PRIORITY CLAIM

[0001] This application claims priority to and all the benefits of United States Provisional Application No. 63/424,601, filed November 11, 2022, the entire contents of which are hereby incorporated by reference.

BACKGROUND

[0002] In a surgical procedure, it is imperative to have an accurate inventory of surgical sponges that are “counted in” to be used in the surgical field, and those “counted out” before conclusion of the surgical procedure. Healthcare professionals follow strict procedures in view of the risks associated with a surgical sponge being inadvertently retained inside a patient. In the past, healthcare professionals have relied upon counting the surgical sponges by hand; however, manual counting requires handling of and exposure to soiled surgical sponges, and is prone to human error. More recently, surgical sponges have been tagged with radiopaque markers, barcodes, and/or wireless transponders, such as radiofrequency identification (RFID) tags, to facilitate electronically counting the surgical sponges wirelessly with a data reader.

[0003] The RFID tags may uniquely identify each of the surgical sponges. There are instances where a user may unintentionally or intentionally present a surgical sponge to the data reader that has already been counted out. The system may be configured to present a notification or alert that a duplicate sponge has been presented. One exemplary manner by which this is implemented is disclosed in commonly-owned United States Patent Publication No. 2022/0246288, published August 4, 2022, the entire contents being hereby incorporated by reference. The notification may help the user to realize an unintentional mishandling of the sponges (e.g. , presented Sponge A to the data reader be counted out, placed Sponge B in a counting or collection bag, then re-presented Sponge A to the data reader).

[0004] The duplicate sponge notifications may become be a nuisance to users in instances in which the data reader detects sponges already counted out but merely collected in relatively close proximity to the data reader. In other words, the user is not actually presenting a duplicate sponge to the data reader, but the data reader detects the sponges collected nearby. In these instances, the duplicate sponge notifications may not represent a “true duplicate” sponge being counted out, and the repeated notifications may be unwarranted. A similar problem may arise in the context of a virtual count in in which the detected sponge is not a “true count out” sponge. Certain systems may use the data reader at lower power levels when counting out the surgical sponges to prevent unwarranted duplicate notifications. However, doing so may make it more difficult for the data reader to detect the sponges that the user wants to count out. The user may undesirably need to bring the item closer to the data reader, improve alignment, and/or make other timing-consuming changes in order to affirmatively count out the sponge. Therefore, there is a need in the art to provide duplicate sponge notifications in a more accurate manner without compromise to the surgical workflow.

[0005] The electronic counting of the surgical sponges beneficially informs the user whether there is a surgical sponge that remains counted in, in which case it needs to be searched for or located. Existing systems may provide alerts to guide the user towards the to-be-located sponge. However, there are instances where the user may have several sponges counted in, but only wishes to locate a subset of those sponges, and more particularly a specific subset of those sponges. Therefore, there is a further need in the art to provide means to locate specific sponges while excluding others from the search.

SUMMARY

[0006] The disclosure is directed to a surgical sponge management system for managing an inventory of surgical sponges during a surgical procedure and thereby preventing retention of the surgical sponges within the patient. An aspect of the invention is a system including means of detecting duplicate surgical sponges based on not only an RFID tag, but also a received signal strength indicator (RSSI) value from the RFID tag. This enables sponges to be located more closely to the reader without being detected as duplicates. Therefore, the system may use a higher power for counting operations without providing unwarranted duplicate sponge notifications. In one implementation, the system indicates to the user that the sponge is a duplicate if the sponge is detected with a RSSI value that meets or is above a predetermined RSSI threshold or a scan-specific RSSI threshold. For example, the RSSI value or values may be associated with the tag type. For another example, the RSSI value or values that are detected when a sponge is initially counted out could then be used to determine the scan-specific threshold. In addition to the RSSI value, the scan-specific threshold could be based on an emitted frequency associated with a first detection of the sponge being counted out, and/or the nominal frequency response spectrum of the tag type. The scan-specific RSSI threshold may be correlated to frequency hopping of the reader. The scan-specific RSSI threshold may account for tags responding differently to different frequencies, for example, based on orientation and distance between itself and the reader.

[0007] Therefore, a method of counting surgical sponges in a surgical procedure with a sponge management system includes the RFID scanner detecting a first detection of the RFID tag of a first of the surgical sponges. The unique identifier stored on the RFID tag is received by the processor (or more than one processor). The first surgical sponge is identified with the processor as counted out from the surgical procedure. The RFID scanner detects a second detection. The second detection may of the RFID tag of the first surgical sponge, or another RFID tag of a second of the surgical sponges. A response signal of the unique identifier or another unique identifier is received by the processor. The first surgical sponge is identified with the processor as a duplicate sponge candidate if the unique identifier associated with the second detection matches the unique identifier associated with the first detection. A received signal strength indicator (RSSI) value as a measure of a power level of the response signal from the second detection of the RFID tag is determined with the processor. If the RSSI value meets a predetermined RSSI threshold, a duplicate sponge notification indicating that the duplicate sponge candidate is a duplicate sponge is presented on a display interface.

[0008] Another method of counting surgical sponges in a surgical procedure with a sponge management system includes the RFID scanner detecting a first detection of the RFID tag of a first of the surgical sponges. The unique identifier stored on the RFID tag is received by the processor. The first surgical sponge is identified with the processor as counted out from the surgical procedure. The RFID scanner detects a second detection of the RFID tag of the first surgical sponge, or detects another RFID tag of a second of the surgical sponges. A response signal of the unique identifier or another unique identifier is received by the processor. The first surgical sponge is identified with the processor as a duplicate sponge candidate if the unique identifier associated with the second detection matches the unique identifier associated with the first detection. A received signal strength indicator (RSSI) value as a measure of a power level of the response signal from the second detection of the RFID tag is determined with the processor. A tag type or a sponge type is determined with the processor based on the unique identifier associated with the second detection. A predetermined RSSI threshold associated with the tag type or the sponge type is accessed from a database. If the RSSI value meets the predetermined RSSI threshold, a duplicate sponge notification indicating that the duplicate sponge candidate is a duplicate sponge is presented on a display interface.

[0009] Still another method of counting surgical sponges in a surgical procedure with a sponge management system includes the RFID scanner detecting a first detection of the RFID tag of a first of the surgical sponges. The unique identifier stored on the RFID tag is received by the processor. A first received signal strength indicator (RSSI) value as a measure of a power level of the response signal from the first detection of the RFID tag is determined with the processor. The first surgical sponge is identified with the processor as counted out from the surgical procedure. The RFID scanner detects a second detection of the RFID tag of the first surgical sponge or another RFID tag of a second of the surgical sponges. A response signal of the unique identifier or another unique identifier is received by the processor. The first surgical sponge is identified with the processor as a duplicate sponge candidate when the unique identifier associated with the second detection matches the unique identifier associated with the first detection. A second RSSI value as a measure of a power level of the response signal from the second detection of the RFID tag is determined with the processor. If the second RSSI value meets a scan-specific RSSI threshold, a duplicate sponge notification indicating that the duplicate sponge candidate is a duplicate sponge is presented on the display interface.

[0010] Still yet another method of counting surgical sponges in a surgical procedure with a sponge management system includes the RFID scanner detecting a first detection of the RFID tag of a first of the surgical sponges. A response signal of the unique identifier stored in the RFID tag is received by the processor. The processor determines whether the first surgical sponge has not been counted in to the surgical procedure or another surgical procedure based on the unique identifier. A received signal strength indicator (RSSI) value as a measure of a power level of the response signal from the detection of the RFID tag is determined with the processor. The processor compares the RSSI value against an RSSI threshold, and identifies the first surgical sponge as virtually counted in to the surgical procedure if the RSSI value meets or is greater than the RSSI threshold. Unique identifiers of remaining surgical sponges from the bundle associated with the first surgical sponge that have not been counted in to the surgical procedure are accessed from memory. The processor identifies the remaining surgical sponges as being counted in to the surgical procedure. A display interface presents an inventory of the surgical sponges. The first surgical sponge of the bundle is identified as being counted out and the remaining surgical sponges of the bundle arc identified as being counted in.

[0011] Another aspect of the disclosure is excluding specific sponges from a search of surgical sponge with guidance from the reader. In one example, the sponges to be excluded may be scanned. In another example, the sponges to be excluded may be selected on a user interface.

[0012] Therefore, a method of searching for surgical sponges with a sponge management system is provided. An input from a user is received on a display interface to locate less than all of two or more of the surgical sponges that remain counted in. An RFID tag of at least one of the surgical sponges to be an excluded surgical sponge is detected with the RFID scanner. The unique identifier stored on the RFID tag is received by the processor. An area of the surgical procedure is scanned with the RFID scanner. The two or more of the surgical sponges that remain counted in are detected by the RFID scanner. Feedback is provided by the RFID scanner to guide the user to a location of at least one of the two or more of the surgical sponges that remain counted in. The processor causes the RFID scanner to not provide the feedback with respect to the excluded surgical sponge based on the unique identifier of the excluded surgical sponge.

[0013] Another method of searching for surgical sponges with a sponge management system includes a display interface receiving a first input from a user to locate less than all of two or more of the surgical sponges that remain counted in. A second input from the user is received on the display interface that at least one of the surgical sponges to be excluded surgical sponges, wherein the unique identifier stored on the RFID tag is received by the processor. An area of the surgical procedure is scanned with the RFID scanner. The two or more of the surgical sponges that remain counted in are detected by the RFID scanner. Feedback is provided by the RFID scanner to guide the user to a location of at least one of the two or more of the surgical sponges that remain counted in. The processor causes the RFID scanner to not provide the feedback with respect to the excluded surgical sponge based on the unique identifier of the excluded surgical sponge.

[0014] Still another method of searching for surgical sponges with a sponge management system includes a display interface receiving a first input from a user to locate less than all of two or more of the surgical sponges that remain counted in. An RFID tag of at least one of the surgical sponges to be an excluded surgical sponge is detected with the RFID scanner. The unique identifier stored on the RFID tag is received by the processor. A second input from the user is received on the display interface that includes at least one of the excluded surgical sponges. The unique identifier stored on the RFID tag is received by the processor. The display interface displays the excluded surgical sponge as being re-included in the search based on the second input. The RFID scanner scans an area of the surgical procedure in which the two or more of the surgical sponges that remain counted in are detected by the RFID scanner. The RFID scanner provides feedback to guide the user to a location of at least one of the two or more of the surgical sponges that remain counted in. The processor causes the RFID scanner to not provide the feedback with respect to the excluded surgical sponge based on the unique identifier of the excluded surgical sponge.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a perspective view of a surgical sponge management system.

[0016] FIG. 2 is a perspective view of a bundle of surgical sponges.

[0017] FIG. 3 is a surgical sponge.

[0018] FIG. 4 is a plot of return signal strength indicator (RSSI) values versus emitted frequency for several RFID tags.

[0019] FIGS. 5-8 are screenshots of a display interface for performing a method of excluding one or more of the surgical sponges from a search.

[0020] FIG. 9 is a flowchart of a method for counting the surgical sponges.

[0021] FIG. 10 is a flowchart of a method for searching for the surgical sponges.

DETAILED DESCRIPTION

[0022] FIG. 1 shows a surgical sponge management system 10 including a stand 12, an electronics subsystem 14, and a dispenser assembly 15. The stand 12 includes a base 18 that is wheeled so as to maneuver the surgical sponge management system 10 within a medical facility. The stand 12 may include a main support 19 coupled to and extending upwardly from the base 18. The dispenser assembly 15 is configured to store and ergonomically dispense sponge sorters 34 and surgical draping. At least one arm 17 is movable from an undeployed position to a deployed configuration in which the arms 17 extend outwardly as shown in FIG. 1. The arms 17 are configured to support sponge sorters 34. The sponge sorters 34 may be hung or suspended from the arms 17, and the surgical sponges 32 may be received within pockets of the sponge sorter 34, most often after being counted out from the surgical procedure.

[0023] The electronics subsystem 14 is supported by the main support 19. The electronics subsystem 14 includes a module base 20, a display interface 22, the data reader 24. The module base 20 may include a mount 26, and the display interface 22 is removably coupled to the mount 26. The display interface 22 may be a tablet displaying a graphical user interface (GUI). The tablet may include a processor 16 , or alternatively the tablet may provide wireless connectivity with remote resources, such as a hospital network or internet server, for remote processing. The module base 20 may define a cradle 28 configured to be removably coupled with the data reader 24. The illustrated implementation shows the cradle 28 being a recess sized to receive and support the data reader 24.

[0024] The data reader 24 is configured to be used as either a handheld device or while supported by the cradle 28, and seamlessly transition between the configurations. More particularly, when supported by the cradle 28, the surgical sponges 32 may be brought near the data reader 24 for the data reader 24 to detect unique identifier associated with a tag associated with the sponges 32. Should it not be feasible to bring the surgical sponges near the data reader 24 or as otherwise desired, the data reader 24 may be efficiently removed from the cradle 50 and actuated near a tag 30 associated with the surgical sponges.

[0025] As used hereinafter, the data reader 24 is an RFID scanner 24 configured to detect tags 30 associated with sponges 32. The RFID scanner 24 includes the physical components and the operating software for generating interrogation signals and receiving responses to the interrogation signals. The physical components may include a signal-generating transmitter, and a signal receiver or transceiver, for example, as disclosed in commonly-owned International Publication No. WO2021/041795, published March 4, 2021, and commonly-owned International Publication No. WO2021/097197, published May 20, 2021, each of which is hereby incorporated by reference in its entirety. Exemplary tags other than RFID tags are disclosed in commonly- owned International Publication No. WO2017/112051, published June 29, 2017, which is hereby incorporated by reference in its entirety. Likewise, other wireless detection technologies may be implemented, particularly those in which a response signal strength from the interrogation signal is determinable.

[0026] Referring now to FIG. 2, a bundle 36 of surgical sponges 32 is shown. The bundle 36 may include a master tag 38 storing identifying data associated with the bundle 36. The data may include the number of sponges 32 in the bundle 36, and/or a unique identifier for each of the sponges 32 contained therein. The surgical sponges 32, as used herein, may be any absorbent article, including but not limited to laparotomy pads, gauzes, towels, chux, and the like. Further, it should be understood that, as an alternative to surgical sponges, objects of the present disclosure may be modified to be used with non-absorbent surgical articles including implants, clips, staples, or surgical instruments. For example, common-owned United States Publication No. 2019/0000589, published January 3, 2019, hereby incorporated by reference, discloses implementations in which a scannable element and a human-readable element are disclosed on forceps and suture needles.

[0027] Each of the sponges 32 may include an absorbent body 40, and the tag 30 coupled to the body 40. The tag 30 may be incorporated within, adhered to, or encapsulated within the layers of the body 40, and/or located proximate to an edge or corner of the surgical sponge 32. As used hereinafter, the tag is an RFID tag 30 detectable by the RFID scanner 24. The RFID tag 30 can include a capacitor and an antenna (not shown), which receives power from the RFID scanner to charge the capacitor of the RFID tag 30. The RFID tag 30 can have an integrated circuit, which includes a reading function, a carrier frequency modulating function, and a read-only memory portion with a burned-in code. The RFID tags 30 may operate at frequencies below, at, or above the megahertz (MHz) range. Exemplary frequencies can include about 13.35 to 14.15 MHz (high frequency), 850 to 950 MHz (ultra-high frequency), or 2.45 to 2.55 GHz (microwave frequency), among others.

[0028] The RFID tag 30 facilitates counting and identifying the sponges 32. The RFID tag 30 may further facilitate locating the sponges 32 within the surgical field. The RFID tag 30 includes a unique identifier for the sponge 32 on which it is disposed. An identification scheme may include a serial number or other identifier that is unique and assigned only to the corresponding one of the sponges 32. For example, the RFID tags 30 may be manufactured with a tag identification (TID) assigned by the manufacturer of the tag integrated circuit (TIC). The TID is typically stored in a write-once memory location, otherwise known as a read-only memory location on the TIC. Therefore, each of the sponges 32 includes the RFID tag 30 storing the unique identifier, namely a Sponge ID (see FIG. 7). In addition to the Sponge ID, other identifiers may include tag type, size, weight, manufacturing date, expiration date, and other information related to the sponges 32. Other features of the identification scheme are disclosed in the aformentioned United States Patent Publication No. 2022/0246288.

[0029] The RFID tags 30 convey the unique identifier by transmitting an electromagnetic signal or wave corresponding to the unique identifier. The processor 16 may be configured to evaluate the strength of the response signal received from the RFID tags 30 and assign a value indicative of the strength of the received signal response. In other words, the system 10 reports the power level of the backscattered response signal in relation to the power level of the initial transmission signal from the RFID scanner 24. The response signal strength indicator (RSSI) value may be used to evaluate the quality of response within an interrogation zone of the RFID scanner 24.

[0030] The data is transmitted to the processor 16, from which the system 10 manages the inventory of sponges 32 during the surgical procedure. In particular, the processor 16 may be configured to identify the sponges 32 as being counted in or counted out based on detections of the RFID tags 30 with the RFID scanner 24. The display interface 22 updates and provides the inventory identifying the types and quantities of the sponges 32 that have been counted in, and the types and quantities of sponges 32 that have been counted out (see FIG. 5).

[0031] As mentioned, in instances where a surgical sponge 32 has already been counted out is again presented to the RFID scanner 24, the system 10 may be configured to present a duplicate sponge notification. The system 10 of the present disclosure advances upon such functionality by preventing unwarranted duplicate sponge notifications. Such advances are accomplished without requiring adjustment of the power level of the RFID scanner 24 and/or requiring additional actions from the user. The system 10 includes the non-transitory computer- readable medium storing instructions configured to be implemented by the processor 16 to effectuate the methods disclosed herein.

[0032] The method may assume that the surgical sponges 32 have already been counted in to the surgical procedure. Referring to FIG. 9, the method (100) includes detecting, with the RFID scanner 24, a first detection of the RFID tag 30 of a first of the surgical sponges 32 (step 102). A response signal is received by the processor 16. In other words, the RFID scanner 24 transmits to the processor 16 the response signal backscattered from the interrogation signal. The response signal from the first detection includes the unique identifier. The unique identifier stored on the RFID tag 30 is transmitted to and received by the processor 16. A first RSSI value may be determined as a measure of the power level of the response signal (step 104). Based on the unique identifier received from the first detection, the processor 16 identifies the first surgical sponge as being counted out from the surgical procedure (step 106). The processor 16 may cause the inventory being displayed on the display interface 22 to be updated accordingly. The method includes detecting, with the RFID scanner 24, a second detection of the RFID tag 30 of the first surgical sponge 32, or another RFID tag 30 of a second of the surgical sponges 32 (step 108). In other words, the user either presents the sponge 32 already counted out to the RFID scanner 24 - unintentionally or intentionally - or presents another surgical sponge 32 that remains counted in.

[0033] Another response signal is received by the processor 16 for the second detection, which includes either the same unique identifier from the first detection or a different unique identifier associated with a surgical sponge 32 that remains counted in. If the unique identifier is not associated with the surgical sponge 32 that remains counted in, then the processor 16 determines the second surgical sponge is not a duplicate, and the inventory being displayed on the display interface 22 is updated accordingly. If, however, the unique identifier from the second detection matches the unique identifier from the first detection, the processor 16 may identify the first surgical sponge as a duplicate sponge candidate (step 108).

[0034] The method includes determining, with the processor 16, the RSSI value from the second detection of the RFID tag 30 (step 110). The RSSI value is compared against a RSSI threshold to be described. If the RSSI value meets or is greater than the RSSI threshold, the processor 16 identifies the duplicate sponge candidate as a duplicate sponge (z.e., a “true duplicate”). A duplicate sponge notification may be presented on the display interface 22 indicating to the user that the presented sponge is a duplicate sponge (step 116). If, however, RSSI value does not meet or is below the RSSI threshold, the processor 16 identifies the duplicate sponge candidate as not being a duplicate sponge. In which case, no duplicate sponge notification is presented on the display interface 22.

[0035] Since the RSSI values are higher with the sponges being closer to the RFID scanner 24, the comparison of the RSSI values against the RSSI threshold effectively requires the “true duplicate” sponges to be within a sponge presenting zone sufficiently close to the RFID scanner 24. Therefore, it is less likely that display sponge notifications will be presented to the user unless the user is actually presenting a duplicate sponge to the RFID scanner 24. As an example, and with reference to FIG. 1, five surgical sponges may have been counted in to the procedure. Two of the surgical sponges have been counted out, and placed the sponge sorter 34, as shown. Depending on the power level of the RFID scanner 24, the RFID scanner 24 may still detect the presence of those sponges 32 within the sponge sorter 34, which may be within one, two, or three feet away from the RFID scanner 24. The response signals from those sponges 32 are transmitted to the processor 16, and therefore the processor 16 may identify the surgical sponges 32 as duplicate sponge candidates. At those distances, however, the RSSI values associated with further detections of the surgical sponges 32 may be below the RSSI threshold. As such, while sufficiently close to be detected generally, the system 10 disregards the surgical sponges 32 as being duplicate sponges. Furthering the example, later in the procedure those sponges 32 (along with the other surgical sponges that remain counted in) may be moved to be weighed for determining blood loss, and returned to the area of the system 10. Perhaps the user mishandled the sponges 32 and placed an incorrect sponge into the sponge sorter 34. Should the user bring one of those two surgical sponges 32 sufficiently close to the RFID scanner 24 (e.g., adjacent to or in contact with), the RSSI value may be sufficiently high to meet or be greater than the RSSI threshold. The system 10 identifies the duplicate sponge candidate as a duplicate sponge, and presents the notification to the user on the display interface 22. The above example is merely illustrative, and other clinical scenarios may more appropriately reflect the clinical conditions to result in the presenting of a duplicate sponge to the RFID scanner 24.

[0036] The RSSI threshold may be a predetermined threshold, and the second RSSI value is compared against the predetermined RSSI threshold (step 112). In one valiant, the RSSI threshold may be a fixed value common to all sponge types. The RSSI values and thresholds may be expressed in decibel-milliwatts (dBm), with greater [negative] values being weaker response signals and thus further from the RFID scanner 24. For example, the RSSI threshold may be a value within the range of approximately -10 to -50 dBm. The predetermined RSSI threshold may be selected to create the sponge presentation zone of a desired size such that sponges other than those brought sufficiently near the RFID scanner 24 are not deemed duplicate sponges. Stated differently, the sponge presentation zone may be considered an imaginary sphere with a center at the RFID scanner 24, wherein the RSSI threshold is selected such that sponges outside the imaginary sphere are not deemed duplicate sponges. In one example, the RSSI threshold may be selected so that the imaginary sphere does not extend to the sponge sorter 34 with the arm 17 positioned in the deployed configuration.

[0037] The system 10 may be compatible with multiple RFID tag types, which may be applied to several different sponge types. These differences may affect the RSSI values that would be detected during count out activities. Therefore, in certain implementations, the RSSI threshold may be based on a tag type of the RFID tag 30. More particularly, RFID tags 30 that are ultra- high frequency (UHF) may have a first RSSI threshold, RFID tags 30 that are high frequency (HF) may have a second RSSI threshold, and RFID tags 30 that are low frequency (LF) may have a third RSSI threshold. Likewise, the RSSI threshold may be based on the sponge type. For examples, the table below lists non-limiting examples of sponge types (e.g., dimensions, plys, etc.) with the associated RSSI thresholds.

[0038] The RSSI thresholds associated with the tag type or the sponge type may be stored in a database, which may be accessed the processor 16. Additionally or alternatively, certain tag types, sponge types, and/or types of other surgical articles may not have an RSSI threshold, in which instance a duplicate notification may be presented upon detection of the RFID tag 30 by the RFID scanner 24 (and the article was previously counted out).

[0039] In certain implementations, the RSSI threshold may be scan-specific, and the second RSSI value is compared against the scan-specific RSSI threshold. More particularly, the scan-specific RSSI threshold may be associated with the RSSI value or values that are detected when the sponge 32 is initially counted out (z'.e., with the first detection). Therefore, exemplary methods may include determining the scan-specific RSSI threshold based on the first detection. The processor 16 determines a second RSSI value a measure of a power level of the response signal from the second detection of the RFID tag. The second RSSI value is compared against the scan-specific RSSI threshold. If the second RSSI value meets or is greater than the scan-specific RSSI threshold, the processor 16 determines the duplicate sponge candidate to be a duplicate sponge. The duplicate sponge notification is presented on the display interface 22 (step 1 16).

[0040] The scan-spccific RSSI threshold may be based on the first unique identifier. For example, the Sponge ID may be correlated to or encoded with data including the scan-specific RSSI threshold that is transmitted to the processor 16 with the first response signal. The processor 16 may be configured to store and later apply the data. Alternatively, the processor 16 may be configured to apply a fixed or variable offset to the data correlated with the Sponge ID. Similarly, the scan-specific RSSI threshold may be based on the first RSSI value, or a fixed or variable offset thereof. For example, if the RSSI value from the first detection of the RFID tag 30 is -35 dBm, the processor 16 may establish the scan-specific RSSI threshold as -35 dBm, or as -25 dBm with a fixed offset of 10 dBm.

[0041] In certain implementations, the scan-specific RSSI threshold may be based on the frequency emitted by the RFID scanner 24 during the first detection, and/or the frequency emitted by the RFID scanner 24 during the second detection. FIG. 4 shows a plot of RSSI values across a range of frequencies for several tags. As is appreciated from the plot, for each one of the tags, the RSSI value varies over the range of frequencies. For reducing reader interference, the RFID scanner 24 may be configured to “frequency hop”; i.e., emit the interrogation signals at different frequencies in a near-continuous or continuous manner. In particular, systems using UHF signals emit the signals in prescribed frequency bands, and the frequency bands are changed throughout use. The RFID scanner 24 may hop randomly or in prescribed sequences. The frequency hopping occurs quickly so when the surgical sponge 32 is presented to the RFID scanner 24, the system 10 may detect it at multiple frequencies with different RSSI values associated with each frequency. Therefore, even if the distance and orientation between the sponge 32 and the RFID scanner 24 remains constant, the RSSI values may vary greatly depending on the frequencies associated with the first and second detections of the RFID tag 30.

[0042] The method may include the processor 16 receiving the emitted frequency associated with the first detection of the RFID tag 30, and determining the scan-specific RSSI threshold based on the emitted frequency. The scan-specific RSSI threshold may be based on the first RSSI value, or a fixed or variable offset thereof, associated with the emitted frequency. As an example and with continued reference to FIG. 4, the first detection of the RFID tag 30 of type 3 (diamond icons) occurs at approximately 950 MHz, for which the first RSSI value is -35 dBm. The processor 16 may establish the scan-specific RSSI threshold of -35 dBM, or as -20 dBm with a fixed offset of 15 dBm. The scan-specific RSSI threshold may be applied for the second detection being within the frequency band, or for all frequencies within the operating range of the RFID scanner 24.

[0043] Alternatively, the system 10 may establish the scan-specific RSSI threshold from the emitted frequency associated with the first detection of the RFID tag 30 as well as the emitted frequency associated with the second detection of the RFID tag 30. Based on the tag type, the sponge type, and/or the unique identifier transmitted to the processor 16, the memory may store calibration data including the RSSI values across the range of emitting frequencies (e.g., the “curves” of the plot of FIG. 4). Based on, for example, the first RSSI value and the emitted frequency at the first detection, the processor 16 may identify the curve for the tag type or the sponge type. The scan-specific RSSI may be established as the corresponding RSSI value for that tag type, or a fixed or variable offset thereof. Then, based on the emitted frequency at the second detection, the scan-specific RSSI threshold is referenced and compared to the second RSSI value. Thus, in some respects, the scan-specific RSSI threshold of the present implementation may “jump” in a corresponding manner to the frequency hopping.

[0044] Furthering the earlier example in which the first detection of the tag 30 (type 3) occurs at approximately 950 MHz with a first RSSI value is -35 dBm, the second detection of the tag 30 occurs at approximately 900 MHz. For the curve associated with the tag type, the scanspecific RSSI threshold may be an offset of -15 dBm from the first RSSI value, as the tag type has a stronger response at 900 MHz. In such an implementation, the scan-specific RSSI threshold may be based on a frequency adjustment factor. Again, the scan-specific RSSI threshold may applied when the second detection is within a same frequency band that includes the emitted frequency, or for all frequency bands.

[0045] The methods described herein advantageously reduce instances where a duplicate sponge notification is presented to the user when otherwise unwarranted. To the extent the duplicate sponge notifications are presented on the display interface 22, the methods include receiving user input to suppress the notifications. The method may include receiving, on the display interface 22, an input in response to the duplicate sponge notification to suppress further duplicate sponge indications for the first surgical sponge. Additionally or alternatively, the input may include suppressing further duplicate sponge indications for all subsequent surgical sponges.

[0046] The methods described herein may also reduce instances in which a surgical sponge 32 (and the other surgical sponges 32 in the bundle 36) is inadvertently “virtually” counted in by ensuring the surgical sponge 32 being detected by the RFID scanner 24 has an RSSI value that meets or is greater than the RSSI threshold. Existing systems, such as those sold under the tradename SurgiCount+ by Stryker Corporation (Kalamazoo, Mich.), enable the user to “virtually” count in the bundle 36 of surgical sponges 32 when a single, “unknown” sponge is presented to be counted out. As used herein, an “unknown” sponge is a surgical sponge 32 that was not counted in to the surgical procedure, and for which there is no indication from the unique identifier that the surgical sponge 32 was used in another procedure. Instances in which the counting in of the surgical sponges 32 are omitted may be due to emergent patient need or human error. As a result, the surgical sponges 32 of the bundle 36 may become dispersed in the operative field such that counting in the surgical sponges 32 in the usual manner is impractical. The virtual count in addresses the problem by counting in the surgical sponges 32 from the bundle 36 in which one of the surgical sponges 32 being counted out was contained. For example, the bundle 36 may include Sponge A, Sponge B, and Sponge C. If Sponge B is virtually counted in during count out, then Sponge A and C will be counted in and Sponge B will be counted out.

[0047] Despite its advantages, the virtual count in process may lead to confusion or annoyance if the surgical sponges 32 are merely detected from a staging or storage area near the system 10, from which the display interface 22 may move between modes or screens in an undesirable or unexpected manner. Therefore, the present disclosure addresses such a shortcoming by including a method in which the surgical sponge 32 being virtually counted in is compared against the RSSI threshold. The method includes detecting, with the RFID scanner 24, a detection of the RFID tag 30 of a first of the surgical sponges 32 in the bundle 36. wherein a response signal of the unique identifier stored in the RFID tag 30 is received by the processor 16. The processor 16 determines that the first surgical sponge 32 has not been counted in to the surgical procedure or another surgical procedure based on the unique identifier. In other words, the processor 16 may access the memory of the RFID tag 30, and/or compare the Sponge ID against a database of those that have been previously used in surgical procedures. The method includes determining, with the processor 16, the RSSI value as a measure of the power level of the response signal from the detection of the RFID tag 30. The processor 16 compares the RSSI value against the RSSI threshold. The RSSI threshold may be the predetermined RSSI threshold, and/or the scan-specific RSSI threshold according to any of the implementations as disclosed and described herein. The processor 16 may identify the first surgical sponge 32 as virtually counted in to the surgical procedure if the RSSI value meets or is greater than the RSSI threshold. If the surgical sponge 32 is being virtually counted in, the method includes accessing, from memory, unique identifiers of remaining surgical sponges 32 from the bundle 36 associated with the first surgical sponge 32 that have not been counted in to the surgical procedure. The processor 16 may identify the remaining surgical sponges 32 as being counted in to the surgical procedure. The inventory may be presented on the display interface 22. The first surgical sponge 32 of the bundle 36 is identified as being counted out and the remaining surgical sponges 32 of the bundle 36 are identified as being counted in.

[0048] As mentioned, the functionality of the RFID tag 30 also facilitates searching for the sponges 32 within or about the surgical field. The inventory being displayed on the display interface 22 may indicate several surgical sponges 32 remaining counted in. While the location of some of those surgical sponges 32 is known, others may not (z.e., a “missing sponge”). The aforementioned SurgiCount+ system facilitates guiding the user to the missing sponges. The RFID scanner may be operated in a “find mode” in the handheld configuration with the RFID scanner providing visual and audible feedback while being moved about the surgical field.

[0049] While the find mode is effective in searching for the missing sponges, it may be desirable to exclude from the search other surgical sponges that remain checked in. In other words, the user may wish to search for the missing sponges, but not for those whose location is not unknown (i.e., not missing sponges). Exemplary clinical scenarios include reconciling the inventory at a personnel shift change or when a body cavity is being closed, and/or retaining “clean up” sponges. The surgical sponges 32 may be not missing, but merely on a table adjacent the surgical field, for example.

[0050] The system 10 of the present disclosure advantageously provides for exclusion of a specific subset of the surgical sponges 32 from the search, and does so in intuitive manners to be described with little disruption in the surgical workflow. FIG. 10 represents a method (200) of searching for or locating the surgical sponges 32 with the system 10, and its exemplary implementations are described with concurrent reference to FIGS. 5-8. At least two surgical sponges 32 remain counted in. The inventory of FIG. 5 indicates that [all] five surgical sponges 32 remain counted in. The method includes receiving, on the display interface 22, an input from the user to locate surgical sponges 32 that remain counted in. FIG. 6 shows the GUI being displayed on the display interface 22 with a “Find Sponges” indicia selected. In instances where more than one surgical sponge 32 remains counted in, a prompt (not shown) may be presented on the GUI and query whether any of the surgical sponges 32 should be excluded from the search. The method includes receiving, on the display interface 22, an input from the user to locate less than all of the two or more of the surgical sponges 32 that remain counted in (step 202). For example, the step may include responding to the query on the prompt in the affirmative. By contrast, if the query is responded to in the negative, the find mode workflow may continue as known.

[0051] In certain implementations, the user may scan the surgical sponges 32 to be excluded from the search. The GUI may instruct the user to remove the RFID scanner 24 from the cradle 50, as shown in FIG. 6. The method may include the step of detecting, with the RFID scanner 24, the RFID tag 30 of at least one of the surgical sponges 32 to be an excluded surgical sponge, wherein the unique identifier stored on the RFID tag 30 is received by the processor 16 (step 204). For example, the user may scan the surgical sponges 32 on the table adjacent the surgical field. The surgical sponges 32 may be scanned simultaneously, or preferably individually, and/or at a lower power level (e.g., approximately 14 dBm). The processor 16 causes the GUI on the display interface 22 to list the excluded surgical sponges. FIG. 8 shows two of the surgical sponges 32 being excluded, along with their sponge type and the unique identifier (e.g. , the Sponge ID). Thus, a subset of the surgical sponges 32 are identified to be excluded from the search. Should the exclusion be in error or otherwise, the user may re-scan the surgical sponge 32, after which the status may be updated on the list or removed from the list. Additionally or alternatively, indicia on the display interface 22 may be selectable to re-include the surgical sponge 32 in the search.

[0052] In certain implementations, the user may select the surgical sponges 32 to exclude from the search. The GUI may present a list of the surgical sponges 32 that have been counted in to the surgical procedure (and not counted out). The list may include sponge type, Sponge ID, and/or scan-in time, among other information. Additionally or alternatively, search functionality may be provided to permit the user to search for one or more of the surgical sponges 32 based on sponge type scan-in time, and the like. The method may include receiving, on the display interface 22, a second input from the user including at least one of the surgical sponges to be excluded surgical sponges, wherein the unique identifier stored on the RFID tag is received by the processor 16 (step 206). The second input may be a selection of a sponge type such that all of the surgical sponges 32 of that sponge type arc treated as excluded surgical sponges from the search. The second input may be a selection of a time range such that all of the surgical sponges counted in within the time range are treated as the excluded surgical sponges. The second input may be associated with any sponge characteristic common to two or more of the surgical sponges 32.

[0053] Based on the second input(s), the list on the GUI may be updated accordingly (e.g., the status column of FIG. 7). The display interface 22 may provide an alert if the unique identifier of the surgical sponges to be excluded does not match any of unique identifiers of the surgical sponges previously counted in to the surgical procedure. In other words, if the user somehow scanned for exclusion a surgical sponge 32 that was not counted in, the alert may be displayed on the GUI. Further, the display interface 22 may provide an alert if the user has scanned or selected all of the surgical sponges 32 to be excluded from the search.

[0054] The method includes scanning, with the RFID scanner 24, an area of the surgical procedure in which the two or more of the surgical sponges that remain counted in are detected by the RFID scanner 24 (step 208). FIG. 8 depicts guidance being provided by the GUI to do so in which the RFID scanner 24 is actuated and moved within or about the surgical field. The RFID scanner 24 provides feedback to guide the user to a location of at least one of the two or more of the surgical sponges that remain counted in (step 210). The processor 16 causes the RFID scanner to not provide the feedback with respect to the excluded surgical sponge based on the unique identifier of the excluded surgical sponge (step 212). The feedback may be audible (e.g., beeping of increasing frequency as the RFID scanner 24 nears the missing surgical sponge), visual (e.g., blinking of a light of increasing frequency as the RFID scanner 24 nears the missing surgical sponge), tactical or haptic, or the like. As the RFID scanner 24 moves near or about the excluded surgical sponges, no output from the RFID scanner 24 is provided.

[0055] The foregoing disclosure is not intended to be exhaustive or limit the invention to any particular form. The terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations are possible in light of the above teachings and the invention may be practiced otherwise than as specifically described.