Biomedical subjects

Manuel Prado

Publications and source records attributed to Manuel Prado.

10 recordsLinked to original sources

PubMed2006

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 PPI's 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.

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PubMed2006

Methodological issues for the information model of a knowledge-based telehealthcare system for nephrology (Nefrotel).

Several studies point out the paradox that classic telemedicine by which doctor interacts remotely with patients in real-time is disappearing despite it has not been widely adopted yet. Many cues indicate that health information technologies will be finally adopted because of the growth in health expenditure and the emerging healthcare challenges. Notwithstanding, a detailed analysis of the referred concern has led us to propose a shift in the paradigm of telemedicine systems. This paper presents the major methodological issues of the information model of a novel telehealthcare system for nephrology (Nefrotel) which supports the cited shift in the paradigm. With this objective, we first revise the technological requirements of the database of Nefrotel, and second analyze the current scenario of health information model standards. Our study has shown that it is possible to ensure the compliance and evolution of Nefrotel with information model standards, maximizing its interoperability.

Computer Communication Networks↗

PubMed2005

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. Milan, Ann. Biomed. Eng. (2004) submitted].

Blood Chemical Analysis↗

PubMed2005

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.

Animals↗

PubMed2005

Double target comparison of blood-side methods for measuring the hemodialysis dose.

BACKGROUND: Despite the fact that urea kinetic modelling has been successfully applied to quantify the hemodialysis since the beginning of the 1980s, there is not a consensus yet concerning which is the most proper dialysis dose index and the method for calculating it. In this work, we propose that a combined measurement of the dialysis dose from two complementary perspectives of the removal process should provide a more complete description of dialysis than a measurement alone. This hypothesis is reviewed and the measuring methods are compared. METHODS: A cross-sectional randomized clinical study over 98 stable ESRD patients submitted to thrice-weekly hemodialysis was carried out with the aim of comparing 16 blood-side methods for measuring the hemodialysis dose from patient and dialyzer perspectives. The availability of urea rebound measurements and computational resources have been taken into account. RESULTS: The outcomes point to four novel blood-side methods as the most accurate for measuring the effective dialysis system Kt/V (mKt/V) in clinical conditions. Their limits of agreement (mean +/- 2.SD) range from 1.93 +/- 2.09% for a non-iterative method without the urea rebound measurement (BUN3) to -0.08 +/- 0.58% for an iterative method with BUN3. The best non-iterative blood-side method for measuring the equilibrated Kt/V (eKt/V) is the second generation formula of Daugirdas (-2.42 +/- 1.05%) when BUN3 is available and the rate equation of Daugirdas and Schneditz (-1.74 +/- 7.91%) when BUN3 is not available. The difference mKt/V-eKt/V is significant and positive, and increases with the dialysis dose in a personalized manner. CONCLUSION: We have confirmed the arguments that support the hypothesis of the study. The best blood-side methods for the combined measurement of dialysis dose as a function of the available resources have been determined.

Adult↗

PubMed2005

Hybrid and customized approach in telemedicine systems: an unavoidable destination.

Several important problems in the majority of industrialized countries have challenged the centralized and overburdened current model of healthcare. Telehealthcare systems are presented as a new paradigm, offering high expectations to provide effective solutions to this picture. With this paper we present a new methodological approach for telehealthcare systems that pursues the generation of clinical and physiological knowledge of the patient in a real time and personalized manner. This approach is based on a computational component, identified as patient physiological image (PPI), which is responsible for generating an image of the state of the patient and therapy devices. Three key issues of the proposed methodological approach are evaluated. With the objective to validate the capability of the PPI to determine the internal state of a patient, a digital simulation experiment over the mathematical model of a PPI is done. Numerical results are compared to those obtained by a validated mathematical model. Secondly, a laboratory prototype of a novel human physical activity monitor that follows the designed methodological approach will be tested, in order to evaluate the trade-off between processing capacity, portability, and cost-efficiency and power consumption, which are necessary to assure its compliance with the methodology. As a third key issue, the capability of our methodology to integrate physiological information belonging to different scales is analyzed. This is done by means of a case study related to the integration of the regulation of water function of AQP2 channels (genomic, proteomic and cellular levels) into a kidney collecting duct epithelium mathematical model of a PPI. The analysis and preliminary evaluation of the proposed telehealthcare methodological approach, featured by an advanced personalization of health assistance, have been satisfactory.

Delivery of Health Care↗

PubMed2004

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.

Blood Urea Nitrogen↗

PubMed2004

The role of urea kinetic modeling in assessing the adequacy of dialysis.

The adequacy of dialysis based on urea kinetic modeling has more than 20 years of history. Its methodological approach has demonstrated a strong capacity to improve the outcomes of the dialysis therapy. However, recent results of clinical interventional studies and necessary advances in new models of dialysis schemes, particularly daily and nocturnal hemodialysis, have led to the question if whether that methodology is suitable to address current challenges. This work tries to reach an answer to that question. The major conclusion is that urea kinetic modeling provides an extraordinary starting point to both keeping the clinical support to physicians and building new pharmacokinetic and physiological models that throw light on the understanding of the basic mechanisms that underlie the chronic renal disease, in a synergetic manner. Despite this promising expectation, misuse and improper extensions of urea kinetic modeling may jeopardize its credibility to nephrologists. Our concern about this issue emerges mainly from the analysis of recent attempts to extend this methodology to more frequent renal replacement therapies.

Computer Simulation↗

PubMed2003

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 patient's 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.

Adult↗

PubMed2002

Virtual center for renal support: technological approach to patient physiological image.

The patient physiological image (PPI) is a novel concept which manages the knowledge of the virtual center for renal support (VCRS), currently being developed by the Biomedical Engineering Group of the University of Seville. PPI is a virtual "replica" of the patient, built by means of a mathematical model, which represents several physiological subsystems of a renal patient. From a technical point of view, PPI is a component-oriented software module based on cutting-edge modeling and simulation technology. This paper provides a methodological and technological approach to the PPI. Computational architecture of PPI-based VCRS is also described. This is a multi-tier and multi-protocol system. Data are managed by several ORDBMS instances. Communications design is based on the virtual private network (VPN) concept. Renal patients have a minimum reliable access to the VCRS through a public switch telephone network--X.25 gateway. Design complies with the universal access requirement, allowing an efficient and inexpensive connection even in rural environments and reducing computational requirements in the patient's remote access unit. VCRS provides support for renal patients' healthcare, increasing the quality and quantity of monitored biomedical signals, predicting events as hypotension or low dialysis dose, assisting further to avoid them by an online therapy modification and easing diagnostic tasks. An online therapy adjustment experiment simulation is presented. Finally, the presented system serves as a computational aid for research in renal physiology. This is achieved by an open and reusable modeling and simulation architecture which allows the interaction among models and data from different scales and computer platforms, and a faster transference of investigation models toward clinical applications.

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