MONITORING DEVICE FOR A THERAPY DEVICE AND PROCESS

Abstract

A monitoring device for monitoring a therapy device, for example, an anesthesia device or a respirator, is provided by which an alarm device for triggering an alarm when the value drops beyond a warning limit (4) is automatically activated when a determined therapy parameter drops beyond this warning limit (4). The warning limit (4) is set automatically in this case. In addition, a therapy device monitored by the monitoring device and especially an anesthesia device as well as a respirator are provided. A process for triggering an alarm as well as a process for treating a patient is also provided.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a graph showing the course of MAC during anesthesia over the time t.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in particular, the conditions corresponding to MAC values at the beginning of an anesthesia are shown at the left-hand edge of the graphic view in FIG. 1. It can be recognized from FIG. 1 that the inspiratory MAC value, MAC_insp (the corresponding curve is designated by 1 and is drawn as a solid line), is raised rapidly to a prominent level for the purpose of rapidly inducing anesthesia. The expiratory MAC value, MAC_exp (the corresponding curve is designated by 2 and is drawn as a broken line), also increases with a time delay. The expiratory MAC value, MAC_expfilt (the corresponding curve is designated by reference number 3 and is drawn as a two-dot broken line), which is filtered as a function of its action beyond the blood-brain barrier, rises with an even longer delay.

The monitoring device of the anesthesia device, by means of which the schematic curves in FIG. 1 were generated, has been set such that a lower warning limit MAC_lowtrsh (designated by reference number 4) is activated or set only when all three MAC values 1, 2 and 3 exceed a lower threshold value 5. This happens at time 7 in FIG. 1. The lower warning limit 4 is seen here in the example according to FIG. 1 at about 70% of the lowest of the three MAC values 1, 2 and 3, i.e., at 70% of MAC value 3. The lower threshold value 5 may be set, for example, at 0.3 MAC. Presetting a comparatively low lower threshold value 5 is meaningful, e.g., in case of a balanced anesthesia with additional intravenous administration of anesthetics, because this entire invention can, of course, be used advantageously in each embodiment for balanced anesthesia as well.

Based on the further rise of the values 1, 2 and 3 (i.e., of the values MAC_insp, MAC_exp and MAC_expfilt), the lower warning limit 4 (MAC_lowtrsh) rises between the points in time 7 and 8 to a level that remains constant between the points in time 8 and 9. Due to the repeated rise of the inspiratory MAC value 1 with a peak at time 10, the values 2 and 3 will also rise, again with a time delay, as a result of which the lower warning limit 4 will also rise slightly between the points in time 9 and 10, following the lowest of the three MAC values determined.

Line 6 (which indicates the value MAC_lowtrsh-max), which is also shown in FIG. 1, indicates a preset maximum for the automatic increase of the lower warning limit 4. This is an upper limit set prior to the anesthesia for the lower warning limit 4, which is, however, not reached by the lower warning limit 4 in the example shown in FIG. 1.

A drop of the inspiratory MAC value 1, which is also followed by a lowering of the MAC values 2 as well as 3 with a time delay, can be recognized beginning from the time 12 in FIG. 1. Since not only the MAC value 1 but also the MAC value 2 have dropped below the lower warning limit 4 at time 13, the conditions for triggering an alarm are met for the monitoring device according to this embodiment (the drop of a MAC value below the warning limit 4 may already be sufficient for triggering an alarm in other embodiments). The monitoring device therefore triggers an alarm between the points in time 13 and 14.

Since two MAC values (here: the MAC values 1 and 2) have already assumed values below the lower threshold value 5 at the time of the alarm at time 13, the physician is asked by means of a dialogue field whether the alarm device could be deactivated, for example, because the end of anesthesia is intended. The physician answered this with a “yes” at time 14, after which the lower warning limit 4 drops to its initial value and the alarm system is thus deactivated. If MAC_exp is higher than MAC_insp, this is also an indicator for the end of anesthesia, so that the alarm system can be deactivated upon a “yes” answer from the therapist or upon approval by the therapist.

It is pointed out that an upper warning limit may, of course, also be provided besides the lower warning limit in each embodiment. All the statements made above concerning the setting of the lower warning limit also apply now to the upper warning limit and can be extrapolated to this if considered by the person skilled in the art to be meaningful.

The taking into account of all three of the MAC values or of the relation thereof to activate the alarm means, as in FIG. 1, advantageously ensures that an anesthesia device monitored by means of the monitoring device is, indeed, also the cause of the anesthesia with a corresponding depth of anesthesia, i.e., that the patient's anesthesia can be attributed to the gaseous anesthetics being monitored. This information is essentially attached to the inspiratory MAC value 1.

If the expiratory MAC value 2 is, moreover, also required to exceed the lower threshold value 5, as in this preferred embodiment according to FIG. 1, this increases the safety of the process further due to the fact that a time shift between the reaching of an inspiratory concentration and the same concentration in the expiratory breathing gas due to diffusion processes and shifts between compartments of the body is taken into account, which contributes to a more precise information on the anesthesia.

If, moreover, the means for automatically setting the lower warning limit 4 of the monitoring device also takes into account the value of the MAC value 3 of the at least one gaseous anesthetic, which is filtered as a function of the action time, or the exceeding of the lower threshold value 5 by this MAC value 3 in case of activation of the alarm means, the action of the gaseous anesthetic being used on cerebral processes is additionally taken into account. The expiratory MAC value 3 filtered as a function of the action time is to be defined as an indicator of the depth of anesthesia, and it takes into account the passage of the gaseous anesthetic being used through the blood-brain barrier, as was already explained above. Thus, it is a more precise parameter of anesthesia than MAC_exp alone. It is expressly pointed out that FIG. 1 shows the case in which only one gaseous anesthetic is used. In the case discussed in detail above, in which not only one gas but a gas mixture is used, the total MAC_expfilt, filtered as a function of the individual action times of the particular individual gases involved, replaces the MAC value 3 according to FIG. 1. Furthermore, a total MAC_insp and a total MAC_exp can replace the MAC values 1 and 2.

It applies to the means used to carry out the present invention that a means can definitely also perform different tasks. Thus, a means for, e.g., determining MAC values and at the time for setting the lower warning limit and/or additional functions may be able to be used.

Provisions are also made according to the present invention for working with more than only one lower warning limit. Thus, the person skilled in the art may provide different warning limits for different MAC values, and a plurality of means are used to determine them, set them, etc. Each of these warning limits may be designed as explained above.

Moreover, it is obvious to the person skilled in the art that a combination of the determination of at least one MAC value and the determination of at least one additional variable, which is not a MAC value, is possible in each embodiment of the present invention. Such an additional variable may be, for example, a volume, a volume flow, a pressure or the like. It is thus possible according to the present invention especially to set the lower warning limit, taking into account at least one MAC value and at least one other variable. It is obvious in this connection that when different variables (for example, a MAC value and a volume value) are determined and used, it is also possible to take into account different lower threshold values (a threshold value for the MAC value and another for the volume value), which must each be exceeded in order to set the lower warning limit.

The present invention proposes a monitoring device for monitoring a therapy device, for example, an anesthesia device or respirator, by means of which an alarm means for triggering an alarm when the value drops below a lower warning limit is automatically activated when at least one determined therapy parameter drops below this lower warning limit 4. The lower warning limit (warning limit) is first set automatically in this case. In addition, a therapy device monitored by means of the monitoring device according to the present invention and especially an anesthesia device as well as a respirator are proposed. The present invention proposes, furthermore, a process for triggering an alarm as well as a process for treating a patient.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

Claims

1. A monitoring device for a therapy device for a patient, the monitoring device comprising: determination means for determining a therapy parameter;alarm means that can be activated to an activated state for triggering an alarm when said therapy parameter is beyond a warning limit in the activated state of said alarm means;automatic alarm means for automatically activating the alarm means when the therapy parameter is beyond a threshold value.

2. A monitoring device in accordance with claim 1, further comprising a means for setting a maximum value for said warning limit.

3. A monitoring device in accordance with claim 1, further comprising a means for filtering the therapy parameter over a time period.

4. A monitoring device in accordance with claim 1, further comprising a means for filtering by means of a sliding mean value.

5. A monitoring device in accordance with claim 1, further comprising a means for setting and/or correcting said warning limit in case of changes in set values by means of a model calculation.

6. A monitoring device in accordance with claim 1, further comprising a means for deactivating the alarm means when a therapy parameter taken into account for setting said warning limit assumes a value equal to or lower than said threshold value.

7. A monitoring device in accordance with claim 1, further comprising a means for automatically setting said warning limit during anesthesia by means of a gas when a minimum alveolar concentration (MAC) value of the gas is above a lower threshold value.

8. A monitoring device in accordance with claim 7, further comprising a means for automatically setting said warning limit at a value that equals a predeterminable percentage of the lowest of the MAC values taken into account for setting said warning limit, an inspiratory MAC value and/or expiratory MAC value and/or a MAC value filtered as a function of the action time and/or another MAC value, of the gas.

9. A monitoring device in accordance with claim 7, wherein said alarm means is activated for triggering an alarm when said inspiratory MAC value and said expiratory MAC value drop beyond said threshold value.

10. A monitoring device in accordance with claim 7, wherein said alarm means has an alarm intensity increasing over the course of time and/or for calculating a point in time at which said MAC value filtered as a function of the action time of the gas will drop beyond said lower threshold value.

11. A monitoring device in accordance with claim 10, further comprising a means for calculating the point in time of the alarm as a function of an action time constant of the particular, fastest acting gas in case of the use of two or more gases.

12. A monitoring device in accordance with claim 7, further comprising a means for determining a MAC value of each gas in case of the use of two or more gases and a means for determining a respective corresponding total MAC value.

13. A monitoring device in accordance with claim 1, wherein the monitoring device is in combination with therapy device components to form a therapy device.

14. A process for triggering an alarm during the treatment of a patient via a monitoring device, the process comprising the steps of: determining a therapy parameter;triggering an alarm by an alarm device that can be activated in an activated state of the alarm means when the therapy parameter passes beyond a warning limit;automatically activating the alarm means when the therapy parameter exceeds a threshold value.

15. A process in accordance with claim 14, wherein a maximum value is determined for said warning limit.

16. A process in accordance with claim 14, wherein a therapy parameter is filtered over a time period.

17. A process in accordance with claim 14, wherein a filtering of the therapy parameter is performed by means of a sliding mean value.

18. A process in accordance with claim 14, wherein changes in set values are taken into account by means of a model calculation for setting and/or correcting said warning limit.

19. A process in accordance with claim 14, wherein said warning limit is set during anesthesia by a gas when a MAC value of the gas exceeds a lower threshold value.

20. A process in accordance with claim 19, wherein said warning limit is set at a value that equals a predetermined percentage of the lowest of the values taken into account for setting said warning limit from a group of MAC values, which comprises an inspiratory MAC value and/or an expiratory MAC value and/or a MAC value filtered as a function of the action time of the gas and/or another MAC value.

21. A process in accordance with claim 19, wherein an alarm is triggered when said inspiratory MAC value and said expiratory MAC value drop beyond said threshold value.

22. A process in accordance with claim 19, wherein the alarm takes place with an intensity increasing over the course of time and/or a point in time at which said MAC value, filtered as a function of the action time, will drop beyond said lower threshold value is calculated.

23. A process in accordance with claim 19, wherein a calculation of the point in time of the alarm is performed as a function of an action time constant of the particular, fastest acting gas if two or more than two gases are used.

24. A process in accordance with claim 19, wherein the alarm device is deactivated when a value taken into account for setting said warning limit assumes a value equal to or lower than said lower threshold value.

25. A process in accordance with claim 19, further comprising the steps of: determining a MAC value of each gas in case of the use of two or more gases; anddetermining a respective corresponding total MAC value.

26. A process in accordance with claim 14, further comprising using the monitoring device as part of a therapy device.

27. A process in accordance with claim 26, further comprising using the therapy device for treating a patient based on at least one therapy parameter.

28. A therapy device for a patient, the therapy device comprising: therapy means for treating a patient based on at least one therapy parameter;a monitoring device including determination means for determining the value of one of the therapy parameters, an alarm device in one of an activated state and a none activated state, said alarm triggering an alarm when the one of the therapy parameters has a value beyond a warning limit in the activated state of said alarm device;automatic alarm means for automatically activating the alarm means when the therapy parameter is beyond a threshold value.