Manuel Prado

Distributed intelligent architecture for falling detection and physical activity analysis in the elderly

A novel approach for the detection of falls, the analysis of body postures, mobility and metabolic energy expenditure of elderly people has been developed. It is based on a distributed intelligence architecture, supported by it wireless personal area network (WPAN) which allows a full 24-hour supervision of the user, both indoor and outdoor home. An open design methodology lets the addition of new sensors for the on-line monitorization or other biosignals. In this paper general guidelines and design issues are reported, with special emphasis on the Intelligent Accelerometer Unit (IAU), based on a four-axis accelerometer, the signals of which are transmitted to the WPAN server (PSE) for on-line processing. The availability of three axis in the median plane provides an inclination measurement with high sensibility. The IAU can be worn like a patch, fixed to the back, at the height of the sacrum. A prototype of the IAU is currently under validation phase, in order to optimize signal transmission between IAU and PSE.

Preliminary evaluation of a full-time falling monitor for the elderly

The article presents the early outcomes of the evaluation of an intelligent accelerometer unit (IAU) utilized for detecting the falling events of elderly people . The overall design of the monitor where the IAU is integrated is briefly exposed. The outcomes of a laboratory study carried out over 8 volunteers show that the device is able to distinguish true falling events from normal activities like fast walking or going up/downstairs. The influences of the subject and the environment have been taken into account profiting from the processing capacity of the monitor distributed architecture.

Viability study of a personalized and adaptive knowledge-generation telehealthcare system for nephrology (NEFROTEL).

OBJECTIVES Several important problems in the majority of countries are challenging the centralized and overburdened current model of healthcare. Telehealthcare is presented as a new paradigm that offers high expectations to solve this picture. In this paper we present the major outcomes of the viability study of a novel personalized telehealthcare system for nephrology (NEFROTEL). METHODS The study evaluates the accuracy and quality of the knowledge generated by two key processing layers, namely, sensor layer and patient physiological image (PPI) layer, in an independent way, thanks to its modular design. The first one was defined by a personalized falling detection monitor, on account of the consequences of falls in chronic renal patients. The second one was analyzed by means of a PPIs prototype based on a urea compartmental pharmacokinetic model. The experimental study of the falling detector monitor has been more extensive than the other because the latter has already been addressed in other works. RESULTS The outcomes show, firstly, the capability of the PPIs to provide integrated and correlated physiological knowledge adapted to each patient, and secondly, demonstrate the reliability of the impact detection function of the adaptive human movement monitor compliant with the NEFROTEL paradigm. CONCLUSIONS The study confirms that NEFROTEL is able to provide knowledge concerning a patient in a manner that cannot be accomplished by the ordinary healthcare model at the present time.

A novel mathematical method based on urea kinetic modeling for computing the dialysis dose

A novel normalized single pool urea kinetic model (nspUKM) for the quantification of the urea removal, dialyzer urea clearance and urea generation rate during a dialysis session, is presented. Its major goal is the computation of an accurate estimate of the fractional dialyzer urea clearance (dKt/V), which is denoted nKt/V, in contrast to the equilibrated Kt/V (eKt/V). This work clarifies the significance of dKt/V as a complement to eKt/V in hemodialysis (HD) prescription and quantification. This new model emerges from a generalization of the standard single pool urea kinetic model (spUKM) of the US National Cooperative Dialysis Study (NCDS), identified as gspUKM. Due to their significance, the standard single pool Kt/V (spKt/V) and the eKt/V are also analyzed from gspUKM in this work, with the aim of achieving a better interpretation of the results. Indices nKt/V, eKt/V and spKt/V have been compared with the dKt/V computed from a published and validated two-pool urea kinetic model (2pUKM). We present the results obtained from a clinical study carried out on a group of 30 end stage renal disease (ESRD) patients. The limits of agreement (mean+/-2S.D. (standard deviation) of the difference) between nKt/V and 2pKt/V were -0.077+/-0.72% (percentage of the dKt/V mean), while between eKt/V and 2pKt/V were -13.75+/-17.39% and between spKt/V and 2pKt/V were -1.61+/-6.54%. These scores prove that the nspUKM model is able to provide a very accurate estimate of 2pKt/V and thus dKt/V, even with high flux (HF) HD. The presented method joins the simplicity of single-pool models to the accuracy of double-pool models, when the target is the identification of the dialyzer urea clearance, urea removal and urea generation rate, although it does not provide a good prediction of the urea dynamics. Finally, we think that our analytical and experimental findings throw light on the behavior and applicability of the different Kt/V indices analyzed.

Renal Telehealthcare System Based on a Patient Physiological Image: A Novel Hybrid Approach in Telemedicine

This paper presents a novel renal telemedicine system, Virtual Center for Renal Support (VCRS), focused on the end-stage renal disease (ESRD) population. The VCRS design modifies the telemedicine paradigm, currently centered on communication technologies and monitoring devices, by emphasizing the way that biosignals are used to extract on-line knowledge to be used by physicians to solve current needs of this population. We begin with an ESRD review, from which a summary of major limitations of current renal health assistance programs is obtained. This is used to form the basis for the VCRS. This work is focused on a theoretical description of the technological architecture of VCRS, followed by a simulation experiment showing some preliminary results from a prototype of a patient physiologic image (PPI) computer component, the major knowledge creator of VCRS. Preliminary results show that PPI technology provides the ability to supervise internal variables representing the patients dynamic behavior. The demonstrated relation between adequate control of extracellular volume and blood pressure suggests that VCRS is able to generate hypovolemia warnings before their occurrence during a hemodyalysis session delivered remotely. However, PPI is not restricted to kinetic models, which were initially chosen because of their successful results in the provision of dialysis. Preliminary results suggest the ability of this telemedicine system to enhance remote patient supervision and care.

Design of antennas for a wearable sensor for homecare movement monitoring

This paper is focused on the discussion of different trade-offs that frequently arise when selecting the appropriate antenna technology for a wireless sensor for home-care applications, and the implications that every decision represents for the overall design. In order to devise an optimum design strategy, the main methodological concerns are illustrated with the example of a wearable movement monitor. The selection of a suitable air interface is based on the comparison among different standards for low-cost, low-power wireless communication devices, and a patch antenna is designed from scratch. Results obtained by simulation show that this design meets all the requirements in terms of shape, size, antenna performance and cost-efficiency, validating the followed approach

Home health telecare and the elderly in Spain: technologies involved and methodological issues

We try to develop a pilot experience in home care teleservices to the elderly through the investigation of solutions based on the application of information technologies and communications. To that end, an individualized attendance to each elderly person will be supplied, which will comprise from the monitoring of certain biological variables, diagnosis and processing, to the advising to his/her family. In addition, a customized service will be offered, not only in the healthcare field, but also at a technological level.

Wearable human movement monitoring device aimed at providing personalized support in healthcare

This paper presents a wearable human movement monitor designed within the context of a telehealthcare system for the elderly. One major characteristic of this device is the capability for an on-line personalization to the user. This capability compels to a trade-off among processing capacity, portability, low cost and power consumption, which are necessary to assure its feasibility. We have performed a preliminary laboratory study to assess the influence of the customization capacity in the reliability of the device for capturing falling events. The study was based carried out over 8 voluntaries and demonstrated that the device is able to distinguish true falling events from normal activities like fast walking or going up/downstairs. Moreover, our outcomes indicate that the subject and the environment have a critical influence on the reliability of the falling detection. This result underlines the importance of providing personalized support in telehealthcare.

Improving hollow fiber dialyzer efficiency with a recirculating dialysate system I : Theory and applicability

The mathematical theory that underlies a novel non-regenerated recirculating dialysate system (RDS) for improving diffusive clearance in hemodialyzers is presented. The theory states the conditions that hemodialyzers must meet to be suitable in RDS optimization. We have verified the applicability of the RDS for several Cuprophan and polysulfone (PS) commercial dialyzers, showing that PS (synthetic) membranes achieve the highest increments of diffusive clearance. A numerical simulation analysis over more general conditions defined by the dimensionless groups of the system demonstrated that the highest diffusive clearance improvements are achieved in dialyzers operating with a low value of the diffusive mass-transfer area/blood flow rate ratio. This study has provided the base for the assessment of the performance of the RDS as compared to several high-efficiency systems, presented in Part II of this work [M. Prado, L. M. Roa, A. Palma, and J. A. Milán, Ann. Biomed. Eng. (2004) submitted].

Improving Hollow Fiber Dialyzer Efficiency with a Recirculating Dialysate System II: Comparison Against Two-Chamber Dialysis Systems

The theoretical basis of the nonregenerated recirculating dialysate system (RDS) was derived in Part I of this work [M. Prado, L. M. Roa, A. Palma, and J. A. Milán, Ann. Biomed. Eng. (2005)]. This system pursues the maximization of the clearance of hollow fiber dialyzers whose performance is controlled by diffusion, as occurred in standard hemodialysis. In this second part we perform a comparison by digital simulation of the RDS against three well-known two-chamber dialysis systems. As a major outcome, the efficiency of the RDS increased by a factor of five–eight with respect to the efficiency of a single dialyzer operating with a number of transfer units equal to 0.1, that is when the diffusive mass-transfer of the dialyzer is exhausted. Present low-flux dialyzers do not take advantage of the full potential of this technique, but the functional domain where high-flux and high-area dialyzers operate could be more suitable to exploit this technique. We conclude that RDS can be a competitive efficient technique for optimizing the dialysis efficiency.