Abstract:
The present disclosure provides a system and method for facilitating user input of alarm settings for a patient monitor. In various embodiments, a pulse oximetry monitor may include a graphical user interface (GUI) which is capable of displaying a graph of blood oxygen saturation percentage over time. The system may be capable of allowing a user to enter an alarm threshold value and/or an alarm integration threshold value. The alarm threshold value may be displayed as a line on the graph, and the alarm integration threshold value may be displayed as a shaded area on the graph. The GUI may include an indicator of where an alarm would be initiated given the graph, the input alarm threshold value, and/or the alarm integration threshold value. The disclosed GUI may provide the user with a clear illustration of how the alarm threshold value and alarm integration threshold value may affect the alarm.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application No. 61/070,838, filed Mar. 26, 2008, and is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates to a user interface for alarm monitor management. 
         [0003]    This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
         [0004]    In the field of healthcare, caregivers (e.g., doctors and other healthcare professionals) often desire to monitor certain physiological characteristics of their patients. Accordingly, a wide variety of monitoring devices have been developed for monitoring many such physiological characteristics. These monitoring devices often provide doctors and other healthcare personnel with information that facilitates provision of the best possible healthcare for their patients. As a result, such monitoring devices have become a perennial feature of modern medicine. 
         [0005]    One technique for monitoring physiological characteristics of a patient is commonly referred to as pulse oximetry, and the devices built based upon pulse oximetry techniques are commonly referred to as pulse oximeters. Pulse oximeters may be used to measure and monitor various blood flow characteristics of a patient. For example, a pulse oximeter may be utilized to monitor the blood oxygen saturation of hemoglobin in arterial blood, the volume of individual blood pulsations supplying the tissue, and/or the rate of blood pulsations corresponding to each heartbeat of a patient. In fact, the “pulse” in pulse oximetry refers to the time-varying amount of arterial blood in the tissue during each cardiac cycle. 
         [0006]    Pulse oximeters typically utilize a non-invasive sensor that transmits light through a patient&#39;s tissue and that photoelectrically detects the absorption and/or scattering of the transmitted light in such tissue. A photo-plethysmographic waveform, which corresponds to the cyclic attenuation of optical energy through the patient&#39;s tissue, may be generated from the detected light. Additionally, one or more of the above physiological characteristics may be calculated based upon the amount of light absorbed or scattered. More specifically, the light passed through the tissue may be selected to be of one or more wavelengths that may be absorbed or scattered by the blood in an amount correlative to the amount of the blood constituent present in the blood. The amount of light absorbed and/or scattered may then be used to estimate the amount of blood constituent in the tissue using various algorithms. 
         [0007]    In addition to monitoring a patient&#39;s physiological characteristics, a pulse oximeter or other patient monitor may alert a caregiver when certain physiological conditions are recognized. For example, a normal range for a particular physiological parameter of a patient may be defined by setting low and/or high threshold values for the physiological parameter, and an alarm may be generated by the monitor when a detected value of the physiological parameter is outside the normal range. When activated, the alarm may alert the caregiver to a problem associated with the physiological parameter being outside of the normal range. The alert may include, for example, an audible and/or visible alarm on the oximeter or an audible and/or visible alarm at a remote location, such as a nurse station. These patient monitors may generally be provided with default alarm thresholds. However, in some instances, it may be desirable to alter the thresholds for various reasons. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Advantages of the disclosure may become apparent upon reading the following detailed description and upon reference to the drawings in which: 
           [0009]      FIG. 1  is a graph illustrating a patient&#39;s measured SpO 2  versus time in accordance with embodiments; 
           [0010]      FIG. 2  is a perspective view of a pulse oximeter coupled to a multi-parameter patient monitor and a sensor in accordance with embodiments; 
           [0011]      FIG. 3  is a block diagram of the pulse oximeter and sensor coupled to a patient in accordance with embodiments; and 
           [0012]      FIGS. 4-8  are exemplary graphical user interfaces of the pulse oximeter in accordance with embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
         [0014]    Different patients may exhibit different normal ranges of physiological characteristic values. Factors such as age, weight, height diagnosis, and a patient&#39;s use of certain medications may affect the patient&#39;s normal ranges of physiological parameters. For example, with a neonate, the normal SpO 2  range may be 80-95 percent. In contrast, for a 40-year-old patient, the normal SpO 2  range may be 85-100 percent. Accordingly, it may be desirable to set different low and/or high thresholds for particular parameters based on the patient being monitored. 
         [0015]    In addition, simply monitoring a patient&#39;s physiological parameters may result in excessive alarms if a parameter repeatedly exceeds a threshold only momentarily. Accordingly, an alarm integration method may be employed to reduce nuisance alarms on patient monitors. An exemplary alarm management system may be the SatSeconds™ alarm management technology available, for example, in the OxiMax® N-600x™ pulse oximeter available from Nellcor Puritan Bennett, LLC, or Covidien. Generally speaking, SatSeconds alarm management operates by integrating an area between an alarm threshold and a patient&#39;s measured physiological parameters over time. For example, a patient&#39;s SpO 2  readings may be charted, as in a graph  2  illustrated in  FIG. 1 . The patient&#39;s SpO 2  readings may be displayed as a plot  3  in the graph  2 . Similarly, a threshold SpO 2  value (e.g., 85 or 90 percent) may be displayed as a line  4  in the graph  2 . Rather than sounding an alarm as soon as the patient&#39;s measured SpO 2  (plot  3 ) drops below the threshold value (line  4 ), the SatSeconds system measures an area  5  (shaded in  FIG. 1 ) by integrating the difference between the plot  3  and the line  4  when the plot  3  is below the line  4 . The area  5  may be known as the SatSeconds value because it is a measure of saturation versus time. When the SatSeconds value exceeds a threshold value (e.g., a preset threshold or a user-input threshold), the caregiver may be alerted that the patient&#39;s oxygen saturation is too low. Due to the nature of this technology, a significant desaturation event  6  (e.g., a large drop in SpO 2 ) may cause the alarm to activate quickly because the SatSeconds threshold value may be exceeded in a short period of time  7 . In contrast, a minor desaturation event  8  (e.g., a drop in SpO 2  (line  4 ) to just below the threshold (line  6 )) may not cause the alarm to be activated quickly. That is, the minor desaturation event  8  may continue for a relatively long period of time  9  before the SatSeconds threshold value is exceeded. Exemplary SatSeconds threshold values may range from 0-200, where a threshold of 0 SatSeconds results in the alarm being activated as soon as the patient&#39;s measured SpO 2  (plot  3 ) drops below the threshold value (line  4 ). 
         [0016]    Because the SatSeconds technology is relatively new in the medical field, it may be desirable to assist the caregiver in efficiently determining the desired SatSeconds threshold value. Accordingly, a patient monitoring system in accordance with embodiments of the present disclosure may include one or more user interfaces which enable the caregiver to change the SatSeconds threshold value and/or the SpO 2  threshold value. In addition, the user interfaces may include graphical representations, as described below, to assist the caregiver in determining the optimal thresholds for a patient. Although the techniques introduced above and discussed in detail below may be implemented for a variety of medical devices, the present disclosure will discuss the implementation of these techniques in a pulse oximetry system. 
         [0017]      FIG. 2  is a perspective view of such a pulse oximetry system  10  in accordance with an embodiment. The system  10  includes a sensor  12  and a pulse oximetry monitor  14 . The sensor  12  includes an emitter  16  for emitting light at certain wavelengths into a patient&#39;s tissue and a detector  18  for detecting the light after it is reflected and/or absorbed by the patient&#39;s tissue. The monitor  14  may be configured to calculate physiological parameters received from the sensor  12  relating to light emission and detection. Further, the monitor  14  includes a display  20  configured to display the physiological parameters, other information about the system, and/or alarm indications. The monitor  14  also includes a speaker  22  to provide an audible alarm in the event that the patient&#39;s physiological parameters exceed a threshold. The sensor  12  is communicatively coupled to the monitor  14  via a cable  24 . However, in other embodiments a wireless transmission device (not shown) or the like may be utilized instead of or in addition to the cable  24 . 
         [0018]    In the illustrated embodiment, the pulse oximetry system  10  also includes a multi-parameter patient monitor  26 . In addition to the monitor  14 , or alternatively, the multi-parameter patient monitor  26  may be configured to calculate physiological parameters and to provide a central display  28  for information from the monitor  14  and from other medical monitoring devices or systems (not shown). For example, the multi-parameter patient monitor  26  may be configured to display a patient&#39;s SpO 2  and pulse rate information from the monitor  14  and blood pressure from a blood pressure monitor (not shown) on the display  28 . Additionally, the multi-parameter patient monitor  26  may emit a visible or audible alarm via the display  28  or a speaker  30 , respectively, if the patient&#39;s physiological parameters are found to be outside of the normal range. The monitor  14  may be communicatively coupled to the multi-parameter patient monitor  26  via a cable  32  or  34  coupled to a sensor input port or a digital communications port, respectively. In addition, the monitor  14  and/or the multi-parameter patient monitor  26  may be connected to a network to enable the sharing of information with servers or other workstations (not shown). 
         [0019]      FIG. 3  is a block diagram of the exemplary pulse oximetry system  10  of  FIG. 1  coupled to a patient  40  in accordance with present embodiments. One such pulse oximeter that may be used in the implementation of the present technique is the OxiMax® N-600x™ available from Nellcor Puritan Bennett LLC, but the following discussion may be applied to other pulse oximeters and medical devices. Specifically, certain components of the sensor  12  and the monitor  14  are illustrated in  FIG. 2 . The sensor  12  may include the emitter  16 , the detector  18 , and an encoder  42 . It should be noted that the emitter  16  may be configured to emit at least two wavelengths of light, e.g., RED and IR, into a patient&#39;s tissue  40 . Hence, the emitter  16  may include a RED LED  44  and an IR LED  46  for emitting light into the patient&#39;s tissue  40  at the wavelengths used to calculate the patient&#39;s physiological parameters. In certain embodiments, the RED wavelength may be between about 600 nm and about 700 nm, and the IR wavelength may be between about 800 nm and about 1000 nm. Alternative light sources may be used in other embodiments. For example, a single wide-spectrum light source may be used, and the detector  18  may be configured to detect light only at certain wavelengths. In another example, the detector  18  may detect a wide spectrum of wavelengths of light, and the monitor  14  may process only those wavelengths which are of interest. It should be understood that, as used herein, the term “light” may refer to one or more of ultrasound, radio, microwave, millimeter wave, infrared, visible, ultraviolet, gamma ray or X-ray electromagnetic radiation, and may also include any wavelength within the radio, microwave, infrared, visible, ultraviolet, or X-ray spectra, and that any suitable wavelength of light may be appropriate for use with the present techniques. 
         [0020]    In one embodiment, the detector  18  may be configured to detect the intensity of light at the RED and IR wavelengths. In operation, light enters the detector  18  after passing through the patient&#39;s tissue  40 . The detector  18  may convert the intensity of the received light into an electrical signal. The light intensity may be directly related to the absorbance and/or reflectance of light in the tissue  40 . That is, when more light at a certain wavelength is absorbed or reflected, less light of that wavelength is typically received from the tissue by the detector  18 . After converting the received light to an electrical signal, the detector  18  may send the signal to the monitor  14 , where physiological parameters may be calculated based on the absorption of the RED and IR wavelengths in the patient&#39;s tissue  40 . 
         [0021]    The encoder  42  may contain information about the sensor  12 , such as what type of sensor it is (e.g., whether the sensor is intended for placement on a forehead or digit) and the wavelengths of light emitted by the emitter  16 . This information may allow the monitor  14  to select appropriate algorithms and/or calibration coefficients for calculating the patient&#39;s physiological parameters. The encoder  42  may, for instance, be a coded resistor which stores values corresponding to the type of the sensor  12  and/or the wavelengths of light emitted by the emitter  16 . These coded values may be communicated to the monitor  14 , which determines how to calculate the patient&#39;s physiological parameters. In another embodiment the encoder  42  may be a memory on which one or more of the following information may be stored for communication to the monitor  14 : the type of the sensor  12 ; the wavelengths of light emitted by the emitter  16 ; and the proper calibration coefficients and/or algorithms to be used for calculating the patient&#39;s physiological parameters. Exemplary pulse oximetry sensors configured to cooperate with pulse oximetry monitors are the OxiMax® sensors available from Nellcor Puritan Bennett LLC. 
         [0022]    Signals from the detector  18  and the encoder  42  may be transmitted to the monitor  14 . The monitor  14  generally may include processors  48  connected to an internal bus  50 . Also connected to the bus may be a read-only memory (ROM)  52 , a random access memory (RAM)  54 , user inputs  56 , the display  20 , or the speaker  22 . A time processing unit (TPU)  58  may provide timing control signals to a light drive circuitry  60  which controls when the emitter  16  is illuminated and the multiplexed timing for the RED LED  44  and the IR LED  46 . The TPU  58  control the gating-in of signals from detector  18  through an amplifier  62  and a switching circuit  64 . These signals may be sampled at the proper time, depending upon which light source is illuminated. The received signal from the detector  18  may be passed through an amplifier  66 , a low pass filter  68 , and an analog-to-digital converter  70 . The digital data may then be stored in a queued serial module (QSM)  72  for later downloading to the RAM  54  as the QSM  72  fills up. In one embodiment, there may be multiple separate parallel paths having the amplifier  66 , the filter  68 , and the A/D converter  70  for multiple light wavelengths or spectra received. 
         [0023]    The processor(s)  48  may determine the patient&#39;s physiological parameters, such as SpO 2  and pulse rate, using various algorithms and/or look-up tables based on the value of the received signals corresponding to the light received by the detector  18 . Signals corresponding to information about the sensor  12  may be transmitted from the encoder  42  to a decoder  74 . The decoder  74  may translate these signals to enable the microprocessor to determine the proper method for calculating the patient&#39;s physiological parameters, for example, based on algorithms or look-up tables stored in the ROM  52 . In addition, or alternatively, the encoder  42  may contain the algorithms or look-up tables for calculating the patient&#39;s physiological parameters. The user inputs  56  may be used to change alarm thresholds for measured physiological parameters on the monitor  14 , as described below. In certain embodiments, the display  20  may exhibit a minimum SpO 2  threshold and a selection of SatSeconds values, which the user may change using the user inputs  56 . The monitor  14  may then provide an alarm when the patient&#39;s calculated SpO 2  integral exceeds the SatSeconds threshold. 
         [0024]      FIG. 4  illustrates an exemplary monitor  14  for use in the system  10  ( FIG. 2 ). The monitor  14  may generally include the display  20 , the speaker  22 , the user inputs  56 , and a communication port  80  for coupling the sensor  12  ( FIG. 2 ) to the monitor  14 . The display  20  may generally show an SpO 2  value  82  (i.e., percentage), a pulse rate  84  (i.e., beats per minute), a plethysmographic waveform (i.e., a plot  86 ), and a graphical representation  88  of the measured SpO 2  value versus time (i.e., a plot  90 ). In addition to displaying a trend of the patient&#39;s SpO 2  value, the graph  88  may serve as an indicator of the SatSeconds value. For example, a set SpO 2  threshold value (i.e., a line  92 ) may be displayed on the graph  88  with the plot  90 . When the measured SpO 2  value (i.e., the plot  90 ) drops below the threshold value (i.e., the line  92 ), an area  94  between the plot  90  and the line  92  may begin to fill in on the display  14 . At this time, the monitor  14  may begin to integrate the difference between the measured SpO 2  value (i.e., the plot  90 ) and the threshold value (i.e., the line  92 ). When the area  94  reaches a set value (i.e., the SatSeconds threshold value), the monitor  14  may indicate to the caregiver that a desaturation event is occurring, for example, by sounding an alarm via the speaker  22 , displaying an alert message on the display  20 , sending a signal to a nurse&#39;s station, or otherwise providing a notification that the patient&#39;s physiological parameters are not normal. 
         [0025]    The user inputs  56  may enable the caregiver to control the monitor  14  and change settings, such as the SpO 2  threshold value and/or the SatSeconds threshold value. For example, an alarm silence button  96  may enable the caregiver to silence an audible alarm (e.g., when the patient is being cared for), and volume buttons  98  may enable the caregiver to adjust the volume of the alarm and/or any other indicators emitted from the speaker  22 . In addition, soft keys  100  may correspond to variable functions, as displayed on the display  22 . The soft keys  100  may provide access to further data displays and/or setting displays, as described further below. Soft keys  100  provided on the display  20  may enable the caregiver to see and/or change alarm thresholds, view different trend data, change characteristics of the display  20 , turn a backlight on or off, or perform other functions. 
         [0026]    As indicated, the caregiver may access an alarm threshold control display  110 , an embodiment of which is illustrated in  FIG. 5 , by selecting the limits soft key  100  ( FIG. 4 ). The alarm threshold control display  110  may enable the caregiver to view and/or change both an SpO 2  threshold  112  and a SatSeconds threshold  114 . In addition, a graphical representation  116  of the effect of the SpO 2  threshold  112  and the SatSeconds threshold  114  may be provided. The graphical representation  116  may include, for example, an exemplary SpO 2  plot  118  and a line  120  corresponding to the SpO 2  threshold  112 . As will be illustrated further, the exemplary SpO 2  plot  118  may remain constant so that the caregiver can clearly see how changes to the SpO 2  threshold  112  and the SatSeconds threshold  114  will affect the alarm settings. 
         [0027]    Based on the SpO 2  threshold  112  and the SatSeconds threshold  114 , an alarm indicator  122  may illustrate the time at which the alarm would be sounded in the SpO 2  plot  118 . That is, given the SpO 2  plot  118  and the thresholds  112  and  114 , the monitor  14  ( FIG. 2 ) would alert the caregiver to a problem at the point indicated by the alarm indicator  122 . A shaded symbol  124  may correspond to the SatSeconds threshold  114  to indicate to the caregiver the size of an area  126  between the threshold line  120  and the plot  118  which must be filled before the alarm would go off. Furthermore, the first area  126  which corresponds to the SatSeconds threshold  114  may be shaded in to enable the caregiver to see where the SatSeconds threshold  114  is first exceeded on the exemplary SpO 2  plot  118 . The shaded in area  126  may correspond to the alarm indicator  122 . 
         [0028]    The thresholds  112  and  114  may be changed via soft keys. For example, an SpO 2  soft key  128  may be selected to change the SpO 2  threshold  112 , or a SatSeconds soft key  130  may be selected to change the SatSeconds threshold  114 . Selection of the threshold  112  or  114  may be indicated, for example, by a backlight, a color change, an underline, or any other indication method. The threshold  112  or  114  may then be changed by pressing increment soft keys  132 . The left increment soft key  132  may be pressed to decrease the threshold  112  or  114 , while the right increment soft key  132  increases the threshold  112  or  114 . It should be understood that the position of the increment soft keys  132  may be reversed. The increment soft keys  132  may be up and down arrows, left and right arrows, a minis sign and a plus sign, “UP” and “DOWN,” or any other indicator which enables the caregiver to clearly adjust the thresholds  112  and  114 . The thresholds  112  and  114  may be displayed as a numerical value  134  (e.g., the SpO 2  threshold  112 ), a virtual knob  136  (e.g., the SatSeconds threshold), or any other value indicator. In addition, the thresholds  112  and  114  may be adjusted in increments of any size. For example, the SpO 2  threshold  112  may be adjusted in increments of 1% while the SatSeconds threshold  114  may be adjusted in increments of 25. A number of discreet values may be available for the thresholds  112  and  114 , or the value adjustment may be continuous. 
         [0029]    As described above, changes in the thresholds  112  and/or  114  are illustrated in the graphical representation  116 . While the SpO 2  plot  118  remains constant, the threshold line  120  may move up or down based on changes to the SpO 2  threshold. Furthermore, in the case of a color display  110 , the SpO 2  threshold value  112  and the line  120  may be the same color, which is different from the other colors in the graphical representation  116 . Similarly, the SatSeconds symbol  124  and the area  126  may change based on the SatSeconds threshold  114 . The SatSeconds threshold  114 , symbol  124 , and area  126  may be illustrated in the same color, which is different from the other colors on the display  110 . By color-coding the display  110 , the caregiver may further see how the threshold values  112  and  114  affect the alarm settings. In addition, the SatSeconds symbol  124  may take on various forms to further illustrate the differences in SatSeconds thresholds  114 . For example, the symbol  124  may be a square which varies in size based on the threshold  114 , or the symbol  124  may be a square of constant size which fills up based on the threshold  114 . 
         [0030]      FIGS. 5-7  illustrate how changes in the SpO 2  threshold  112  and the SatSeconds threshold  114  are illustrated in the graphical representation  116 . For example, in  FIG. 5  the SatSeconds threshold  114  is increased from 25 ( FIG. 4 ) to 100. The SpO 2  threshold  112  remains at 85%, unchanged from  FIG. 4 . The alarm indicator  122  in  FIG. 5  is moved over relative to the alarm indicator  122  in  FIG. 4  because the SatSeconds threshold  114  is greater. In addition, two areas  126  in which the SpO 2  plot  118  drops below the SpO 2  threshold line  120  are not shaded in because the SatSeconds threshold  114  is not reached before the plot  118  again goes above the line  120 . The SatSeconds symbol  124  is illustrated as a larger square in  FIG. 5 , corresponding to the high SatSeconds threshold  114 . 
         [0031]      FIG. 6  illustrates the difference in alarm settings when the SpO 2  threshold  112  is increased from 85% ( FIG. 5 ) to 90% ( FIG. 6 ). The SatSeconds threshold  114  is constant from  FIG. 5  to  FIG. 6 . As the alarm indicator  122  and the area  126  illustrate, the SatSeconds threshold  114  is reached earlier in  FIG. 6  than in  FIG. 5 . Because the SpO 2  plot  118  does not go above the SpO 2  threshold line  120  after the first desaturation event, calculation of the SatSeconds value is not reset. Therefore, the alarm will be activated earlier for the given plot  118 . 
         [0032]    Finally,  FIG. 7  illustrates the effect that reducing the SatSeconds threshold  114  to zero will have on the alarm settings. At a threshold  114  of zero, the alarm will be activated as soon as the SpO 2  plot  118  falls below the threshold line  120 , as illustrated by the indicator  122 . There is no shaded area  126  because the SatSeconds integration, as described above, is not needed in this example. 
         [0033]    While only certain features have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within their true spirit.