[01] Hemanshu R. Pota, School of Engineering & IT, the University of New South Wales, Canberra BC, Australia. [02] Rajeev Ramakrishna, Graduate School of Medicine, the University of Wollongong, Wollongong, Australia.

This note describes the design of a flexible pressure controller used in a multi-chamber portable therapeutic device. The device presents many novel features. There is a complete flexibility in setting the pressure profile for each of the chambers according to the needs of individual patients. The device is programmable via a personal computer and a USB interface. The design is optimised for power use and can be run on a battery for over a thousand cycles. The set pressure profile is tracked using a continuous pressure feedback and a proportional-derivative-integral controller. This paper also includes patient data to show the effectiveness of this multi-chamber device. The tests on the patients were conducted using a prototype built using the design described in this paper.

Chronic Venous Disorder (CVD), Intermittent Pneumatic Compressor (IPC), Deep Vein Thrombosis (DVT), Feedback Control, Pressure Sensing

[01] K. J. Astrom, C.C. Hang, P. Persson, and W.K. Ho. Towards intelligent PID control. Auto- matica, 28(1):1–9, 1992. [02] Karl Johan Astrom and Richard M. Murray. Feedback Systems: An Introduction for Scien- tists and Engineers. Princeton University Press, NJ 08540 USA, 2008. [03] J. C. Doyle, B. A. Francis, and A. R. Tannenbaum. Feedback Control Theory. Maxwell Macmillan International, Sydney, 1992. [04] C. A. Desoer and M. Vidyasagar. Feedback Systems: Input-Output Properties. Academic Press, New York, 1975. [05] J. D. Milic. Chronic venous disease. Medicographia, 33:253–258, 2011. [06] R. J. Morris. Intermittent pneumatic compression - systems and applications. J Medical Engineering Technology, 32(3):179–188, 2008. [07] Nicolaides, A. N., Allegra, C., Bergan, J., Bradbury, A., Cairols, M., Carpentier, P., Taft, A. (2008). Management of chronic venous disorders of the lower limbs guidelines according to scientific evidence. International Angiology, 27(1), 1-59. [08] Yung-Wei Chi, Marlin Schul, Kathleen Gibson, Mel Rosenblatt, Lowell Kabnick, and Michael Jaff. Chronic venous disorder registry: A new perspective. Phlebology August 2014 29: 415-427, doi: 10.1177/0268355513484143. [09] Amsler, F. & BlÃttler, W. (2008), 'Compression Therapy for Occupational Leg Symptoms and Chronic Venous Disorders †“a Meta-analysis of Randomised Controlled Trials', European Journal of Vascular and Endovascular Surgery 35(3), 366-372. [10] Eklof, B.; Perrin, M.; Delis, K. T.; Rutherford, R. B. & Gloviczki, P. (2009), 'Updated terminology of chronic venous disorders: The VEIN-TERM transatlantic interdisciplinary consensus document', Journal of Vascular Surgery 49(2), 498-501. [11] Raju, S. (2014), 'Deep Veins: From Valve Surgery to Iliac Stents: The Journey and the Future', Indian Journal of Vascular and Endovascular Surgery 1(1), 14-15. [12] CE Davies, G Woolfrey, N Hogg, J Dyer, A Cooper, J Waldron, R Bulbulia, MR Whyman, and KR Poskitt. Maggots as a wound debridement agent for chronic venous leg ulcers under graduated compression bandages: a randomised controlled trial. doi: 10.1177/0268355514555386. [13] Radak Djordje, Ilijevski Nenad, Kolar Jovo, Sagić Dragan, Antonić Želimir, Tanasković Slobodan, Aleksić Nikola, Babić Srdjan, and Otašević Petar. Incidence and distribution of extravascular compression of extracranial venous pathway in patients with chronic cerebrospinal venous insufficiency and multiple sclerosis. Phlebology August 2014 29: 476-479, doi: 10.1177/0268355513486638. [14] C. A. Desoer and M. Vidyasagar. Feedback Systems: Input-Output Properties. Academic Press, New York, 1975. [15] J. D. Milic. Chronic venous disease. Medicographia, 33:253–258, 2011. [16] R. J. Morris. Intermittent pneumatic compression - systems and applications. J Medical Engineering Technology, 32(3):179–188, 2008.