Patent Application
20140135603
1. Technical Field
The present disclosure relates to patient monitoring and, more particularly, to systems and methods for monitoring the oxygen saturation of a patient's blood.
2. Background of Related Art
In the United States, about 4,800 babies are born every year with critical congenital heart defects (“CCHDs”), which pose significant risks to babies whose conditions go undiagnosed. In an effort to diagnose CCHDs at an early stage, screening for CCHDs has been added to the Recommended Uniform Screening Panel for newborns.
Pulse oximetry screening is a non-invasive technique used to measure the percent oxygen saturation of hemoglobin in a patient's arterial blood (SpO2). Pulse oximetry screening is used as a diagnostic tool for diagnosing CCHDs in newborns, as low SpO2 levels may potentially indicate the presence of a CCHD. However, pulse oximetry screening is also used to monitor SpO2 levels in other applications, e.g., to monitor SpO2 levels above and below a surgical site after an arterial-related surgery.
The present disclosure relates to systems and methods for screening a patient, generally including receiving a set of first SpO2 readings from a first sensor over a time period, receiving a set of second SpO2 readings from a second sensor over the time period, calculating an average first SpO2 value based on some or all of the first SpO2 readings, calculating an average second SpO2 value based on some or all of the second SpO2 readings, calculating a differential value based on some or all of the first SpO2 readings and some or all of the second SpO2 readings, and determining a screen result based upon the average first SpO2 value, the average second SpO2 value, and the differential value. The differential value may be, for example, an average differential value or an accumulation differential value.
The aspects and features of the present disclosure are advantageous in that they provide for a more accurate indication of the SpO2 levels in a patient's blood, reducing the likelihood of false results (false negatives and false positives) that may occur due to unreliable data and/or data abnormalities, e.g., spikes, valleys, etc., at any particular point-in-time. The aspects and features of the present disclosure are also advantageous in that they allow for the exclusion of data from a particular period of time (or particular periods of time) determined to be unreliable, thus reducing the influence of unreliable data on the overall results. The aspects and features of the present disclosure are further advantageous in that they provide for the display of current and average data as well as additional SpO2 level metrics on a bedside device and/or a remote device, thus allowing a user, e.g., a healthcare provider, to readily ascertain both the current status of the patient and the status of the patient over an elapsed period of time.
Certain embodiments of the present disclosure may include some, all, or none of the above advantages and/or one or more other advantages readily apparent to those skilled in the art from the drawings, descriptions, and claims included herein. Moreover, while specific advantages have been enumerated above, the various embodiments of the present disclosure may include all, some, or none of the enumerated advantages and/or other advantages not specifically enumerated above.
The present disclosure and its various aspects and features are described hereinbelow with reference to the accompanying drawings, wherein:
Referring to
Patient monitoring devices 110 may include one or more bedside monitoring devices 111, 112 one or more portable monitoring devices 113, 114, and/or any other suitable device(s) for visual monitoring, audible monitoring, monitoring of physical characteristics, physiological conditions, or other measurables, or otherwise monitoring a patient under observation. For example, portable monitoring devices 113, 114 may be configured as a pulse oximeter for measuring the percent oxygen saturation of hemoglobin in arterial blood (SpO2). In particular, first and second sensors 115, 116 disposed on the patient's right hand and left foot, respectively, may be provided for sensing SpO2 levels at these locations and relaying the same to portable monitoring device 114, although greater or fewer sensors and/or sensors in different locations may also be provided, depending on a particular purpose. Further, sensors 115, 116 may be connected to the same device (as shown), or each sensor 115, 116 may be connected to a different device. Portable monitoring device 114 may be configured to process and display the SpO2 data (or other patient data) on a visual display 117 thereof and/or may be configured to relay the SpO2 data (or other patient data) to one or more servers 120, 130, 140, e.g., data server 120, this may be done wirelessly as shown with respect to portable monitoring device 114, or as a wired connection as shown with respect to portable monitoring device 113. Bedside monitoring devices 111, 112 and portable monitoring devices 113, 114 may similarly be employed to monitor other characteristics, conditions, measurables, or to otherwise monitor the patient and to process the patient data, display the patient data, and/or relay the patient data to data server 120. Patient monitoring devices 110 may be wirelessly coupled to data server 120, or may be coupled to data server 120 via a wired connection. Patient monitoring devices 110 may include any suitable software, firmware, and hardware for these purposes.
Data server 120, as mentioned above, is configured to receive patient data from patient monitoring devices 110, although application server 130 and/or web server 140 may additionally or alternatively be configured to receive patient data from patient monitoring devices 110. One or more of servers 120, 130, 140 may further be configured to store the patient data in a database, process the patient data, and/or transmit the patient data between servers 120, 130, 140, to patient monitoring devices 110, and/or to remote devices 150. Servers 120, 130, 140 may include any suitable software, firmware, and hardware for these purposes.
Remote devices 150 request and receive the patient data, process the patient data, if needed, and display the patient data to a user, e.g., via a display monitor, user interface, browser, and/or application running on the remote device 150. Remote devices 150 may further be configured to receive input from a user, e.g., to manipulate the displayed data, set parameters for the displayed data, etc. Remote devices 150 may include any suitable software, firmware, and hardware for these purposes.
Turning now to
System 210 generally includes a storage 212, a memory 214, a processor 216, a user interface (UI) 218, an output 222, and an input 224. Storage device 212 may include any suitable component(s) operable for storing data, e.g., patient data received via input 224, such as, for example, a magnetic disk, flash memory, optical disk, or other suitable data storage device. Memory 214 may include any computer memory, e.g., RAM or ROM, mass storage media, removable storage media, combinations thereof, or any other suitable computer-readable storage medium, storing instructions for causing processor 216 to execute particular functions, e.g., to process the patient data. Processor 216 may include any suitable component(s), e.g., a central processing unit (CPU), operable to execute instructions stored in memory 214 to process and manipulate patient data, e.g., stored in storage device 212 or received via input 224, for output to UI 218 or to output 222. Processor 216 is further configured to receive, via input 224 and/or US 218, information, data, and/or control parameters for processing and manipulating the patient data in accordance with user-selected settings and user input. UI 218 functions to output the processed patient data for visual display, e.g., in graphical and/or numerical form, to the user and/or allows for the input of data, setting of parameters, etc., by the user. Output and input 222, 224, respectively, are provided to facilitate communication between system 210 and the other components of system 10. In particular, input 224 is configured to receive patient data to be processed, e.g., data sensed by first and second sensors 115, 116.
Turning now to
Referring to
With general reference to
Referring to
With continued reference to
The “Screening Threshold” settings of minimum time 450, minimum tolerance 460 and maximum accumulation threshold 470 allow the user to further customize the screening for a particular purpose. The minimum time corresponds to the minimum screening time. That is, a result determination will not be registered unless the minimum screening time has elapsed. Such a feature helps ensure that a sufficient amount of data, over a sufficient amount of time, is obtained so as to promote accuracy and minimize the bias of data anomalies. The maximum accumulation threshold and minimum tolerance will be described in greater detail below.
Referring to
Turning to
During screening (S510), as mentioned above, a plurality of first readings are obtained by first sensor 115 and a plurality of second readings are obtained by second sensor 116 (S604 and S606, respectively) over time t=0 to t=T. The intervals at which readings are taken may be constant, e.g., one reading every second, and/or may be set by the user to provide a desired level of granularity. In either configuration, the readings may be taken manually by a user or automatically taken by sensors 115, 116 and/or portable patient monitoring devices, 113, 114, e.g., independently of the user, at the prescribed intervals. The readings, obtained from sensors 115, 116 in the form of electrical signals, are input into input 224 of system 210, which may be partially or wholly embodied within portable patient monitoring device 114, one or more of the other patient monitoring devices 110, one or more of servers 120, 130, 140, and/or one or more of remote devices 150. The electrical signals received from sensors 115, 116 are converted into SpO2 readings, e.g., via processor 216, and are stored in a database, e.g., in storage 212. An exemplary data set of SpO2 readings obtained from first and second sensors 115, 116, respectively, is provided in TABLE 1:
During screening, as mentioned above, the current SpO2 readings are displayed on main display screen 300 numerically as indicated by reference numerals 312, 316. A graphical representation 330 of past readings from time t=0 (or a previous time period) to current is also displayed on main display screen 300. Once screening is complete, the screen data is analyzed (S520) to determine a screen result (S530), as will be described in greater detail below.
Turning now to
The average values of the plurality of first and second readings and the average differential value are calculated cumulatively and continuously, e.g., the averages are recalculated after each interval to include the readings corresponding to the next successive interval, and are displayed on main display screen 300 as indicated by reference numerals 322, 326, and 346, respectively. The average first and second values and the average differential value calculated from the exemplary data set of SpO2 values in TABLE 1, above, is provided in TABLE 3:
Based on the average first value, average second value, and average differential value, a screen result (S530) can be determined, as will be described in greater detail below. Alternatively, where only monitoring a patient is desired (as opposed to screening a patient to determine a particular result), the graphical and numerical displays of the current and average first values, current and average second values, and current and average differential values provide the user with an indication of the patient's SpO2 levels at any particular point-in-time as well as over an elapsed period of time.
Turning now to
Once calculated, the tolerance value is compared to a minimum tolerance (S814), e.g., a minimum percentage of time wherein the readings and/or values are acceptable, which may be set or confirmed via the indicator 460, “Minimum % Tolerance,” of setting screen 400. The tolerance value, as indicated by reference numeral 370, is displayed on main display screen 300, while the minimum tolerance is displayed on main display screen 300 as a superscript of the percentage in tolerance value. If the tolerance value is less than the minimum tolerance (“NO” in S814), the process proceeds to S816, wherein the screen result can be determined without further analysis/determination, e.g., solely on the tolerance value (or values, where multiple tolerance values are provided). The determined result may depend on the particular data used in calculating the tolerance value, e.g., whether the first readings, second readings, and/or differential values are used. For example, where the first and/or second readings are used in determining the tolerance value, it can be determined that the screen result is positive if the tolerance value is less than the minimum tolerance, as the tolerance value indicates that a substantial percentage of the first and/or second readings were outside their respective limits. As another example, where only the differential values are used, the result may be an unknown test result, because the tolerance value indicates that a significant portion of the data obtained over the time period t=0 to t=T may be unreliable. Alternatively or additionally, the tolerance value (whether or not it exceeds the minimum tolerance) may be provided as one of several metrics displayed on main display screen 300 from which the user can determine the screen result or use in evaluating the screen data.
With momentary reference to
Referring again to
In general, the tolerance value provides an indication as to the test result and/or test reliability over the time t=0 to t=T. That is, a tolerance value below the minimum tolerance may indicate a significant number of positive readings or a significant number of unreliable readings during screening, despite the fact that the readings at any given point-in-time may be within acceptable ranges. This feature helps prevent false negative results. On the other hand, a tolerance value above the minimum tolerance may indicate a large majority of negative readings or at least that there is no sensor error, despite the fact that infrequent and/or minimally significant spikes may occur at any given point-in-time to help prevent false positive or false unknown results. As will be described below, these spikes may be caused by patient movement and may not accurately reflect actual SpO2 levels. The present disclosure contemplates eliminating the data corresponding to these spikes from use in the screen result determination to further help prevent false positive results.
Turning now to
With regard to motion being detected (S908), for example, during the time period t1 to t2, any readings from the time period t1 to t2 are excluded from the calculation of the average values and average differential value (S912, S915, S916, respectively). For example, using the exemplary data of TABLE 1, above, if motion is detected from time intervals 6 through 8, these values would be eliminated from calculating the average values and average differential value (S912, S915, S916, respectively). The average values and average differential values in this example, wherein the readings from intervals 6 through 8 are excluded, are shown in TABLE 4:
As can be appreciated, and as shown via comparison of TABLES 3 and 4, eliminating readings taken during periods of motion serves to provide a more accurate indication of the patient's true SpO2 levels. It is further contemplated that other known conditions that may alter screening data may be sensed and those time periods also eliminated from calculating the above-described values, e.g., periods of technical error (sensor malfunction, sensor disconnection, weak signals), periods of other physical or physiological conditions (sleeping, coughing), etc.
Turning now to
As mentioned above, accumulation may be used to determine the screen result. More specifically, as an alternative or in addition to determining whether the average differential value is less than the third threshold, the accumulation value, i.e., the accumulated differential value, may be compared to the accumulation value threshold to determine whether the accumulation value is less than the accumulation value threshold. If the accumulation value is less than the accumulation value threshold (and/or the average differential value is less than the third threshold) and either the average first value is greater than the first threshold or the average second value is greater than the second threshold, the screen result is determined to be “NEGATIVE” because the accumulation value is within acceptable limits and at least one of the first and second average values is above its respective threshold. Otherwise, the screen result is determined to be “POSITIVE.”
The above-described screen result determination in step S530 may be used as the sole determining factor, from which processor 216 may signal UI 218 and/or output 222 to display a corresponding result on main display screen 300 via the screen result indicator 390. Alternatively, the screen result determination in step S530 may be used in conjunction with any or all of the other above-described data, metrics, and calculations in determining a result, depending on a particular purpose. For example, processor 216 may be configured to signal UI 218 and/or output 222 to display a corresponding screen result based upon the determine screen result step S530 and for example, the tolerance determination. That is, a screen result may be displayed as “POSITIVE” or “NEGATIVE” only if the both the determine screen result step S530 and the tolerance determination (detailed above) provide a similar result, while an “UNKNOWN” result is displayed otherwise. Alternatively, all of the above-described data, metrics, and calculations, may be presented to a user, e.g., via main display screen 300, such that the user may make a determination as to the screen results based on this information and depending on the particular patient, purpose of the screen, or other factors.
While several embodiments of the disclosure have been shown in the drawings and described in detail hereinabove, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow. Therefore, the above description and appended drawings should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.
