Wireless bedside Vital Signs monitoring unit

Transcription

1 Wireless bedside Vital Signs monitoring unit A. Trigo 1, J.P. Cunha 1,2, M.B.Cunha 1,2, William Xavier 1 and Nuno Silva Ferreira 1 1 IEETA Instituto de Engenharia Electrónica e Telemática de Aveiro 2 Departamento de Electrónica e Telecomunicações da Med-e-Tel Luxembourg, 22 April

2 Introduction Some Facts Increasing cost of Health Services Due to an aging population[1] The change in the Hospital usage pattern (rise in admissions, but a fall in length stay)[2] Expensive Hospital monitoring equipment and Human resources Need for use of gels and wires Goal Create a platform for patient monitoring 2

3 Clinical Scenarios TeleCardio Monitoring patients with cardiac problems ECG, Heart Rate Monitoring hypertension patients Blood Pressure TeleRecover Monitoring patients which have been submitted to surgical intervention ECG, SaO2, Temperature, Blood Pressure 3

4 Geographic scenarios At the Hospital Moving patients to less equipped Hospital infirmaries in order to free Hospital resources Have medical doctors on call instead of having them present in Hospital infirmaries. At Home Telemedicine - Remote monitoring Allowing trigger alarms Patient self monitoring 4

5 The needs Patient Increase monitoring comfort and portability Provide patient remote monitoring in order to avoid Hospital visits Hospital Fast response to critical situations Health Care Professional Remote monitoring through a friendly interface Hospital Administration Lower monitoring costs, free Hospital resources, Integrate the new platform with existing HIS, cover several infirmaries 5

6 Satisfying the needs Patient centric platform based on low cost acquisition units and on a distributed system Cover several infirmaries Build up an equipment, called Bedside unit which must be Miniaturized, modular, scalable, easy to use, comfortable, portable, affordable and secure Implement a medical interface which must be Easy to use, secure and integrable with existing HIS 6

7 System use cases[3] 7

8 System architecture 8

9 Bedside Unit Implemented oem modules ECG SaO2 Temperature Blood Pressure External module (not usually available on the box due to it power consumption, but still pluggable on one of the Bedside unit available slots) 9

10 Bedside unit ECG module One channel ECG 50hz,100hz and 300hz Signal acquired Ecg wave points information Pulse information Serial connection Size 77 x 54 x 17mm 10

11 Bedside unit SaO2 module Two possible probes Finger Ear Signal acquired Size 77 x 54 x 17mm SaO2 wave points information SaO2 value information Serial connection 11

12 Bedside unit Temperature module Temperature probe Two channels Serial connection Size 77x44x17mm 12

13 Bedside unit External blood pressure module Blood Pressure Cuffs Signal measurement mmhg systolic, diastolic and mean pressure Serial connection Size 68 x 128 x 34 mm 13

14 Bedside unit Inner box communication All boards have serial communication interface RS232 peer-to-peer limitation All boards start transmitting when connected to power supply There is a concentrator and transmission module Bus communication network needed to connect all boards serial boards and transmission module CAN BUS[4] selected Existing experience 14

15 Bedside unit RS232 - CAN Bus bridge size 30x20x4 mm ECG board with the RS232-Can Bus bridge Since we have a CAN BUS architecture and our acquisition modules have a serial interface, a RS232 Can Bus transceiver was built. This bridge is fixed to the board of the desired acquisition model 15

16 Bedside unit Concentration and transmission module Concentration module Size 70x50x20mm Bluetooth module Size 60x20x15mm Signal packing Responsible for packing all the data acquired by the different acquisition modules with the signal protocol format. CRC16 data stream error detection Based on the PIC18F258 from Microship[5] Bluetooth connection to PDA or ProxyPC 16

17 Bedside unit PDA Tungsten T3[6] Telemedicine mode Stores and forwards acquired signals to the Set Top Box / ProxyPC On request Limit storage capacity Bluetooth Piconet RFCOMM sockets communication with the ProxyPC Stand alone mode For home self monitoring 17

18 The assembled Bedside unit box Three of the four available slots occupied with the connectors to ECG electrodes, SaO2 and temperature probe connectors Two possible configurations With or without the PDA Two rechargeable lithium polymer batteries (95x60x6mm) which allow a 6 hours non stop operation, with the PDA. 18

19 ProxyPC / Set Top Box Emulated serial connection over Bluetooth PDA not present, assumes Piconet Master mode with the Transmission module Stores patient data locally JAX-RPC web services[7] to perform the available operations SOAP messages to transfer the acquired vital signs to HIS network Existing Hospital PC required, no need to buy a new one 19

20 ProxyPC web services Telemedicine available operations Query existing modules Online monitoring Start exam acquisition Start exam acquisition with preset time Stop exam acquisition Offline monitoring Start exam, with PDA schedule configuration Upload acquired vital signals (exams) Search/List for patients and exams stored locally on the ProxyPC and/or on the PDA 20

21 Central server Responsible for data storing From time to time the data stored on the ProxyPCs is send to the central server. Has a HISA[8] compliant RDMS to store Hospital information from medical doctors personal data to the patient vital signs acquired data. Application server Web services tier to provide data to client applications No direct access to the database 21

22 Clinical web access Small EPR (Electronic Patient Record) Search, view and perform patients exams Select modules for patient exam Start/Stop exams (Online mode) Schedule PDA exams (Offline mode) Access control 22

23 Applet exam viewer View acquired signals Work with acquired signals Scroll and Zoom 23

24 Software Server RDMS and Web All open source software RDMS server MySql database Web and Application server J2SE 1.4.2_03 Tomcat container Apache Axis 1.1 Struts 1.1 framework 24

25 On going work Miniaturization New temperature module based on two small digital sensors 99,98% size reduction (77x44x17mm ->3x5x0,5mm ) 99,4% cost reduction (500 -> 3 ) Comfort Evolution to the wearable concept Partnership with Textile Institute for a wearable prototype Built in sensors and board modules end of wires! 25

26 Advantages Miniaturization 20x20x7cm box size Modular and scalable New modules developed only have to support the communication data stream protocol Low cost Easy to use (Portal and Applet) Known technology for end users, almost every one knows how to use an Internet Browser Query, start, stop and upload operations 26

27 Advantages Comfortable Portable Secure No wires between the bedside unit and ProxyPC The end of wires with wearable concept evolution Gel free electrode[9] The Bluetooth enabled box allows the patient to move around the house SSL 128 bit secure connections Users control access PDAs MAC ADDRESS access control 27

28 References [1] Missoc-Info 03/ Health Care in Europe European Communities, [2] B. G. Celler, N. H. Lovell, and D. K. Y. Chan, The potential impact of home telecare on clinical practice, Med. J. Australia, vol. 171, pp , [3] Fowler, M. (1997): UML Distilled- Applying the standard Object Modeling Language. Addison-Wesley [4] CAN in Automation. CAN Specification 2.0, Part A [5 ]Microship PIC18FXX8 Data Sheet [6] Palm OS Programmer's API Reference, Palm OS 5 SDK (68K) R3 Palm [7] Apache Axis [8] CEN/TC 251. Medical Informatics - Healthcare Information System Architecture (HISA) Part 1: Healthcare Middleware Layer. ENV :1998; Feb [9] P. Justino, J.P. Cunha et al., Active Impedance Adaptation EEG: An integrated amplifier in Electrodes, BioEng 2001 Proceedings, pp. 47,