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Overview of Wireless Sensor Networks Applications in Medical Care Presenter: Ahmed Shawki Bayoumi Agenda • • • • • Main Idea Main Achievements Challenges Related pictures Innovation Abstraction The main idea of using the Wireless Sensor Networks in Healthcare is improving the quality of life of patients and doctor-patient efficiency, where it enables clinicians to monitor patients remotely and give them timely health information, reminders, and support – potentially extending the reach of health care by making it available anywhere, anytime. Overview of Medical Applications Utilization of different assets independent of their geographical location Multidisciplinary collaboration Facilitates the dissemination of medical knowledge to practicing doctors and medical students Allows doctors in remote and rural areas to consult with specialists in urban areas Specialist Researcher Patient Doctor Stage Model of the Medical Practice New and better medical devices are continuously introduced to detect vital signals and present them in a suitable format for healthcare givers The interpretation can be regarded as a data compression and data conformity process The physicians make a treatment prescription based on the patient’s medical history and current clinical reports by consulting the evidence-based database, pharmaceutical handbook and other resources Healthcare Wireless Network Expansion Each day more and more equipment is going “wireless” from pulse-oximeters to more complex patient vital signs monitors and ventilators Environments must scale from a few clients to 100’s on a single subnet External factors such as nearby TV and radio stations can affect overall performance. Interoperability profiles and standards are required to ensure plug-and-play operation in heterogeneous environments WSN Topology Medical information collected by sensors on the patient’s body (WPAN) is displayed on a bedside monitor This information is also transmitted to another hospital location for remote monitoring, e.g., a nurses’ station) In case of emergency, when the patient is moved from his/her room to the intensive care unit, these communications need to be maintained Radio frequency identification Facilitates the management of assets (wheel chairs, scanners, ambulatory equipment, etc) Improves patient localization and helps caregivers to provide services without delays Enhances the process of drug administration (identification, distribution, localization, returns and disposal) Facilitates the automatic data capture and the follow-up of blood and biological samples Mobile reader Pharmaceutical product management Access point RFID Server Wallmounted reader Medical and chirurgical equipment tracking Bracelet Fixed reader Patient Identification and tracking Equipment localization and tracking Agenda • • • • • Main Idea Main Achievements Challenges Related pictures Innovation Remote monitoring Reduce the number of patients transferred to urban hospitals Allows tele-consultation and tele-diagnosis including the option of obtaining opinions of distant experts Facilitates the patient remote monitoring with instantaneous data transmission for analyses and follow-ups Allows remote handling of medical equipment (tele-surgery) and direct action of the expert on the patient Improves coordination of first-responders workers during in the event of catastrophes or emergency cases Mobile monitoring platform Data capture Mobile device GSM GPRS WiMax Internet Real-time patient monitoring Wireless Body Area Network Wireless Body Area Network The personal server can be implemented on an Internet-enabled PDA or a 3G mobile phone, or a regular laptop of desktop computer. It can communicate with remote upper-level services in a hierarchical type architecture. Its tasks include: Initialization, configuration, and synchronization of WBAN nodes Control and monitor operation of WBAN nodes Collection of sensor readings from physiological sensors Processing and integration of data from the sensors Secure communication with remote healthcare provider Mobile Devices Facilitates the mobility of doctors, practitioners and caregivers Allows access to patient information at any moment, everywhere and on real time Improves automatic data gathering through barcode or RFID reading Allows the immediate sharing of patient information and results Improves the internal communication within the caregiver team and with the support staff Helps to reduce paper Wired network Cellular phones Laptop Hospital systems PACS Radiology Lab Pharmacy Etc. Patient record Computer on wheels PDA (Personnel digital assistant) Tablet PC Wireless router (Wi-Fi) Wearable Monitoring Systems Fabric electrodes have been used to monitor EKG and respiratory activity Framework for Medical Image Analysis The remote medical image repositories communicate through different types of network connections with the central computing site that coordinates the distributed analysis. DICOM The Digital Imaging and Communications in Medicine (DICOM) standard is created by the National Electrical Manufacturers Association (NEMA) to aid the distribution and viewing of medical images. DICOM is the most common standard for receiving scans from a hospital. A single DICOM file contains both a header (which stores information about the patient’s name, the type of scan, image dimensions, etc), and all of the image data DICOM images can be compressed both by the common lossy JPEG compression scheme as well as a lossless JPEG scheme A single 500-slice MRI can produce a 68 MB image file Activity Sensors They can be useful in monitoring patients undergoing physical rehabilitation such as after a stroke The Pluto custom wearable designed at Harvard incorporates the TI MSP430 microprocessor and ChipCon CC 2420 radio Pluto can run continuously for almost 5 hours on a rechargeable 120 mAh lithium battery It has a Mini-B USB connector for programming and to recharge the battery The software runs under TinyOS Pulse Oximeter Non-invasive technology used to measure the heart rate (HR) and blood oxygen saturation (SpO2) The technology used is to project infrared and near-infrared light through blood vessels near the skin By detecting the amount of light absorbed by hemoglobin in the blood at two different wavelengths the level of oxygen can be measured The heart rate can also be measured since blood vessels contract and expand with the patient’s pulse which affects the pattern of light absorbed over time Computation of HR and SpO2 from the light transmission waveforms can be performed using standard DSP algorithms Pulse Oximeter Smiths Micro Power Oximeter Board Length: 39 mm Width: 20 mm Height: 5.6 mm 6.6 mA at 3.3 V, typical power:22 mW Pulse range: 30-254 bpm SpO2: 0 to 99% Data is transmitted from the oximeter board at a rate of 60 packets per second (5 bytes per packet) Minolta Pulsox-2 Size: W69xH60xD28 mm Weight: approx. 70g (with 2 AAA batteries) Electrocardiograph (EKG) The most common type of EKG involves the connection of several leads to a patient’s chest, arms, and leg via adhesive foam pads. The device records a short sampling, e.g. 30 seconds, of the heart’s electric activity between different pairs of electrodes When there is need to detect intermittent cardiac conditions a continuous EKG measurement is used. This involve the use of a two- or three-electrode EKG to evaluate the patient’s cardiac activity for an extended period The EKG signal is small (~ 1mV peak-to-peak). Before the signal is digitized it has to be amplified (gain > 1000) using low noise amplifiers and filtered to remove noise Electrocardiograph The P wave is associated with the contractions of the atria (the two chambers in the heart that receive blood from outside) The QRS is a series of waves associated with ventricular contractions (the ventricles are the two major pumping chambers in the heart) The T and U waves follow the ventricular contractions Electrocardiograph IMEC has recently developed a wireless, flexible, stretchable EKG patch for continuous cardiac monitoring Placed on the arm or on the leg the same system can be used to monitor muscle activity (EMG) The patch includes a microprocessor, a 2.4 GHz radio link and a miniaturized rechargeable lithium-ion battery The total size is 60x20 mm2 Data is sampled between 250 and 1000 Hz an continuously transmitted The battery has a capacity of 175 mAh which provides for continuous monitoring from one day to several days Agenda • • • • • Main Idea Main Achievements Challenges Related pictures Innovation Critical Development Areas 1. Enabling Technologies for Future Medical Devices i. ii. iii. iv. Interoperability Real-time data acquisition and analysis Reliability and robustness New node architectures 2. Embedded, Real-Time, Networked System Infrastructures i. Patient and object tracking ii. Communication amid obstructions and interference iii. Multi-modal collaboration and energy conservation iv. Multi-tiered data management 3. Medical Practice-Driven Models and Requirements i. Records and data privacy and security ii. Role-based access control and delegation in real-time iii. Unobtrusive operation Critical Development Areas Cont. Interoperability: There is need for intercommunication among medical devices and clinical information systems. This has been accomplished with a number of medical products. Infusion pumps and ventilators commonly have RS-232 ports, and these devices can communicate with many physiological monitoring instruments. Products to link medical equipment and personal communication devices exist as well However, virtually all of these are specialized applications—custom interfaces unique to the two devices being linked To address the medical device plug-and-play interoperability problem, a single communications standard is needed. Critical Development Areas Cont. Real-time data acquisition and analysis: The rate of collection of data is higher in this type of network than in many environmental studies. Efficient communication and processing will be essential. Event ordering, time-stamping, synchronization, and quick response in emergency situations will all be required. Reliability and robustness: Sensors and other devices must operate with enough reliability to yield highconfidence data suitable for medical diagnosis and treatment. Since the network will not be maintained in a controlled environment, devices must be robust. New node architectures: The integration of different types of sensors, RFID tags, and back-channel long-haul networks may necessitate new and modular node architectures. Critical Development Areas Cont. Patient and object tracking: Tracking can be considered at three levels: symbolic (e.g., Room 136 or X-Ray Lab); geographical (GPS coordinates of a patient on an assisted living campus); relational/associational . It is complicated by the presence of multiple patients, nonpatient family members, and leaving the range of the home network. Communication amid obstructions and interference: In-building operation has more multi-path interference due to walls and other obstructions, breaking down the correlation between distance and connectivity even further. Unwanted emissions and latching are likely to be rigorously restricted and even monitored due to safety concerns, particularly around traditional life-critical medical equipment. Critical Development Areas Cont. Multi-modal collaboration and energy conservation: Limited computational and radio communication capabilities require collaborative algorithms with energy-aware communication. Richly varied data will need to be correlated, mined, and altered. Heterogeneous devices will be on very different duty-cycles, from always-on wired-power units to tiny, stealthy, wearable units, making rendezvous for communication more difficult. Multi-tiered data management: Data may be aggregated and mined at multiple levels, from simple on-body filtering to cross-correlation and history compression in network storage nodes. Embedded real-time databases store data of interest and allow providers to query them. Critical Development Areas Cont. Records and data privacy and security: Data collected by the network is sensitive, and ownership issues are not always clear. It is likely that the healthcare provider owns the sensor and network devices, yet the data pertain to the patient. Data must be available during emergencies, but access should leave a non-reputable “trail," so abuses can be detected. Any priorityoverride mechanisms must be carefully designed. One may want to filter out “privacy-contaminated” data, for example, a patient walks into the wrong room. The system should not “leak” this information through sensors being monitored in the room. Role-based access control and delegation in real-time: Doctors may delegate access privileges to other doctors and nurses; family members may monitor quality-of-care for nursing home residents. The system may have DRM-like issues: “read but not copy,” “view but not save," etc. Also, patients may have read but not write privileges for the collected sensor data, in order to avoid fraud. Critical Development Areas Cont. Unobtrusive operation: Stealth ness is desirable, particularly for in-home and nursing home applications, where intrusive technology may not be tolerated. “Invisible” sensors are both socially more acceptable (draw less attention, more dignified) and more dangerous (unwanted tagging and surveillance). Agenda • • • • • Main Idea Main Achievements Challenges Related pictures Innovation Some Healthcare WSN Equipments Healthcare WSN Equipments Places Healthcare WSN Infrastructure Agenda • • • • • Main Idea Main Achievements Challenges Related pictures Innovation HL7 Health Level 7 (HL7) standard is designed to enable different health care applications to exchange clinical and administrative data The most recent version of the HL7 specification uses XML messaging as its foundation HL7 also allows the use of trigger events, i.e. when a patient’s EKG waveform is available causes a request for that observation data to be sent to another information system Activity Sensors They can be useful in monitoring patients undergoing physical rehabilitation such as after a stroke The Pluto custom wearable designed at Harvard incorporates the TI MSP430 microprocessor and ChipCon CC 2420 radio Pluto can run continuously for almost 5 hours on a rechargeable 120 mAh lithium battery It has a Mini-B USB connector for programming and to recharge the battery The software runs under TinyOS Wireless Body Area Network Wearable Monitoring Systems Fabric electrodes have been used to monitor EKG and respiratory activity Clinical Data vs Wireless Technologies Biomedical Data Type Typical File Size EKG recording Electrical signal 100 kB Electronic Stethoscope Audio 100 kB X-Ray Still image 1 MB 30s of ultrasound image Moving image 10 MB Technology Data Rate Frequency Spectrum GSM 9.6 kbps 900/1800/1900 MHz GPRS 171.2 kbps 900/1800/1900 MHz EDGE 384 kbps 900/1800/1900 MHz 3G/UMTS 2 Mbps 1885 MHz – 2200 Mhz