TECHNICAL FIELD

[0001] The subject matter described herein relates to an adjuster for adjusting alarm sensitivity and/or specificity of a medical device.

BACKGROUND

[00021 Existing medical device alarm systems have fixed sensitivity and specificity. In the case of conventional threshold alarms, such as those used in nearly all monitoring devices today, an upper and lower threshold are set (usually preset by the manufacturer) for each vital sign (e.g., 120 bpm and 60 bpm for the heart rate). When the vital sign exceeds a threshold, the device may wait for a fixed time period (e.g., 6 seconds) before sounding an alarm. Conventional threshold alarms are very sensitive, rarely, if ever, missing a clinically significant event. However, this high sensitivity comes at a cost of low specificity, with as many as 90% of all al arms being clinically irrelevant (nuisance alarms).

[0003] Newer algorithms employ variable delays to increase specificity. For example, some alarm algorithms employ a delay that decreases as the vital sign strays further from the threshold. For example, a heart rate upper threshold may still be set at

120 bpm, but the delay varies from 6 to (SO seconds depending on the distance from the threshold. At 125 bpm, the system may wait a full 60 s before alarming. But if the heart rate increases to 180 bpm, the system may only wait 6 s to alarm. Such soft thresholds promise to significantly increase the specificity of threshold alarms. However, increased specificity conies at a cost of decreased sensitivity. [0004] Perfect sensitivity may not always be necessary for safe patient care. The prevailing view of alarms is that they must detect all clinically significant events to ensure patient safety. For example, in an increase in heart rate and blood pressure, current alarming practice does not distinguish between an elderly patient undergoing major cardiac surgery and a healthy young patient undergoing minor elective surgery. Both are considered equally dangerous. However, while this event may lead to morbidity or mortality in the elderly ill patient, it may likely have no consequences for the young healthy patient. Sensitivity can be reduced in some patient populations without significantly increased risk of patient harm.

SUMMARY

[0005] Variations of the present subject matter are directed to methods, systems, devices, and other articles of manufacture that are provided to enable adjustment of alarm sensitivity of a medical device.

[0006] The present subject matter provides an alarm system that includes a sensor, a display, and an input mechanism. The sensor is configured to transmit sensor data to the alarm system. The display is configured to display a graphical representation of a selected sensitivity setting selectable from a plurality of sensitivity settings each comprising one or more corresponding triggers for generating an alarm. The input mechanism is configured to receive an input representing the selected sensitivity setting and transmit the input to the alarm system. Based on the input, the alarm system is configured to compare the sensor data against the one or more corresponding triggers of the selected sensitivity setting and trigger the alarm when the sensor data meet at least one of the one or more corresponding triggers of the selected sensitivity setting. [0007] The present subject matter also provides an alarm system that includes a display and an input mechanism. The display is configured to display a graphical representation of a selected sensitivity setting selectable from a plurality of sensitivity settings each comprising one or more corresponding triggers for generating an alarm. The input mechanism is configured to receive an input representing the selected sensitivity setting and transmit the input to the alarm system. Based on the input, the alarm system is configured to compare sensor data against the one or more corresponding triggers of the selected sensitivity setting and triggering the alarm when the sensor data meet at least one of the one or more corresponding triggers of the selected sensitivity setting.

[0008] The present subject matter also provides an alarm system that includes a display and an input mechanism. The display is configured to display a graphical representation of a selected sensitivity setting selectable from a plurality of sensitivity settings each comprising one or more corresponding triggers for generating an alarm. The input mechanism is configured to receive an input representing the selected sensitivity setting and transmit the input to the alarm system.

[0009] One or more of the fol lowing features can be included in any feasible combination. For example, in some variations, the sensitivity settings are configured such that a lower sensitivity setting includes one or more corresponding triggers that are less likely to trigger the alarm than a higher sensitivity setting. In some variations, the one or more corresponding triggers of the lower sensitivity setting include an increased upper threshold and/or a decreased lower threshold. [0010] In some variations, the sensitivity settings are configured such that a higher sensitivity setting includes one or more corresponding triggers that are more likely to trigger the alarm than a lower sensitivity setting. In some variations, the one or more corresponding triggers of the higher sensitivity setting include a decreased upper threshold and/or an increased lower threshold ,

[0011] In some variations, the one or more corresponding triggers of the lower sensitivity setting include a longer delay time. In some variations, the one or more corresponding triggers of the higher sensitivity setting comprises a shorter delay time.

[0012] In some variations, the system can be further configured to reset to a default setting after a specified time period; verify a permission of a user, and accept the input only if the user has the permission; record a time when the input is received;

generate an alert when the input is received; and/or count a number of times the alarm has been triggered,

[0013] In some variations, when the number of times the alarm has been triggered exceeds a re-deterrnined amount, the alarm system resets the sensitivity setting to a default setting.

[001 ] In some variations, the default setting corresponds to a most sensitive setting. In some variations, the system can be further configured to estimate how many alarms would have been generated during a time period for the selected sensitivity setting based on historical data.

[0015] The present subject matter also provides a method of generating a medical alarm. The method includes receiving sensor data from a sensor. The method also includes displaying a graphical representation of a selected sensitivity setting selectable from a plurality of sensitivity settings each comprising one or more corresponding triggers for generating an alarm. The method receives an input representing the selected sensitivity setting, and based on input, compares the received sensor data against the one or more corresponding triggers of the selected sensitivity setting, and triggers the alarm when the sensor data meet the one or more corresponding triggers ofthe selected sensitivity setting.

[0016] One or more ofthe following features can be included in any feasible combination. For example, in some variations, the sensitivity settings are configured such that a lower sensitivity setting includes one or more corresponding triggers that are less likely to trigger the alarm than a higher sensitivity setting.

[0017] In some variations, the one or more corresponding triggers ofthe lower sensitivity setting include an increased upper threshold and/or a decreased lower threshold; a longer delay time; and'or a decreased delay time gradient.

[001 ] In some variations, the sensitivity settings are configured such that a higher sensitivity setting includes one or more corresponding triggers that are more likely to trigger the alarm than a lower sensitivity setting. These triggers ofthe higher sensitivity setting can include one or more of: a decreased upper threshold and/or an increased lower threshold; a shorter delay time; and an increased delay time gradient,

[0019] In some variations, the method can further include one or more of: resetting to a default setting after a specified time period; verifying a permission of a user, and ac cepting the input only if the user has the permission; recording a time when the input is received; generating an alert when the input is received; counting a number of times the alarm has been triggered; resetting the sensitivity setting to a default setting when the number exceeds a pre-detemiined amount (e.g., the default setting can corresponds to a most, sensitive setting); and estimating how many alarms would have been generated during a time period for the selected sensitivity setting based on historical data.

[0020] Non -transitory computer program products (i.e., physically embodied computer program products) are also described that, store instructions, which when executed by one or more data processors of one or more computing systems, causes at least one data processor to perform operations herein. Similarly, computer systems are also described that may include one or more data processors and memor coupled to the one or more data processors. The memory may temporarily or permanently store instructions that cause at least one processor to perform one or more of the operations described herein. In addition, methods can be implemented by one or more data processors either within a single computing system or distributed among two or more computing systems. Such computing systems can be connected and can exchange data and/or commands or other instructions or the like via one or more connections, including but not limited to a connection over a network (e.g. the Internet, a wireless wide area network, a local area network, a wide area network, a wired network, or the like), via a direct connection between one or more of the multiple computing systems, etc.

[0021] The subject matter described herein provides many advantages. For example, by providing adjustable alarm sensitivity, a user such as a clinician can tailor the alarm setting to the patient being monitored. Thus, for example, alarm fatigue can be reduced and clinician responsiveness can be increased. BRIEF DESCRIPTION OF THE FIGURES

[0022] FIG 1 is a graphical illustration of a sensitivity adjuster in accordance with the current subject matter;

[0023] FIG. 2 is a graphical illustration of another sensitivity adjuster in accordance with the current subject matter;

[0024] FIGS 3 and 4 are graphical illustrations of variations of global alarm, sens itivity adj listers ;

[0025] FIGS. 5 and 6 are graphical illustrations of variations of system -level alarm sensitivity adjusters;

[0026] FIGS. 7 and 8 are graphical illustrations of variations of parameter- level alarm sensitivity adjusters;

[0027] FIGS. 9A and 9B are graphical illustrations of variations of sensitivity adjusters that provide alarm estimation based on global sensitivity settings;

[0028] FIGS. 1 OA and lOB are graphical illustrations of variations of sensitivity adjusters that provide alarm estimation based on system-level sensitivity settings;

[0029] FIGS. 1 1 A and 1 I B are graphical illustrations of variations of sensitivity adjusters that provide alarm estimation based on parameter-level sensitivity settings;

[ 0030] FIG . 22 is a diagrammatic illustration of a system in accordance with the current subject matter;

[0031] FIG. 13 is a process flow diagram of a method in accordance with the current subject matter; and [0032] FIG. 14 is a process flow diagram, of another method in accordance with the current subject matter.

DESCRIPTION

[0033] The current subject matter provides, in some variations, an alarm system with a variable sensitivity and/or specificity adjuster that can be set based on, for example, the patient's status. Sensitivity generally refers to the true positive rate of detecting a condition (e.g. the percentage of patients suffering a given condition who are correctly detected as having that, condition). Specificity generally refers to the true negative rate of detecting a condition (e.g. the percentage of patients not, suffering a given condition who are correctly detected as not, having that condition). Ideally, an alarm system should have perfect sensitivity and specificity simultaneously. Such a system would always detect the condition when present, and would never falsely detect the condition when absent. However, the ideal system is impossible to realize. There generally exists a trade-off between sensitivity and specificity, such that increasing one decreases the other. The sensitivity and/or specificity adjuster described herein would adjust the parameters of this trade-off, increasing sensitivity at the expense of decreased specificity, or increasing specificity at the expense of decreased sensitivity. For brevity, the term "sensitivity adjuster" is being used throughout this application to refer to an adjuster for adjustment of alarm sensiti vity, specificity, or both.

[0034] FIG. 1 shows an example of a sensitivity adjuster of the present subject matter. Here, the sensiti vity adjuster 100 takes the form of a sensiti vity slider 1 1 0 having a graduated scale 120 representing an "index of concern" (loC) for the patient.

The loC can range, for example, from 0-10 where 0 represents relatively low concern (e.g., healthy patient) and 10 represents relatively high concern (e.g., very ill patient). A. user (e.g., a clinician like a doctor or a nurse) can set the loC based on one or more factors to increase or decrease the sensitivity and/or specificity. The factors can include, for example, the patient's demographies (age, weight, etc.), medical history, current condition, the medical treatment being delivered, and the care area (e.g., operating room, intensive care unit, general ward).

[0035] FIG. 2 shows a variation ofthe sensitivity adjuster. Here, sensitivity adjuster 200 is similar to the one shown in FIG. 1 , except that that sensitivity adjuster 200 takes the form of a sensiti vity knob 210 and loC 220 (from 0-10).

[0036] In other variations, the Index of Concern can be represented in other ways, such as (for example) alphabetical, alphanumeric, colors, and or other

terms/phrases and combinations. The sensitivity adjuster can be represented in other forms on a display. For example, instead of a scale, the display can simply show the selected number representing the selected IoC.

[0037] FIGS. 3 and 4 are variations ofthe sensitivity adjusters shown in FIG. 1 and 2, and are configured to allow a selec tion of a global sensiti vity setting. Here, global sensitivity adjuster 300 includes a global sensitivity slider 310 and a global Index of Concern 320, Similarly, global sensitivity adjuster 400 includes a global sensitivity knob 41 0 and a global Index of Concern 420.

[0038] FIG. 5 illustrates a system-level alarm sensitivity adjuster 500. In some variations, this type of adjuster can be provided by itself, or it can be accessed in addition to a global sensitivity setting, for example, to override a global setting for a specific physiological system. Here, a system-level alarm sensitivity adjuster 500 is provided to allow adjustment of alarm sensitivity related to the cardiovascular system . The cardiovascular system being monitored includes the heart rate (HR) 530, arterial pressure (ART) 540, and central venous pressure (CVP) 550. These parameters are shown for illustrative purposes only. For example, other combinations of parameters, including additional parameters can be included. System-level alarm, sensitivity adjuster 500 can also be applied to other physiological systems (e.g. the respiratory system, which may include parameters such as respiration rate, minute ventilation, inspired oxygen, expired carbon dioxide, air flow, airway pressure, and blood oxygen saturation). The system-level alarm sensitivity adjuster 500 includes a system-level sensitivity slider 510 and IoC 520.

[0039] FIG. 6 shows a system-level alarm sensitivity adjuster 600 that is similar to that sho wn in FIG. 5, except that it is represented in the form of a system-level alarm sensitivity knob 61 0 and IoC 620.

[0040] FIG. 7 shows a parameter-level alarm sensitivity adjuster that al lows an adjustment of the sensitivity setting related to a specific parameter. This type of adjuster can be provided by itself, or can be accessed in addition to a global and/or system-level setting to override the global and system-level settings for a specific physiological parameter. Here, the parameter-level alarm sensitivity adjuster is configured to allo an adjustment of sensitivity of the heart rate. Heart rate sensitivity adjuster 700 includes a parameter- level sensitivity slider 710 and IoC 720.

[0041] FIG. 8 shows a variation of the parameter-level alarm sensitivity adjuster of FIG. 7. Heart rate sensitivity adjuster 800 differs from that shown in FIG. 7 in that it is represented in the form of a sensitivity knob 810 and IoC 820. [0042] FIGS. 9A and 9B show examples of a system 900 in accordance with the present subject matter, which is configured to estimate how many alarms would have been generated based on the selected global sensitivity setting and the patient's parameter history. For example, when "3" sensitivity (loC 920) is selected using the sensitivity slider 910, the system estimates, based on the patient's parameter history, that 5 alarms would have been generated in the last hour (FIG. 9 A). When "7" sensitivity (loC) is selected, the system estimates that 1 8 alarms would have been generated in the last hour.

[0043] FIGS. 1 OA and lOB show examples of a system 1000 in accordance with the present subject matter, which is configured to estimate how many alarms would have been generated during a time period based on the selected system-level alarm sensitivity setting and the patient's parameter history. In FIG. 1 OA, the system shows that when "4" sensitivity (IoC 1020) is selected using the sensitivity slider 1010, the system estimates that 7 alarms would have been generated in the last hour. And when "1 0" sensitivity (IoC) is selected, the system estimates that 24 alarms would have been generated in the last hour.

[0044] FIGS. 1 1 A and 1 I B show examples of a system 1 100 in accordance with the present subject matter, which is configured to estimate how many alarms would have been generated based on the selected parameter-level alarm sensitivity setting and the patient's parameter history. In FIG. 1 1 A, the system shows that when "7" sensitivity (IoC 1 120) is selected using sensitivity slider 5 5 50, 6 alarms would have been generated in the last hour. And when "4" sensitivity (IoC) is selected, the system estimates that 3 alarms would have been generated in the last hour. [0045] In some variations, the system can allow the clinician to select one or more other time periods (e.g., the past 12 hours, 24 hours, etc.) for alarm estimation. In some variations, alarm estimations can be estimated based on, for example, a patient type representative of the patient's health (e.g., post-surgery, elderly, high risk, etc.).

[0046] FIG. 12 schematically shows a general view of components of a system 1200 for generating alarm according to the present subject matter. System 1200 includes a controller 1210, which includes one or more data processors 1220 and memor 1230 (including one or more of, e.g.,: ROM, RAM, computer storage medium, etc.). Memory 5230 can include computer instructions that when executed by the one or more data processors 1220 performs one or more steps of the present subject matter.

[0047] System 1200 also includes one or more sensors 1241 -2243 (e.g., physiological sensors) that are connected to controller 1210 via data connections 1245, 1246, and 1247. These data connections can be wired or wireless as is known in the art. Controller 1210 is configured to recei ve one or more data from each of the sensors and determine one or more parameters or measured values based on the data from the sensors. In some variations, controller 1210 can also be configured to compare the parameters against preset values or value ranges (triggers). Controller 1210 can also be configured to detect, for example, duration of time interval of the deviation of the parameter from the present normal values or value ranges, beyond a certain threshold value or threshold value range (trigger).

[0048] System 1200 also includes a display 1250, which is connected to controller 1210 via data connection 1251 (e.g., wired or wireless as known in the art). The controller 1210 can be configured to display one or more data on the display 1250 via a user interface. For example, the controller 1210 can he configured to display the sensitivity adjuster as discussed above (and other data if desired).

[0049] System 1200 can include a speaker 1260 connected to controller 1210 via data connection 1261 (e.g., wired or wireless as known in the art). The controller 1210 can he configured to generate an audio (e.g., a beep) when an alarm condition has been triggered,

[0050] System 1200 also includes an input 1270 which is connected to controller 1210 via data connection 1271 (e.g., wired or wireless as known in the art). Input 5270 can include, for example, one or more dials, keys, or other input means to allow user to interact with controller 1210 to select, for example, a sensitivity setting.

[0051] FIG. 53 shows a process flow of the present subject matter. In this example, a method sensitivity adjustment is provided. The method includes displaying a graphical representation of the current (e.g., default or previously selected) Index of Concern (loC) (1 310); receiving an input from the user (e.g., using an input mechanism such as a dial or adjuster) representing a change to the Index of Concern (1320);

translating the Index of Concern into an alarm sensitivity setting (1330); and updating the alarm algorithm with the new sensitivity setting (1340), In some variations, the Index of Concern include a plurality of sensitivity settings each comprising one or more corresponding triggers for generating an alarm (alarm algorithm).

[0052] FIG . 54 shows a process flow of the present subject matter. In this example, a method of generating a medical alarm based on a sensitivity setting is provided. The method includes receiving sensor data from a sensor ( 1410); receiving an input representing the selected sensitivity setting (1420) (for example, selected using at least partly the process shown in FIG. 13); and analyzing the sensor data with an alarm algorithm, the algorithm's parameters having been adjusted according to the sensitivity setting (1430). The method compares the analyzed sensor data against the one or more corresponding triggers of the selected sensitivity setting (1440), and triggers the al arm when the sensor data meet, at least one of the one or more corresponding triggers of the selected sensitivity setting (1450).

[0053] In some variations, the loC controls tuning triggers can be pre-set, for example, by the manufacturer, based on an algorithm. For instance, the IoC can be configured to correspond to a range of sensitivity in which a higher setting corresponds to a higher alarm sensitivity and a corresponding decrease in specificity (fewer missed events, but more nuisance alarms). Conversely, a lower setting corresponds to a lower alarm sensitivity, but a higher specificity (fewer nuisance alarms, but more missed events).

[0054] In some variations, sensitivity/specificity can be adjusted by scaling the alarm delay time. Shorter delay times lead to increased sensitivity and decreased specificity. For example, in a patient with a low IoC (low concern; low sensitivity), the alarms may use delays ranging from 6s to 60s depending on how far the parameter is above the threshold. In a patient with a higher IoC (higher concern; higher sensitivity), the alarms may use shorter delays ranging from 3s to 30s depending on how far the parameter is above the threshold.

[0055] In some variations, sensitivity/specificity can be adjusted by changing the alarm delay time gradient. The gradient is defined as the rate at which the delay time decreases as the deviation from the threshold increases. Increased gradient leads to increased sensitivity and decreased specificity. For example, in a patient with a low loC (low concern; low sensitivity), a heart rate of 1 bpm above the threshold may set a delay of 60s before alarming, while a heart rate of 25 bpm above the threshold may set a delay of 45s. In a patient with a higher loC (higher concern; higher sensitivity), a heart rate of 1 bpm above the threshold may still set a delay of 60s before alarming, but a heart rate of 25 bpm above the threshold may set a delay of only 30s.

[0056] In some variations, the loC can represent a linear range of sensitivity adjustments. In some variations, the loC represents a non-linear range of sensitivity adjustments.

[0057] In some variations, controller 1210 is configured to reset to a default setting after a specified time period. This can be provided, for example, to force the clinician to reassess the sensitivity setting periodically. This can be advantageous in patients who are receiving longer term care, such as in an intensive care unit. The patient's condition may deteriorate or improve over time, and the original loC setting may no longer be relevant days later. The system can improve patient safety by forcing a periodic IoC reassessment,

[0058] In some variations, controller 1210 is configured to verify a permission of a user (e.g., a clinician) and accept the input (e.g., change of sensitivity setting) only if the user has the permission. Such permission can be verified, for example, by checking the user ID, or using a password. This can ensure that only a qualified clinician can adjust the sensitivity setting.

[0059] In some variations, the controller is configured to record a time (and the identity of the clinician, if desired) when the input is received. The controller can also be configured to generate an alert when the input is received. This can help prevent, inadvertent sensitivity adjustments, and to provide a record of who changed the setting and when it was changed.

[0060] In some variations, the controller is configured to count a number of times the alarm has been triggered. The controller can also be configured to reset the sensitivity setting to a default if a pre-determined number of times that the alarm has triggered has been exceeded. In some variations, the default setting can be the most sensitive setting. This can also help prevent inadvertent sensitivity adjustments and provides additional safety.

[0061] In some variations, the controller can be configured to generate a recommendation to the clinician to lower the sensitivity setting when too any false alarms have been generated (e.g., the number of false alarms exceeds a pre-defined number). This can help the clinician to set a more appropriate sensitivity setting, for example, to reduce alarm fatigue.

[0062] One or more aspects or features of the subject matter described herein can be realized in digital electronic circuitry, integrated circuitry, specially designed application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) computer hardware, firmware, software, and/or combinations thereof. These various aspects or features can include implementation in one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device. The programmable system or computing system may include clients and servers. A client and server are generally remote from, each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

[0063] These computer programs, which can also be referred to as programs, software, software applications, applications, components, or code, include machine instructions for a programmable processor, and can be implemented in a high-level procedural language, an object-oriented programming language, a functional

programming language, a logical programming language, and/or in assembly/machine language. As used herein, the term "machine-readable medium" refers to any computer program product, apparatus and/or device, such as for example magnetic discs, optical disks, memory, and Programmable Logic Devices (PLDs), used to provide machine instructions and/or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal used to provide machine instructions and/or data to a programmable processor. The machine-readable medium can store such machine instructions non-transitorily, such as tor example as would a non-transient solid- state memory or a magnetic hard drive or any equivalent storage medium. The machine- readable medium can alternatively or additionally store such machine instructions in a transient manner, such as for example as would a processor cache or other random access memory associated with one or more physical processor cores.

[0064] To provide for interaction with a user, one or more aspects or features of the subject matter described herein can be implemented on a computer having a display device, such as for example a cathode ray tube (CRT) or a liquid crystal display (LCD) or a light emitting diode (LED) monitor for displaying information to the user and a keyboard and a pointing device, such as for example a mouse or a trackball, by which the user may provide input, to the computer. Other kinds of devices can be used to provide for interaction with a user as well. For example, feedback provided to the user can be any form, of sensory feedback, such as for example visual feedback, auditory feedback, or tactile feedback; and input from the user may be received in any form, including, but not limited to, acoustic, speech, or tactile input. Other possible input devices include, but are not limited to, touch screens or other touch-sensitive devices such as single or multi-point resistive or capacitive trackpads, voice recognition hardware and software, optical scanners, optical pointers, digital image capture devices and associated interpretation software, and the like.

[Θ065] In the descriptions above and in the claims, phrases such as "at least one of or "one or more of may occur followed by a conjunctive list of elements or features. The term "and/or" may also occur in a list of two or more elements or features. Unless otherwise implicitly or explicitly contradicted by the context in which it is used, such a phrase is intended to mean any of the listed elements or features indi vidually or any of the recited elements or features in combination with any of the other recited elements or features. For example, the phrases "at least one of A and Β;" "one or more of A and Β;" and "A and/or B" are each intended to mean "A alone, B alone, or A and B together," A similar interpretation is also intended for lists including three or more items. For example, the phrases "at least one of A, B, and C;" "one or more of A, B, and C;" and "A, B, and/or C" are each intended to mean "A alone, B alone, C alone, A and B together, A and C together, B and C together, or A and B and C together." In addition, use of the term "based on," above and in the claims is intended to mean, "based at least in part on," such that an unrecited feature or element is also permissible.

[0066] The subject matter described herein can be embodied in systems, apparatus, methods, and/or articles depending on the desired configuration. The implementations set forth in the foregoing description do not represent all

implementations consistent with the subject matter described herein, instead, they are merely some examples consistent with aspects related to the described subject matter. Although a few variations have been described in detail above, other modifications or additions are possible. In particular, further features and/or variations can be provided in addition to those set forth herein. For example, the implementations described above can be directed to various combinations and subcombinations of the disclosed features and/or combinations and subcombinations of several further features disclosed above. In addition, the logic flows depicted in the accompanying figures and/or described herein do not necessarily require the particular order shown, or sequential order, to achieve desirable results. Other implementations may be within the scope of the following claims.