INVESTIGATING THE USE OF IMPEDANCE PLETHYSMOGRAPHY FOR DETECTING DECREASED BLOOD FLOW IN DIABETIC PATIENT LIMBS
- 1. INVESTIGATING THE USE OF IMPEDANCE PLETHYSMOGRAPHY FOR DETECTING DECREASED BLOOD FLOW IN DIABETIC PATIENT LIMBS Mirza Taimoor Sultan BAIG Advisor: Assoc. Prof. Mustafa İlker Beyaz JANUARY 2023
- 2. Outline • Introduction • Impedance Plethysmography • Motivation • Literature Review • Contribution • COMSOL Multiphysics 5.6 • Geometrical Model • Theoretical Calculation • Tissue properties • Simulation Result • Circuit Diagram • Physical Implementation • Experimental Result • Conclusion
- 3. Modern Methods of Measuring Blood Flow Ultrasound transducer Source: (Wearable Compact Blood Flow Sensor _ MEMS_Microfabricated Products _ NTTAT Advanced Technology Product Introduction Site, n.d.) Sphygmomanometer Source: (Aneroid Vérnyomásmérő És Sztetoszkópkészlet Egészségügyi Kézi Otthoni Vérnyomásmérő Széria Mandzsetta És Sztetoszkóp _ Wish, n.d.) Digital Sphygmomanometer Source: (Buy Saint Health Arm Automatic Blood Pressure Monitor BP Sphygmomanometer Pressure Meter Tonometer for Measuring Arterial Pressure at Affordable Prices — Free Shipping, Real Reviews Wi, n.d.) • This system is made up of an app specifically designed for smartphones and a sensor gadget. • Visualizations such as animations of heartbeats or blood flow graphs are then generated by the smartphone based on this data. • It is a digital blood pressure monitor. • It is portable, easy to use, and rapidly and accurately detects blood pressure and pulse. • It is also called blood pressure cuffs. • Cuffs are used to stop blood flow in arteries by wrapping them around the upper arm and inflating them.
- 4. Modern Methods of Measuring Blood Flow PPG Wristwatch Source: Reader, R. (2022). Apple partner is developing a wearable to track blood sugar. In Fast Company. Retrieved from https://www.fastcompany.com/90730050/apple-partner-rockley-photonics- blood-sugar Pulse Oximeter Source: (SPO2 Finger Pulse Oximeter Fom a Reputed Online Medical Supply Store _ HealthConnection, n.d.) • A Non-Intrusive method for taking blood pressure using PPG Technique. • It can be worn on the wrist • Oximeters are tiny, non-invasive gadgets that may connect to a finger or toe. • It can tell how well the heart is supplying blood to the hands and feet.
- 5. Modern Methods of Measuring Blood Flow Electrocardiogram ECG Source: (USA Medical and Surgical Supplies, 2018) Holter Meter Source: (Johns Hopkins Medicine, 2019) • At an early age of minor cardiovascular issues and signs of initial heart malfunction, an electrocardiogram or ECG is a simple, fast, and common test used to diagnose and catch an overview of the problem. • It is a safe procedure that captures the electrical activity of the heart. • A Holter blood pressure device is worn by the patient for twenty-four hours. • If the increase in blood pressure readings is to rule out or confirm the diagnosis of hypertension .
- 6. What is impedance plethysmography? • A method that can measure plethysmography and identify the arterial pulse waveform is called bioelectrical impedance. this technique is collectively known as impedance plethysmography. • By infusing a minute amount of AC into the body and then detecting the potential caused by blood flow, it gauges changes in blood volume. Source: (Impedance Plethysmography (IPG) - Medis, n.d.)
- 8. Source: Ansari, S. (2013). Motion artifact reduction in impedance plethysmography signal. ProQuest Dissertations and Theses, 116
- 9. Motivation • Monitoring the blood flow device is not affordable for everyone. • Expensive devices need to be precise and close to accuracy for the patient, however, it is directly proportional to the price they pay. • Everyone especially diabetic patients can measure their existence if the blood flow at home. • When the blood flow stops this device will give a signal that you should go to a doctor immediately. • To make a Portable and wearable device that everyone can afford easily.
- 10. Literature Review • According to Isabel Morales’ research, the foot impedance plethysmography was carried out with two distinct kinds of electrodes, using 1mA/10kHz and finding the impedance of the foot. • In this study Piuzzi research is an ultimate technique selected that makes use of a current with a frequency of 50 kHz that is injected into the thorax of the subject using a couple of textile electrodes. • In this study of Ramkumar & Babu, blood flow was performed using a fuzzy logic toolbox with many different activities, measured before and after the 25 seconds of breath-holding activity. The plethysmographic waveform of forearm impedance can be used to analyze the changes in a heartbeat that are correlated with the changes in heart stroke volume. Source: Morales, I., Gonzalez-Landaeta, R., & Simini, F. . Pressure sensors used as bioimpedance plantar electrodes: A feasibility study. 2021 IEEE International Symposium on Medical Measurements and Applications,
- 11. Contribution • In this work we are investigating using multiple electrodes to see the additional data going to make testing easier. • Our research is primarily focusing on the amount of blood flow through the finger of the upper limb for diabetic patients.
- 12. COMSOL Multiphysics 5.6 • We are using COMSOL Model physics to investigate the tests. • The geometrical model of the test is on the 2D dimension. • In the COMSOL we are using electrical current physics and we are choosing the frequency domain.
- 13. Geometrical Model • This geometry model was constructed to demonstrate the internal structure of the forefinger. • Electrodes numbering 1,2,3 and 4 are attached to the surface of the forefinger. • This way it is easier for our software to detect the best frequency penetrated across the layers.
- 14. Frequency-Dependent Tissue Properties • The layers presented in the geometrical model namely: skin, fat, muscle, bone, and artery will produce different values at different frequencies. • A theoretical view of these values is shown. • Depicting permittivity and conductivity. The dielectric properties of tissues at different frequencies: (a) Electrical conductivity (S/m) (a) Electrical permittivity Source: (Tissue Frequency Chart » IT’IS Foundation, n.d.)
- 15. Simulation Results 0 100000 200000 300000 400000 500000 600000 700000 800000 900000 IMPEDANCE FREQUENCY ELECTRODE 1,2,3REAL(0%) z1 Z2 Z3 0 100000 200000 300000 400000 500000 600000 700000 800000 900000 IMPEDANCE FREQUENCY ELECTRODE 1,2,3REAL(15%) Z1 Z2 Z3 • When the heart is diastolic condition. • When the heart is systolic condition. Artery expands 15% of its original value, because when the heart pumps and supplies blood to the artery then the artery size will be expanded.
- 16. Simulation Results -6 -5 -4 -3 -2 -1 0 1 2 3 1 3.16227766 10 31.6227766 100 316.227766 1000 3162.27766 10000 31622.7766 100000 316227.766 1000000 3162277.66 10000000 3.16E+07 100000000 3.16E+08 1000000000 3.16E+09 1.00E+10 3.16E+10 1.00E+11 Impedance Frequency Electrode 1 (15%-0%) Real Part -4 -3 -2 -1 0 1 2 Impedance Frequency Electrode 2 (15%-0%) Real Part -4 -3 -2 -1 0 1 2 1 3.16227766 10 31.6227766 100 316.227766 1000 3162.27766 10000 31622.7766 100000 316227.766 1000000 3162277.66 10000000 3.16E+07 100000000 3.16E+08 1000000000 3.16E+09 1.00E+10 3.16E+10 1.00E+11 Impedance Frequency Electrode 3 (15%-0%) Real Part • The simulation result shows us that the output of electrodes 2 and 3 has given nearly the same values. Therefore, we would choose one out of electrodes 2 and 3.
- 17. Simulation Results • Finally, we took 100 Hz as the optimal frequency to get 1 as our result. -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 Impedance Frequency Electrode 1 -Electrode 2 (15%-0%)
- 18. Circuit Diagram Block Diagram of Position of electrodes top-bottom Block Diagram of Position of electrodes Side-bottom -6 -4 -2 0 2 4 6 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 Oscilloscope • We are using 4Vpp with respect to frequency 100Hz /10KHz. • We try to look at the changes in peak-to-peak voltages.
- 19. Physical Implementation • Visualization of the electrodes clipped on the forefinger. Top Bottom Side Bottom
- 20. Top-Bottom Results -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 Voltage Time Using 100Hz Frequency Using 10KHz Frequency -0.05 0 0.05 0.1 0.15 0.2 0 5 10 15 20 25 30 voltage Time • Resulting graphs of the top bottom with 100Hz and 10KHz.
- 21. Side-Bottom Result Using 100Hz Frequency -0.15 -0.1 -0.05 0 0.05 0.1 0 0.05 0.1 0.15 0.2 0.25 0.3 Voltage Time Using 10KHz Frequency -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 Voltage Time • Resulting graphs of the side bottom with 100Hz and 10KHz.
- 22. Conclusion • The finger-simplified model was created in model geometry. A framework made up of five parts was used to build the finger. (i.e., skin, fat, artery, muscle, and bone) • The study includes COMSOL simulation results compared with experimental results to obtain the optimum parameters for this technique. The COMSOL simulation uses 4 electrodes in different positions with a current of 10mA giving the optimal frequency of 100Hz. • It was shown that multiple electrodes can be useful in obtaining impedance change. • This is useful because signals can not be obtained from one pair, or to further support the results.
- 23. Conclusion • The study was performed under normal resting conditions where an experimental procedure was set up to measure the impedance response from the finger. • Experiment results were not conclusive as more sensitive impedance analyzers are required. • This research will be helpful to find out the heartbeat using impedance plethysmography.
- 24. References of Literature Review • Morales, I., González-Landaeta, R., & Simini, F. (2021). Bioimpedance plethysmography with capacitive electrodes and sole force sensors: Comparative trial. Journal of Physics: Conference Series, 2008(1). https://doi.org/10.1088/1742-6596/2008/1/012018 • Piuzzi, E., Pisa, S., Pittella, E., Podestà, L., & Sangiovanni, S. (2020). Wearable belt with built-in textile electrodes for cardio—respiratory monitoring. Sensors (Switzerland), 20(16), 1–15. https://doi.org/10.3390/s20164500 • Ramkumar, M., & Babu, C. G. (2017). A Comprehensive Analysis of Forearm Impedance Plethysmography for the Maximally Non Invasive Monitoring and Measurement of Heart Pumping Function. SSRN Electronic Journal, 1(2), 178–184. https://doi.org/10.2139/ssrn.2942416
- 25. Thank you