Patent Publication Number: US-2013245387-A1

Title: Location based wireless medical device

Description:
The present application relates to wireless devices. In particular, it relates to wireless sensor networks, such as body area networks (BANs) or patient area networks (PANs), which monitor a patient&#39;s physiological parameter and transmit a data regarding the sensed parameters to a control system. 
     Patients have traditionally been monitored using sensing units connected by wires to a base station. These wires inhibited the patient mobility and were labor intensive to install. To improve patient mobility, facilitate installation, and eliminate wire clutter, wireless sensing units have been developed. Certain patients require continuous monitoring of physiological parameters, such as ECG, SpO 2 , blood pressure, blood sugar, or the like. Though well enough to move about the community, they were restricted to a hospital room, the hospital ward, a convalescent room, or their home to facilitate continuous monitoring of physiological parameters. To venture out of these areas, the patients would be unmonitored. 
     In order to continuously monitor patient physiological parameters without constraining their activities, it is desirable to be able to mount sensors on the body of the patient, which are light and compact as possible while also being capable of communicating wirelessly with each other and a base station. A body area network (BAN) includes multiple nodes which are typically sensors that can be either wearable or implantable in to the human body. The nodes monitor vital body parameters and/or movements, and communicate with each other over a wireless medium. The nodes can transmit physiological data from a body to a control unit from which the data can be forwarded, in real-time, to a hospital, clinic, or elsewhere over a local area network (LAN), wide area network (WAN), a cellular network, or the like. 
     Wireless technology provides convenient and unobtrusive connectivity between these devices. With the advances in energy efficient, reliable, low cost and high rate wireless technology, a variety of wireless consumer electronic devices have become integral part of our day to day life. Due to the portable nature of many of these devices, the likelihood of their proliferation beyond the regions in which they are authorized to operate has increased significantly. In particular, the wireless medical sensor devices designed to operate, in, on and around the human body to monitor and control various physiological parameters are expected to be carried globally by humans. Average human beings are unlikely to be aware of complex regulations governing the use of wireless devices. This means that the portable wireless devices must have provisions to reconfigure themselves to comply with local regulations. 
     The requirements for designing wireless BANs include providing convenient and unobtrusive connectivity between the nodes while maintaining energy efficient, reliable, low cost, high rate wireless connectivity and while adhering to geopolitical regulatory requirements regarding the use of the radio spectrum. The regulatory requirements mandate the compliance with technical requirements such as frequency-band usage, duty cycle limitations, bandwidth, maximum transmit power limitations, specific absorption rate, etc. However, these regulatory requirements are not harmonized worldwide. For example, 433.05-434.79 MHz band is designated as a license-free Industrial Scientific and Medical (ISM) band in Europe but not in US. On the other hand 902-928 MHz band is designated as a license-free ISM band in US but not in Europe. Therefore, wireless devices authorized to operate in one region may not be legally authorized to operate in another region. Even if the spectrum used by the device is available worldwide, the transmit power, duty cycle and other restrictions may be different in different regions thereby inhibiting the free movement of wireless devices across the border. 
     Due to the portable nature of many of these devices and the expected integration into day to day life, the likelihood that the wireless BAN devices being carried globally beyond the region in which they are authorized to operate should be planned for while understanding that the average patient is unlikely to be aware of local regulations governing the use of the wireless devices in that region. This poses a severe risk for the patient because non-compliant, unauthorized use of the wireless device can be detrimental to the wireless transmission functions between the devices which can interfere with sensing and/or therapeutic functions. There exists a need for wireless BANs and wireless portable devices to adjust wireless transmission parameters to meet local regulatory requirements for wireless transmission. 
     The present application provides a new and improved method and system for location based wireless patient monitoring and therapy delivery which overcomes the above-referenced problems and others. 
     In accordance with one aspect, a wireless medical device is presented. The wireless medical device includes at least one of a sensor which monitors physiological data of a patient and an actuator which delivers therapy to the patient. A wireless transceiver, which has a plurality of selectable operating parameters, transmits and/or receives information packets related to at least one of the monitored physiological data and delivered therapy. A location management module ascertains a current geographical position of the wireless medical device and determines a corresponding geographical region associated with the current geographical position. The location management module controls the wireless transceiver to operate according to one of the plurality of operating profiles based on the determined geographical region. 
     In accordance with another aspect, a method for wirelessly transmitting medical information is presented. The method includes at least one of monitoring physiological data of a patient and delivering therapy to the patient. Information packets related to at least one of the monitored physiological data and delivered therapy are wirelessly transmitted and/or received via a wireless transceiver. A current geographical position of the wireless medical device is ascertained and a corresponding geographical region associated with the current geographical position is determined. The wireless transceiver is controlled to operate according to one of the plurality of operating profiles based on the determined geographical region. 
     One advantage is that wireless medical devices maintain compliance to local regulatory requirements for wireless transmissions regardless of geographical location. 
     Still further advantages of the present invention will be appreciated by those of ordinary skill in the art upon reading and understand the following detailed description. 
    
    
     
       The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. 
         FIG. 1  is a diagrammatic illustration of a medical wireless network; 
         FIG. 2  is a detailed illustration of one of the wireless medical devices of  FIG. 1 ; 
         FIG. 3  is a diagrammatic illustration of the hub medical device of  FIG. 1 ; and, 
         FIG. 4  is a flow chart illustrative of a method of operation. 
     
    
    
     With reference to  FIG. 1 , a plurality of wireless medical devices includes a hub medical device  10  and a plurality of other wireless medical devices  12 , which form a personal area network (PAN) or a body area network (BAN)  13 , arranged approximate to a patient&#39;s body for monitoring and recording various physiological parameters, administering therapy, or the like. The wireless medical devices  12  communicate wirelessly to the hub medical device  10 . Various wireless medical devices  12  are contemplated, such as an inner-ear sensor  14  connected to an associated electronic module  16  which is disposed at least partially in the patient&#39;s ear to measure temperature, blood pressure, pulse rate, or the like. As another example, the wireless medical devices  12  can include an ECG monitor having a plurality of ECG sensors or electrodes  18  connected to an electronic module  20  which measures and interprets the sensed signals. As another example, an SpO2 sensor  22  senses blood oxygen and pulse rate, which are communicated by an associated electronics module  24 . As another example, an infusion pump or other actuator  26  injects or otherwise dispenses medications into the patient&#39;s body under the control of electrical signals from an associated electrical module  28 . Other wireless medical devices  12  which sense physiological parameters or deliver therapy includes pacemakers, hearing aids, vision aids, prosthetic limbs, artificial organs, and the like. 
     The wireless hub  10  conveys the received signals from the wireless medical devices  12  to other wireless medical devices  29 , such as computer workstations, cellular phones, personal digital assistants, tablet computers, and the like, via an infrastructure network  30 . It should be appreciated that the hub device can be a dedicated hub for the wireless medical device  12  or a multifunction device such as a cellular phone, personal digital assistant, tablet computer, and the like. Communications between the hub and the wireless network  30  can be via a wireless local area network (LAN) based on the IEEE 802.11 standards, via a wireless wide area network (WAN) such as a cellular network, via a campus area network (CAN), via a metropolitan area networks (MAN), via relatively high power RF transmissions, or the like. 
     The wireless medical devices  12  and the hub  10  may interact with one another in various configurations. For example, in a star network, each of the wireless medical devices  12  communicates directly with the hub medical device  10 . The hub device receives acknowledgment signals or beacon signals from the devices  12  to, for example, synchronize the devices in anticipation of sending and receiving information packets, control signals, and the like, from the hub  10 . In a mesh network, the devices  12  communicate directly with each other and the hub  10 . Some of the devices  12  may communicate directly with the hub  10  or they may communicate with the hub  10  via other devices, such as computer, PDA&#39;s, mobile phone, or the like. These other devices may also communicate with other wireless medical devices  29  directly or via the infrastructure network  30  rather than via the hub  10 . 
     With reference to  FIG. 2 , each wireless medical device  12  includes at least one of a sensor  14 ,  18 ,  22 , which monitors physiological data of the patient or an actuator  26  which delivers therapy to the patient. The electronics module  20 ,  24 ,  28 , associated with each sensor, actuator, or combination, includes a wireless transceiver  40  with a transmitter  42  and a receiver  44  which transmit and receive, respectively, information packets related to at least one of the monitored physiological data and/or the delivered therapy to/from at least one of the neighboring wireless medical device  12  and the wireless hub  10 . Each wireless transceiver has as plurality of selectable operating parameters, such as frequency, duty cycle, bandwidth, maximum transmit power, and the like. 
     Each wireless medical device  12  includes a location management module  46 . The location management module  46  ascertains a current geographical position of the wireless medical device  12  and determines a geographical region associated with the current geographical position. Tracking the geographical region, e.g. North America, Europe, Asia, South America, etc., of the wireless medical device ensures that the operation of transceiver  40  complies with the local regulatory requirements for wireless transmission for that region. Each geographical region is associated with at least one operating profile. Each operating profile defines a plurality of operating parameters for the wireless transceiver  40  which are associated with the geographical region. For example, an operating profile is defined for the United States of America (USA) which defines a transmission frequency, duty cycle, bandwidth and maximum transmit power for the transmitter  42  as mandated by the Federal Communications Commision (FCC). It should be appreciated that multiple operating profiles for a single geographical region are contemplated. Conversely, a single operating profile maybe associated with multiple geographical regions. 
     Once the geographical region is determined, the location management module  46  controls the wireless transceiver  40  to operate according to one of the operating profiles based on the determined geographical region. In one embodiment, the operating profiles are stored in a profile memory  48  of the wireless medical device  12 . In another embodiment, the operating profiles are stored remotely and accessed wirelessly or received wirelessly by the transceiver  40 . The operating profiles may be stored in a memory unit of the hub device  10 . The hub device may transmit the operating profile or the wireless medical device  12  may request the appropriate operating profile. Alternatively, the hub device  10  and/or wireless medical device  12  may wirelessly access the stored operating profiles via the infrastructure network  30 . In this arrangement, the operating profiles are stored on a computer readable medium that is part of a computer workstation or server which is part of a LAN, WAN, CAN, MAN, or the like. 
     A communication module  50  receives physiological information sensed by the sensor  14 ,  18 ,  22  via a sensor or actuator control module  52 . The control module  52  also communicates with the actuator  26  to control its operation in accordance with received information packets. The communication module packages the sensed information and other transmission information such as acknowledgments, and the like, into information packets. The communication module controls the transceiver  40  to transmit the packets with an operating profile dictated by the location management module  46 . It should be appreciated that the wireless medical device may include multiple transmitters  42  as part of the transceiver  40 . Operating constraints may limit a single transmitter from operating at widely distinct frequencies. For example, a single transmitter may be capable of operating at the proposed 2.36 GHz MBAN frequency and the license free 2.4 GHz frequency. However, a second transmitter may be required to operate at the license free 433.05-434.79 MHz Industrial Scientific and Medical (ISM) band in Europe. 
     In one embodiment, each wireless medical devices  12  includes a user input  54 , such as a switch, button, touch pad, input device, or the like, which is operated to input the corresponding geographical region to the location management module  46 . As a switch, the user input  54  includes a plurality of user selectable position each of which is associated with at least one geographical region. As a button, the user may cycle through button presses of the user input  54  to select a corresponding geographical region or the user may select one of a plurality of buttons, each being associated with at least one geographical region. It should be appreciated that other user inputs  54 , such as joystick, keypad, keyboard, touch-screen, touchpad, or the like, are also contemplated. 
     In another embodiment, each wireless medical device  12  includes an optional global positioning module  56  which determines a current geographical position using trilaterization of timing signals receive from global positioning satellites. The global positioning module  56  determines the current geographical location of the wireless medical device  12  and transmits the current geographical location to the location management module  46 . From the current geographical position, the location management module  46  determines the geographical region in which the wireless medical device  12  currently resides. 
     With reference to  FIG. 3 , in another embodiment, the wireless medical device wirelessly receives the current geographical location from the hub device  10 . The hub medical device  10  includes a first transceiver  40 ′ which communicates with the other wireless medical devices of the body network and a second transceiver  40 ″ which communicates with the infrastructure network  30 . The wireless hub may be connected with a physiological data sensor and/or an actuator like the other wireless medical devices  12 , or may function merely as a central controller or coordinator and for transferring physiological and/or therapy related information to and from the network  30 . Similarly to the wireless medical devices  12 , the hub  10  includes a location management module  46 ′ which ascertains a current geographical position of the hub  10  and determines an associated geographical region associated with the current geographical position. The location management module  46 ′ controls the wireless transceivers  40 ′,  40 ″ to operate according to one of the operating profiles based on the determined geographical region. The location management module  46 ′ receives the current geographical position from at least one of a user input  54 ′, global positioning module  56 ′, and via the infrastructure network  30 . The user input  54 ′ and global positioning module  56 ′ function similar to that of the wireless medical devices  12 . Using an input device, such as a switch (as illustrated), button, keyboard, joystick, keypad, touch-screen, touchpad, or other suitable input device, the user can select a geographical region. 
     As previously described, the hub  10  includes a profile memory  48 ′ which stores the operating profiles for the wireless medical devices  12  and their transceivers  40  and the transceivers  40 ′,  40 ″ of hub  10 . Updated operating profiles which reflect changes in regulatory requirements can be obtain wirelessly from the infrastructure network  30  via the transceiver  40 ″. This is also advantageous if new frequency bands are introduced, for example the proposed MBAN band in the United States. Other changes include frequency band ranges, changes in duty cycle, changes in transmit power, or the like. 
     Communication modules  50 ′,  50 ″ receive and transmit information packets to/from the wireless medical devices  12  and the infrastructure network  30 , respectively. The communications module  50 ′ controls the transceiver  40 ′ to transmit the packets with an operating profile dictated by the location management module  46 ′. Accordingly, The communications module  50 ″ controls the transceiver  40 ″ to transmit the packets with an operating profile dictated by the location management module  46 ′. If the hub unit  10  is connected with a sensor or actuator, then it also includes a sensor or actuator control module  52 ′. 
     With reference to  FIG. 4 , a method for selecting an operating profile and informing other wireless medical devices  12  is illustrated. In one embodiment, the hub device  10  acts as a master device, e.g. in a star network, which advertises the geographical region, current geographical position, or operating profile using information packets or beacon packets. The hub  10  determines the current geographical location (S 70 ) from at least one of a user input  54 ′, global positioning module  56 ′, and via the infrastructure network  30 . The location management module  46 ′ determines a geographical region (S 72 ) in which the hub  10  and wireless medical devices  12  currently reside according to the determined current geographical location. If a change in the geographical region is detected (S 74 ), the location management module  46 ′ retrieves the operation profile(s) associated with the geographical region (S 76 ) from at least one of the profile memory  48 ′ or from a remote location via the infrastructure network  30 . The location management module  46 ′ controls the communication modules  50 ′,  50 ″ (S 78 ) to operate according to the operation profiles retrieved in step S 76 . The communication module  50 ′ controls the transceiver  40 ′ to transmit a beacon message to advertise the operating profile (S 80 ) to the wireless medical devices  12 . In another embodiment, the operating profile is embedded as part of an information packet, e.g. in a packet/frame transmission the operating profile can be embedded in the MAC address header or the PHY layer, and advertised as such. In a further embodiment, the geographical region or current geographical position rather than the operating profile is advertised to the wireless medical devices  12 . After the wireless medical devices  12  have received the advertised operating profile or geographical region, a personal area network is created (S 82 ) and monitoring of physiological data and therapy deliver may ensue (S 84 ). 
     In another embodiment, the devices  10 ,  12  of the personal area network operate in a peer to peer configuration, e.g. in a mesh network. If one device detects a change in the geographical region which necessitates a change in the operating profile, then the device  10 ,  12  which detected that change advertises at least one of the geographical region and required operating profile. If the device includes a global position module  56 ,  56 ′, then it may also advertise the current geographical position. Upon hearing the advertised mode switch command, the location management module  46 ,  46 ′ of the neighboring wireless devices  10 ,  12  controls the transceivers  40 ,  40 ′,  40 ″ accordingly. 
     The invention has been described with reference to the preferred embodiments. Modifications and alterations may occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be constructed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof