Source: https://patents.google.com/patent/EP2256494B1/en
Timestamp: 2019-06-25 16:11:51
Document Index: 198391118

Matched Legal Cases: ['art 220', 'art 250', 'art 420', 'art 460', 'art 460', 'art 470', 'art.\n9']

EP2256494B1 - System for monitoring physiological characteristics according to the user biological state - Google Patents
System for monitoring physiological characteristics according to the user biological state Download PDF
EP2256494B1
EP2256494B1 EP10177011.3A EP10177011A EP2256494B1 EP 2256494 B1 EP2256494 B1 EP 2256494B1 EP 10177011 A EP10177011 A EP 10177011A EP 2256494 B1 EP2256494 B1 EP 2256494B1
EP10177011.3A
EP2256494A1 (en
John C. Mueller, Jr
Jeff B. Sanders
Edward S. Nielsen
2004-06-03 Priority to US10/860,114 priority Critical patent/US7399277B2/en
2005-05-20 Application filed by Medtronic Minimed Inc filed Critical Medtronic Minimed Inc
2005-05-20 Priority to EP05755120A priority patent/EP1759201B1/en
2010-12-01 Publication of EP2256494A1 publication Critical patent/EP2256494A1/en
2016-10-27 First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=37684661&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP2256494(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
2017-01-11 Publication of EP2256494B1 publication Critical patent/EP2256494B1/en
This invention relates generally to medical monitoring systems. More specifically, this invention relates to a device for monitoring physiological characteristics in individuals including those associated with physiological conditions (e.g. monitoring blood glucose levels in diabetics).
A variety of electrochemical sensors have been developed for detecting and/or quantifying specific agents or compositions in a patient's blood. Notably, glucose sensors have been developed for use in obtaining an indication of blood glucose levels in a diabetic patient. Such readings are useful in monitoring and/or adjusting a treatment program which typically includes the regular administration of insulin to the patient. Periodic blood glucose readings significantly improve medical therapies using semi-automated medication infusion devices. Some exemplary external infusion devices are described in U.S. Patent Nos. 4,562,751 , 4,678,408 and 4,685,903 , while some examples of automated implantable medication infusion devices are described in U.S. Patent No. 4,573,994 .
Electrochemical sensors can be used to obtain periodic measurements over an extended period of time. Such sensors can include a plurality of exposed electrodes at one end for subcutaneous placement in contact with a user's interstitial fluid, blood, or the like. A corresponding plurality of conductive contacts can be exposed at another end for convenient external electrical connection with a suitable monitoring device through a wire or cable. Exemplary sensors are described in U.S. Patent Nos. 5,299,571 ; 5,390,671 ; 5,391,250 ; 5,482,473 ; and 5,586,553 .
Conventional glucose monitoring systems are somewhat limited in features that they provide to facilitate the monitoring of blood glucose levels. Typically, a glucose monitor can take readings as directed by the user and might provide a warning if a reading is deemed at an unsafe level (e.g., a hyper- or hypoglycemic condition). However, by the time the warning occurs, the user may already be experiencing negative symptoms. Furthermore, it may be unacceptable to address this by simply reducing (or raising) the value which triggers an indicator (e.g. a display, an alarm or the like) of an unsafe condition, because this may prompt a user to take "remedial" action (such as administering an additional bolus) when no unsafe condition would have actually materialized. Such an approach merely increases the occurrence of false positive alarms. As a consequence, the unnecessary "remedial" action can actually provoke an unsafe condition. As described above, although existing glucose monitors adequately detect blood glucose levels upon entering the hyperglycemic (or hypoglycemic) range, they do not anticipate these conditions.
A monitor carried on a patent's wrist is shown in document US 2003/0187336 . This device acquires data both by asking the patient questions and by direct measurement for example using accelerometers. A monitor in the field of glycemic control is shown in documents US 2003/0208113 and US 2003/0125612 .
Thus, conventional glucose monitoring systems are somewhat limited in features they provide to facilitate the monitoring of blood glucose levels. There is a need for monitoring systems for a physiological characteristic (such as blood glucose levels) with convenient features and settings that allow users flexibility in tailoring the system's operation to their personal needs and lifestyle. Particularly, there is a need for such systems that provide advanced alarm functions to reduce or eliminate redundant alarms. In addition, there is a need for monitoring systems that allow a convenient review of measurement and alarm histories.
The invention is as defined in claim 1 below. Optional features are set out in the dependent claims.
FIG. 1A is a block diagram of a characteristic monitor;
FIG. 1B is a block diagram of a telemetered characteristic monitor;
FIG. 2A is a flowchart of a status check algorithm for a characteristic monitor;
FIG. 2B is a flowchart of screens for entering a reference value to calibrate a characteristic monitor;
FIGS. 4D and 4E illustrate respectively flowcharts of screens for setting hypoglycemia and hyperglycemia alarms with underlined text indicating that it is blinking on the current screen, awaiting to be changed by the user; from screen 1-8, SEL aborts and goes to the next major screen;
FIG. 4F illustrates a flowchart of screens for setting a hyperglycemia alarm snooze with underlined text indicating that it is blinking on the current screen, awaiting to be changed by the user; from screen 1-2, SEL aborts and goes to the next major screen;
FIG. 4G illustrates a flowchart of screens for reviewing a history of glycemia alarms;
FIG. 5 illustrates a reminder function;
FIG. 7 illustrates screens for viewing real-time and historical measurements of a physiological characteristic value;
FIG. 8E illustrates a screen employing a graphical display of which provides the concentrations of a physiological characteristic over a specific time scale as well as information regarding the physiological significance of that concentration (e.g. too high, in zone, too low etc.) where the information regarding the physiological significance of that concentration is delineated in a row-like display pattern. Alternative arrangements of this type of display pattern include a gradual transition between the stripes of the row-like display pattern as well as arrangements where stripe colors (e.g. yellow and red) can vary over time and represent warning levels that are preselected (e.g. set by the user);
Described are methods and systems for the convenient operation of monitoring physiological characteristics ("characteristic monitoring systems"). The description provided here encompasses the architecture of the apparatus as well as its control and convenience features. The control and convenience features can be implemented in a wide range of detailed characteristic monitoring system designs. Although there are primarily described glucose monitors used in the treatment of diabetes, the arrangements described are applicable to a wide variety of patient treatment programs where a physiological characteristic is periodically monitored to use in estimating the responsive treatment. For example, they can be used to determine the status and/or levels of a variety of characteristics including those associated with agents such as hormones, cholesterol, medication concentrations, pH, oxygen saturation, viral loads (e.g., HIV), or the like. As is known in the art, a sensor for the characteristic monitor can be implanted in and/or through subcutaneous, dermal, sub-dermal, inter-peritoneal or peritoneal tissue. Such sensors typically communicate a signal from the sensor set to the characteristic monitor.
Arrangements include specific features associated with a physiological characteristic monitoring apparatus (e.g. a continuous glucose monitor, glucose test strip meters and the like) that are designed to facilitate a users monitoring and/or control of a physiological characteristic of interest (e.g. blood glucose concentrations). Typically such physiological characteristic monitoring devices are coupled to one or more complementary medical apparati (e.g. sensor sets, infusion pumps and the like). In preferred embodiments, the sensor set and monitor are for determining glucose levels in the blood and/or body fluids of the user without the use of, or necessity of, a wire or cable connection between the transmitter and the monitor. Physiological characteristic monitors of the invention can be incorporated in to a wide variety of medical systems known in the art such as with infusion pump systems that designed to control the rate that medication is infused into the body of a user. Such infusion pump systems can include a physiological characteristic monitor which provides information to a user that facilitates the user's subsequent use of a drug delivery system (e.g. one that calculates a dose to be delivered by a medication infusion pump). In such contexts, the meter associated with the physiological characteristic monitor may also transmit commands to, and be used to remotely control, the delivery system. Preferably, the physiological characteristic monitor is used to monitor the glucose concentration in the body of the user, and the therapeutic agent that is infused by the delivery system into the body of the user includes insulin. Illustrative systems are disclosed for example in U. S. Patent Nos. 6,558,351 and 6,551,276 ; WO 00/19887 and WO 00/18449 ; as well as WO 2004/008956 and WO 2004/009161 .
The physiological characteristic monitoring apparatus can be used in combination with a wide variety of other devices, for example in a closed loop infusion system designed to control the rate that medication is infused into the body of a user. Such a closed loop infusion system can include a sensor and an associated meter which generates an input to a controller which in turn operates a delivery system (e.g. one that calculates a dose to be delivered by a medication infusion pump). In such contexts, the meter associated with the sensor may also transmit commands to, and be used to remotely control, the delivery system. Such systems can be fully automated with the sensor transmitting information to a processor that determines whether a medication dose is needed, with such processors further being coupled to an infusion pump which then infuses the appropriate medication. Alternatively, the systems can be partially automated, for example where a processor makes a recommendation to the user, with the user's approval then activating the infusion pump. Illustrative systems are disclosed for example in U. S. Patent Nos. 6,558,351 and 6,551,276 ; PCT Application Nos. US99/21703 and US99/22993 ; as well as WO 2004/008956 and WO 2004/009161 .
The described characteristic monitor systems are primarily adapted for use in subcutaneous human tissue. Alternatively, embodiments of the invention can be placed in a variety of other types of physiological milieus, such as muscle, lymph, organ tissue, veins, arteries or the like, as well as being used in related environments such as animal tissue. They can provide sensor readings on an intermittent, near-continuous or continuous basis.
The described arrangements include sensing and advanced predictive functions of the monitor which are designed to anticipate unsafe conditions for a user before they occur. In addition, predictive functions can be employed so that a user can obtain feedback to obtain a desired physical objective, such as maximizing athletic performance. Other functions of the monitor include multiple programmable alarms and reminders and diagnostic functions. Advanced alarm functions also include an alarm repeat delay function and a snooze function that can be set by a user. Embodiments of the invention can include advanced display tools to facilitate easy and quick interpretation of information related to the user's condition, including a display function for an alarm history as well as a history of measurements.
FIG. 1A is a block diagram of a characteristic monitoring system 100. The characteristic monitoring system 100 generally includes a sensor set 102 that employs a sensor that produces a signal that corresponds to a measured characteristic of the user, such as a blood glucose level. The sensor set 102 communicates these signals to a characteristic monitor 104 that is designed to interpret these signals to produce a characteristic reading or value for the user, i.e. a measurement of the characteristic. The sensor signals enter the monitor 104 through a sensor input 106 and through the sensor input 106 the signals are conveyed to a processor 108. The processor 108 determines and manipulates the sensor readings within the monitor 104. In addition, but not limited to, the characteristic monitor 104 provides additional functions that will aid in the treatment regime to which the characteristic reading applies. For example, but not limited to, the monitor may track meals, exercise and other activities which affect the treatment of diabetes. These additional functions can be combined with or independent from the characteristic readings determined by the monitor 104. Monitors can for example be coupled to an infusion pump that can further provide a medication to a user. Optionally the monitor is designed to be inconspicuous, for example a monitor design that resembles a wristwatch.
The data port 116 can be used for the monitor 104 to communicate with a computer 118. To facilitate communication, the monitor 104 may interface with the computer 118 through a communication station 120 that can serve as a docking station for the monitor 104, for example. The data port 116 within the monitor 104 can be directly connected to the computer 118. Through the communication link, data may be downloaded from the monitor 104, such as stored characteristic readings, settings, programs and other information related to the monitor's function. Thus, advanced analysis can be performed on the computer 118, freeing memory 110 within the monitor 104. Data such as characteristic readings, settings and programs can also be downloaded to the monitor 104. In this way, the monitor 104 can be conveniently reprogrammed without requiring tedious manual entry by the user.
FIG. 1B is a block diagram of a telemetered characteristic monitoring system. In this system 200, the sensor input 106 of the monitor 104 is a wireless receiver, such as a radio frequency (RF) receiver. The sensor set 102 provides a signal via wired link to a telemetered monitor transmitter 202, where the signal is interpreted and converted to an RF signal. The wireless receiver sensor input 106 of the monitor 104 converts the signal to data understandable to the monitor processor. With some advantages, the telemetered characteristic monitoring system can perform any or all the functions of the characteristic monitoring system of FIG. 1A.
A characteristic monitoring system 100, includes a sensor set 102 and characteristic monitor device 104. The sensor set 102 generally utilizes an electrode-type sensor. However, in alternative arrangements, the system can use other types of sensors, such as electrically based sensors, chemically based sensors, optically based sensors, or the like. In further alternative arrangements, the sensors can be of a type that is used on the external surface of the skin or placed below the skin layer of the user. Preferred surface mounted sensors utilize interstitial fluid harvested from underneath the skin. In this context for example, real-time interstitial sensor glucose values can be correlated with blood glucose values. The sensor set 102 is connected to the monitor device 104 and provides a signal based upon the monitored characteristic (e.g., blood glucose). The characteristic monitor device 104 utilizes the received signal to determine the characteristic reading or value (e.g., a blood glucose level). In still other arrangements the sensor may be placed in other parts of the body, such as, but not limited to, subcutaneous, dermal, sub-dermal, inter-peritoneal or peritoneal tissue
The telemetered characteristic monitor transmitter 202 generally includes the capability to transmit data. In alternative arrangements the telemetered characteristic monitor transmitter 202 can include a receiver, or the like, to facilitate two-way communication between the sensor set 102 and the characteristic monitor 104. In alternative arrangements the characteristic monitor 104 can be replaced with a data receiver, storage and/or transmitting device for later processing of the transmitted data or programming of the telemetered characteristic monitor transmitter 202. In addition, a relay or repeater (not shown) can be used with a telemetered characteristic monitor transmitter 202 and a characteristic monitor 104 to increase the distance that the telemetered characteristic monitor transmitter 202 can be used with the characteristic monitor 104.
For example, a relay can be used to provide information to parents of children using the telemetered characteristic monitor transmitter 202 and the sensor set 102 from a distance. The information can be used when children are in another room during sleep or doing activities in a location remote from the parents. In a related arrangement, a relay can be used to provide information to medical professional and/or related caregiver regarding the physiological status of a user (e.g. a hypoglycemic event) in a situation where that event has not been acknowledged and/or addressed by the user within a specific time parameter (e.g. 15-45 minutes). In one illustrative embodiment, a physiological characteristic monitoring system includes a relay that automatically dials a predetermined telephone number as part of a notification scheme for an event that has not been acknowledged and/or addressed by the user. In further arrangements, the relay can include the capability to sound an alarm. In addition, the relay can be capable of providing telemetered characteristic monitor transmitter 202 data from the sensor set 102, as well as other data, to a remotely located individual via a modem connected to the relay for display on a monitor, pager or the like. The data can also be downloaded through the communication station 120 to a remotely located computer 118 such as a PC, laptop, or the like, over communication lines, by modem, wired or wireless connection. Wireless communication can include for example the reception of emitted radiation signals as occurs with the transmission of signals via RF telemetry, infrared transmissions, optical transmission, sonic and ultrasonic transmissions and the like. As disclosed herein, some arrangements can omit the communication station 120 and use a direct modem or wireless connection to the computer 118. In further arrangements, the telemetered characteristic monitor transmitter 202 transmits to an RF programmer, which acts as a relay, or shuttle, for data transmission between the sensor set 102 and a PC, laptop, communication station 118, a data processor, or the like. In further alternatives, the telemetered characteristic monitor transmitter 202 can transmit an alarm to a remotely located device, such as a communication station 118, modem or the like to summon help.
In addition, further arrangements can include the capability for simultaneous monitoring of multiple sensors and/or include a sensor for multiple measurements.
The characteristic monitor device 104 receives characteristic information, such as glucose data or the like, from the sensor set 102 and displays and/or logs the received glucose readings. Logged data can be downloaded from the characteristic monitor 104 to a PC, laptop, or the like, for detailed data analysis. In further embodiments, the characteristic monitoring system 100, 200 can be used in a hospital environment, or the like. Still further arrangements can include one or more buttons to record data and events for later analysis, correlation, or the like. Further buttons can include a sensor on/off button to conserve power and to assist in initializing the sensor set 102. The characteristic monitoring system 200 can also be employed with other medical devices to combine other patient data through a common data network system.
In some arrangements the sensor set 102 can monitor the temperature of the sensor set 102, which can then be used to improve the calibration of the sensor. For example, for a glucose sensor, the enzyme reaction activity may have a known temperature coefficient. The relationship between temperature and enzyme activity can be used to adjust the sensor values to more accurately reflect the actual characteristic levels. In addition to temperature measurements, the oxygen saturation level can be determined by measuring signals from the various electrodes of the sensor set 102. Once obtained, the oxygen saturation level can be used in calibration of the sensor set 102 due to changes in the oxygen saturation levels and its effects on the chemical reactions in the sensor set 102. For example, as the oxygen level goes lower, the sensor sensitivity can be lowered. In alternative arrangements, temperature measurements can be used in conjunction with other readings to determine the required sensor calibration.
In preferred arrangements, the sensor set 102 facilitates accurate placement of a flexible thin film electrochemical sensor of the type used for monitoring specific blood parameters representative of a user's condition. Preferably, the sensor monitors glucose levels in the body, and can be used in conjunction with automated or semi-automated medication infusion devices of the external or implantable type as described in U.S. Pat. Nos. 4,562,751 ; 4,678,408 ; 4,685,903 or 4,573,994 to control delivery of insulin to a diabetic patient. In addition, the monitor characteristic monitor 104 may typically be integrated into such a medication infusion device so that medication delivery and monitoring are conveniently provided within a single device.
The flexible electrochemical sensor can be constructed in accordance with thin film mask techniques to include elongated thin film conductors embedded or encased between layers of a selected insulative material, such as polyimide film or sheet, and membranes. The sensor electrodes at a tip end of the sensing portion are exposed through one of the insulative layers for direct contact with patient blood or other body fluids, when the sensing portion (or active portion) of the sensor is subcutaneously placed at an insertion site. The sensing portion is joined to a connection portion that terminates in conductive contact pads, or the like, which are also exposed through one of the insulative layers. In alternative arrangements, other types of implantable sensors, such as chemical based, optical based, or the like, can be used. Further description of flexible thin film sensors of this general type are be found in U.S. Patent. No. 5,391,250 , entitled "METHOD OF FABRICATING THIN FILM SENSORS". The connection portion can be conveniently connected electrically to the monitor 104 or a telemetered characteristic monitor transmitter 202 by a connector block (or the like) as shown and described in U.S. Pat. No. 5,482,473 , entitled "FLEX CIRCUIT CONNECTOR". Thus subcutaneous sensor sets 102 are configured or formed to work with either a wired or a wireless characteristic monitoring system 100, 200.
FIG. 2A is a flowchart 220 of an exemplary status check algorithm for a characteristic monitor which can be used in a device according to the present invention. Beginning at the default time screen 222 showing the current time, a user can press a key (e.g. the UP key) to initiate the status check. The processor 108 first performs a sensor activity condition check 224 to determine if there is an expired or dead sensor. If the sensor is determined to be dead, the display 114 shows a sensor "REPLACE" prompt 226 with the current time, which indicates that the sensor has expired and replacement of the sensor set 102 is required immediately. If the sensor is determined to be active by the sensor activity check 224, the processor 108 performs a telemetry condition check 228 to determine if the monitor 104 is synchronized with the telemetered monitor transmitter 202 coupled to the sensor set 102. If the monitor 104 and the transmitter 202 are not synchronized, a "NO SYNC" indicator 230 is shown on the display 114. If the devices are synchronized, a calibration condition check 232 is performed by the processor 108 to determine first whether a calibration of the sensor set 102 is pending (i.e., whether the monitor 104 is currently processing a previously entered blood glucose reference value, for example from a meter, to calibrate the sensor set 102). If a calibration is pending, the display 114 shows a "PENDING" indicator 234. If a calibration is not pending, the processor 108 checks whether the sensor calibration is currently valid 236. If the calibration is not valid, the display shows an "ENTER BG" indicator 242 with the current time, which indicates that a blood glucose reference value (e.g., from a blood glucose meter) is required by the monitor 104 to calibrate the sensor set 102. If the calibration is valid, the processor 108 then checks that the sensor expiration time is after the next calibration due time 238, and the display 114 shows a "BG DUE" indicator 240 with the time that the next calibration is due. If the sensor expiration time is before the next calibration due time, the display 114 shows the "REPLACE" prompt 226 with the time that the sensor will expire and replacement of the sensor set 102 can be required.
FIG. 2B is.an exemplary flowchart 250 of screens for entering a reference value to calibrate a characteristic monitoring system 100, 200. While a calibration is pending or valid as a result of entry of a calibration reference value (e.g., a blood glucose value measured by a blood glucose meter), the display 114 shows the calibration reference value and time of the most recent valid entry in the meter screen 252. In particular arrangements the time of the most recent valid entry is unaffected by a change in a system time setting of the monitor 104. In other arrangements the time of the most recent valid entry may be shifted in accordance with a change in a system time setting of the monitor 104. From the meter screen 252, pressing a button (e.g., the ACT/activate button) allows entry of a new calibration reference value in the entry screen 254. After entry of the new value (e.g., using the up and down arrow buttons and then pressing the ACT/activate button), the display 114 shows a confirmation screen 256, which requires confirmation of the value entered (e.g., by pressing the ACT/activate button) to release the display to the default time screen 258.
The arrangements herein described include different types of continuous glucose monitors that identify trends in blood glucose dynamics to facilitate enhanced treatment of diabetes. In general, a first illustrative monitor can be used to anticipate a glucose "crash" (or other hypoglycemic incident) before the onset of debilitating symptoms. Another illustrative monitor can be used to detect an inadequate nocturnal basal rate and alert the patient in order to avoid an impaired fasting glucose incident. Another illustrative monitor can anticipate hyperglycemic (or hypoglycemic) incidents by detecting trends toward those levels and help the patient avoid such incidents. Another illustrative monitor can assist a patient in maximizing athletic performance in endurance type activities (e.g., a marathon race) by detecting trends toward hypoglycemic levels.
The disclosed arrangements monitor the dynamics of a physiological characteristic such as blood glucose levels. These arrangements utilize this dynamic monitoring to provide functionality including the anticipation of glucose crash and alerting the patient, the detection of inadequate nocturnal basal rate, the anticipation of hyperglycemic (or hypoglycemic) incidents and maximizing athletic performance. All of these features can be implemented in software operating in the monitor's microprocessor and/or designed into an application specific integrated circuit (ASIC) or other specialized circuitry. Also, dynamic glucose monitoring functions use periodic measurements of a glucose level.
In one arrangement, a monitor anticipates a glucose crash by monitoring trends in glucose levels. For example, the monitor can alert the patient when glucose levels are rapidly decreasing. By monitoring such trends or a rate information of measured glucose levels, the monitor can provide a much better warning system to alert the user with enough time to stabilize and reverse a dangerous physiological condition.
In some arrangements, the monitor measures glucose more frequently than typical glucose monitoring devices. For example, one arrangements measures approximately every minute, whereas other monitors measure at a lower rate (e.g., but not limited to, once per 5 minutes). Frequent measurements are taken because of the short time intervals which are evaluated. Alternative arrangements may utilize more frequent measurements, such as, but not limited to, 10 seconds, 1 second, or the like.
In an illustrative arrangement, the monitor periodically measures glucose, analyzes the present trend, determines whether a glucose crash incident is probable and appropriately alerts the patient. At some frequent interval (e.g., but not limited to, once per minute), the device measures the glucose level, applies a smoothing filter to the result, and records the filtered value. The smoothing filter may take a weighted sum of past sensor values (so called finite impulse response- FIR -filter), a weighted sum of past sensor values and past filtered values (so called infinite impulse response - IIR-filters), may use simple clipping algorithms (e.g. limit the percent change in filtered output), or employ models to predict the output (e.g. Weiner and Kalman filter designs). For example, if the most recent (filtered) value is in the "qualifying range", the monitor can calculate the slope of a line fit to the most recent values (most likely, but not limited to, using a Saritzky gulag filter) and determine if the slope is steeper than a selected threshold rate (e.g., but not limited to, 3% or declining at more than 30 mg/dL in ten minutes). If the slope equals or exceeds the threshold rate, a glucose crash incident is likely and the monitor alerts the patient accordingly.
Those skilled in the art will understand that in some arrangements the qualifying range can be a closed range (e.g., but not limited to, between 100 and 150 mg/dL) and in other arrangements the qualifying range can be an open range (e.g., but not limited to, greater than 100 mg/dL). By first identifying whether a most recent value is within the qualifying range, further calculation of the dynamic behavior of the physiologic characteristic can be avoided. Thus, the determination of a glucose crash can be unconcerned with rate magnitudes occurring when the current characteristic value is outside of the range (of course, other alarms, which merely monitor the current characteristic value, can be triggered when the reading is too high or too low). However, in alternate embodiments, the slope can be calculated and compared to the threshold rate with every new value. In further arrangements, multiple qualifying ranges and threshold rates can be applied to evaluate the glucose dynamics and determine triggering a glucose crash warning.
In one preferred arrangement, the monitor determines that a glucose crash is likely if three criteria are met. The criteria are as follows. The first, dG/dT (the rate of glucose level change) is negative, can be considered for example in situations where blood glucose levels are dropping (e.g., but not limited to, when a value pertaining to the rate of glucose change is negative). The second, |dG/dT| exceeds a threshold rate, can be considered in contexts, for example where a specified blood glucose change rate is exceeded for a specified sustained period (e.g., but not limited to, greater than 3% per minute for 10 minutes). The third, G, the glucose level, can be considered for example, when this value begins dropping starting within a specified range, (e.g., but not limited to, 100 - 150 mg/dL).
In some arrangements, these criteria can be parameterized to allow the user to customize the values. The qualifying range, threshold rate and period can be general values, applied to all users, or determined from factors specific to the individual user. For example, the monitor can include a feature to adjust the qualifying glucose level range, the maximum rate of glucose change, or in some arrangements, the sustained time period length. In addition, in some arrangements any or all of the dynamic glucose monitoring functions can enabled or disabled, selectively or together.
The following control program pseudo code provides an example of a programming routine performed by the processor of the monitor.
FIG. 3A is a flowchart of a method for anticipating a glucose crash 300. At block 302, a characteristic level is repeatedly measured to obtain a group of characteristic level values. Following this at block 304, a smoothing filter can be applied to the group of characteristic level values to produce a filtered measurement value. The filtered measurement value is recorded at block 306. At block 308 it is determined if the recorded value falls within a qualifying range (e.g., but not limited to, between 100 to 150 mg/dL). If not, the process returns to block 302. If the recorded measurement is within the range, a slope of a line fit to a recent series of recorded filtered values is calculated at block 310. The calculated slope is compared to a threshold rate (e.g., but not limited to, -3% per minute) at block 312. If the calculated slope is not steeper than the threshold rate the process returns to block 302. If the slope exceeds the threshold rate, an anticipated glucose crash is indicated at block 314. Alternative arrangements may utilize similar logic for when the glucose level is already outside of the range and continues to drop. In addition in an alternative preferred arrangement, one can utilize a raw data measurement (e.g. a group of characteristic level values) to determine a derivative as an alternative to using a filtered measurement value to determine a derivative.
In another arrangement, the characteristic monitor can be used to detect an inadequate nocturnal basal rate. This arrangement generally applies to diabetic patients using an insulin infusion device that continually administers insulin at a patient controlled basal rate. The monitor detects an inadequate basal rate (i.e., but not limited to, "low basal rate" or a "high basal rate"), by monitoring trends in glucose levels. The monitor then alerts a patient in the early morning, when glucose levels are high and relatively steady, low and relatively stable or changing rapidly. This gives the patient time to adjust the basal rate of the infusion device upward or downward to and avoid an impaired fasting glucose incident.
The monitor operates to track the characteristic level rate. For example, every 5 minutes the monitor measures and records the glucose level. Once a day (e.g., but not limited to, 3 hours before to the anticipated wakeup time), the monitor calculates the average blood glucose and the rate of blood glucose change for the previous hour. The monitor can then determine a prediction of the "morning glucose" level at wake up based upon the calculated average blood glucose and the rate of blood glucose change. In one arrangement the "morning glucose" is predicted assuming that the rate of change remains constant, however in other arrangements nonlinear characteristic curves and functions can be applied in making the prediction. If the anticipated "morning glucose" level is greater than a high threshold value (e.g., but not limited to, 126 mg/dL), or less than a low threshold value (e.g., but not limited to, 60 mg/dL), an alarm is sounded. This will allow time for the infusion device basal rate to be adjusted appropriately. In alternative arrangements different times before anticipated wakeup, different high threshold values, or different low threshold values, may be used.
In some arrangements the triggering criteria can also be parameterized to allow the user to customize the values. In some arrangements, the user is allowed to set the values for the controlling parameters. For example, the user can set the qualifying low and high glucose levels as well as the anticipated waking time. For each of the settings a default value can be used in the absence of a user setting. For example, a default low glucose level of 60 mg/dL, a default high glucose level of 126 mg/dL and an anticipated waking time of 7:00 AM can be used. In addition, the entire function can be enabled and disabled.
FIG. 3B is a flowchart of a method for detecting an inadequate nocturnal basal rate 320. At block 322, the method begins by measuring a characteristic level to obtain a measurement value. The value is recorded at block 324. Measuring and recording is repeated periodically to obtain a series of values at block 326. At block 328, the average of the series of values is calculated. At block 330, a slope of a line fit to the series of values is calculated. The calculated slope and average of the series of values are then used to determine a predictive curve at block 332. At block 334, the curve is extrapolated to predict a glucose level at wakeup. Those skilled in the art understand that such calculations are not limited to slope y = mx + b, and that, in this context, one can use alternative filtered arrangements as are known in the art. The extrapolation is performed some time before wakeup (e.g., but not limited to, 3 hours prior) to provide enough time to correct any impending negative condition. The predicted glucose level is compared to an acceptable range at block 336. If the predicted glucose value falls within the range, the process ends. If the predicted glucose value falls outside the range, a morning glucose incident is reported at block 338.
In another arrangement, a glucose monitor anticipates a hyperglycemic (or hypoglycemic) incident by monitoring trends in glucose levels. The monitor alerts the patient when a "relatively steady increase" (or decrease) in glucose levels occurs. The monitor periodically measures glucose, analyzes the present trend, determines whether a hyperglycemic (or hypoglycemic) incident is probable and appropriately alerts the patient.
In one arrangement, the device measures glucose values at a specific time interval (e.g. once every minute), and then, e.g. at 5 minute intervals, applies a smoothing filter to this group of values and records the filtered value. If the most recent (filtered) value exceeds a threshold value (e.g., but not limited to, 180 mg/dL), the monitor calculates the slope of a line fit to a recent series of recorded values (for example, but not limited to, six values). If the slope is greater than a threshold rate (e.g., but not limited to, 3% per minute), a hyperglycemic incident is likely and the monitor alerts the patient. For hypoglycemic incidents, values and thresholds corresponding to low glucose levels would be used.
The threshold value is applied in a similar manner to the "qualifying range" applied in determining a glucose crash previously discussed. The threshold value effectively operates as an open range (e.g., but not limited to, greater than 180 mg/dL). In other arrangements, the threshold value can be a closed range. Therefore, determining a hyperglycemic incident can be unconcerned with values below the threshold value (as determining a hypoglycemic incident can be unconcerned with values above a threshold value). In one arrangement, a slope calculation can be avoided if the current reading is outside the range. However, in alternate arrangements, the slope can be calculated and compared to the threshold rate with every new reading. In further arrangements, multiple qualifying ranges and threshold rates can be applied to evaluate the glucose dynamics and determine triggering a hyperglycemic (or hypoglycemic) incident warning.
Here again, in some arrangements the criteria can be parameterized to allow the user to customize the controlling values for anticipating hyperglycemic (or hypoglycemic) incidents. For example, some arrangements can allow the user to set the glucose threshold level and/or the threshold rate. Default parameters can also be used if no user settings are provided (e.g., but not limited to, a threshold level of 180 mg/dL and a maximal rate of 3% per minute). This function can also be enabled and disabled
FIG. 3C is a flowchart of a method for anticipating a hyperglycemic incident 350. The method begins at block 352 by repeatedly measuring a characteristic level to obtain a group of values. At block 354, a smoothing filter is applied to the group of values to obtain a filtered measurement value. The filtered value is recorded at block 356. The recorded value is compared to a threshold value at block 358. If the recorded value does not exceed the threshold value (e.g., but not limited to, 180 mg/dL), the process returns to block 352. If the recorded value does exceed the threshold value, a slope of a line fit to a recent series of values is calculated at block 354. The calculated slope is compared to a threshold rate (e.g;, but not limited to, +3% per minute) at block 362. If the slope is not steeper than the threshold rate, the process returns to block 352. If the slope is steeper than the threshold rate, an anticipated hyperglycemic incident is reported at block 364. For hypoglycemic incidents, corresponding steps for low glucose levels would be used. As noted previously, estimates of dG/dt may be calculated by a variety of methods known in the art including the slope (and that such calculations are not limited to, for example, determinations based on y = mx + b).
In such arrangements, the monitor anticipates low glucose levels and alerts the athlete to ingest carbohydrates. It is important to note that this arrangement is not strictly anticipating hypoglycemic incidents. Instead it is anticipating low glucose levels where it would otherwise be too late for the athlete to compensate by ingesting carbohydrates and still perform effectively and/or at full capacity.
In one arrangement, once a minute, the device measures a glucose level, applies a smoothing filter and records the filtered value at 5-minute intervals. If the most recent recorded (i.e., filtered) value is in a qualifying range (e.g., but not limited to, 60 - 140 mg/dL), the processor calculates the slope of a line fit to the most recent six filtered values and determines if the slope is steeper than -1 % (i.e., but not limited to, 30 mg/dL in 30 minutes). If the rate of decline exceeds this threshold, a low glucose level is likely and the monitor alerts the athlete accordingly. Thus, for example, but not limited to, to trigger an alarm, the glucose level rate; dG/dT, is negative with a magnitude greater than 1% per minute for 3 0 minutes beginning in range 60 - 140 mg/dL.
Similar to the glucose crash monitor, in arrangements for maximizing athletic performance, the qualifying range can be a closed range (e.g., but not limited to, between 60 and 140 mg/dL) or an open range (e.g., but not limited to, less than 140 mg/dL). By first identifying whether a most recent value is within the qualifying range, further calculation of the dynamic behavior of the physiologic characteristic is. avoided. However, other alarms which merely monitor the current characteristic value can be triggered when the reading is too high or too low. In alternate arrangements, the slope can be calculated and compared to the threshold rate with every new value. In further arrangements, multiple qualifying ranges and threshold rates can be applied to evaluate the glucose dynamics and determine triggering a low glucose warning.
FIG. 3D is a flowchart of a method for maximizing athletic performance 370. The process begins at block 372, where a characteristic level is repeatedly measured to obtain a group of characteristic level values. Following this at block 374, a smoothing filter can be applied to the group of characteristic level values to produce a filtered measurement value. The filtered measurement value is recorded at block 376. At block 378 it is determined if the recorded value falls within a qualifying range (e.g., but not limited to, between 60 to 140 mg/dL). If not, the process returns to block 372. If the recorded measurement is within the range, a slope of a line fitted to a recent series of recorded filtered values is calculated at block 380. The calculated slope is compared to a threshold rate (e.g., but not limited to, -1% per minute) at block 382. If the calculated slope is not steeper than the threshold rate the process returns to block 372. If the slope exceeds the threshold rate, an anticipated low glucose level is indicated at block 384. As noted previously, estimates of dG/dt may be calculated by slope as well as other methods known in the art.
The arrangements described herein can utilize various advanced alarm functions. For example, in some arrangements multiple alarms can be independently set by the user. In further arrangements, user input can direct review of the alarm history and also alter the alarm display to suit the user's preference. Alarm settings can also include an alarm snooze or "blackout" period as well as an alarm repeat delay.
The arrangements described can employ multiple alarms that can be independently set by the user. For example, a continuous glucose monitoring system can have multiple alarms for different glucose values. The system can allow a user to set threshold glucose values that define a "narrow" glucose range (as compared to the ordinary alarm limits). If the user's glucose level passes outside the "narrow" range, an alarm can sound. This alarm alerts the user to monitor his glucose levels more closely. The system can sound a second alarm (preferably having a sound distinguishable from the first "narrow" range alarm) in the event the user's glucose level reaches a more dangerous condition requiring immediate action. Alarm indications may be audible, tactile, vibratory, visual, combinations of alarm indications, or the like. In the case of visual alarm indications, but not limited to, green lights can be displayed while the user's glucose level remains within the defined "narrow" range; yellow for the first alarm level; and red for the second alarm level. The visual alarm indications may flash and/or also be combined with other alarm indications.
Although the above example describes a two-layer alarm system, further arrangements can incorporate multiple alarm layers. In addition, the alarms can be set in ranges, or separate high and low glucose level alarms can be set. Distinctive sounds can be used for each alarm. For example, each successive high glucose level alarm can have, but is not limited to having, a higher pitch. Successive low glucose level alarms can each have, but are not limited to having, lowering pitches. Alternately, intermittent or wavering volumes that also increase in pitch according to the severity of the condition can be used. In still other arrangements, the user can select or program alarm tones and other sounds and assign them to the various alarms. Also, in some arrangements, these distinguishable alarms can also be set at different volume levels. In addition, as discussed above, the alarms are not limited to audible signals; some embodiments of the invention can also utilize visual alarms, such as flashing lights or displays, or tactile alarms, such as vibrating indicators.
In still further arrangements, threshold values and associated alarms can be set according to a schedule. For example, but not limited to, particular alarms can be set to be active only during selected portions of the day.
FIG. 4A illustrates a multiple alarm function. A plot of the monitored characteristic value 400 (e.g., blood glucose) changing over time is shown. A typical alarm range 402 is defined by an upper threshold value 404 and a lower threshold value 406. If the monitored characteristic value 400 should exceed the defined range and cross either threshold, an alarm is initiated to indicate to the user to check his blood glucose. In one arrangement, a distinctive alarm can be associated with the alarm range 402. Thus, the same alarm is produced whether the range 402 is exceeded by passing the upper threshold value 404 or the lower threshold value 406. In other embodiments, distinctive alarms can be assigned to each threshold value 404, 406. In further arrangements, other alarm ranges can also be set. For example, a second narrower range 408 can be set with a lower upper threshold value 410 than that of the wider range 402; and a higher lower threshold value 412 than that of the wider range 402. As with the wider range 402, an alarm is initiated if the narrower range is exceeded by the monitored characteristic value 400. Here also, alarms can be the same or different for each threshold value 410, 412.
The ability to set different ranges and associated alarms allows the monitor to immediately convey some information about the condition of the user even before checking the actual readings. Particularly, using the narrower range 408 and associated alarms allows the user to know of a negative trend that does not require the same urgency as an alarm triggered by the wider range 402. In effect, the user is able to set multiple alarms, each indicating a different level of urgency and/or different conditions. In some arrangements, threshold values for alarms can also be set independent from ranges.
Instill further arrangements, alarms or indicators can be set according to the direction in which a threshold value is crossed by the monitored characteristic value 400. For example, as the monitored characteristic value 400 crosses a lower threshold value 412 from the narrow range (e.g., but not limited to, at point 414), one type of alarm can be provided. However, when the monitored characteristic value 400 crosses a lower threshold value 412 from the wider range 402 (e.g., but not limited to, at point 416), another type of alarm can be provided. The difference in the alarms is appropriate because only the former case indicates a worsening of the user's condition. In the latter case, the transition actually indicates an improvement in the user's condition. Thus, in some arrangements alarms will only be given when crossing a threshold indicates a worsening of the user's condition. In other arrangements, an indicator will also be given when a threshold has been crossed in an improving direction. In these cases, either the same indicator (sound, light, display or other) or different indicators can be used. In a similar manner, reminders can be set to indicate to a user various conditions (not necessarily negative) that will aid in convenient therapy management.
The multiple alarm function can be readily incorporated with any of the individual alarm functions and settings such as discussed hereafter.
In further arrangements a physiological characteristic monitor can incorporate various individual alarm functions and settings to enhance convenient operation by a user. As typical of the monitoring system 100, 200 shown in FIGS. 1A and 1B, the monitor includes a sensor input capable of receiving a signal from a sensor, the signal being based on a sensed physiological characteristic value of a user, and a processor for operating an alarm based on user input from an input device. The alarm indicates an alarm condition where the sensed physiological characteristic value exceeds a set range. In preferred arrangements, the physiological characteristic value is a measurement related to a blood glucose level in the user and the alarm indicates a glycemic condition. Operating the alarm comprises setting parameters of the alarm based on the user input from the input device. For example, the blood glucose level or value that will activate a hypoglycemia or hyperglycemia alarm may be set by the user utilizing the input device. The hypoglycemia alarm may be set to trigger if the user's blood glucose level is less than or equal to 60, 65, or 70 mg/dl (or any other desired level), and the hyperglycemia alarm may be set to trigger if the user's blood glucose level is greater than or equal to 150, 160, or 175 mg/dl (or any other desired level).
FIGS. 4B and 4C illustrate the hypoglycemia and hyperglycemia alarm screens, respectively. In each case, the display shows the measurement of the concentration of blood glucose indicating the glycemic condition, preferably until the alarm is acknowledged by the user. Furthermore, the display shows a time of the alarm. In particular arrangements the alarm indicates the glycemic condition only if the monitor is calibrated, although in alternative arrangements the alarm may indicate the glycemic condition regardless if the monitor is calibrated.
In the illustrated embodiment, the display shows a LOW indicator when the measurement of the concentration of blood glucose is below a specified level for a hypoglycemia alarm, such as 60 mg/dl. Similarly, the display shows a HIGH indicator when the measurement of the concentration of blood glucose is above a , specified level for a hyperglycemia alarm, such as 150 mg/dl. In some arrangements, alarm indications may be other visual indicators (e.g., lights, flashing displays, or the like), audible, tactile, and/or vibratory. For example, a hypoglycemia alarm can be indicated by at least two audible descending tones, and a hyperglycemia alarm can be indicated by at least two audible ascending tones.
In further arrangements an alarm repeat delay period is employed. Subsequent alarms are prevented for the alarm repeat delay period after the measurement of the concentration of blood glucose first indicates a glycemic condition. For example, the alarm repeat delay period can be less than 20 minutes (e.g. approximately 17.5 minutes) for the glycemic condition comprising a hypoglycemic condition. In another example, the alarm repeat delay period is less than 1 hour (e.g. approximately 52.5 minutes) for the glycemic condition comprising a hyperglycemic condition. In alternative arrangements, the alarm repeat delay period may be other time periods, such as 10 minutes, 15 minutes, 30 minutes, 1 ½ hours, 2 hours, or the like.
In particular arrangements, the level of the measurement of the concentration of blood glucose from the sensor that will trigger a low limit (or hypoglycemia) alarm or a high limit (or hyperglycemia) alarm can be set based upon input from the user. Particularly, these two alarm levels can be separately set. FIGS. 4D and 4E show exemplary hypoglycemia and hyperglycemia alarm setting algorithms, respectively. FIG. 4D shows an exemplary hypoglycemia alarm setting flowchart 420. To begin setting the hypoglycemia alarm, from the hypoglycemia alarm setting screen 422, the ACT/activate button is pressed, and the hypoglycemia alarm activation screen 424 is entered. From this screen 424, the user can select setting the hypoglycemia alarm on, off or entering the alarm repeat setting function menu. If the user sets the hypoglycemia alarm off and presses the ACT/activate button, an alarm off confirmation screen 426 is presented. If the hypoglycemia alarm is set on and the ACT/activate button is pressed, the low limit entry screen 428 is presented. The low limit entry screen 428 allows the user to scroll through low limit alarm level settings using up and down arrow buttons to specify that the hypoglycemia alarm will trigger if the user's blood glucose level is less than or equal to 60, 65, or 70 mg/dl, or any other desired level. After setting the low limit alarm level, pressing the ACT/activate button again presents a hypoglycemia low limit alarm level confirmation screen 430 for confirming the specified hypoglycemic blood glucose level.
From the hypoglycemia alarm activation screen 424, if the alarm repeat setting function is selected, the alarm repeat display screen 432 is entered, which allows the user to set a period for delaying a repeated check of the hypoglycemia alarm condition. The current alarm repeat delay period is shown in the alarm repeat display screen 432. Pressing the ACT/activate button allows the user to enter the repeat time select screen 434. Alternatively, the alarm repeat display screen 432 may be omitted, and the repeat time select screen 434 is entered once the alarm repeat setting function is selected. In the repeat time select screen 434, the alarm repeat delay period blinks while being set by the user utilizing the input device. The user can scroll through a list of delay increments and select the desired alarm repeat delay period from the list of delay increments. The alarm repeat delay period has a default value of 20 minutes for the hypoglycemia (low limit) alarm level. For convenience, the scrolled list of delay increments can wrap around, beginning again when one end of the list is reached. For the low limit alarm level, the alarm repeat delay period can be selected from a group of values differing in 10 minute increments. For example, the alarm repeat delay period can be selected from 20, 30, 40, 50 and 60 minutes for the low limit alarm level. In alternative arrangements, the alarm repeat delay period may be selected from a group of values differing in other time increments, such as 5, 15, or 20 minutes, or further, may be specified using up and down arrow buttons and then pressing the ACT/activate button. After selecting the alarm repeat delay period, pressing the ACT/activate button displays the alarm repeat delay confirmation screen 436 for confirming the period selection.
The alarm repeat delay period for the hyperglycemia alarm is set in the same manner as that for the hypoglycemia alarm described above with respect to FIG. 4D; however, the alarm repeat delay period is typically set separately for a low limit alarm level and a high limit alarm level because the desired delays are different in each case. In general, the hyperglycemia alarm repeat delay period may be longer than that of the hypoglycemia alarm. From the hyperglycemia alarm activation screen 444, if the alarm repeat setting function is selected, the alarm repeat display screen 452 is entered, which allows the user to set a period for delaying a repeated check of the hyperglycemia alarm condition. The current alarm repeat delay period is shown in the alarm repeat display screen 452. Pressing the ACT/activate button allows the user to enter the repeat time select screen 454. Alternatively, the alarm repeat display screen 452 may be omitted, and the repeat time select screen 454 is entered once the alarm repeat setting function is selected. In the repeat time select screen 454, the hyperglycemia alarm repeat delay period is selected in a manner similar to the hypoglycemia alarm repeat delay period described above with respect to FIG. 4D, and then pressing the ACT/activate button displays the alarm repeat delay confirmation screen 456 for confirming the period selection. The alarm repeat delay period can have a default value of 1 hour for the hyperglycemia (high limit) alarm level. For the high limit alarm level, the alarm repeat delay period can be selected from a group of values differing in 30 minute increments. For example, the alarm repeat delay period can be selected from 1, 1½, 2, 2½ and 3 hours for the hyperglycemia alarm level. In alternative arrangements, the alarm repeat delay period may be selected from a group of values differing in other time increments, such as 15 or 20 minutes or 1 hour, or further, may be specified using up and down arrow buttons and then pressing the ACT/activate button.
As disclosed herein, arrangements that incorporate a plurality specific alarm features can be used to optimize the utility of the alarm functions associated with hypoglycemia and/or hyperglycemia. In an alarm associated with hypoglycemic events for example, one can monitor a plurality of relevant physiological characteristic and can further utilize multiple alarm modes for alerting the user as to the status of the one or more characteristics. For example, an illustrative first alarm can be based upon a detection scheme for physiological glucose levels reaching a predetermined concentration (i.e. a dangerously low concentration). An illustrative second alarm can be based upon a detection scheme for a specific rate in which physiological glucose concentrations are changing in the user. In such situations, the arrangements disclosed herein can provide a first alarm based upon the rate of glucose concentration change in advance of a second alarm that is predicated upon physiological glucose concentrations reaching a predetermined threshold concentration. In such arrangements the physiological characteristic threshold criteria for triggering an alarm can be modulated to for example, modulate the period of time between the first and second alarm functions according to the needs of the user.
In certain arrangements a user can employ a device that monitors both of the above-noted glucose detection schemes simultaneously. In such arrangements the device can employ a combination of the two alerts where the predetermined triggers for the various alarm functions are different. For example it is observed that when both the rate and specific concentrations of glucose are monitored, the rate change detector usually alerts before the fixed threshold change detector but has a higher false alarm rate. Consequently certain arrangements can employ a combination of the two alerts where the threshold for the physiological parameter that triggers each alert are different. In one such arrangement for example, the fixed concentration threshold parameter can be a higher or more stringent than the rate of concentration change threshold parameter. Such combinations provide devices that exhibit a good sensitivity while minimizing false alerts. In such contexts, one can further use information about both the rate of change and the current value to create a rule or mathematical formula which allows one to maximize the efficiency of detection while minimizing the occurrence of false alerts.
One such illustrative arrangement is a device, comprising a sensor input capable of receiving at least one signal from a sensor, the signal being based on a plurality of sensed physiological characteristic values of a user of the device; and a processor coupled to the sensor input for operating a plurality of alarms based on the received signal from the sensor; wherein the processor is capable of. activating each of the plurality of alarms according to a different sensed physiological characteristic value of the plurality of sensed physiological characteristic values. Preferably, the plurality of sensed physiological characteristic values include the blood glucose concentrations in the user; and the rate of change of blood glucose concentrations in the user over a predetermined time period. In such devices, a first alarm can be activated when glucose concentrations exhibit a predetermined rate of change and a second alarm can be activated when glucose concentrations reach a predetermined value. Optionally the criteria for activating the first alarm are more stringent than the criteria for activating the second alarm. In this context, criteria for activating an alarm are considered to be more stringent when they are based on parameters associated with greater physiological stress (e.g. a higher blood glucose concentration in hyperglycemia and/or a lower blood glucose concentration in hypoglycemia).
In a preferred arrangement, the processor is capable of activating an alarm based on an evaluation of both the blood glucose concentrations in the user and the rate of change of blood glucose concentrations and the alarm is activated based on a mathematical comparison of the blood glucose concentrations in the user and the rate of change of blood glucose concentrations in the user. In an exemplary arrangement, the alarm is activated when the relationship between the blood glucose concentrations in the user and the rate of change of blood glucose concentrations in the user meet a certain criteria. Optionally such criteria are determined by one or more mathematical formulae or algorithms that are based upon calculations that consider the specific the relationship between the blood glucose concentrations in the user and the rate of change of blood glucose concentrations in situations typically considered dangerous to the user.
FIG. 4F illustrates a hyperglycemia alarm snooze setting flowchart 460. The hyperglycemia alarm snooze function sets an alarm snooze period for temporarily disabling the alarm. The snooze function is set by the user utilizing the input device. In some arrangements, the alarm snooze period is only available for a hyperglycemia alarm, although in other arrangements, the alarm snooze period may also be available for a hypoglycemia alarm. Generally, the snooze function is available only when the snooze period is running and the monitor is calibrated, although in alternative arrangements, the snooze function may be available regardless if the monitor is calibrated. Further, the alarm snooze period is preferably deactivated upon any adjustment of the hyperglycemia alarm setting described above with respect to FIG. 4E. The snooze setting flowchart 460 begins at the snooze display screen 462, which can be entered by scrolling past the default time screen 464 and the BG due screen 466. From the snooze display screen 462, pressing the ACT/activate button will produce the snooze time select screen 468. In this screen 468, a user can select the desired period for the snooze function to operate, and the alarm snooze period blinks while being set by the user utilizing the input device. The alarm snooze period can be set by the user scrolling through a list of snooze period increments and selecting the desired alarm snooze period from the list of snooze period increments. For example, the list of snooze period increments can include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 hours, and for convenience, the list of snooze period increments wraps around as it is scrolled by the user. In alternative arrangements, the snooze period may be selected from a list of other time increments, such as 15 or 30 minutes, or further, may be specified using up and down arrow buttons and then pressing the ACT/activate button. When the snooze function is activated, the display shows time remaining of the alarm snooze period and an indicator (e.g. an "S") showing that the snooze function is active.
Just as with the alarm repeat delay, the multiple alarm function can also be incorporated with the alarm snooze function. For example, the snooze function can be set differently for hypoglycemic alarms and hyperglycemic alarms of different severities. The snooze function can function normally when a lower threshold hyperglycemic alarm is set (i.e. ignore the alarm). However, when a higher threshold hyperglycemic alarm is set, the snooze function may be overridden due to the severity of the user's condition.
FIG. 4G illustrates glycemia alarm history review. Operating the alarm history review can allow a user to review a historical list of the alarms indicating a glycemic condition occurrence. The alarm history review flowchart 470 shows the alarm history is entered by pressing the ACT/activate button from the alarms menu screen 472. If no alarm history exists, a screen 474 indicating "NONE" can be displayed. However, if at least one alarm event has occurred, the entries can be displayed in a historical list 476. In arrangements, the display shows a single glycemic alarm in the historical list at a time. The display shows a physiological characteristic value (e.g. blood glucose value) and time of the glycemic condition occurrence indicated for each alarm in the historical list. The time of the glycemic condition occurrence can also include a date of the alarm. Further, the display can show at least a portion of the time of the glycemic condition occurrence in blinking text. The historical list typically includes a limited number of stored entries. For example, the historical list can comprise the 20 most recent alarms indicating a glycemic condition occurrence. In alternative arrangements, the historical list may include more or less alarms, such as the 10, 15, 30, or 50 most recent alarms.
Some alarm functions are designed to accommodate anticipated temporary behaviors of the users. For example, in the typical case where the characteristic value is a blood glucose level, it has been observed that when a user of the monitor is awakened from sleep by low blood glucose alarm from the monitor, there is often a period of disorientation. The disorientation may be particularly significant because the effect of low blood glucose level is made more severe at night Consequently, in such a situation the user may begin pushing buttons on the device somewhat randomly in an attempt to quickly issue a bolus from the infusion device. This can result in an incorrect dosage or settings being altered without being realized by the user. Special functions can be invoked to alleviate the problems associate with this disorientation.
As mentioned previously, in a typical arrangement described, the monitor may be included as part of an infusion device system. In such arrangements the monitor and the infusion device may both be controlled through the same input device, e.g. keypad 112. In addition, information regarding both the monitor and infusion device may be displayed on the same display 114.
The problem of night disorientation described above does not only involve a function of the monitor alarm. The function of the infusion device can also be modified.
Any of the functions described below to deal with night disorientation can be set in the monitor and/or infusion device to be invoked in different ways. For example, the user can activate a night mode upon retiring to bed (and deactivate it upon waking). One or more of the functions are activated while in night mode. In an embodiment of the present invention, one or more of the functions can be automatically set to operate during a specified period designed to correspond with the user's usual sleep. In any case, the function(s) may be divided into two related systems. A first system delays accepting input from the user when an alarm wakes the user. A second system provides an earlier warning to the user when sleeping than when awake. In addition, the two may also be combined.
A first system of the invention as noted above operates to eliminate mis-operation of monitor and/or infusion device by requiring preventing input until disorientation of the user has abated somewhat. This may be done by an ordinary delay or, preferably by requiring a predetermined input before normal operation is restored. In one example when the night mode is activated and a low blood glucose alarm or shutoff has occurred, operation of the infusion device and/or monitor may be blocked until the user has provided the proper input. Blocking the device(s) operation may be performed by automatically invoking a "block" function that is built into the device (that is normally manually invoked by the user) or a simple keypad/button lockout. Alternately, a separate user "test" can be invoked such that the user must enter a specified key sequence (e.g. a numeric code) before operation of the device(s) is restored. Requiring such user input insures that any disorientation has passed before allowing operations such as delivering medication or altering other settings.
A typical example of this is a device comprising a sensor input capable of receiving a signal from a sensor, the signal being based on a sensed physiological characteristic value of a user of the device; and a processor coupled to the sensor input for operating an alarm based on the received signal from the sensor, wherein the processor activates the alarm according to a first criteria when the user is awake; and a second criteria when the user is asleep. Such devices are designed for example to adapt to a number of situations in which a user may exhibit different behaviors during time periods when they are typically asleep as compared to time periods when they are typically awake. For example, in the typical case where the characteristic value is a blood glucose level, it has been observed that when a user of the monitor is awakened from sleep by low blood glucose alarm from the monitor, there is often a period of disorientation. The disorientation may be particularly significant because the effect of low blood glucose level is made more severe at night.
The likelihood night disorientation can be reduced by providing an earlier warning to the user regarding a low blood glucose level. In some embodiments, this may be characterized by purpose driven application of the multiple alarm function described above. Different alarm thresholds may be set to be active at different times. For example, a higher low blood glucose alarm threshold is set for sleeping hours than for waking hours. Alternately, the night alarm level (e.g. a higher low blood glucose alarm threshold) can be manually activated upon retiring to sleep and cancelled upon waking as mentioned above. Multiple alarm thresholds (e.g. two levels of low blood glucose alarms) may also be applied within the night mode as well.
A typical example of this embodiment is a device comprising a sensor input capable of receiving a signal from a sensor, the signal being based on a sensed physiological characteristic value of a user; and a processor coupled to the sensor input for operating an alarm, based, an the sensed physiological characteristic value of the user from the received signal from the sensor; wherein the processor activates the alarm and delays accepting input from the user when the alarm awakens the user. In an illustrative embodiment of the invention, the physiological characteristic value is a blood glucose measurement and delaying accepting input from the user is applied to a low blood glucose alarm or a high blood glucose alarm. In preferred embodiments of the invention, the processor delays accepting input from the user until the user provides a predetermined input such as entering a numeric code or executing a button sequence. Optionally, delaying accepting input from a user who is most likely asleep when the alarm sounds is set according to a schedule based on a time of day, or alternatively, is set by the user before sleeping.
In examples embodying the invention, an early warning regarding a low blood glucose level to the user may be provided through a dynamic measurement, as described above. Employing a dynamic measurement (e.g. monitoring a rate change of the blood glucose level) enables the monitor to better anticipate a low blood glucose level. See section 3, above. In this case, a fast declining blood glucose rate, e.g. -2.0 mg/dL per minute or greater (which may be indicated by a single down arrow on the graphical display) will cause an adjustment in the low blood glucose alarm threshold value. For example, the fast declining blood glucose rate can trigger a low blood glucose threshold value to be raised by 6 mg/dL. Thus, the low blood glucose alarm will sound sooner than it otherwise would without the adjustment based on the fast declining blood glucose rate, allowing the user to wake up and make a correction with less chance of disorientation. Similarly, an even greater declining rate, e.g. a -4.0 mg/dL or greater (which may be indicated by a double down arrow on the graphical display) will cause a greater adjustment in the low blood glucose alarm threshold value. For example, this sharp declining blood glucose rate can trigger a blood glucose threshold value to be raised by 12 mg/dL, providing an even earlier warning than the first fast declining blood glucose rate. In the case of multiple alarms with different thresholds, the adjustment(s) may be applied to all of the low blood glucose alarms so that the same set of alarms operate but at adjusted levels.
Another option allows the user to set reminders that can be provided by the monitor. The reminders can be alarm signals (including, but not limited to, auditory, visual, tactile, etc.) that are initiated after a timer has run to prompt the user to take action or merely inform the user of a particular status. The reminder is started (i.e. the timer is initiated), when an event occurs and/or certain conditions are met. The alarm signals can be the same or different based upon the triggering events or conditions. These reminders can be used to further assist the user in managing insulin delivery for optimum results. For example, but not limited to, reminders can be set for event markers, blood glucose values, reference values, high or low sensor measurements.
One aspect behind the use of these reminders is that they also serve to prevent redundant and excessive alarms for the user. For example, if the timer is removed from the previously described high or low measurement reminder, the result would be a simple hypoglycemia or hyperglycemia alarm. Using a reminder, however, the message is not that the user's blood glucose is out of range. Rather, the reminder's message is to check the user's blood glucose with a meter, or the like. If a user's blood glucose is very near an alarm triggering threshold, an alarm might be triggered repeatedly as the value passes back and forth across the threshold. A reminder will set a timer, preventing duplicative warnings for a short period of time, but reminding the user to check blood glucose again when that period has expired. This can provide a better or easier path through the regulatory process. Thus, reminders are less likely to become a nuisance to the user and also prompt more useful data collection. In alternative arrangements, the alarm is triggered again, regardless of the presence of a time, if the glucose level continues to change in the direction of the trend.
FIG. 5 illustrates a reminder function triggered by high or low characteristic values. A plot of a monitored characteristic value 500 (such as, but not limited to, blood glucose) is shown. One or more ranges 502, 504 define safe characteristic values (e.g., but not limited to, a first range 502 being a warning range and a second range 504 being a critical range), such as can be employed using multiple alarms as previously described. When a range is exceeded (e.g., but not limited to, at time 506), an alarm can be triggered but also a timer is started such that a reminder is also initiated after its expiration (e.g., but not limited to, at time 508). Over the timer period further occurrences of exceeding the threshold (e.g., but not limited to, at point 510) will not result in a duplicative alarm.
Another option is to provide meaningful retrospective information to the patient using the sensor. In particular, a retrospective display of one or more physiological values can provide significantly useful data. As disclosed, the retrospective displays can be designed in a variety of ways to provide various useful information. For example, but not limited to, as the sleeping user receives no benefit from a real-time display, a retrospective view of data is important. While a simple listing of previous values has value, it can be time consuming to review, provides information that is difficult to visualize and comprehend and requires significant memory space within the device. Providing useful information that is easy to understand and that can be stored within a small memory space is very important. The ability to review data from the previous sleep period is particularly helpful to a user with nocturnal hypoglycemia or "dawn effect", as there is typically no witness to the real-time display. These measures can be even more important in cases where the alarm system can exhibit many false positives and/or false negatives, which might otherwise frustrate the user and lead to non-use of the monitor.
FIG. 6C illustrates a characteristic value distribution data presentation. A simple distribution of sensor values offers a very powerful tool. Preferably, the distribution is described in percentages that are automatically scaled with the duration of monitor use. Optionally, a monitor can include the total time of use with a percentage distribution. Awareness of a total time provides perspective for reviewing the percentage distribution. A time based distribution can also be used, but requires the total time to be included in the analysis as a reference. A distribution can also be presented based upon the total number of readings, but requires the total time is required in the analysis.
For example, a "hyperglycemic area" can be calculated as the sum of the differences between the readings and the hyperglycemic alarm limit. A "hypoglycemic area" can be calculated from the sum of all the differences between the hypoglycemic alarm limit and the readings. A "hyperglycemic index" is calculated by taking the "hyperglycemic area" and dividing it by the duration of sensor use. Similarly, the "hypoglycemic index" can be calculated by taking the "hypoglycemic area" divided by the duration of sensor use.
Various alarms and/or monitoring aspects discussed above may be combined or utilized with other alarms and/or monitoring aspects. The possible embodiments and/or combinations should not be limited to the specific arrangements described above.
In other arrangements a physiological characteristic monitor 104 is used for reviewing a history of measurements of the sensed characteristic value based on user input from an input device with a display for showing the history of the measurements of the sensed characteristic value. As discussed above with respect to the alarm history, the display may show the measurements only within a specified range, such as the operational range of the sensor (e.g. 40 to 400 or 20 to 600 mg/dl). Outside the specified range, a HI or LO indicator is shown.
FIG. 7 illustrates the real-time and history display 700. Three exemplary screens 702, 704, 706 are shown for the display of real-time or historical measurement data. The in-range screen 702 is used when the measurement is within the specified range; the actual measurement is shown. The high screen 704 (showing a HI indicator) is used when the measurement is above the specified range, and the low screen 706 (showing a LO indicator) is used when the measurement is below the specified range. The display shows a no measurement indicator where no value was recorded in the history.
The user input also directs scrolling through a history of the measurements of the sensed characteristic value. In a typical arrangement the display shows a single measurement at a time. The display shows a time of acquisition by the sensor for each measurement in the history. In the example in-range screen 702, the current measurement is being shown, indicated by the "NOW" indicator. The time of acquisition can be shown as a value relative to a most recent measurement of the history. For example, the high and low screens 704, 706 each show values measured 5 hours and 25 minutes before the current time interval. Alternatively, the actual date and time of the measurement may be shown.
The history of the measurements of the sensed characteristic value can be scrolled through in even time increments. In further arrangements, the even time increment can have a selectable size (e.g. selectable between 5 minute or 30 minute increments), and the selected time increment can be indicated on the display as the history is reviewed. The history itself can comprise a fixed total period from the present backward. For convenience, scrolling through the history wraps around after an end of the history is reached.
In further arrangements, when no measurement is currently available, the NOW indicator can be replaced by a status message indicating no calibration, noise or a missed measurement.
In further arrangements, a graphical display is employed in the monitor 104 (which may be combined with an infusion device) to allow for a user to readily apprehend the current and historical measurements of the characteristic value tracked by the monitor 104.
Arrangements discussed herein include devices which display data from measurements of a sensed physiological characteristic (e.g. blood glucose concentrations) in a manner and format tailored to allow a user of the device to easily monitor and, if necessary, modulate the physiological status of that characteristic (e.g. modulation of blood glucose concentrations via insulin administration). One illustrative arrangement is a device comprising a sensor input capable of receiving a signal from a sensor, the signal being based on a sensed physiological characteristic value of a user; a memory for storing a plurality of measurements of the sensed physiological characteristic value of the user from the received signal from the sensor; and a display for presenting a text and/or graphical representation of the plurality of measurements of the sensed physiological characteristic value (e.g. text, a line graph or the like, a bar graph or the like, a grid pattern or the like or a combination thereof). Preferably, the graphical representation displays real time measurements of the sensed physiological characteristic value. Such devices can be used in a variety of contexts, for example in combination with other medical apparati. In preferred arrangements the device is used in combination with at least one other medical device (e.g. a glucose sensor) and receives a signal from this device that is transmitted via a wired or wireless connection. Wireless communication can include for example the reception of emitted radiation signals as occurs with the transmission of signals via RF telemetry, infrared transmissions, optical transmission, sonic and ultrasonic transmissions and the like. Most preferably, the device is an integral part of a medication infusion pump (e.g. an insulin pump). Typically in such devices, the physiological characteristic values includes a plurality of measurements of blood glucose.
In typical arrangements, the physiological characteristic value measurement is displayed in a graphical format, a text format or a combination thereof. For example, the graphical representation can comprise a color coded set of one or more indicators of the status of the physiological characteristic. In a specific arrangement the graphical representation comprises one or more trend indicators, indicating an approximate rate trend in the sensed physiological characteristic value over a recent series of the plurality of measurements (e.g. the four most recent measurements of the sensed physiological characteristic value). Optionally the graphical representation further comprises a vertical cursor which allows a user to alternatively select measurements of a sensed physiological characteristic value from the graphical format or from a text format. For example, the display can include a scrolling vertical cursor, allowing individual Blood Glucose measurements in the graphics plot to be selected, with the Blood Glucose value and the time the measurement was made displayed in a text portion of the screen.
In a specific illustrative arrangement the physiological characteristic value can be a blood glucose measurement and the color coded set of indicators can comprise a grid of nine indicators including three rate trend categories including going down, stable and going up and three current measurement categories including low, in zone and high where a single rate trend category and a single current measurement category are indicated simultaneously. Optionally in such arrangements going down and low and going up and high can be indicated in red; going down and high and going up and low can be indicated in yellow; going down and in zone, going up and in zone, stable and high and stable and low can be indicated in orange; and stable and in zone can be indicated in green.
In yet another illustrative arrangement the physiological characteristic value is a blood glucose measurement and the graphical representation comprises a graphical plot of at least a portion of the plurality of measurements of the sensed blood glucose measurement where a horizontal axis comprises a time scale and a vertical axis comprises a blood glucose measurement scale. Optionally, the graphical plot can comprise a color coded set of indicators. For example, a color coded set of indicators can comprise horizontal bands corresponding to various levels of danger (e.g. hyperglycemia or hypoglycemia) corresponding to each of the plurality of measurements of the sensed blood glucose measurement. Optionally, the color coded set of indicators can comprise a color of the graphical plot indicating a current danger level corresponding to a current blood glucose measurement. In certain arrangements the graphical plot can be continuously updated in real-time such that the shown portion of the plurality of measurements of the sensed blood glucose measurement comprises a most recent period.
In other arrangements where a graphical representation comprises one or more trend indicators, the trend indicators can comprise about five symbols indicating for example a fast increasing rate, a moderate increasing rate, a negligible rate change, a moderate decreasing rate and/or a fast decreasing rate, respectively. The symbols can comprise any one of a variety of suitable symbols, for example arrows, with two up arrows, a single up arrow, no indicator, a single down arrow and two down arrows, corresponding respectively to for example, the fast increasing rate, the moderate increasing rate, the negligible rate change, the moderate decreasing rate and the fast decreasing rate. In one such arrangement, the physiological characteristic value is a blood glucose measurement and the fast increasing rate is at least approximately +3 mg/dl, the moderate increasing rate is between approximately +3 mg/dl and +1 mg/dl, the negligible rate change is between approximately +1 mg/dl and -1 mg/dl, the moderate decreasing rate is between approximately -1 mg/dl and -3 mg/dl and the fast decreasing rate equal or exceeding -3 mg/dl. In an illustrative arrangement, trend indicators indicate the average glucose rate of change over the last 4 measurements: Double up arrow for an average increase equal to or greater than 3 mg/dl. Single up arrow for an average increase less than 3 and equal to greater than 1 mg/dl. No arrow for an average increase or decrease less then 1 mg/dL. Single down arrow for an average decrease less than 3 and equal to greater than 1 mg/dl. Double down arrow for an average decrease equal to or greater than 3 mg/dl.
In typical arrangements, the display is tailored to a specific set of criteria that are associated with an analyte to be sensed. For example, in a display tailored to provide information on blood glucose, the blood glucose measurement scale can be selectively displayed in mg/dl or mmol/l. In the context of the analyte itself for example, the blood glucose measurement scale can comprise a fixed measurement range from approximately 0 to 314 mg/dl or approximately 0 to 17.2 mmol/l. In addition, the time scale can comprise a time range selectively changed to show different periods of a plurality of blood glucose measurements. In an illustrative example, the time range is selectively changed as either a 3 hour period or a 24 hour period. Optionally, the time range shows the 3 hour period the graphical plot comprises approximately 36 blood glucose measurements, each approximately five minutes apart. In certain arrangements, when the time range shows the 3 hour period each hour of the graphical plot is marked by a vertical line. In a specific arrangement, when the time range shows the 24 hour period the graphical plot comprises approximately 72 blood glucose measurements, each approximately 20 minutes apart.
9. Illustrative Specific Arrangement
The following describes a specific preferred arrangement comprising a insulin infusion device having an monitor that provides a display of physiological glucose values and a user interface.
In this specific arrangement, software associated with the device can allow the entry of a number of user values such as a "Sensor ON/OFF" function that allows the user to turn the sensor on or off. When the sensor is turned ON, features such as those described below can be enabled. When the Sensor is turned off, the options will not be displayed in the pump menus. Options include a Sensor Transmitter ID Number which allows the user to enter the ID number of the sensor transmitter. Another option is aLow Glucose Level which allows the user to select the Low Glucose Alarm Level. This parameter can have a minimum of 50 mg/dl. It can have a maximum equal to 10mg/dl below the High Glucose Level set by the User. The default can be 50 mg/ml. It can provide a visual feedback of the new selection. Another option is a Low Glucose Snooze which can define the time period between the first Low Glucose Alarm and any subsequent Low Glucose alarm. It can have a minimum of 5 minutes and a maximum of 60 minutes. The default can be 20 minutes. Another option is a Low Glucose Suspend which allows allow the user to select the Low Glucose Suspend Level. The default can be Off. If turned On, this parameter can have a minimum of 40 mg/dl. It can have a maximum equal to 10mg/dl below the Low Glucose Level set by the User (see previous paragraph), up to 120 mg/ml. Once turned on, the default can be 40 mg/ml. It can provide a visual feedback of the new selection. Another option is a High Glucose Level which allows allow the user to select the High Glucose Alarm Level. The default can be Off. If turned On, this parameter can have a minimum equal to 10 mg/dl above the Low Glucose Level set by the User (see previous two paragraphs). It can have a maximum of 400 mg/dl. Once turned on, the default can be 200 mg/ml. It can provide a visual feedback of the new selection. Another option is a High Glucose Snooze which can define the time period between the first High Glucose Alarm and any subsequent High Glucose alarm. It can have a minimum of 5 minutes and a maximum of 180 minutes. The default can be 60 minutes. Another option is a Glucose Format which can allow the user to select glucose values to be displayed in units of mg/dl or mmol/l. The default can be mg/dl. It can provide a visual feedback of the new selection. Another option is a Communication Failure Alert Period (Missed Data) which can allow the user to set the time period that will lapse between the loss of communications and a loss of communications alarm. This parameter can have a minimum value of 5 minutes and a maximum value of 40 minutes. After 40 minutes, the pump can re-sync automatically. If the re-sync fails, a Link Error alarm is generated and the communication stops. The default can be 30 minutes. Another option is a Calibration Reminder, a value which can define the time before the sensor Calibration is required to remind the user. The minimum value can be Off. The Maximum value can be 4 hours. The default value can be 1 hour.
In this preferred arrangement, the following sensor trend values can be utilized in the glucose calculations. A first sensor trend value is a High Positive Trend Threshold which can define the High Positive Trend Threshold limit that will result in a display of two up arrows. The value can be 3mg/dl per minute averaged over 20 minutes. This can be defined as a change between the current glucose value and the 20-minute-old glucose value. Another sensor trend value is a Low Positive Trend Threshold which can define the Low Positive Trend Threshold limit that will result in a display of one up arrow. The value can be 1mg/dl per minute. Another sensor trend value is a Low Negative Trend Threshold which can define the Low Negative Trend Threshold limit that will result in a display of one down arrow: The value can be -1mg/dl per minute. Another sensor trend value is a High Negative Trend Threshold which can define the High Negative Trend Threshold limit that will result in a display of two down arrows. The value can be -3mg/dl per minute. Another sensor trend value is a Glucose Calibration / Calculation which can calibrate the glucose value using the raw data from the sensor. Optionally a mathematical formula or algorithm is used in this calculation. For example, the glucose can be calculated by multiplying the glucose raw data value by the calibration factor.
This preferred arrangement includes a Glucose Graphical History Screen which can be activated by pushing the ESC key, and can stay active for some period of time (e.g. 2 minutes) before transitioning to the default "Idle" screen. This can display information including the current glucose level as measured by the Sensor, displayed in units selected by the user. These can be displayed graphically in 5-minute intervals, with each data point 2 pixels wide. The most recent data can be on the right side of the display. An alphanumeric display of the glucose data or reasons that the data is not displayed can be included. The current value of High Glucose Level set by the user can be displayed as a dashed line on the graph. The current value of Low Glucose Level set by the user can be displayed as a dashed line on the graph. Glucose Trend Indicator: High or Low Glucose Trend can be displayed as a single or double up arrow while the user is viewing the Current Glucose Value.
The screen can display the time of the sensor value measurement, for example in the form of time markers. There can be a vertical dashed line at each clock hour on the 3-hour display. There can be a vertical dashed line at Noon and Midnight on the 24-hour display. The graphic screen can display a visual indication of data above and below the range of the display screen. The terms "HIGH" and "LOW" can be displayed in the alphanumeric display. The graphic screen can visually display the time of any boluses within the time displayed on the graph. This can be done with a bar at the bottom of the screen.
The screen can include a cursor. Consequently, the user can scroll a vertical cursor left and right through the points on the graph, and the time, and the glucose value for each data point can be displayed. This can be done using the up and down buttons. When displaying data that is not the current value, the screen can have a different appearance to alert the user that the data is historical, not current. This may be done by flashing the numbers or using an inverse font. It can also display the term "History". The user can be able to change the screen from a 3 hour width to a 24 hour width by pushing a single button. In this mode, the screen can display 24 hours of data at 20-minute intervals. In this display, each time period can be only one pixel wide. The display can incorporate features to identify to the user that this is a 24-hour display, not the three-hour display. This may be done by putting the night hours (6pm to 6am) in inverse font, placing the terms "3 hour" or "24 hour" on the display, both, or another method. There can be a vertical line at Noon and Midnight.
The device can further include a calibration glucose entry which allows the user to enter the reference glucose values from an external meter reading. The frequency of this entry can be based on the sensor calibration requirements. The User can get a reminder at a user selectable time period prior to the required entry time. The measurement can be entered manually or can be communicated to the device via a wired or wireless connection. Wireless communication can include for example the reception of emitted radiation signals as occurs with the transmission of signals via RF telemetry, infrared transmissions, optical transmission, sonic and ultrasonic transmissions and the like. When the Paradigm™ Link meter is used, the glucose measurement is sent to the pump automatically via RF. Alternatively, one can use an arrangement disclosed herein in combination with any one of the wide variety of other medical devices known in the art such as those produced by Therasense, Roche, Bayer or Abbot laboratories.
The device can have a number of alarm functions. When an alarm condition occurs, the pump can display the alarm to the user on the pump screen and via the selected alert mechanism. The pump can provide the ability to clear the display and return to the action previously in progress. A cleared sensor or glucose alarm can not be reissued for a user specified time after the user clears the alarm. Alarm conditions include a communications error alarm where the alarm can be set when the pump doesn't receive valid data for the time period specified by the use, a sensor low battery alarm which can activate when the sensor transmitter sends a low battery signal, a sensor dead battery alarm which can activate when the sensor transmitter sends a dead battery signal, a low glucose alarm which can be set when the current glucose level is equal to or below the low glucose level set by the user, and a shutoff limit alarm which can be set when the current glucose level is equal to or below the shutoff limit level set by the user and which can suspend pumping and warn the user following the alarm protocol. The error message can be similar to " low glucose - pumping suspended", a high glucose alarm which can be set when the current glucose level is equal to or above the high glucose level set by the user, a calibration required alarm which can be set when 12 hours have elapsed since the last reference glucose value has been entered (this time period can be determined based on the sensor calibration requirements), a sensor end of life alarm which can be set when the pump calculates that the sensor has reached its end of life, a calibration needed alarm which can inform the user a calibration is needed in short period of time. The user can set the time delay between this alarm and the calibration required alarm. The device also includes a glucose alarm history where the pump can display the sensor glucose alarm values as a tabular display of time and alarm information, with the ability to scroll forward and backward in time. This function can be combined with other history tables.
a sensor input (106) capable of receiving a signal from a sensor (102), the signal being based on a sensed physiological characteristic value of a user of the device; and
a processor (108) coupled to the sensor input (106) for operating an alarm based on the received signal from the sensor (102);
wherein the processor (108) is configured to activate the alarm according to:
a first criterion threshold during waking hours; and
a second different criterion threshold during sleeping hours;
wherein the sensed physiological characteristic is a measurement of glucose;
wherein the processor (108) is configured to provide an alarm warning at an earlier timepoint during sleeping hours as compared to during waking hours by selecting said second different criterion threshold for the activation of said alarm during sleeping hours,
wherein the criterion includes:
The device of claim 1, wherein providing the alarm warning at an earlier timepoint is applied to multiple alarms.
The device of claim 1, wherein the processor is configured to activate the alarm to provide the alarm warning at an earlier timepoint by monitoring a rate of change in the sensed physiological characteristic value and adjusting an alarm threshold value when the rate exceeds a predetermined rate limit.
The device of claim 3, wherein physiological characteristic value is a blood glucose measurement, providing earlier warning to the user is applied to a low blood glucose alarm and the rate limit comprises a declining blood glucose rate.
The device of claim 4, wherein the rate limit is between approximately minus 2.0 mg / dl and approximately minus 4. 0 mg / dl.
The device of claim 3, wherein adjusting the alarm threshold criteria comprises raising a low blood glucose alarm threshold.
The device of claim 6, wherein the low blood glucose alarm threshold is raised by approximately 6 mg / dl.
The device of claim 6, wherein the low blood glucose alarm threshold is raised by approximately 12 mg/dl.
The device of claim 6, wherein the low blood glucose alarm threshold is raised by approximately 6 mg / dl and the rate limit is approximately minus 2.0 mg / dl.
The device of claim 6, wherein the low blood glucose alarm threshold is raised by approximately 12 mg/dl the rate limit is approximately minus 4.0 mg / dl.
The device of claim 1, wherein said processor is configured such that said sleeping hours and said waking hours are set according to a schedule based on the time of day.
The device of claim 1, wherein said processor is configured to accept a user input to set said sleeping hours by user input before sleeping, and to set said waking hours by manually canceling said setting on waking.
The device of any preceding claim, wherein the processor is configured to delay accepting input from the user when the processor activates the alarm according to the second criterion.
The device of claim 13, wherein the delay is until the user provides a predetermined input.
The device of claim 14, wherein the predetermined input is a numeric code or a button sequence.
EP10177011.3A 2001-12-27 2005-05-20 System for monitoring physiological characteristics according to the user biological state Active EP2256494B1 (en)
US10/860,114 US7399277B2 (en) 2001-12-27 2004-06-03 System for monitoring physiological characteristics
EP05755120A EP1759201B1 (en) 2004-06-03 2005-05-20 System for monitoring physiological characteristics according to the user biological state
EP05755120A Division EP1759201B1 (en) 2001-12-27 2005-05-20 System for monitoring physiological characteristics according to the user biological state
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EP2256494A1 EP2256494A1 (en) 2010-12-01
EP2256494B1 true EP2256494B1 (en) 2017-01-11
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EP10177011.3A Active EP2256494B1 (en) 2001-12-27 2005-05-20 System for monitoring physiological characteristics according to the user biological state
EP05755120A Active EP1759201B1 (en) 2001-12-27 2005-05-20 System for monitoring physiological characteristics according to the user biological state
EP10178254.8A Active EP2256495B1 (en) 2001-12-27 2005-05-20 System for monitoring physiological characteristics according to the user biological state
EP10178251.4A Revoked EP2259057B1 (en) 2001-12-27 2005-05-20 System for monitoring physiological characteristics according to the user biological state
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DK (3) DK2256495T3 (en)
JP2009244006A (en) * 2008-03-31 2009-10-22 Dkk Toa Corp Measuring apparatus indicating amount of change in ion concentration
JP2016189860A (en) * 2015-03-31 2016-11-10 日本光電工業株式会社 Medical instrument, medical system, and communication state check method
JP3538399B2 (en) * 2001-08-21 2004-06-14 コーリンメディカルテクノロジー株式会社 Patient monitoring equipment
2005-05-20 EP EP10177011.3A patent/EP2256494B1/en active Active
2005-05-20 CA CA2816310A patent/CA2816310C/en active Active
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EP2256495B1 (en) 2015-07-29
EP2259057B1 (en) 2016-01-27
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JP5594935B2 (en) 2014-09-24
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AT484745T (en) 2010-10-15
US9833199B2 (en) 2017-12-05 Receivers for analyzing and displaying sensor data
CN103400028B (en) 2017-04-12 Means to optimize insulin dosage regimen for a patient
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