the body temperature threshold and if the at least one of the cardiac physiologic parameter values does not exceed the cardiac physiologic parameter threshold; or ii) classifying an infection of the person as a systemic infection if the at least one of the body temperature values exceeds the body temperature threshold and if the at least one of the cardiac physiologic parameter values exceeds the cardiac physiologic parameter threshold, wherein the cardiac physiologic parameter is a heart rate or a heart rate at rest, wherein the computer-readable program causes the processor to determine an excess of the cardiac physiologic parameter threshold if the heart rate or the heart rate at rest is at least 110% of a mean heart rate or a mean heart rate at rest, respectively, over a first number of last days prior to the determining, wherein the first number is a number chosen from a range between 3 and 400.

13. Method for distinguishing between a local infection and a systemic infection of a patient to whom an active implantable medical device has been implanted, the method comprising the following steps: a) repeatedly sensing a body temperature of a patient to whom an active implantable medical device has been implanted with a temperature sensor of the active implantable medical device, wherein the active implantable medical device further comprises a processor, a memory unit, and a detection unit configured to detect a cardiac physiologic parameter; b) storing body temperature values obtained in step a) in the memory unit; c) repeatedly sensing a cardiac physiologic parameter of the patient; d) storing cardiac physiologic parameter values obtained in step c) in the memory unit; e) determining whether at least one of the body temperature values exceeds a predefined body temperature threshold; f) if an excess of the predefined body temperature threshold has been determined, determining whether at least one of the cardiac physiologic parameter values exceeds a predefined cardiac physiologic parameter threshold, wherein the at least one of the cardiac physiologic parameter values has been determined in the same time period as the at least one of the body temperature values exceeding the body temperature threshold; g) i) classifying an infection of the patient as a local infection if the at least one of the body temperature values exceeds the body temperature threshold and if the at least one of the cardiac physiologic parameter values does not exceed the cardiac physiologic parameter threshold; or ii) classifying an infection of the patient as a systemic infection if the at least one of the body temperature values exceeds the body temperature threshold and if the at least one of the cardiac physiologic parameter values exceeds the cardiac physiologic parameter threshold, wherein the cardiac physiologic parameter is a heart rate or a heart rate at rest, wherein the computer-readable program causes the processor to determine an excess of the cardiac physiologic parameter threshold if the heart rate or the heart rate at rest is at least 110% of a mean heart rate or a mean heart rate at rest, respectively, over a first number of last days prior to the determining, wherein the first number is a number chosen from a range between 3 and 400.

14. Method according to claim 13, wherein the method further comprises deciding to examine and/or treat the patient in a hospital specialized on the treatment of infectious diseases if the infection of the patient has been classified as systemic infection.

15. Method according to claim 14, wherein the hospital is a hospital specialized on the treatment of COVID-19.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Further details of aspects of the present invention will be explained in the following with respect to exemplary embodiments and accompanying Figures. In the Figures:

[0068] FIG. 1A shows a plot on the mean daily body temperature of a first patient to whom an active medical implant has been implanted;

[0069] FIG. 1B shows activity data of the same patient as in FIG. 1A in the same time period;

[0070] FIG. 1C shows mean heart rate values of the same patient as in FIG. 1A in the same time period;

[0071] FIG. 1D shows mean resting heart rate values of the same patient as in FIG. 1A in the same period;

[0072] FIG. 2A shows a plot on the mean daily body temperature of a second patient to whom an active medical implant has been implanted;

[0073] FIG. 2B shows activity data of the same patient as in FIG. 2A in the same time period;

[0074] FIG. 2C shows mean heart rate values of the same patient as in FIG. 2A in the same time period;

[0075] FIG. 2D shows mean resting heart rate values of the same patient as in FIG. 2A in the same period; and

[0076] FIG. 3 shows a schematic representation of an implantable medical device of an embodiment of the present invention; and

[0077] FIG. 4 shows a schematic representation of an evaluation unit used in conjunction with the implantable medical device in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

[0078] FIG. 1A shows the mean daily body temperature of a first patient carrying an active implantable medical device 10, namely, an implantable pulse generator. The body temperature is measured a plurality of times a day, wherein the individual body temperature values are averaged to obtain a mean daily body temperature. This mean daily body temperature is stored in a memory unit of the implantable pulse generator.

[0079] On a few occasions in July and November, the mean daily body temperature was equal to or higher than 38° C., i.e., it has exceeded a body temperature threshold of 37.9° C. Since the body temperature fell quickly again below the before-mentioned threshold, these events were not further evaluated in detail. However, the mean daily body temperature values of March show a higher number of individual body temperature values exceeding the body temperature threshold of 37.9° C., thus indicating an infection of the patient.

[0080] FIG. 1B shows the activity of the patient. No clear trend is observable, even though it appears that the activity in March is slightly lower than in the preceding months, in particular with respect to the last recorded March days in which the body temperature exceeded the body temperature threshold. However, the activity of the patient does not appear to be a good indicator for distinguishing a local infection from a systemic infection.

[0081] The situation is different when considering the daily mean heart rate that is plotted in FIG. 1C. It is striking that the daily mean heart rate raised in March to values significantly above 90 beats per minute (bpm). Similar daily mean heart rate values could have been observed on two single days in October and in November, wherein the November value coincided with an increased body temperature of the patient. However, this were single-day events not being indicative for a manifested infection of the patient. In contrast, in March, the daily mean heart rate was on eight days higher than 90 beats per minute.

[0082] A similar situation can be observed when considering the daily mean heart rate at rest, as can be seen from FIG. 1D. This daily mean heart rate at rest was higher than 80 beats per minute on eight days in March, but only on one day in the preceding months. Thus, the patient experienced both a body temperature of equal to or higher than 38° C. and a daily mean heart rate of higher than 90 bpm as well as a daily mean heart rate at rest of higher than 80 beats per minute on the same days in March.

[0083] This is taken as an indication of a systemic infection since both the body temperature and the further cardiac physiologic parameter have exceeded the respective threshold.

[0084] FIG. 2A shows the body temperature values of another patient also carrying an active implantable medical device 10, namely, an implantable pulse generator. Here, also a body temperature increase above 38° C. was observed in March (FIG. 2A).

[0085] Furthermore, the activity of the patient was decreased with respect to the previous days (FIG. 2B).

[0086] However, the daily mean heart rate did not significantly deviate from the previously obtained values (FIG. 2C). In particular, it did not exceed a threshold of 89 bpm over more than 2 consecutive days.

[0087] Furthermore, also the daily mean heart rate at rest did not significantly deviate from the previously obtained value and was only on one single day higher than 80 beats per minute (FIG. 2D).

[0088] When taking the body temperature values of the second patient and either the daily mean heart rate values or the daily mean heart rate values at rest of the second patient together, no clear trend of the body temperature value and at least one of the further cardiac physiologic parameters could be observed. Thus, this clearly indicates that the second patient only suffers from a local infection so that the patient is not advised to be further examined and/or treated in a hospital specialized on infectious diseases like COVID-19. Rather, the hospital or doctor who has implanted the active implantable medical device 10 should take care of the patient and treat the local (pocket) infection in a classic way as needed by the patient.

[0089] FIG. 3 shows a schematic representation of an implantable medical device 10 (e.g., an active cardiac implant) for detecting a cardiac physiologic parameter and a body temperature of a person. The active medical implant 10 includes a (first) processor 120 in two-way communication with a (first) memory unit 122, a detection unit 126, a data communication unit 128 and a temperature sensor 132. The detection unit 126 serves for detecting a cardiac physiologic parameter(s) of a patient to whom the implantable medical device 10 is implanted. The temperature sensor 132 serves for sensing a body temperature(s) of the same patient. The (first) memory unit 122 comprises a (first) computer-readable program that causes the (first) processor 120 to perform the various steps described/explained above when executed on the (first) processor 120.

[0090] FIG. 4 shows a schematic representation of an evaluation unit 40 used in conjunction with the implantable medical device 10 in accordance with an embodiment of the present invention. The evaluation unit 40 is located separate from the active implantable medical device 10. The body temperature values measured by the temperature sensor 132 and the cardiac physiologic parameter values measured by the detection unit 126 are transmitted, via the data communication unit 128, to the evaluation unit 40 located outside a body of the person. The evaluation unit 40 comprises a second processor 420 in two-way communication with a second memory unit 422. The second memory unit 422 comprises a second computer-readable program that causes the second processor 420 to perform the various steps described/explained above when executed on the second processor 420.

[0091] It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teachings of the disclosure. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternate embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention, which is to be given the full breadth thereof. Additionally, the disclosure of a range of values is a disclosure of every numerical value within that range, including the end points.