JPH08103415A - Patient alarm detecting method using target mode - Google Patents

Abstract

PURPOSE: To generate an alarm even in the transitional mode during the period from entering clinical treatment to the final tranquil state of a patient. CONSTITUTION: Physiological parameters of a patient are detected by an electrocardiograph(ECG) sensor 12, a pressure sensor 14, an Sp O2 sensor 16 and a temperature sensor 18 attached to the patient. The obtained parameter values are input to a system processor 20 and displayed by a display 24. Thereby, the patient's state is monitored, after the target limit of the physiological parameters is set up in correspondence with the selection of the user, a target mode is started and a dynamic limit of the physiological parameters variable in correspondence with the time passed is set up. An alarm is generated when the dynamic limit and one of the detected parameter values are out of the dynamic limit until one of the detected parameter values falls in the target limit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical monitor for a patient, and more particularly to a method for detecting a patient alarm using a target mode for detecting an alarm when the patient's condition is intentionally changed. Is.

[0002]

2. Description of the Related Art Patient monitor devices are commonly used to monitor the condition of patients in, for example, coronary care units and intensive care units of hospitals.
These devices typically include an ECG attached to the patient.
(Electrocardiograph) sensor, blood pressure sensor,
And a bedside monitor with one or more sensors, such as temperature sensors. The sensor measures various physiological parameters of the patient. The measured parameters are processed by the system processor. The processed information can be displayed on a video display screen and stored for later analysis. The patient's physiological information from several bedside monitors can be sent to a central station located at the nursing station, for example.

Bedside patient monitors and central stations are capable of displaying physiological parameters as waveforms and / or numerical values. Another important function of the patient monitor is to raise an alarm if one or more physiological parameters indicate that the patient needs attention. Such alerts are necessary because it is infeasible to constantly observe the display screen of the patient monitor. Alarms are usually issued both visually and audibly.

The conventional way of specifying alarm criteria is to set constant upper and lower thresholds for measurements such as heart rate. When the measured value exceeds the upper threshold value or falls below the lower threshold value, an alarm is issued. This approach is not adapted to situations where the clinician deliberately alters the patient's condition by, for example, administering an anesthetic or drug. Such interventions may cause the patient's heart rate, blood pressure, and other physiological parameters to fall outside certain alarm limits, and these changes may cause alarms, even if they are predicted normal. Become. Many clinicians, as mentioned above, turn alarms off or disable them, as they would be bothered by a patient monitor that would generate an alarm if they deliberately change the patient's condition. When turning off the alarm, the clinician is responsible for constantly monitoring the patient's condition during the intervention process. This can result in inadequate monitoring. If the clinician resets the alarm limit to the desired steady-state parameter value after the intervention, the patient monitor indicates that the parameter value has not yet reached the final value defined by the new alarm limit.
Immediately raise an alarm.

[0005]

A variety of more sophisticated alarm criteria have been proposed. For example, JSGravenstei
n (Z.S.Gravenstein) Other editing,
1980 Essential Noninvasiv Monitoring in Anes
thesia (“essentially non-noxious monitor in anesthesia”),
"Thoughtful Alarms" by JHPhilip and "Overview: Creating Practical Alerms for the Futur" by LHPhilip in 1989, pages 191-201.
e ”(Summary: Creation of practical warnings for the future).
Such an approach can be unnecessarily complex for relatively simple patient monitoring requirements and does not address alarm detection when the patient's condition is intentionally changed.

[0006]

According to a first aspect of the invention, means are provided for detecting a patient alarm. The method is utilized in a patient monitoring device including at least one sensor for measuring the value of a physiological parameter and a processor for processing the measured parameter value and providing information representative of the measured parameter value. It In accordance with the present invention, a patient monitoring device, in response to a user selection, sets a target limit for a physiological parameter, initiates a target mode after setting the target limit, and changes the physiology over time. To set dynamic limits for dynamic parameters, and if any of the measured parameter values are outside the dynamic limits, an alarm is generated until any of the measured parameter values are within the target limits Execute a method consisting of steps.

The dynamic limits are generally set to converge to the target limits as a function of time. Dynamic limits should be initiated at the beginning of the intervention procedure. The target mode is preferably terminated when any of the measured parameter values are within target limits. After exiting the target mode, an alarm will be issued if any of the measured parameter values are outside the target limits. After the alarm is issued, the target mode can be restarted by the user.

According to another aspect of the invention, a patient monitoring device comprises a sensor for measuring the value of a physiological parameter and a processor for processing the measured parameter value measured by the sensor. It The processor is responsive to a user selection to set a target limit for the physiological parameter, a means for initiating a target mode after the target limit is set, and a set of time-varying physiological parameters. Means for setting dynamic limits, means for comparing measured parameter values with dynamic limits, and if any of the measured parameter values fall outside the dynamic limits, any of the measured parameter values Consists of means for issuing an alarm until the target limits are met.

[0009]

1 is a block diagram of a patient monitoring system suitable for incorporating the alarm detection technique of the present invention. The bedside monitor 10 as a patient monitoring device is typically located at the patient's bedside and comprises one or more transducers or sensors attached to the patient. The transducer can include ECG sensors 12, pressure sensors 14, S _P O ₂ sensor 16, and temperature sensor 18. The number and type of sensors are arbitrary. The sensor detects various physiological parameters of interest.

The physiological parameter measurements obtained by the sensor are provided to the system processor 20.
Generally, the output signal of an analog sensor is amplified and digitally converted by an analog-to-digital converter (not shown).
Converted to data. The digital data representing the sensor signal is processed by the processor, that is, the system processor 2
0 is supplied. The system processor 20 includes a system memory 22, a display device 24 (typically a video display screen), a display controller 26, and an operator interface 28 for monitoring the patient's condition and providing information to the user. Works in tandem. As the system processor 20, for example, a Motorola 68
A 0x0 microprocessor is possible.

The information displayed on the display device 24 includes a waveform of one or more physiological parameters, a numerical value of one or more physiological parameters, and an alarm indicating that the patient needs attention. Generally, the alarm is also sounded. The physiological parameter information obtained by the sensor can be stored in system memory 22 for subsequent analysis. Information on the patient's condition
It is also possible to supply to the station. An example of a bedside monitor of the type shown in FIG. 1 is the model M1176A manufactured and sold by Hewlett-Packard Company.

With reference to FIG. 2, an alarm detection technique according to the present invention will be clarified. In the case of FIG. 2, the heart rate is shown as a function of time. However, it is clear that the present invention can be applied to any physiological parameter that can be problematic in connection with interventional procedures.
The present invention is also compatible with interventional procedures by which the clinician deliberately changes the patient's condition or situation. An example is changing the patient's condition by administering an anesthetic or other drug. However, the invention is compatible with any procedure or intervention that intentionally alters a patient's physiological parameters.

In the example of FIG. 2, the patient's heart rate as a function of time is represented by curve 40. Initially, the patient's heart rate is in the range of about 100-110. For example, as a result of an interventional procedure such as administering a drug, a patient's heart rate is expected to drop to a range of approximately 50-70 over a particular time period. Both the magnitude of the change and the time required for the change are important factors in determining whether the patient's response to the intervention was normal or abnormal.

With prior art devices, the clinician may turn off the alarm associated with heart rate or other parameter being measured during the transition between the intervention and the patient's final steady state, or Or it was possible to prevent them from working. Clinicians could also effectively disable alarms by setting alarm limits at very wide intervals. In any case, during the potentially critical period, the clinician was constantly unsatisfied, constantly monitoring patient parameters.

In accordance with the present invention, the clinician sets a target limit for each physiological parameter that is expected to change as a result of the intervention procedure. The physiological parameters are
Some parameters are directly measured, or
It may also be a parameter calculated from one or more measurements. Examples of calculated parameters are heart rate and heart index. The target limits set the upper and lower limits of the acceptable range for steady-state values of physiological parameters after the intervention procedure. In FIG. 2, an upper target limit 42 and a lower target limit 44 are shown. When the clinician sets new upper and lower target limits 42 and 44, the system processor 20 causes the new upper and lower target limits 42 and 44, the current measured values of the parameters, and the current and target limits. Pre-programmed for the time allowed for transitions between,
Alternatively, based on the information entered by the user, the dynamic limit 5
Set 0 and 52. The dynamic limits 50 and 52 border the measured parameter values during a period that begins at the beginning of the intervention procedure and ends when the measured parameter values are within the upper and lower target limits 42 and 44. Set the upper and lower limits.

During the transition period, the bedside monitor 1
0 enters the target mode and monitors the transition state after the intervention procedure starts. The measured parameter values are dynamic limits 50 and 5
As long as it stays within the range of 2, the alarm is not issued and the measured parameter value will eventually fall within the range of the upper target limit 42 and the lower target limit 44. At this point, the target mode ends. As soon as the parameter value exceeds the dynamic limit, as indicated by curve 56, an alarm is triggered.
In the case of the example of FIG. 2, this represents an increase rather than a decrease in the expected heart rate. The measured parameter value is the curve 5.
Once the dynamic limit is exceeded, as indicated at 8, again, an alarm is issued immediately. In the case of the example of FIG. 2, this indicates that the heart rate is decreasing faster than expected,
It may also indicate that the patient needs attention. In either case, the prior art device raises the alarm during the transition where it is most likely to be inoperable.

In the example of FIG. 2, the dynamic limits 50 and 52 are
Shown as spaced straight lines with equal slope as a function of time. In general, the dynamic bound can be any time function. Furthermore, the upper and lower dynamic limits can be different time functions or the intervals can be varied as a function of time. The dynamic limit can also be increased as a function of time if the measured parameter value is expected to increase after the intervention. Finally, if the measured parameter value is expected to return to its initial value within a certain time period, the dynamic limit can be raised and then lowered as a function of time, and vice versa. Is also possible. In any case, the dynamic limit crosses the target limit within a limited time period and the measured parameter value must, within that range, reach the target limit, a time "window".
Will be formed. In the example of FIG. 2, the dynamic limits 50 and 52 are at points 64 and 66, respectively.
The upper target limit 42 is crossed.

Dynamic limits are set for an interventional procedure based on the expected normal response to the interventional procedure.
The important parameters of the dynamic limit are the upper and lower limits as a function of time, and the measured parameter value is the upper target limit.
2 and the time required to reach the lower target limit 44. The dynamic limit is as shown by the arrow 60 in FIG.
It is preferably set based on the measured parameter value at the time of intervention. Assuming that the intervention procedure is initiated immediately after setting the target limits by the clinician, as indicated by arrow 62 in FIG. 2, dynamic limits 50 and 52 can be set at the time the target limits are set. Is. Alternatively, the operator interface 28 (FIG. 1) of the bedside monitor 10 can include a key to signal the start of an interventional procedure to the device. When the intervention is initiated, the device initiates the target mode and compares the measured parameter values with the dynamic limits. When the measured parameter value falls within the upper and lower target limits 42 and 44, the target mode ends. Optionally, the device can also indicate that the measured value has reached the target limit and the target mode has ended. After the end of the target mode, an alarm is triggered whenever the measured parameter value exceeds the upper and lower target limits 42 and 44.

Another option is to allow the user to re-initiate the target mode if the clinician's judgment indicates that the patient's condition is satisfactory after the alarm is issued. When the target mode is restarted, the target limits will be the same, but the dynamic limits will be recalculated based on the current measurements of physiological parameters.

3 and 4 are flow charts of the alarm detection technique of the present invention utilizing target mode. In the preferred embodiment, the alert detection technique of the present invention is implemented as a software program running on system processor 20 (FIG. 1). The present invention is, for example, C / C +
+ Can be implemented by programming language.

The user sets the physiological parameters in step 70. The target limit is based on the predicted steady state range of parameter values after the intervention procedure. Target limits can be set for each physiological parameter that is expected to change as a result of the intervention. The setting of the target limit in step 70 starts the target mode. In step 72, the current measured parameter value is checked against the target limit. If it is determined in step 74 that the measured value is within the target limits, then in step 76 the target mode ends. If the current measurement is outside the target limits, then in step 78 the time required for the physiological parameter to reach the target limits is determined. The time required may be reprogrammed and stored in system memory 22 for a particular procedure, or via operator interface 28,
It is also possible for the user to select. Next, step 8
At 0, dynamic limits are set based on the time required, target limits, and current values of physiological parameters. As mentioned above, the dynamic limits can be set as soon as the user selects the target limits, or
Until the user tells the system to start the intervention procedure,
It is possible to delay.

In step 82, each measured parameter value is checked against dynamic limits. If any of the measurements fall outside the dynamic limits, as shown at step 84, then at step 86 an alarm is generated. The alarm corresponds to the condition illustrated by curves 56 and 58 in FIG. If the measured value is determined to be within the dynamic limits in step 84, it is compared to the target limit in step 88. If it is determined in step 88 that the measured value is within the target limit, in step 90,
Goal mode ends. Then, when the measured parameter value exceeds the target limit, an alarm is issued. If, in step 88, the measured parameter value is determined to be outside the target limit, the procedure returns to step 82 to match the next measured parameter value with the dynamic limit. Therefore,
If the measured value remains within the dynamic limits, no alarm is issued. The measured values eventually fall within the target limits and the target mode ends in step 90.

While we have shown and described what are considered to be the preferred embodiments of the invention, it will be apparent to those skilled in the art that it does not depart from the scope of the invention as defined in the claims. , Various changes and modifications can be made.

Although the respective embodiments of the present invention have been described in detail above, in order to facilitate understanding of the respective embodiments, the respective embodiments are summarized and listed below.

(1). At least one sensor (12, 14 ,;) for measuring the value of a physiological parameter of a patient
16, 18), and a patient alarm detection method in a patient monitor device (10) including a processor (20) for processing the measurement parameter value measured by the sensor to obtain information representing the measurement parameter value. , In response to the user's selection, a physiological parameter target limit (4
2, 44) and (70) starting the target mode after setting the target limit.
Setting (80) a dynamic limit (50, 52) of a physiological parameter that varies with time; comparing a measured parameter value with the dynamic limit (50, 52); If any of the measured parameter values fall outside the dynamic limits (50, 52), then an alarm is generated until any of the measured parameter values fall within the target limits (42, 44). 86) and a patient alarm detection method utilizing a target mode composed of

(2). Furthermore, it is a patient alert detection method using the target mode described in 1 above, which includes the step of terminating the target mode when any of the measured parameter values falls within the range of the target limit.

(3). In the step of setting dynamic limits,
A method for detecting a patient alarm utilizing the target mode according to 1 above, including the step of starting the dynamic limit at the start of an intervention procedure.

(4). Furthermore, it is a patient alarm detection method using the target mode described in 1 above, which includes the step of restarting the target mode after the alarm is generated.

(5). In the step of setting dynamic limits,
A patient utilizing the goal mode of claim 1 including current measurements of physiological parameters therein, and later including the steps of setting a dynamic upper and dynamic lower limit that intersects the target limits. This is an alarm detection method.

(6). It comprises a sensor (12, 14, 16, 18) for measuring the value of a physiological parameter and a processor (20) for processing said measured parameter value, said processor responsive to a user selection. Means for setting (70) the target limits (42, 44) of the physiological parameter, and after setting said target limits,
Set a means for initiating (78) the target mode and dynamic limits (50, 52) that vary over time (8).
0), a means for comparing (82, 84) the measured parameter value with the dynamic limit (50, 52), and any of the measured parameter values is the dynamic limit (50, 52). 52) outside the range of 52), means for issuing an alarm (86) until any of the measured parameter values fall within the target limits (42, 44). Is.

(7). 7. The patient monitor apparatus of clause 6, wherein the processor further comprises means for exiting the target mode when any of the measured parameter values fall within the target limits.

(8). 7. A patient monitoring device as described in 6 above, wherein the means for setting the dynamic limit includes means for initiating the dynamic limit at the beginning of an intervention procedure.

(9). The display device is included, and the processor includes means for displaying on the display device that the target mode has ended.
The patient monitor device according to 1.

(10). The means for setting a dynamic limit includes a current measurement of a physiological parameter in between, and later means for setting a dynamic upper and lower limit that intersects the target limit. The patient monitor apparatus according to 6 above, which is included.

[0035]

As described above, according to the present invention, after setting the target limit of the physiological parameter of the patient in response to the selection by the user, the target mode is started and the movement of the physiological parameter which changes with time is started. Set a dynamic limit, compare the set parameter value to the dynamic limit, and alert if any of the measured parameter values fall outside the dynamic limits until one of the measured parameter values falls within the target limits. The alarm can also be generated during the transitional mode between the clinician's intervention and the patient's final steady state, so that during the transition, the clinician constantly updates the patient's parameters. No need to monitor.

[Brief description of drawings]

FIG. 1 is a block diagram of a patient monitoring device suitable for implementing the present invention.

FIG. 2 is a graph of heart rate as a function of time showing target and dynamic limits utilized in accordance with the present invention.

FIG. 3 is a flowchart of a patient alert detection method utilizing a target mode according to the present invention.

FIG. 4 is a flow chart of a patient alarm detection method utilizing a target mode according to the present invention.

[Description of reference numerals] 10 bedside monitors 12 ECG sensor 14 pressure sensor 16 S _P O ₂ sensor 18 Temperature sensor 20 system processor 22 system memory 24 display 26 display controller 28 operator interface 42 the upper target limit 44 below Target limit 50, 52 Dynamic limit

Claims (1)

[Claims] 1. At least one sensor (12, 14, 16,) for measuring the value of a physiological parameter of a patient.
18) and a processor (1) including a processor (20) for processing the measurement parameter value measured by the sensor to obtain information representing the measurement parameter value (1).
0) In the method for detecting a patient alarm according to 0), in response to a user's selection, setting a target limit (42, 44) of a physiological parameter; and, after setting the target limit, starting a target mode. (78) setting a dynamic limit (50, 52) of a physiological parameter that varies over time (80); comparing a measured parameter value with the dynamic limit (50, 52); One of the measured parameter values is the dynamic limit (5
0, 52) outside the range of 0, 52), an alarm is generated until any of the measured parameter values fall within the range of the target limit (42, 44). Patient alarm detection method to use.