22-01-2013, 10:31 AM
CARDIAC DISORDER DIAGNOSIS THROUGH NADI (PULSE) USING BIOMEDICAL INSTRUMENTATION
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ABSTRACT
Diagnosing Diseases through pulse – “finding any disease using nadi” is an automated system to find the diseases and its related information about the human body. This project provides detailed information and reports on patients by obtaining their nadi as a time series. The nadi pulses are sensed by the fingertip, which actually measure the pressure exerted by the artery. These pulsations are very minute in pressure units and a set of three such pressure transducers is mounted on the wrist to sense three location pulses, namely Vata, Pitta and Kapha. The electrical signal proportional to the pressure experienced, in differential mode, by the pressure sensing element is then digitized using the 16-bit multifunction data acquisition card NI USB-6210 (National Instruments, TX, USA), having an interface with the personal computer. The data is captured at a sampling rate of 500 Hz (which is sufficiently higher than the Nyquist criteria) for a predetermined length of time. Our application shows the probable disease results according to the pulse waveform and pressure applied at the sensing element per unit time. Hence our Indian Medicine Practitioners can use this system as automated computer-aided diagnostic tool.
INTRODUCTION
Diagnostic system followed by ancient Indian Medicine Practitioners in Fig (1). In ancient literatures, be it Siddha, Ayurveda, Chinese, Unani, or Greek, pulse based diagnosis has its own unparalleled importance.
The organ under distress is zeroed down by feeling the palpation from the three fingers (index, middle and ring) placed on the radial artery. These pulsations dictate the physiological status of the entire human body. This is a tedious and delicate process and hence it takes years of practice to master this art Fig (1). As a result this approach is subjective in nature. Ayurveda meaning the ‘science of life’ believes that cosmos comprises of five basic elements – air, water, earth, fire and space. Human life is considered as a conglomeration of three humors (Vata, Pitta and Kapha), seven dhatus (tissues) and three mains (waste products).
WORKING MODEL OF THE SYSTEM
The nadi pulses are sensed by the fingertip, which actually measure the pressure exerted by the artery. These pulsations are very minute in pressure units and therefore their acquisition is very challenging. For this, initial experiments were carried out using a ‘1 PSI’ pressure sensor from ‘Sensym Products’; but were found to be inadequate for capturing the intricacies of the pulse. Hence, we have currently adopted ‘Millivolt Output Medium Pressure Sensor’ [Mouser Electronics, Inc.] with tiny diaphragm at the center, and having ‘0–4 inch H2O’ pressure range As shown in Fig. 2, a set of three such pressure transducers is mounted on the wrist to sense three location pulses, namely Vata, Pitta and Kapha. The electrical signal proportional to the pressure experienced, in differential mode, by the pressure sensing element is then digitized using the 16-bit multifunction data acquisition card NI USB-6210 (National Instruments, TX, USA), having an interface with the personal computer. The data is captured at a sampling rate of 500 Hz (which is sufficiently higher than the Nyquist criteria) for a predetermined length of time. We use the data acquisition software LABVIEW (National Instruments, TX, USA), which controls the digitization as well. The minimum change in the signal, which can be measured, depends solely on the resolution of the digitizer.
LAB-VIEW PROCESSING
There are different methods of HRV (Heart Rate Analysis). One of the methods is time domain analysis. This method extracts a few special measures using only the temporal RR interval signals. Another method is spectral analysis. This method interpolates the RR interval at a certain rate and transforms this interval into the frequency domain. There are some standards for these two methods. Other methods such as non-linear analysis and the time frequency analysis have been discussed and researched.
Transmitter
The transmitter is a standard industrial amplifier with 4–20 mA output, which linearizes and conditions the signal. While connecting to 16-bit digitizer, the 4-20mA is converted to 2–10 V through a resistor (500 ohm). It also provides the zero and span adjustments. The zero adjustment is calibrated to adjust the zero, such that at zero pressure (atmospheric pressure), the output is 4 mA. The span adjusts the degree of amplification for output of the signal. The data obtained in this way is usually corrupted because of implicit and explicit electronic and electrical noise, but the noise level obtained in our developed system is negligible, after proper shielding.
CONCLUSIONS
This system will be very useful to our Indian Medicine Practitioners as an automated computer-aided diagnostic tool. The tool diagnoses the chronic diseases of the human body. It reveals detailed and related information of the human body.
For Example when the tool diagnoses lung disease for a patient then it will reveal the overall information related to that particular lung disease such as predetermined monitory, causes, symptoms, complications etc. Medical practitioners will also have a clear idea about which part of the body is affected by the disease, so that the curative medicine can be provided appropriately. This tool will be very much useful in our Government Hospitals, Primary Health Centre (Department of Indian Medicine) in the exact diagnosis of diseases. In Government Hospitals and Primary Health Centre even a staff nurse or a attendee can handle this tool with safety for diagnosing the disease so that the doctors can able to visit more patients with out any confusions. Like Electronic Diabetes, Blood Pressure measuring instrument even common people can use this system in their home itself. By this they can self diagnose the disease. To predetermine a serious or a complicated disease in its Premonitory stage itself so that our Practitioners can able to treat the diseases in its earlier stage by avoiding further complications. This system will help our practitioners in a quick and uniform diagnosis of disease.