Continuous patient monitoring
A device for monitoring a physiological variable determines a starting value for a self-adjusting alarm limit based on an abnormal state of the physiological variable. The device determines a new value for the self-adjusting alarm limit from physiological data values received during a time window. When the new value for the self-adjusting alarm limit moves in a targeted direction, the device resets the self-adjusting alarm limit at the new value.
1. A device for monitoring a physiological variable, comprising:
at least one processing device; and
a memory device storing instructions which, when executed by the at least one processing device, cause the device to:
determine a starting value for a self-adjusting alarm limit based on an abnormal state of the physiological variable;
receive a plurality of physiological data values from a physiological sensor during a time window;
determine a new value for the self-adjusting alarm limit based on a calculation of the plurality of physiological data values received during the time window;
when the new value for the self-adjusting alarm limit moves in a targeted direction, reset the self-adjusting alarm limit at the new value; and
wherein a length of the time window is adjustable to adjust a sensitivity level of the self-adjusting alarm limit.
2. The device of claim 1 , wherein the instructions further cause the device to:
when the new value for the self-adjusting alarm limit moves in a direction opposite of the targeted direction, trigger an alarm.
3. The device of claim 1 , wherein when the self-adjusting alarm limit is an upper alarm limit, the targeted direction is a decreasing targeted direction; and wherein when the self-adjusting alarm limit is a lower alarm limit, the targeted direction is an increasing targeted direction.
4. The device of claim 1 , wherein the new value for the self-adjusting alarm limit is based on a percentile calculated from the physiological data values received during the time window.
5. The device of claim 1 , wherein the new value for the self-adjusting alarm limit is based on a standard deviation of the physiological data values received during the time window.
6. The device of claim 1 , wherein the instructions further cause the device to:
determine an updated value for the self-adjusting alarm limit from physiological data values received during a subsequent time window;
when the updated value for the self-adjusting alarm limit moves in the targeted direction, reset the self-adjusting alarm limit at the updated value; and
when the updated value for the self-adjusting alarm limit moves in a direction opposite of the targeted direction, trigger an alarm.
7. The device of claim 6 , wherein the instructions further cause the device to:
determine a plurality of updated values for resetting the self-adjusting alarm limit during successive time windows until one or more exit criteria are satisfied.
8. The device of claim 7 , wherein the one or more exit criteria include a target value within a normal range of the physiological variable.
9. The device of claim 7 , wherein the one or more exit criteria include a time limit.
10. The device of claim 1 , wherein the instructions further cause the device to:
receive artifact data;
determine whether the artifact data exceeds a predetermined threshold amount; and
when the artifact data exceeds the predetermined threshold amount, exclude the physiological data values affected by the artifact data when determining the new value for the self-adjusting alarm limit, or alter a display of the physiological data values on a display device.
11. The device of claim 1 , wherein the instructions further cause the device to:
receive a treatment event;
determine an expected effect of the treatment event on the physiological data values; and
alter a display of the physiological data values based on the expected effect.
12. The device of claim 11 , wherein the physiological data values are displayed to include the treatment event and a modified range overlayed on the physiological data values, wherein the modified range has upper and lower limits based on the expected effect.
13. The device of claim 12 , wherein the upper and lower limits of the modified range are curves that show expected increases and decreases in the physiological data values.
14. The device of claim 13 , wherein the modified range is shaded differently based on where the modified range overlaps a normal range of the physiological data values.
15. A method of continuous physiological monitoring, comprising:
determining a starting value for a self-adjusting alarm limit based on an abnormal state of a physiological variable;
receiving a plurality of physiological data values from a physiological sensor during a time window;
determining a new value for the self-adjusting alarm limit based on a calculation of the plurality of physiological data values received during the time window;
resetting the self-adjusting alarm limit at the new value when the new value for the self-adjusting alarm limit moves in a targeted direction;
adjusting a length of the time window to adjust a sensitivity level of the self-adjusting alarm limit; and
triggering an alarm when the new value for the self-adjusting alarm limit moves in a direction opposite of the targeted direction.
16. The method of claim 15 , further comprising:
determining an updated value for the self-adjusting alarm limit from physiological data values received during a second time window;
resetting the self-adjusting alarm limit at the updated value when the updated value for the self-adjusting alarm limit moves in the targeted direction; and
triggering the alarm when the updated value for the self-adjusting alarm limit moves in a direction opposite of the targeted direction.
17. The method of claim 15 , further comprising:
receiving artifact data;
determining whether the artifact data exceeds a predetermined threshold amount; and
excluding the physiological data values affected by the artifact data when determining the new value for the self-adjusting alarm limit, or altering a display of the physiological data values when the artifact data exceeds the predetermined threshold amount.
18. The method of claim 15 , further comprising:
receiving a treatment event;
determining an expected effect on the physiological data values based on the treatment event, the expected effect being a targeted effect or a side effect; and
altering a display of the physiological data values based on the expected effect.
19. The method of claim 18 , further comprising:
displaying the treatment event overlayed on the physiological data values; and
displaying a modified range overlayed on the physiological data values, the modified range having upper and lower limits based on the expected effect of the treatment event.