Inventory control system in hospital environments using RFID technology

Abstract

An inventory control system in hospital environments using RFID technology, characterized in that it comprises: - a means of controlling access for healthcare personnel to a warehouse (A) configured to detect the entry or exit of said healthcare personnel in the warehouse (A); - a set of RFID tags attached, directly or indirectly, to objects such as materials, instruments or medicines; - at least one first antenna (1) configured to detect the presence of the RFID tags in the warehouse (A); - at least one second antenna (2) configured to detect the presence of the RFID tags in a waste bin (5) located in a room outside the warehouse (A); a processing means (3) in communication with the means of controlling access for healthcare personnel in the warehouse (A) and with the first and second antennas (1, 2) to receive the information detected by said antennas (1, 2) and store it in a database (4).

Description

Inventory control system in hospital environments using RFID technology OBJECT OF THE INVENTION The present invention belongs to the field of inventory management in hospitals. The object of the invention is an automated inventory control system for hospital environments based on RFID technology. BACKGROUND OF THE INVENTION Inventory control in a hospital is essential to ensuring patients receive the best possible care. Hospitals use a vast amount of specialized equipment, materials, and medications to treat patients. If the right products are unavailable where and when needed—for example, because they are stolen, lost, damaged, or expired—surgeries can be canceled, treatments delayed, and, in general, time and resources are wasted. Furthermore, such incidents can damage the healthcare facility's reputation. Therefore, in this context, proper inventory tracking is vital. Currently, this is done using traditional systems, such as manual entries in a notebook and the corresponding management of incoming and outgoing items as updates or new lines. Another method is the use of barcode scanners with specialized software to perform similar tasks to the notebook method. This solution controls entries and exits digitally, preventing transcription errors. Both systems require staff involvement, and if the established procedure is not followed, the inventory will again become unbalanced. More modern stock management systems exist for healthcare facilities, based on smart cabinets equipped with access codes and processing logic. The drawback of this solution lies in the diversity of brands and models available, with each cabinet having its own software and operating logic for patient data entry. This complicates operations for healthcare staff when cabinets from different manufacturers coexist in the same storage area. DESCRIPTION OF THE INVENTION The inventors of this application have solved this problem by means of an inventory control system based on RFID technology in which material movements are automatically detected and recorded in just a few minutes. This allows for complete and constantly updated control over the materials available in the warehouses and those removed by authorized personnel. Materials are also detected at the end of their useful life when they have been consumed, removed from stock, and the software communicates this information to the relevant departments (physicians, supervisor, materials manager, supplies and general warehouse, purchasing department, finance department, etc.). Furthermore, the speed of inventorying and the systems used allow for distinguishing between the materials used in each of the different interventions, consultations, or other similar routines. The system provides valuable information to healthcare professionals, other healthcare and administrative services involved, management, and external suppliers who have access to monitor their stocks; and most importantly, it offers greater safety to patients by allowing immediate monitoring of expiration dates, health alerts, etc., of existing materials, informing them through various means to ensure staff care. This system can manage inventories of different materials, including medical consumables, implants, prostheses, operating room plates and screws, medicines, dressings, garments and linen material, including textile, surgical and disposable material, as well as everything required for rigorous hygiene, maintenance and sterilization. All these aspects are monitored using RFID tags that, when attached to or inserted into products, allow for their detection and tracking of movements between warehouses or at final points of consumption within the hospital. Furthermore, there are RFID tag models resistant to sterilization processes, ensuring proper functioning in all types of environments. This guarantees that even surgical instruments can be tagged to monitor their sterilization procedures. In this document, the term "hospital environment" refers to any building or facility whose primary use is to provide healthcare services to a specific group of patients, including direct and auxiliary services such as laundry and linen, as well as administrative services that benefit from the information provided by the information system (Management, Purchasing, Supplies and General Warehouse, Accounting, Financial Management, etc.). Healthcare services can be of any type, including both diagnosis and treatment, and particularly the performance of surgeries of any kind. In this document, the term "RFID tag" refers to small, sticker-like devices that can be attached to or embedded in products or healthcare personnel identification items. RFID tags contain an antenna that allows them to receive and respond to radio frequency requests from an RFID transceiver, which in this document is referred to as the "RFID antenna." In this document, the term "RFID antenna" refers to an antenna that periodically emits a radio frequency signal designed to interrogate RFID tags located within its detection range. In this context, it is understood that the RFID antenna is also associated with a transceiver and a decoder that allow the extraction and decoding of the information contained in the signals emitted by the RFID tags. However, for the sake of simplicity, the transceiver and decoder are not explicitly described in this document. The inventory control system for hospital settings of the present invention essentially comprises the following elements: a means of controlling access to the warehouse for healthcare personnel, a set of RFID tags for identifying objects, first and second RFID antennas, a processing unit, and a database. Each of these elements is described in greater detail below. a) Means of controlling access of healthcare personnel to the warehouse The access control system for healthcare personnel is configured to detect their entry into or exit from the warehouse. This access control system can be any conventional type, such as those based on identification cards read at the warehouse entrance using any suitable technology. The underlying concept is that it is known at all times which individuals enter and exit the warehouse so that, as described later, items whose absence is detected are assigned to them as soon as they leave the warehouse, or their assignment is removed if the item is found to be missing upon their entry. In a preferred embodiment, healthcare personnel access to the warehouse is detected by additional RFID tags attached, for example, to ID badges or wristbands. In this way, the healthcare facility does not need to implement an access control system for the warehouse; the system of the invention itself provides the means to identify individuals entering and exiting the warehouse. b) RFID Tags This refers to a set of RFID tags attached, directly or indirectly, to objects such as materials, instruments, or medications used to provide healthcare services. The materials, instruments, or medications can be of any type, including those used during a surgical procedure as well as those required for any other type of patient treatment. In general, RFID tags can be attached to the boxes or packaging of materials, instruments, or medications in any known way. Alternatively, there may be cases where the tags are attached directly to the material, instrument, or medication. In either case, the tags preferably include an adhesive for attaching them to the objects. c) First antenna This is, at least, a first antenna configured to detect the presence of RFID tags in a warehouse. Naturally, if healthcare personnel identify themselves using additional RFID tags, the first antenna will also detect their presence in the warehouse. In principle, the number and arrangement of the antennas are not limited, provided they are capable of detecting the RFID tags housed within the warehouse. In this context, the warehouse refers to an enclosed space, typically enclosed by walls, where the materials, instruments, or medications whose position is to be monitored by the system of the invention are stored. The detection range of at least the first antenna covers only the interior volume of the warehouse. Therefore, the first antenna(s) always detect RFID tags located inside the warehouse. For example, the system may include several first antennas distributed throughout the warehouse so that the resulting detection range coincides with the warehouse's interior volume. In other words, the first antenna(s) only detect RFID tags located inside the warehouse, but do not detect RFID tags located outside the warehouse. To ensure this, the system of the invention preferably comprises a shielding coating on walls that enclose the warehouse. The shielding coating has a material that reflects the radiation emitted by the RFID antenna, such as a metallic material. For example, the shielding coating may comprise aluminum panels or a metallic paint made of aluminum or another suitable metal. In short, the concept is that the first antenna or antennas provide information that allows real-time determination of the RFID tags present in the warehouse at any given moment, making it possible to deduce whether any RFID tag is entering or leaving the warehouse. Combined with the information provided by the access control system, it is possible to determine, for example, whether a member of the healthcare staff is entering or leaving the warehouse, and if that person is carrying any of the items identified by RFID tags. d) Second antenna This involves a second antenna or antennas configured to detect the entry or exit of RFID tags from a waste bin located in a room outside the warehouse. To achieve this, the second antenna or antennas are positioned inside the waste bin in such a way that the combined detection range is limited to the area inside the bin. Note that the term "trash can" refers to any container, receptacle, box or similar intended to dispose of, or store for later management, any of the objects mentioned above in this document. For example, in a particularly preferred embodiment of the invention, the waste bin comprises a housing with a top opening for inserting used items and a door for inserting a container below said top opening. In this case, the second antenna is located inside the housing, and the housing further comprises shielded walls to prevent the escape of radiation emitted by the second antenna. Preferably, the top opening has a lid equipped with shielding to prevent radiation escape. The waste bin may also include a door or top opening sensor configured to switch the second antenna on or off when such opening or closing is detected. This prevents healthcare personnel near the waste bin from being exposed to radiation emitted by the second antenna. e) Processing medium and database The processing medium is in communication with the first and second antennas to receive the information detected by these antennas and store it in the database. In principle, the processing medium can be of any type, provided it has the processing capacity and connectivity necessary to perform the tasks described herein. For example, the processing medium can be one of the following: a microprocessor, a microcontroller, an ASIC, an FPGA, a DSP, or a PLC. Preferred embodiments of the invention have used a Raspberry Pi device. Furthermore, communication between the processing unit and the first and second antennas, as well as with the database, can be of any type. For example, in a particularly preferred embodiment of the invention, it is wireless communication, preferably via Bluetooth, Wi-Fi, Zigbee, GSM, UMTS, 3G, 4G, or 5G. Alternatively, in another preferred embodiment, it is wired communication. Well, the processing medium is configured to determine, based on this information: - The objects, identified by the set of RFID tags, that are stored in the warehouse at any given time. When the first antenna detects an object leaving the warehouse, it identifies which person, using the access control system, is responsible for that object. An object leaving the warehouse is detected when it goes from being detected in the warehouse to not being detected in the warehouse. - When the second antenna detects an object entering the trash can, it determines which person is no longer responsible for it. An object entering the trash can is detected when it goes from being undetected to being detected in the trash can. When the first antenna detects that an object that previously left the warehouse re-enters the warehouse, the person identified by the access control system is no longer responsible for it. The entry of an object into the warehouse is detected when that object goes from being undetected in the warehouse to being detected in the warehouse. Additionally, in a particularly preferred embodiment of the invention, the system further comprises: f) At least one means of turning off the first antenna The first antenna's shutdown mechanism is configured to turn it off when medical personnel are detected entering the warehouse. This significantly reduces the radiation received by medical personnel entering the warehouse, thus improving safety. To determine if people are present in the warehouse, in a preferred embodiment, the first antenna's shutdown means is in communication with the access control means, so that it receives information about the entry and exit of healthcare personnel in the warehouse. Alternatively, the first antenna's shutdown means can be in communication with a healthcare personnel presence detector in the warehouse. For example, the presence detector can be one or more of the following: a motion sensor, a light sensor, a thermal sensor, a volumetric sensor, and a light switch position sensor. Thanks to this configuration, it is possible to fully automate the location of each and every item identified by the set of tags, meaning that no action is required from healthcare personnel. The system, based on rapid inventory counts, autonomously detects the entry or exit of materials, instruments, or medications from the warehouse using the first RFID antenna, which sends the information to the processing unit, and from there to the database. Naturally, when materials, instruments, or medications enter or leave the warehouse, they are carried by healthcare personnel, who are also automatically identified by the access control system. Based on this information, when an item leaves the warehouse, the system automatically assigns it to the person whose departure is detected.Similarly, when an object enters the storage area and the person carrying it leaves without it, the system automatically considers the object to have been stored there. Finally, when the second antenna detects an object being placed in the waste bin, that object is removed from the tracking system, and the person carrying it (the one who removed it from the storage area) is no longer responsible for it. In these cases, processes can be triggered to transmit the information to different software programs or interested parties with the available data. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1A-1E show different phases of an object tracking process using the system of the present invention. Figs. 2A-2B show two perspective views of a waste bin according to the present invention, respectively closed and open. PREFERRED EMBODIMENT OF THE INVENTION The process of tracking an object is described below using an example system according to the present invention, with reference to the attached figures. The system in this example is installed in a hospital setting, although for the purposes of this example it is simplified by considering only three spaces: a storage room (A), a corridor, and an operating room (Q). The storage room (A) is a room accessed through a door (P) that opens onto the corridor. The operating room (Q) is another room accessed through a different door on the opposite side of the same corridor (P). The warehouse (A) is equipped with four antennas (1), which in this example are located in the corners of the room. The warehouse (A) is shielded by an interior lining of its walls with aluminum panels, ensuring that readings are limited to the area being monitored. This arrangement guarantees the detection of any RFID tag located inside the warehouse (A), while RFID tags outside the warehouse (A), even if nearby (for example, passing through the aisle in front of door (P)), are not detected. The intervention room (Q), on the other hand, is not fully sensorized, but only a waste bin (5) located inside it. Although not shown in detail, a second antenna (2) is positioned inside the waste bin (5) to detect the insertion of RFID tags. As described earlier in this document, the detection range of the second antenna (2) comprises only the interior space of the waste bin (5). Figures 2A and 2B show in greater detail the appearance of an example of a waste bin (5) according to the invention. As can be seen, the waste bin (5) consists of a casing (51) essentially in the shape of a parallelepiped, having a top opening (52) and a side door (53). The side door (53) opens by means of a mechanism to allow the insertion of a container (100) inside, such that when the door (53) is closed, the container (100) is positioned below the top opening (52). The top opening (52) has a closing lid (521). Although not visible in the figures, the inner walls of the casing (51) are coated with a shielding material, for example, aluminum, which ensures that the radiation emitted by the second antenna (2) located inside does not escape to the outside. Note that the lid (521) of the top opening (52) is also shielded.Additionally, the waste bin (5) may have door (53) or lid (521) opening sensors for the top opening (52) so that, when such an opening is detected, the second antenna (2) is switched off in order not to radiate to people located around it. The first and second antennas (1, 2) have wireless communication capabilities that allow the exchange of information with a processing unit (3), which can be located anywhere suitable within the hospital. The processing unit (3), in turn, communicates with a database (4) via a suitable communication medium, either wired or wireless. This configuration ensures that information about the location of the RFID tags detected by the antennas (1, 2) is transmitted in real time to the database (4). The objects whose position is to be monitored are identified by a set of RFID tags. These objects, which as mentioned earlier in this document can be of any type, including materials, instruments, or medications, have the corresponding RFID tag affixed in a suitable location, usually on the box or packaging. The following describes an example of the use of the system of the present invention. As shown in Fig. 1A, an object identified by an RFID tag is stored in the warehouse (A). The presence of the object's RFID tag is automatically detected by one or more of the first antennas (1), and this position is reported from the first antenna (1) to the processing device (3), and from there to the database (4). The database (4) then stores in a file that this RFID tag is inside the warehouse (A). This is represented schematically in Fig. 1A by a small box. At a certain point, the object is needed for use in the procedure room (Q). A member of the healthcare staff moves towards the storage room (A) along the corridor (Fig. 1A) until they enter the storage room (A), as shown in Fig. 1B. When the person identifies themselves at the entrance to the storage room, for example, by presenting a card for automatic reading by a conventional system, their presence inside the storage room is reported to the database (4). The information in the database file (4) is updated: both the object's RFID tag and the person are now in the storage room. The person finds the object, picks it up, and moves along the corridor toward the intervention wing (Q). This situation, shown in Fig. 1C, is automatically detected. The access control system detects the person's departure, and the first antennas (1) stop detecting the object's RFID tag. The immediate conclusion is that the person has taken the object identified by the RFID tag. This information is sent by the first antennas (1) to the database (4), which automatically updates the file information. Now both the person and the object are in transit somewhere else in the hospital. Furthermore, since they left simultaneously, it is recorded that the identified person is responsible for the object identified by the RFID tag. As shown in Fig. 1D, the person enters the intervention room (Q) and, either themselves or another person, removes the object from its packaging and throws the packaging into the waste bin (5). Although not shown in this figure, the waste bin (5) is similar to the one shown in Figs. 2A and 2B. The RFID tag attached to the object's packaging is automatically detected by the second antenna (2) located inside the waste bin (5), and this detection is communicated, via the processing device (3), to the database (4). The database file (4) is updated: the identified person is no longer listed as responsible for the object. The object is removed from the tracking system, thus closing the loop.

Claims

1. An inventory control system in hospital settings using RFID technology, characterized in that it comprises: - a means of controlling access for healthcare personnel to a warehouse (A) configured to detect the entry or exit of said healthcare personnel in the warehouse (A); - a set of RFID tags attached, directly or indirectly, to objects such as materials, instruments, or medicines; - at least one first antenna (1) configured to detect the presence of the RFID tags in the warehouse (A); - at least one second antenna (2) configured to detect the presence of the RFID tags in a waste bin (5) located in a room outside the warehouse (A); a processing means (3) in communication with the means of controlling access for healthcare personnel in the warehouse (A) and with the first and second antennas (1, 2) to receive the information detected by said antennas (1, 2) and store it in a database (4). 2.An inventory control system according to claim 1, further comprising at least one means for switching off the first antenna (1) configured to switch off said first antenna (1) when the entry of healthcare personnel into the warehouse (A) is detected.

3. An inventory control system according to claim 2, wherein the switching means is in communication with the access control means to receive information about the entry and exit of healthcare personnel into the warehouse (A).

4. An inventory control system according to claim 2, wherein the switching means is in communication with a healthcare personnel presence detector in the warehouse (A).

5. An inventory control system according to claim 4, wherein the healthcare personnel presence detector is one of the following: a motion sensor, a light sensor, a thermal sensor, a volumetric sensor, and a light switch position sensor. 6.Inventory control system according to any of the preceding claims, further comprising a shielding coating on walls that delimit the warehouse (A).

7. Inventory control system according to claim 6, wherein the shielding coating comprises aluminum panels or metallic paint.

8. Inventory control system according to any of the preceding claims, wherein the waste bin (5) comprises a housing (51) with an upper opening (52) for the insertion of used items and a door (53) for the insertion of a container (100) below said upper opening (52), the second antenna (2) being located inside the housing (51), and said housing (51) further comprising shielded walls to prevent the escape of radiation. 9.Inventory control system according to claim 8, wherein the upper opening (52) has a cover (521) provided with shielding to prevent radiation leakage.

10. Inventory control system according to any of claims 8-9, wherein the waste bin (5) further comprises a door (53) or upper opening (52) opening sensor configured to switch the second antenna (2) on or off when such opening or closing is detected.

11. Inventory control system according to any of the preceding claims, wherein the RFID tags comprise an adhesive for attaching them to objects.

12. Inventory control system according to any of the preceding claims, wherein the detection volume of at least the first antenna (1) covers only the interior volume of the storage area (A), so that it continuously detects the RFID tags located therein. 13.An inventory control system according to claim 12, comprising several first antennas (1) distributed throughout the interior of the warehouse (A), such that the resulting detection volume coincides with the interior volume of the warehouse (A).

14. An inventory control system according to any of the preceding claims, wherein communication between the processing medium (3) and the first and second antennas (1, 2) is wireless.

15. An inventory control system according to claim 14, wherein communication between the processing medium (3) and the first and second antennas (1, 2) is carried out via Bluetooth, Wi-Fi, Zigbee, GSM, UMTS, 3G, 4G, or 5G.

16. An inventory control system according to any of claims 1-13, wherein communication between the processing medium (3) and the first and second antennas (1, 2) is wired. 17.Inventory control system according to any of the preceding claims, wherein the processing medium (3) is one of a microprocessor, a microcontroller, an ASIC, an FPGA, a DSP or an automaton.