4.Safety requirements in a multiparametric patient monitoring system:

a)Defribillation protection:Targeting medical equipment such as defibrillators as well as ECG diagnostics and monitoring systems, the MAX30034 defibrillation protection device from Maxim Integrated Products protects against defibrillation pulses and ESD. Compared to existing approaches and components, it simplifies design, provides >75% space savings, and trims the bill of materials, all while significantly improving performance. Designers of defibrillators and ECG monitors face a challenge, as their ECG input amplifiers must withstand high-voltage pulses for cardiac resuscitation. These pulses can easily damage the sensitive electronic circuitry which captures the millivolt level heart signals. Preventing this damage has required a three-layer, multi-component approach combining a per-channel GDT and/or TVS device, as well as ESD-protection diodes. Further, leakage current (a critical parameter) is relatively high, at about 1-2nA. Maxim's four-channel defibrillation protection device uses an innovative topology from an advanced semiconductor process to absorb and harmlessly redirect these high-energy pulses away from sensitive circuitry. This small and robust device needs only two external pairs of resistors for each channel to provide design simplicity, smaller overall size, and lower leakage current. The device replaces the primary-level GDTs and/or TVSs, as well as secondary-level ESD diodes which are the conventional solutions for mandated circuit protection. The device can withstand over 100,000 defibrillation pulses without failure and still maintain a leakage current under 10pA (100x less than GDT/TVS-based approaches).

b)Pulse maker Elimination:

In modern day digital ECGs, ECG filter settings can beautify the tracings, but vital information can be filtered out, as in this case, which is quite common. In the illustration below, 0.08 Hz is the high pass filter, meaning that the ECG amplifier passess all frequencies above that limit. 40 Hz is the low pass filter, indicating that all frequencies below that can pass through.

Pacemaker spike (pacemaker artefact, pacemaker stimulus) being a high frequency signal, is effectively filtered out by the above filter setting. Hence the above ECG is likely to be diagnosed as left bundle branch block (LBBB) at one look,  though we are missing the P waves before each QRS complex which would be expected in a simple LBBB with sinus rhythm.

The pacemaker spikes are easily seen when the same ECG is repeated with a change in the low pass filter to 150 Hz. In fact both atrial and ventricular pacing spikes are seen before each QRS complex, with an interval in between. Hence this person has a functioning dual chamber pacemaker in situ. The paced P waves are of low amplitude and hardly visible (or it could be lack of atrial response to atrial pacing – atrial capture failure). This highlights the importance of appropriate ECG filter settings for each case.

The high pass filter is meant to filter out baseline fluctuations due to respiration and other low frequency signals, while low pass filter avoids muscle potential interference (EMG artefact). In addition, most ECG machines have a notch filter at 50 Hz to specifically filter out line voltage interference.

5.The following will be the proccess of qualification for the medical device which is being designed:

PROCESS OF REGISTRATION

Before October 1, 2021, producers and exporters of newly approved medical devices were supposed to register with the Drugs Controller General of India (“DCGI”). Some medical devices, however, are exempt from the registration requirement because they are already regulated or have been reported to be regulated (e,g, 37 items which are existed before, refer Table 2). The government has simplified the registration procedure, and it is no longer necessary to hire a full-service marketing registration or authorisation agent. By submitting the following information, any importer or maker of Newly Notified Medical Devices will be able to register online.

1. Name of the corporation, firm, or other legal entity.
2. Name and location of the manufacturing facility (for devices manufactured in India only)
3. Medical equipment specifications and standards (for imported devices only)
4. Medical device information (generic name, model number, intended use, class of medical device, material of construction, dimensions (if applicable), shelf life, sterile or non-sterile status, and brand name only if registered under Indian trade mark legislation)
5. Certificate of compliance with respect to ISO 13485 standard accredited by National Accreditation Board for Certification Bodies or International Accreditation Forum in respect to such medical devices
6. Free sale certificate from the country of origin (for imported devices only)
7. A duly signed undertaking stating that the information furnished by the applicant is true and authentic.

The registration number is issued when the documents are submitted online. Only when a registration number is generated successfully will the registration be complete. The new amendment’s registration deadline declaration for newly notified medical devices is October 1, 2021. Until registration is acquired, the importer or producer will be unable to promote and sell their newly notified medical equipment in India.However, there are 37 kinds of medical devices that were regulated or notified before to February 11, 2020 and are exempt from the new rule’s registration requirement, allowing them to continue operating under the licence issued by the relevant licencing body.

Every producer and importer who receives a registration number for their medical equipment must show the number on the label. The declaration of a registration number, on the other hand, has no bearing on the registration deadline (October 1, 2021). Unless DCGI orders otherwise, labelling is an urgent obligation that will begin as soon as the registration number is provided.

IMPLEMENTATION OF ISO-13485 IN NEWLY NOTIFIED DEVICES FOR REGISTRATION REQUIREMENT

A certificate of compliance with ISO-13485 (Medical Devices – Quality Management Systems – Requirements for Regulatory Purposes) is required for registration of a Newly Notified Medical Device. A registered importer or maker of a medical device should adhere to ISO 13485 criteria at all times. ISO 13485 is responsible for the establishment, documentation, and execution of a quality management system, which must be amended from time to time by an independent audit.

WHAT HAPPENS WHEN LICENSE IS NOT OBTAINED ON TIME?

If a maker or importer of a newly reported medical device does not get registration on time the DCGI halts its operations until registration is secured. Under the Legal Metrology (Packaged Commodity) Rules of 2011, the importer or manufacturer of all medical devices (whether regulated or unregulated) must now state the date of import or production on the device’s label. As a result, all devices made or imported must be tagged with a DCGI registration number. If it fails to display the registration number, DCGI or the applicable state licencing authorities will take action. If a breach of the MDR is discovered, a criminal prosecution with a sentence of imprisonment and a fine may be issued. Any stockpile of medical devices sold without a licence or registration might be confiscated.

The new MDR 2020 regulations ensure that every medical equipment, whether made in India or imported, is subjected to quality control before being distributed or sold on the market. The government has also provided the industry enough time to implement ISO 13485 and quality management systems. The timetable for acquiring a licence and registration for medical equipment, including previously uncontrolled medical devices, will provide pharmaceutical corporations a break. Now it is up to the industry to play its role in reinforcing the Indian consumer’s and worldwide community’s confidence in the quality and safety of medical devices marketed in India.

6.The screen layout has been planned as follows:The top most part part of the screen will consist of patient's details such as his/her name ,weight,height ,age ad also the name of the doctor which the person is being consulted to.

below these details willbe the following parameters

ECG:

An electrocardiogram, abbreviated as ECG or EKG, is a measurement of the electrical activity of the heart during the cardiac cycle and can be used to identify if there are any issues with the normal functioning of the heart. Heart muscles are self-excitable and generate electrical impulses. It has become the most commonly used test in patients’ evaluation and an essential part of cardiac care plans.

PPG:

Photoplethysmography (PPG) is a simple optical technique used to detect volumetric changes in blood in peripheral circulation. It is a low cost and non-invasive method that makes measurements at the surface of the skin.

The technique provides valuable information related to our cardiovascular system. Recent advances in technology has revived interest in this technique, which is widely used in clinical physiological measurement and monitoring.

Principle of PPG

PPG makes uses of low-intensity infrared (IR) light. When light travels through biological tissues it is absorbed by bones, skin pigments and both venous and arterial blood.

Since light is more strongly absorbed by blood than the surrounding tissues, the changes in blood flow can be detected by PPG sensors as changes in the intensity of light.

The voltage signal from PPG is proportional to the quantity of blood flowing through the blood vessels. Even small changes in blood volume can be detected using this method, though it cannot be used to quantify the amount of blood.

A PPG signal has several components including volumetric changes in arterial blood which is associated with cardiac activity, variations in venous blood volume which modulates the PPG signal, a DC component showing the tissues’ optical property and subtle energy changes in the body.

Some major factors affecting the recordings from the PPG are site of measurement and the contact force between the site and the sensor.

Blood flow variations mostly occur in the arteries and not in the veins.

Below these two parametric waves we have the following specification

heart rate:

 rate (or pulse rate)^[1] is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excrete carbon di oxide, but is also modulated by numerous factors, including, but not limited to, genetics, physical fitness, stress or psychological status, diet, drugs, hormonal status, environment, and disease/illness as well as the interaction between and among these factors.^[2] It is usually equal or close to the pulse measured at any peripheral point.

Bood Pressure:

Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" refers to the pressure in the large arteries. Blood pressure is usually expressed in terms of the systolic pressure (maximum pressure during one heartbeat) over diastolic pressure (minimum pressure between two heartbeats) in the cardiac cycle. It is measured in millimeters of mercury  above the surrounding atmosphere pressure.

Tempreature:It is the tempressure measured of the body , which is absolutely important for maintaining bod's metabolism.

Last But not the least Gaslvanic skin response is also showed

The galvanic skin response (GSR, which falls under the umbrella term of electrodermal activity, or EDA) refers to changes in sweat gland activity that are reflective of the intensity of our emotional state, otherwise known as emotional arousal.

Our level of emotional arousal changes in response to the environment we’re in – if something is scary, threatening, joyful, or otherwise emotionally relevant, then the subsequent change in emotional response that we experience also increases eccrine sweat gland. Research has shown how this is linked to emotional arousal \

6.

The wearable data acquisition hardware connects to the vest with sensors integrated and is worn around the waist of the wearer. Fig. 3 illustrates the block diagram of wearable data acquisition (DAQ) hardware which houses the complete electronics for signal conditioning, digitization, processing and wireless transmission of vital parameters along with 

the GPS data. The wearable data acquisition hardware is designed to keep the size minimum and power consump- tion to minimum. The power for the complete wearable data acquisition hardware is provided by a rechargeable 7.4 V,

−

1.8 Ah Li-ion battery. The 7.4 V is regulated to give  5 and

+5 V DC supply using a DC–DC converter and a voltage reg- ulator circuit and is fed to analog and digital sections. The battery is charged with a charger rated 8.2 V, 800 mA. The wearable data acquisition hardware can work continuously for 4.5 h, once the battery is fully charged.

S. no.	Physiological parameter	Sensor	Parameter range
1	Electrocardiogram (ECG)	Silicon rubber with pure silver fillings	Frequency: 0.5 Hz–100 Hz; amplitude: 0.25–1 mV
2	Photoplethysmogram (PPG)	Red light 630 nm	Frequency: 0.5 Hz–20 Hz
3	Blood pressure (BP)	Derived by analyzing ECG and PPG waveform	Systolic: 50–300 mmHg; diastolic: 40–140 mmHg
4	Body temperature	Thermistor (PT100) resolution 0.39 ▲/◦C	0–40 ◦C
5	Galvanic skin response (GSR)	Ag–AgCl electrodes	0–100 K▲
6	Heart rate (HR)	Derived from ECG waveform	40–250 beats/min

7.

the remote monitoring station, the heart rate (HR) is computed by analyzing the ECG wave, by accurately deter- mining QRS complex for every beat. The QRS complexes are isolated for every beat by high pass filtering the filtered ECG signal and are compared against a set threshold to detect the presence of a beat. Pulse period is incremented by one during every sample period. Since each sample occurs every 1/250 s it is easy to track the time scale based on the number of counts in the pulse period variable. The pulse period is accumulated for every beat, and is used for the calculation of heart rate, which is given by HR = 1/(pulse period/(sampling rate 60)). The heart rate is computed for every 10 s and averaged for every minute and displayed in the software in units of beats per minute.

Non-invasive of blood pressure measurement is desirable in monitoring patients during surgical operations or in inten- sive care units and for wearable monitoring applications. PTT is commonly accepted as a good technique for non- invasive BP measurement during steady state and dynamic exercise. The earlier cuff-less non-invasive systolic blood pressure measurement was measured with acceptable accu- racy by calibrating to individual patient by measuring the pulse arrival time (time interval from apex of ECG to onset of PPG) and blood pressure measured by conventional method during resting and actively exercising for a large group of patients. The systolic and diastolic blood pressure values are determined by means of an algorithm using pulse velocity and wave shape characteristics from continuous ECG and PPG data [31–35]. Blood pressure is related to the inverse of the pulse arrival time squared and the fractional change in pulse volume for each passing pulse. Instead of individually measuring the PTT and fractional change in blood volume, an alternate measure (1/C_dx) related to PTT and ∆V/V is utilized, which is defined as the time from the peak of the R-wave of ECG to the point at which the pulse waveform has gone 50% raising font of PPG wave. The systolic (P_Si) and diastolic (P_Di) blood pressures for the ith pulse related to 1/C_dx and instantaneous heart rate are given by the following

relationships [36].

i

PSi = [ks(Cdx)2] + ksys cal

i

P_Di = [k_d(C_dx)²] + [K_IHRIHR_i] + k_{dia cal}

i

where (C_dx)² is defined as measure related to pulse wave velocity and fractional change in blood volume (∆V/V); 1/C_dx defined as the time from the peak of the R-wave on the ECG to the point at which the pulse waveform, measured at the finger, has gone half way up its up-slope; IHR_i the instanta- neous heart rate for the ith pulse; K_s, K_d and K_IHR the fixed constants; K_{sys cal} and K_{dia cal} are the systolic and diastolic calibration constants [36,37].

The diastolic BP computed from 1/C_dx without instanta- neous heart rate (IHR) has not given accurate values [38]. The diastolic pressure is the arterial pressure that exists at the end of the diastolic pressure decay, by adding IHR to C_dx has given more accurate calculation of diastolic BP. The diastolic BP of an individual for a particular heart beat is related to the duration of decay and is inversely proportional to the IHR of that pulse. Higher the IHR, higher will be the diastolic BP expected to be and lower the IHR, the lower the diastolic BP [36]. During the dynamic conditions of the subject the heart rate variations are high as compared to the resting condition of the subject. Heart rate is found to have significant influ- ence in the pulse transmit time assessment in elderly subjects [39].

 

Relationship between BP, 1/C_dx is individual dependent; a practical and convenient method to derive the calibration constants for each individual is to be carried out. To account for the individual differences between patients, the blood den- sity term and the particular waveform characteristics of the ECG and pulse waveform signals, a calibration is required. To determine the calibration constant, the subject is requested to relax for about 5 min. The ECG and PPG signals are recorded for 10 s without any noise, baseline wander and motion arti- fact, and 1/C_dx and heart rate is computed and stored. Now using a standard oscillometric BP machine, three sets of systolic and diastolic BP readings are recorded. The heart rate (C_dx)², measured systolic and diastolic blood pressure values are substituted to the P_Si and P_Di equations, from which there are two unknown in P_Si and three unknown in P_Di. The equations are solved empirically and the con- stants are determined. From the determined constants and measured IHR and 1/C_dx, beat-to-beat systolic and diastolic BP is estimated. For correct calibration, the BP is measured in different blood pressure levels. The calibration constants obtained from 25 subjects during the initial calibration are given in Table 2.

The blood pressure is computed for every 10 s and averaged for 1 min and displayed in units of mmHg. The temperature is displayed in units of ^◦C and is averaged and updated for every 10 s. The GSR signal is displayed as con- ductance in units of µmho/cm², updated every second. The

 

 

Table 2

Calibration constants obtained from individual calibration by measuring blood pressure using automatic blood pressure machine and measurement of pulse transmit time

s)

 

0.38

Subject Age (years) BP*   IHR* (bpm)       Cdx* (m/     Systolic (mmHg) Diastolic (mmHg)   1 20 103 ± 5.5 62 ± 2.5 73 ± 8               4.70 ±

Ks Ksys cal Kd KIHR Kdia cal   1.647   49.879   0.0970   0.3424   38.9573 1.030 70.953 0.0663 0.5937 34.2758 0.928 65.998 0.0154 0.2373 61.5647 0.759 39.752 0.0083 0.4616 36.2270 0.657 63.121 0.0089 0.1223 61.1546 0.871 61.955 0.0970 0.6826 18.6268 1.246 55.497 0.2394 0.2011 58.0709 0.878 56.340 0.0430 0.4143 41.9091 1.311 61.380 0.5285 0.2829 19.0522 1.653 26.250 0.1335 0.1727 46.8288 1.005 57.729 0.2481 0.2915 44.6823 0.775 72.617 0.3930 0.1815 34.5845 0.936 39.654 0.4302 0.1562 27.1069 0.9261 42.643 0.2900 0.0202 52.2723 1.4507 40.329 0.4313 0.4001 23.6667 1.0512 60.932 0.0461 0.5302 18.8547 0.5479 66.003 0.1740 0.1437 48.2579 1.1435 19.517 0.1706 0.2563 37.4564 0.7013 42.707 0.1326 0.4402 28.2611 1.2686 18.394 0.0526 0.6313 26.8731 0.7967 36.787 0.2522 0.2985 22.8511 0.7226 50.870 0.5781 0.0463 17.5583 0.7811 57.101 0.0617 0.1014 66.0814 0.6090 55.749 0.2071 0.4265 31.2424 0.7499 53.441 0.4240 0.1054 29.4998

2               22                     118 ± 2.8                 81 ± 2.1                       75 ± 2               6.79 ± 0.2

3               28                     120 ± 3.7                 80 ± 1.5                       79 ± 4               7.65 ± 0.25

4               58                     106 ± 2.6                 71 ± 1.5                       79 ± 5               9.35 ± 0.18

5               29                     116 ± 2.9                 71 ± 3.4                       87 ± 5               7.44 ± 0.21

6               34                     120 ± 1.5                 87 ± 3.6                       90 ± 5               8.20 ± 0.11

7               24                     123 ± 7.3                 96 ± 1.5                       93 ± 7               7.49 ± 0.51

8               38                     115 ± 3.6                 73 ± 2.6                       69 ± 3               8.17 ± 0.25

9               24                     106 ± 1.5                 62 ± 2.5                       79 ± 4               6.32 ± 0.10

10               26                     126 ± 3.5                 67 ± 3.2                       63 ± 6               7.86 ± 0.23

11               41                     133 ± 4.0                 92 ± 2.0                     104 ± 4               9.72 ± 0.28

12               28                     113 ± 4.2                 71 ± 4.9                       81 ± 5             7.165 ± 0.29

13               48                     105 ± 3.9                 67 ± 2.1                       74 ± 4               8.38 ± 0.27

14               45                     122 ± 2.6                 79 ± 1.7                       92 ± 2               9.32 ± 0.18

15               29                     103 ± 1.7                 72 ± 1.7                       73 ± 3               6.57 ± 0.11

16               27                     109 ± 2.5                 70 ± 4.1                       89 ± 3               6.67 ± 0.18

17               52                     119 ± 6.8                 78 ± 4.9                       83 ± 7               9.72 ± 0.27

18               49                     117 ± 4.1                 71 ± 1.5                       75 ± 3               9.32 ± 0.29

19               60                     116 ± 3.7                 78 ± 4.6                       85 ± 3             10.24 ± 0.26

20               45                     115 ± 2.5                 82 ± 2.8                       83 ± 2               8.81 ± 0.17

21               56                     125 ± 4.3                 75 ± 2.6                       80 ± 3             10.58 ± 0.31

22               52                     121 ± 3.1                 77 ± 1.7                       86 ± 2               9.88 ± 0.14

23               43                     122 ± 4.5                 80 ± 2.1                       82 ± 3               9.13 ± 0.13

24               24                     120 ± 5.1                 80 ± 2.0                       61 ± 3             10.25 ± 0.34

25               48                     121 ± 2.5                 77 ± 2.3                       82 ± 4               9.53 ± 0.17

* Mean ± S.D.

 

 

 

geo-location information such as latitude, longitude and alti- tude information is updated every 5 min.

 

• Clinical validation

 

The medical validation was carried out to study the con- sistency and reliability of the data recordings from Smart Vest as compared to standard measurement method. The study was conducted on 25 healthy male subjects in the age group between 21 and 60 and their prior consent was obtained. The clinical validation of the device was carried out for 30 min on each subject during standing and walk- ing, and the physiological parameters were simultaneously acquired from Smart Vest and commercially available auto- matic BP machine working on oscillometric principle, Lloyds Pharmacy Ltd. (Model KD 525) and portable ECG monitor Delmar Reynolds (Lifecard CF), both the systems fulfilling CE norms. The systolic and diastolic blood pressure, and from the ECG waveform RR intervals, QRS duration and QT intervals were analyzed statistically according to the method described by Bland–Altman [40] and plotted as the difference in measurements against the mean of the two measurement. The average of the differences between the two methods was used to calculate the overall bias and the standard deviation of the differences between the methods was used to calculate the precision. The bias and precision were determined for each vital parameter data and were analyzed to estimate the performance of the device.

 

 

2.    Results

 

Prototypes of the Smart Vest system has been developed and tested for functionality and comfort levels of the wearer. Fig. 4 illustrates the developed prototype of the wearable data acquisition hardware, which weighs 460 g. Fig. 5 illustrates the remote monitoring station with wireless receiver hard-

 

 

Fig. 4. Prototype of the developed wearable data acquisition hardware, with wireless communication and global positioning system integrated.

 

 

Fig. 5. Remote monitoring station with wireless communication system.

 

ware interfaced to the USB port and the customized remote monitoring software. Fig. 6 illustrates the screen shot of the remote monitoring software with the medical data of ECG, heart rate, PPG waveform, blood pressure, body temperature and GSR are displayed along with the patient data and geo- location. The Smart Vest has been tested for performance and safety as per the IEC 60601-1 and 60601-2-27A standards and important results are given in Table 3.

−

−

−

−

The statistical analysis of vital parameter data recorded with the Smart Vest and standard measurement method when the subject was standing and walking were computed. The bias for systolic BP during standing and walking was 0.462 and 0.557 mmHg, respectively, and precision was 8 and 10 mmHg while standing and walking, respectively. The diastolic BP bias during standing and walking was 0.567 and  0.287 mmHg, respectively, and precision was 6 and 8 mmHg, respectively. The Bland–Altman plots for the sys- tolic and diastolic BP while standing is given in Figs. 7 and 8, respectively, and during walking in Figs. 9 and 10, respec- tively.

 8.Since this is a multiparametric monitiring system made specifically for armed forces it has no requirement in ICU .but if yyou want to view several different data from diffent wearable monitoring systems, then tht would require connecting the different monitiring station to a larger station  through a common USB cable of taking multiple inputs but only a single output.

9.

The tele-monitoring architecture of wearable data acqui- sition hardware is achieved by 16-bit microcontroller (dsPIC30f6014), which is the heart of the wearable data acquisition system to control and coordinate various activi- ties, it has modified Harvard architecture, with MAC engine, 144 MB of on-chip flash memory. The controller runs on a 40 MHz clock frequency and can perform up to 30 MIPS of operations. As illustrated in Fig. 3, the conditioned sen- sor outputs are fed to the microcontroller, which has a built-in 12-bit analog-to-digital converter (ADC) for digitization. The ADC being unipolar, the ECG and PPG being bipolar signals are level shifted and fed to the ADC for digitization. The analog signals are sampled at 250 samples/s at 12-bit resolu- tion. The processor has three serial ports, which are designed to interface with the wireless communication module, GPS module, and third port reserved for PDA or PC interface. The wireless transceiver module (Xstream^TM) is interfaced to the host processor port B, through a CMOS-level asynchronous serial port directly. The global positioning system module (uTracker^TM) has a serial interface and is interfaced with the port C of the processor. The GPS module is programmed to read the satellite information and transfer the NMEA [29] for- mat data to the processor. The port A is interfaced to RS232 standard 9-pin connector, which is provided to connect the PC or PDA for data analysis and debugging.

−

The data after being acquired by the wearable data acqui- sition hardware is now framed in the form of packets for 1 s of data and is transmitted wireless to the remote monitoring station. The communication module operates in the 2.4 GHz ISM band with transmit power of 50 mW and receiver sen- sitivity of 105 dBm. The module works on the Frequency Hopping Spread Spectrum (FHSS) technique [30] instead of the conventional master–slave concept. The communica- tion module has the capability to transmit over the air RF baud rate of 19,200 bauds. The maximum range over line- of-sight communication can be achieved up to 180 m in the urban or indoor using an antenna gain of 1.9 dBi. The range of transmission can be further increased by use of high gain antenna. The communication module utilizes three layers of addressing to communicate between modules. Only modules with the matching addresses are able to communicate. The three main networking layers are Vendor Identification (VID) number, channel or network address, and module address. Each networking layer provides a separate layer of filtra- tion. The data communication between the modules is packet

based, i.e. the data shifted into one module is packetized and sent out the antenna port. The packets that do not have an exact match for the VID and channel or network fields are discarded.

The remote monitoring station uses the 24XStream^TM communication receiver which interfaces with the serial or USB port of the computer or laptop. The remote monitoring software receives the packets of data from the wearable data acquisition hardware and checks the validity of packets and then further processes it. The packet structure contains the header, data and tail. The data are segregated into the indi- vidual fields and the data are further processed. The ECG and PPG signals are displayed continuously as per the standards and other parameters like heart rate, blood pressure, GSR and body temperature are computed and displayed in the remote monitoring software.

 11.

Recent technological advances in sensors, low-power microelectronics and miniaturization, and wireless network- ing will enable wireless sensor networks for human health monitoring. A number of tiny wireless sensors, strategically placed on the human body, create a wireless body area net- work that can monitor various vital signs, providing real-time feedback to the user and medical personnel is going to rev- olutionize health monitoring in the near future [16,45]. But a number of ongoing research efforts are focusing on vari- ous technical, economic, and social issues, many technical hurdles still need to be resolved in order to have flexible, reli- able, secure, and power-efficient wireless body area network suitable for medical applications [46,47].

The wireless transmission range of medical data to remote monitoring station needs to be improved. Attempts have been made with the infrastructure oriented wireless networks but the current quality and reliability of patient monitoring with infrastructure-oriented wireless networks have not been very satisfactory due to the unpredictable and spotty coverage. Ad hoc wireless networks can be formed among mobile and wearable patient-monitoring devices for improving the

 

 

 

coverage of patient monitoring when infrastructure-oriented networks are not accessible with very high reliability [48].

For use by a soldier or person who is on the move for longer duration, the developed Smart Vest needs to be upgraded by the integration of MEMS and CNT based sensors, with ruggedized, reliable, miniature electronics that will withstand the vagaries of weather and the battlefield environment. In the future, the modern solider system will equip every sol- dier with a wearable computer with a wireless connection. The wearable physiological monitoring system will provide feedback for the doctors to determine current state of a sol- dier without having to put themselves at risk by physically accessing the soldier.

The processor has three serial ports, which are designed to interface with the wireless communication module, GPS module, and third port reserved for PDA or PC interface. The wireless transceiver module (Xstream^TM) is interfaced to the host processor port B, through a CMOS-level asynchronous serial port directly. The global positioning system module (uTracker^TM) has a serial interface and is interfaced with the port C of the processor. The GPS module is programmed to read the satellite information and transfer the NMEA [29] for- mat data to the processor. The port A is interfaced to RS232 standard 9-pin connector, which is provided to connect the PC or PDA for data analysis and debugging.

−

The data after being acquired by the wearable data acqui- sition hardware is now framed in the form of packets for 1 s of data and is transmitted wireless to the remote monitoring station. The communication module operates in the 2.4 GHz ISM band with transmit power of 50 mW and receiver sen- sitivity of 105 dBm. The module works on the Frequency Hopping Spread Spectrum (FHSS) technique [30] instead of the conventional master–slave concept. The communica- tion module has the capability to transmit over the air RF baud rate of 19,200 bauds. The maximum range over line- of-sight communication can be achieved up to 180 m in the urban or indoor using an antenna gain of 1.9 dBi. The range of transmission can be further increased by use of high gain antenna. The communication module utilizes three layers of addressing to communicate between modules. Only modules with the matching addresses are able to communicate. The three main networking layers are Vendor Identification (VID) number, channel or network address, and module address. Each networking layer provides a separate layer of filtra- tion. The data communication between the modules is packet

 

based, i.e. the data shifted into one module is packetized and sent out the antenna port. The packets that do not have an exact match for the VID and channel or network fields are discarded.

The remote monitoring station uses the 24XStream^TM communication receiver which interfaces with the serial or USB port of the computer or laptop. The remote monitoring software receives the packets of data from the wearable data acquisition hardware and checks the validity of packets and then further processes it. The packet structure contains the header, data and tail. The data are segregated into the indi- vidual fields and the data are further processed. The ECG and PPG signals are displayed continuously as per the standards and other parameters like heart rate, blood pressure, GSR and body temperature are computed and displayed in the remote monitoring software.