A digital instrument for venous muscle pump test

Photoplethsymography for non-invasive diagnostics

Abstract: Photo-plethysmo-graphy (PPG) is a noninvasive method of obtaining a signal proportional to blood volume changes using light. From the initial trials seven decades back, the PPG technique has grown leaps and bounds and today its application has become indispensible not only during surgical procedures but also in patient monitoring in critical care environment. This paper traces the path of advancement of this technique and highlights the research outcomes of an "Indo German" collaborative research between Indian Institute of Technology Madras, Chennai, India and Technical University (RWTH) Aachen, Germany funded by ministry of science (BMBF), Germany, Research projects funded by Department of Science and Technology and Department of Biotechnology, Government of India.

A Review of Photoplethysmography-based Physiological Measurement and Estimation, Part 1: Single Input Methods*

Abstract: Photoplethysmography can be used to estimate many physiological parameters based on features extracted from the measured waveform. Following the single parameter estimations that have been reviewed in part 1 of this paper, we here review methods where the waveform is used in conjunction with other measured physiological signals. Being a low-cost, non-invasive, and user friendly technique, many PPG-based physiological data extraction methods are being researched. The parameters reviewed that can be estimated using the PPG waveform plus additional inputs include cardiac output, blood pressure, venous function assessment, blood oxygen saturation, and fetal heart rate and fetal oxygen saturation. The different processing techniques, algorithms and methods are reviewed in addition to providing a comparison of results with the reference standards to validate the different methods. Future research considerations for each parameter estimation are also discussed. This paper could be helpful for future research on PPG based wearable devices for physiological multi-parameter estimations.

Automatic detection of the end of the Empting Maneuvers in venous muscle pump test

Abstract: Venous refilling time (VRT) can diagnose the presence of venous system diseases. In order to calculate the VRT it is necessary to determine the End of the Empting Maneuvers (EEM). The automation of this process has been identified as a difficult task. Some methods described previously have some difficulties that could be solved. This paper proposes a new method for the automatic detection of the EEM. The new proposed method was compared with other based on sound signals. The annotations made by two trained human observers on 41 photoplethysmography records, were also used as a reference for evaluating the methods. The presented method was more accurate, showing a performance comparable to the observers.

Approaches and Algorithms for Resource Management in OFDMA Access Mode: Application to Mobile Networks of New Generation

Abstract: The increased need for speed and mobility is the cause of the rapid evolution of mobile radio systems during the last decade. In mobile radio communication systems for broadband (e.g. UMTS, HSDPA, WiMax, LTE, … etc.), an intense research activity on optimization and radio resource management techniques (RRM Radio Resource Management) is conducted. Management and resource optimization are two themes dealt with separately. This study achieves two goals: achieving an overview of different methods and approaches for allocation of radio resources and focus on the optimization algorithms dedicated to the allocation of resources in the single cell case by deploying one of the most promising access technologies in terms of speed called OFDMA.

Photoplethysmography and its application in clinical physiological measurement.

Abstract: Photoplethysmography (PPG) is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue. It is often used non-invasively to make measurements at the skin surface. The PPG waveform comprises a pulsatile ('AC') physiological waveform attributed to cardiac synchronous changes in the blood volume with each heart beat, and is superimposed on a slowly varying ('DC') baseline with various lower frequency components attributed to respiration, sympathetic nervous system activity and thermoregulation. Although the origins of the components of the PPG signal are not fully understood, it is generally accepted that they can provide valuable information about the cardiovascular system. There has been a resurgence of interest in the technique in recent years, driven by the demand for low cost, simple and portable technology for the primary care and community based clinical settings, the wide availability of low cost and small semiconductor components, and the advancement of computer-based pulse wave analysis techniques. The PPG technology has been used in a wide range of commercially available medical devices for measuring oxygen saturation, blood pressure and cardiac output, assessing autonomic function and also detecting peripheral vascular disease. The introductory sections of the topical review describe the basic principle of operation and interaction of light with tissue, early and recent history of PPG, instrumentation, measurement protocol, and pulse wave analysis. The review then focuses on the applications of PPG in clinical physiological measurements, including clinical physiological monitoring, vascular assessment and autonomic function.

Design of Pulse Oximeters

Abstract: Normal oxygen transport (S A Clark). Motivation of pulse oximetry (D J Sebald). Blood oxygen measurement (J Farmer). Light absorbance in pulse oximetry (O Wieben). Light-emitting diodes and their control (B W J Bourgeois). Photodetectors and amplifiers (J S Schowalter). Probes (M V S Reddy). Electronic instrument control (K S Paranjape). Signal processing algorithms (S Palreddy). Calibration (J S Schowalter). Accuracy and errors (S Tungjitkusolmun). User interface for a pulse oximeter (A Lozano-Nieto). Applications of pulse oximetry (J B Ruchala). Glossary. Index.

Design of Pulse Oximeters (Medical Science Series)

Abstract: Design of Pulse Oximeters is the latest in IOPPs Medical Science Series, the official book series of IFMBE and IOMP. The book is edited by Professor John Webster from the University of Wisconsin who has a substantial international reputation in bioengineering for producing lucid text books. With this sort of pedigree I looked forward to reviewing it. I was not disappointed. This is an excellent book, comprehensive, up-to-date and to be recommended to anyone involved in detailed use of pulse oximetry data or developing pulse oximetry techniques themselves. The first three chapters set the scene. The book starts with the physiology of oxygen transport itself and moves on to consider why the measurement is made and to set it in the context of blood oxygen measurement in general. This start gives the book firm roots which reduces the chance of the reader losing track of the physiological or diagnostic reasons for pursuing the detailed technical methods reported in the following chapters. After a chapter on the details of light absorption in blood and tissue that describes all the relevant physical limitations to the method, the book launches into detailed discussion of electronic design, signal processing, instrument control and probe design. The last few chapters are concerned with calibration, accuracy, user interface design and applications. The chapter on user interface design is particularly welcome. It is very easy for designers of equipment to lose sight of this aspect of design in instruments that will be used in environments where bad interface design can have a deleterious effect on human factors performance. Throughout the book instructional objectives are given for each chapter and the bibliographies of the majority of chapters are long enough to give students using the book starting points for further reading. From a teaching point of view the book could be used as an extended, in-depth case study of the implementation of a physiological measurement technology. It is a pity that the price of £60.00 in the UK will make it difficult to make the book compulsory in post-graduate physiological measurement courses.