Group 38: Karthik Krishnan, Matthew Everett, Satish Chandrasekhar

PROGRESS REPORT: BLOOD PRESSURE MONITORING IN LOW

RESOURCE SETTINGS

NEED• Hypertension as a predictor for more serious CV disease

• Underdiagnosis

• India: 16% of adults

• US: 6% of adults

• Limiting factors

• Cost

• Speed

• Training

SCOPE• Safe, rapid screening of blood pressure

• Aimed at low resource settings in the US and India

• Administered by healthcare workers without significant medical training

• Adaptation of current technologies

DESIGN SPECIFICATIONSSpecification Target

Cost <$100

Speed <20 seconds

Ease of use • No medical training needed• Direct output of data: no interpretation on part of user• Storage of data for 100+ patients

Portability <2.27 kg (5 lbs)

Reusability • All components reusable• Components should be able to handle 5 years of use

Accuracy ±5 mmHg relative to LC300 clinical monitor

DIRECT METHODS OF MEASUREMENT

• Auscultatory

• Most commonly used

• Stethoscope/sphygmomanometer

• Korotkoff sounds

• Vascular unloading

• Relies on photoplethysmography

• Feedback loop to determine BP

Figure 2. Photoplethysmography with VUT [27]

Figure 1. Auscultatory BP Measurement [29]

DERIVED METHODS• Oscillometric

• Common for public/personal use

• Output is mean arterial pressure

• Pulse wave velocity

• Usually measures arterial stiffness

• Derive blood pressure through modeling arteries as pipes

Figure 3. Oscillometric Pressure Identification [34]

ANALYSIS OF MEASUREMENT METHODS

Specification Weight Auscultatory Oscillometric PWV CannulationVascular

Unloading

Ease of use 10 3 10 8 1 8

Speed 9 6 6 9 2 8

Cost 7 10 5 8 3 7

Portability 7 10 8 9 5 8

Reusability 7 10 10 10 3 10

Accuracy 5 8 6 6 10 8

Total   334 345 380 155 374

OUTPUT INTERFACE• Smartphone output

• Android

• iOS

• Digital interface

• Low cost

• Customizable

• Analog output

• Pressure gauge

• Possibility for bias

• Interpretation required

ANALYSIS OF OUTPUT INTERFACES

Specification Weight iOS Android Custom Digital Analog

Ease of use 10 9 9 7 4

Speed 9 7 7 8 8

Cost 7 2 5 6 8

Reusability 6 10 10 10 10

Accuracy* 5 9 9 8 7

Total   272 293 284 263*Based on ability to filter

inputs

POWER

• Replaceable batteries

• Solar power

• AC Charging

• USB HostFigure 4. USB Host power for external devices [5]

ANALYSIS OF POWER SOURCES

Specification WeightAlkaline Batteries AC Power Solar Power USB

Ease of use* 10 7 8 6 9

Speed** 9 10 7 3 5

Cost 7 3 6 5 6

Portability 7 10 6 10 8

Reusability 7 5 10 10 10

Accuracy*** 5 0 0 0 0

Total   296 307 272 303

*Reflects convenience as well

**Charging speed

***Not affected by power source

FINAL DESIGN• Pulse wave velocity measurement

• Android smartphone output

• USB Bridge

Figure 5. Pulse Wave Velocity Measurement [35]

REFERENCES1. "7-Segment Single Digit Display." - Lite-On Inc. N.p., n.d. Web. 23 Oct. 2014.

2. "Android's Market Share in India over 90%: IDC - The Times of India." The Times of India. N.p., n.d. Web. 23 Oct. 2014.

3. "Arduino - ArduinoBoardBT." Arduino - ArduinoBoardBT. N.p., n.d. Web. 23 Oct. 2014.

4. "WT11i Bluetooth Class 1 Module." – Bluegiga. N.p., n.d. Web. 23 Oct. 2014.

5. Android. "USB Host." Android Developers. Android, n.d. Web. 23 Oct. 2014. <http://developer.android.com/guide/topics/connectivity/usb/host.html>.

6. HardwareBook. "Universal Serial Bus (USB)." - HwB. Hardware Book, n.d. Web. 23 Oct. 2014. <http://www.hardwarebook.info/Universal_Serial_Bus_%28USB%29>.

7. Learning About Electronics. "How to Build a DC Power Supply." How to Build a DC Power Supply. Learning About Electronics, n.d. Web. 23 Oct. 2014. <http://www.learningaboutelectronics.com/Articles/How-to-build-a-DC-power-supply.php>.

8. Mohankumar, D. "Solar Charger for 6V Battery." Solar Charger Circuit for 6V Battery. ElectroSchematics, n.d. Web. 23 Oct. 2014. <http://www.electroschematics.com/4746/solar-charger-circuit/>.

9. O’Brien, E.; Petriel, J.; Littler, W.; de Swiet, M.; Padfield, P.L.; Altman, D.G.; Brand, M.; Coats, A.; Atkins, N. The British Hypertension Society protocol for the evaluation of blood pressure measuring devices. J. Hypertens. 1993, 11, S43–S62.

10. Pickering, T.G.; Blank, S.G. Blood Pressure Measurement and Ambulatory Blood Pressure Monitoring. In Hypertension: Pathophysiology, Diagnosis and Management; Laragh, J.H., Brenner, B.M., Eds.; Raven Press: New York, NY, USA, 1990; p. 89.

11. Pickering, T.G.; Hall, J.E.; Appel, L.J.; Falkner, B.E.; Graves, J.; Hill, M.N.; Jones, D.W.; Kurtz, T.; Sheps, S.G.; Roccella, E.J. Recommendations for blood pressure measurement in humans and experimental animals, Part1: Blood pressure measurement in humans: A statement for professionals from the subcommittee of professional and public education of the American Heart Association council of high blood pressure research. Hypertension 2005, 45, 142–161.

12. X. F. Teng , Y. T. Zhang, “Continuous and Noninvasive Estimation of Arterial Blood Pressure Using a Photoplethysmographic Approach,” Proceedings of the 25* Annual lnlematianal Conference of the IEEE EMBS, Sep 2003

REFERENCES13. Joshi, Shashank R., Banshi Saboo, et. al. "Prevalence of Diagnosed and Undiagnosed Diabetes and Hypertension in India—Results from the

Screening India's Twin Epidemic (SITE) Study." Diabetes Technology & Therapeutics 14.1 (2012): 8-15. Web.

14. Yoon, Sung S., Vicki Burt, Tatiana Louis, and Margaret D. Carroll. "Hypertension Among Adults in the United States, 2009–2010."Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 02 Oct. 2012. Web. 19 Sept. 2014.

15. NIH. "What Is High Blood Pressure?" What Is High Blood Pressure?NHLBI, NIH, 2 Aug. 2012. Web. 19 Sept. 2014.

16. Janusz Kaczorowski, PhD, Martin Dawes, MB, BS, MD, FRCGP, Mark Gelfer, MD. Measurement of blood pressure: New developments and challenges. BCMJ, Vol. 54, No. 8, October, 2012, page(s) 399-403 — Articles.

17. Ogedegbe, Gbenga, and Thomas Pickering. "Principles and Techniques of Blood Pressure Measurement." Cardiology Clinics 28.4 (2010): 571-86. Web.

18. "Arterial Tonometry for Blood Pressure Measurement." Research & Development in Computing, Education, Biosciences, Chemistry, Earth & Space, Security & Defense, Sensing & Devices. N.p., n.d. Web. 23 Oct. 2014.

19. "Medscape Log In." Medscape Log In. N.p., n.d. Web. 23 Oct. 2014.

20. Nelson, M. R., J. Stepanek, M. Cevette, M. Covalciuc, R. T. Hurst, and A. J. Tajik. "Noninvasive Measurement of Central Vascular Pressures With Arterial Tonometry: Clinical Revival of the Pulse Pressure Waveform?" Mayo Clinic Proceedings 85.5 (2010): 460-72. Web.

21. Ragot, S. "Comparison of Three Blood Pressure Measurement Methods for the Evaluation of Two Antihypertensive Drugs: Feasibility, Agreement, and Reproducibility of Blood Pressure Response." American Journal of Hypertension 13.6 (2000): 632-39. Web.

22. "Sentry Health Monitors LC 300." Sentry Health Monitors LC 300. N.p., n.d. Web. 23 Oct. 2014.

23. Sesso, H. D., M. J. Stampfer, B. Rosner, C. H. Hennekens, J. M. Gaziano, J. E. Manson, and R. J. Glynn. "Systolic and Diastolic Blood Pressure, Pulse Pressure, and Mean Arterial Pressure as Predictors of Cardiovascular Disease Risk in Men." Hypertension 36.5 (2000): 801-07. Web.

REFERENCES24. Rajzer, Marek W., Wiktoria Wojciechowska, Marek Klocek, Ilona Palka, Małgorzata Brzozowska-Kiszka, and Kalina Kawecka-Jaszcz. "Comparison

of Aortic Pulse Wave Velocity Measured by Three Techniques: Complior, SphygmoCor and Arteriograph." Journal of Hypertension 26.10 (2008): 2001-007. PubMed. Web.

25. Allen, John. "Photoplethysmography and Its Application in Clinical Physiological Measurement." Physiological Measurement 28.3 (2007): R1-R39. Web.

26. Doshi, Hardik, Alan B. Weder, Robert L. Bard, and Robert D. Brook. "Does “Hidden Undercuffing” Occur Among Obese Patients? Effect of Arm Sizes and Other Predictors of the Difference Between Wrist and Upper Arm Blood Pressures." The Journal of Clinical Hypertension 12.2 (2010): 82-88. Web.

27. Bondi. Vascular Unloading. Digital image. Vascular Unloading. N.p., n.d. Web. <http://en.wikipedia.org/wiki/Continuous_noninvasive_arterial_pressure#mediaviewer/File:Vascaular_unloading.png>.

28. Khandoker, A.H.; Black, J.; Palaniswami, M., "Smartphone-based low cost oximeter photoplethysmography," Electrical and Computer Engineering (ICECE), 2010 International Conference on , vol., no., pp.634,637, 18-20 Dec. 2010 doi: 10.1109/ICELCE.2010.5700773

29. Auscultatory Blood Pressure Measurement. Digital image. N.p., n.d. Web. <http://o.quizlet.com/3b21ZF2ZI7o.daAvcfwr3Q_m.png>.

30. Asif-Ul-Hoque, M.; Ahsan, M.S.; Mohajan, B., "Measurement of Blood Pressure Using Photoplethysmography," Computer Modelling and Simulation (UKSim), 2011 UkSim 13th International Conference on , vol., no., pp.32,35, March 30 2011-April 1 2011 doi: 10.1109/UKSIM.2011.16

31. "Piezo Element." - SEN-10293. N.p., n.d. Web. 23 Oct. 2014. <https://www.sparkfun.com/products/10293>.

32. "7 Series Wrist Blood Pressure Monitor." Omron Healthcare. N.p., n.d. Web. 24 Oct. 2014. <http://omronhealthcare.com/products/7-series-wrist-blood-pressure-monitor-bp652/>.

33. Ancillare. "BpTRU - BPM-100 Clinical Blood Pressure Monitors." BpTRU - BPM-100 Clinical Blood Pressure Monitors. Ancillare, 2011. Web. 19 Sept. 2014. <http://ancillare.com/bptru/products.html#bpm_100>.

34. Oscillometric BP Measurement. Digital image. N.p., n.d. Web. <http://web.squ.edu.om/med-Lib/MED_CD/E_CDs/anesthesia/site/content/figures/3030F03.gif>.

35. Pulse Wave Velocity Measurement. Digital image. N.p., n.d. Web. <http://www.mirow.de/main/project/medic/mediwave/messschem_en.gif>.