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The validation of a blood flow meter is presented. This flow meter is based on the transit time method that uses two ultrasound transducers and a reflector. The measuring is based on the time difference of the upstream and the downstream ultrasound transit time. The validation was based on the norm ANSI Std. N42.17A-2003 of blood flow protocol. We used a flow simulator system with 3 mm pipe, bi-distilled...
This work proposes a new theoretical framework for the water transport in the cerebral environment. The approach is based on Multiple-Network Poroelastic Theory (MPET) and is a natural extension of poroelasticity, a well reported technique applied to cerebrospinal fluid (CSF) transport. MPET accounts for the transport of CSF and blood simultaneously, as they permeate and deform the cerebral tissue...
Small calibre (<;;6mm) polytetrafluoroethylene (PTFE) bypass grafts have poor medium and long term patency due to the development of neointimal hyperplasia at the distal anastomosis. The inelasticity of PTFE is implicated in this mechanism of failure. We have developed a novel polyhedral oligomeric silsesquioxane (POSS) nanocage incorporated into a poly(carbonate)urethane (PCU) biomaterial with...
A smart miniaturized system is being proposed for the isolation and characterization of circulating tumor cells (CTCs) directly from blood. Different microfluidic modules have been designed for cell enrichment and -counting, multiplex mRNA amplification as well as DNA detection. With the different modules at hand, future effort will focus on the integration of the modules in a fully automated, single...
In this study, a new portable type Self-Monitoring Blood Glucose (SMBG) device, which is driven automatically from the blood sampling to the blood glucose measurement, is developed to establish the point-of-care technology in the ubiquitous medical care. It aims to overcome human errors due to the complicated manual operation of commercial SMBG devices. In this study, I mainly discuss the development...
Long term extracorporeal membrane oxygenation can be used in cases of severe lung failure to maintain sufficient gas exchange without the need to apply higher ventilation pressures which damage the lung additionally. The use of cardiopulmonary bypass devices is well established inside the operating room. The usage of such devices as long-term support in the intensive care unit is still experimental...
An image-based red blood cell (RBC) automatic counting system is presented for wild animals blood analysis. Images with 2048×1536-pixel resolution acquired on an optical microscope using Neubauer chambers are used to evaluate RBC counting for three animal species (Leopardus pardalis, Cebus apella and Nasua nasua) and the error found using the proposed method is similar to that obtained for inter observer...
This paper presents two alternative approaches to characterize the pharmacodynamics of propofol anesthesia in children, using State Entropy as a clinical end point. The first approach is the traditional approach where the pharmacodynamic model is described in terms of an effect-site equilibration rate constant and the Hill equation. In the second approach (the monitor-decoupled approach) the dynamics...
Deep body temperature reveals individual physiological states, and is important in patient monitoring and chronobiological studies. An innovative dual-heat-flux method has been shown experimentally to be competitive with the conventional zero-heat-flow method in its performance, in terms of measurement accuracy and step response to changes in the deep temperature. We have utilized a finite element...
This paper presents the changes in the electrical variables induced in a 3D thigh model with femoral diaphyseal fracture when it is magnetically stimulated. Three cases with particular geometries of the models were considered: skin, muscle, cortical bone (CB), bone marrow, metal pin, and fracture shape. Fracture shape included electric properties for blood, cartilage, trabecular bone (TB), and cortical...
The aim of this study is to model the blood glucose metabolism of type 1 diabetic patients using free-living data. The proposed method considers the effect of diet, medication and exercise on blood glucose levels. Compartmental models are used to quantify the absorption of subcutaneously administered insulin, the absorption of glucose from the gut following a meal, as well as the effects of exercise...
This paper reports a method that aims to quantify the changes of tumour vascular structure as a result of drug treatment. The measures we have investigated to date include: vessel radii, inter-branch lengths, tortuosity and branch angles. We show that the distribution of vessel radii is better modelled as a gamma distribution as opposed to the log-normal distribution asserted by other researchers...
Capillary - tissue fluid exchange is controlled by the blood pressure in the capillary and the osmotic pressure of blood (pressure of the tissue fluid outside the capillaries). In this paper, we develop a mathematical model to simulate the movement of bacteria into and within a capillary segment. The model is based on Fokker-Planck equation and Navier-Stocks equations that accounts for different boundary...
This study investigated the usefulness of the very low spectral content of single-channel airflow recordings to help in the diagnosis of the obstructive sleep apnea (OSA) syndrome. Additionally, we evaluated whether airflow frequency components in the 0.01 - 0.10 Hz band are linked with desaturations in blood oxygen saturation (SaO2) recordings due to apnea events. The relationship between changes...
Renal failure patients provide a good model of fluid overload with the process of hemodialysis leading to central hypovolemia. This study aims to assess if hemodialysis induces identifiable changes in ear photoplethysmographic waveform variability (PPGV). The results are based on data collected from 10 kidney failure patients undergoing regular hemodialysis; classified as either fluid removal or non-fluid...
In North America, an estimated 30,000 patients annually experience an aneurysmal subarachnoid hemorrhage (SAH). In approximately five percent of these patients, the hemorrhage is not visible on computerized tomography scans due to the inability to image blood at time intervals greater than 12 hours post symptom onset. For these patients (many of which have experience a sentinel hemorrhage that is...
The Empirical Mode Decomposition (EMD) is a method to decompose non linear, non stationary time series into a sum of different modes, named Intrinsical Mode Functions each one having a characteristic frequency. In the present work we used the EMD to investigate the properties of the recorded sounds from the Arteriovenous fistula on hemodialysis patients. Phonoangiographic signals coming from two different...
In an attempt to overcome the limitations of current techniques for monitoring abdominal organ perfusion, a prototype reflectance fiber optic photoplethysmographic (PPG) sensor and processing system was evaluated on seventeen anaesthetized patients undergoing laparotomy. Good quality PPG signals were obtained from the large bowel, small bowel, liver and stomach. Simultaneous PPG signals from the finger...
Photoplethysmography (PPG) is a technique widely used to monitor volumetric blood changes induced by cardiac pulsations. Pulse oximetry uses the technique of PPG to estimate arterial oxygen saturation values(SpO2). In poorly perfused tissues, SpO2 readings may be compromised due to the poor quality of the PPG signals. We have developed a new multimode PPG measurement system which utilizes a reflectance...
In this paper the impact of different meals and rapid insulin were estimated as Finite Impulse Response Models from a data set of 18 patients. Based on these models short-term individualized predictors were tested for 20 and 60 minute prediction. The predictors were evaluated using Clarke Grid Analysis and had on average more than 94% and 75% in the A zone and less than 1% and 3% in the errorous C/D/E...
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