-
[show abstract]
[hide abstract]
ABSTRACT: Abstract Background: When designing a complete process of daily telerehabilitation, it should be borne in mind that patients should be furnished with properly designed methodologies for executing specific motion tasks and the assessment of the relevant parameters. In general, such a process should comprehend three basic elements in both the hospital and the home: (a) instrumented walkways, (b) walking aids or supports, and (c) equipment for the assessment of parameters. The objective, with gait being the focus, of this study was thus to design a simple, portable kit-as an alternative to the complex and expensive instruments currently used-to be easily interfaced or integrated with the instrumented walkways and aids/supports both for self-monitoring while patients are exercising with their own aids and for clinical reporting. Materials and Methods: The proposed system is a portable kit that furnishes useful parameters with feedback to both the patient and the trainer/therapist. Capable of being integrated with the most common mechanical tools used in motion rehabilitation (handrail, scales, walkways, etc.), it constantly monitors and quantitatively assesses progress in rehabilitation care. It is composed of one step counter, photo-emitter detectors, one central unit for collecting and processing the telemetrically transmitted data, and a software interface. Results and Discussion: The system has been successfully validated on 16 subjects at the second level of the Tinetti test in a clinical application for both home and the hospital. The portable kit can be used with different rehabilitation tools and on varying ground rugosity. Advantages include (a) very low cost, when compared with optoelectronic solutions or other portable devices, (b) very high accuracy, also for subjects with imbalance problems, compared with other commercial solutions, and (c) integration (compatibility) with any rehabilitative tool.
Telemedicine and e-Health 02/2013; · 1.42 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Fetal cardiac surgery (FCS) represents a challenging issue for the in utero treatment of congenital heart defects. However, FCS has still not gained the sufficient reliability for clinical practice due to an incompletely elucidated fetal stress response. For example, blood sampling can contribute to its onset, leading to fetoplacental unit dysfunction, one of the main causes of failure of the surgical procedure. In order to address this issue, the role of the autonomic control system during an experimental procedure of cardiac bypass on ewe fetuses was investigated by means of recurrence quantification analysis (RQA), a well-recognized method for the analysis of nonlinear systems. RQA was applied to time series extracted from fetal arterial pressure recordings before and after the cardiac bypass established by means of an extracorporeal circuit, including an axial blood pump, and taking advantage of the capability of the placenta to work as a natural oxygenator. Statistically significant correlations were found among RQA-based metrics and fetal blood gas data, suggesting the possibility to infer the clinical status of the fetus starting from its hemodynamic signals.This study shows the relevance of RQA as a complementary tool for the monitoring of the fetal status during cardiac bypass.
The International journal of artificial organs 06/2012; 35(5):376-84. · 1.86 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Multiresolution analysis of heart rate variability derived from aortic blood pressure, acquired before and after (30 and 60min)
experimental fetal cardiac bypass performed on five ewe's fetuses, was used to investigate the physiological response to an
invasive clinical approach. Tachograms were implemented and analyzed by wavelet transform in order to verify the existence
of a quantitative relationship between arterial blood gases and time series in the very-low (0.021 < f < 0.084Hz) and low (0.084 < f < 0.337Hz) frequency band. Multiresolution analysis showed an average decreasing trend from basal condition for all the
fetuses investigated in the very-low frequency band, while an opposite trend was highlighted in the low frequency band: this
resulting behavior could be related to the temporal evolution of blood gas data. Finally, a slight decrease of sympatho-vagal
balance was monitored 30min after the cardiac bypass was discontinued compared to basal condition. Multiresolution analysis
could give more insights on fetal hypoxemia and could also represent a minimally invasive monitoring tool to limit the damage
to the fetoplacental unit during experimental fetal cardiac surgery.
Annals of Biomedical Engineering 04/2012; 34(5):799-809. · 2.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: With the increasing use of artificial organs, blood damage has been raising ever more clinical concern. Blood trauma is in
fact a major complication resulting from the implantation of medical devices and the use of life support apparatuses. Red
blood cells damage predictive models furnish critical information on both the design and the evaluation of artificial organs,
because their correct usage and implementation are thought to provide clear and rational guidance for the improvement of safety
and efficacy. The currently adopted power-law shear-induced haemolysis prediction model lacks sensitivity with respect to
the cumulative effect of previously applied stress magnitudes. An alternative model is proposed where a mechanical quantity
was defined, able to describe the blood damage sustained by red cells under unsteady stress conditions, taking into account
the load history. The proposed formulation predicted the same trend as the available experimental data. The obtained results
have to be considered a preliminary validation of the basic hypothesis of this modified red blood cell damage prediction model.
To date, the necessity to design further experiments to validate the proposed damage function clashes with the limitations
inherent to current systems to get the time-varying shear stress completely under control.
Biomechanics and Modeling in Mechanobiology 04/2012; 4(4):249-260. · 3.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Today the risk factors related to the use of Video Display Terminals (VDT) are assessed by investigating the actual activities at the VDT through subjective questionnaires and/or quantitative measurements. Questionnaire outcomes are quite imprecise and seldom objective. Quantitative measurements (EMG recordings, electrogoniometers, motion analysis systems) mostly prevent subjects from moving freely while working at the VDT. The paper presents an automatic tool for the monitoring of activity at VDTs, using a quantitative, objective approach. The suitability of the proposed tool was fully tested in the laboratory, both in terms of functionalities, accuracy of the tool, and acceptance by the subjects involved. The outcomes show that the tool allows for a detailed analysis of VDT activities and may be used to improve VDT-related risk analysis with high accuracy and good acceptance by workers.
Computer methods and programs in biomedicine 11/2011; 107(2):294-307. · 1.14 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We investigated the use of surface electromyography with biofeedback for telerehabilitation. The aim was to investigate the therapist's point of view, and the general acceptability of the system for the patient and for the therapist. The system allowed a therapist to modulate the rehabilitation protocol remotely, by changing the configuration variables, e.g. threshold and duration. The case study focused on a patient with arm impairment following a stroke. After two weeks of daily usage, there were some differences between the patient and the therapist about the ease of use of the equipment. However, there was general agreement about the usefulness of the system, ease of the performed tasks, appropriateness of the performed tasks and overall opinion. Wireless technology would reduce the complexity of the tasks required of the patient.
Journal of telemedicine and telecare 01/2010; 16(4):204-6. · 0.92 Impact Factor
-
Annali dell'Istituto superiore di sanita 01/2010; 46(2):113-4. · 0.94 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The paper approaches a new technological scenario relevant for the introduction of the digital cytology (D-CYT) in the health service. A detailed analysis of the state of the art on the status of the introduction of D-CYT in the hospital and more in general in the dispersed territory has been conducted. The analysis was conducted in a form of review and was arranged into two parts: the first part focused on the technological tools needed to carry out a successful service (client server architectures, e-learning, quality assurance issues); the second part focused on issues oriented to help the introduction and evaluation of the technology (specific training in D-CYT, health technology assessment in-routine application, data format standards and picture archiving computerized systems (PACS) implementation, image quality assessment, strategies of navigation, 3D-virtual-reality potentialities). The work enlightens future scenarios of actions relevant for the introduction of the technology.
Annali dell'Istituto superiore di sanita 01/2010; 46(2):115-22. · 0.94 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The paper describes a fundamental feature of digital cytology relevant to the implementation of the technology in the hospital net services: the electronic recording of the virtual slides (VS) in the hospital information system (HIS) through a picture archiving and communication system (PACS). Starting from the digital cytology (D-CYT) state of art and considering the most important products in the field, particular attention has been devoted in this review to the comparison with the digital radiology (D-RAD). Two main indications emerged from the study: 1. there is not a standard in the digital files relevant to the virtual slides in D-CYT, while in D-RAD the standard digital imaging and communications in medicine (DICOM), introduced by the National Electrical Manufacturers Association (NEMA), has been adopted from several years; 2. the PACS in D-CYT are not standardized from manufacturers. The study makes a proposal of a useful software architecture to improve the PACS integration for D-CYT applications, with potentialities in the HIS.
Annali dell'Istituto superiore di sanita 01/2010; 46(2):130-7. · 0.94 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This paper aims at delivering a structured overview of telerehabilitation literature by analysing the entire set of articles under the search terms "telerehabilitation" or "tele-rehabilitation" to portray "state of the art" ten years after the publication of the first scientific article on the topic. A structured study has been conducted by considering all those articles containing the word "telerehabilitation" or "tele-rehabilitation". Medline, Embase, Cochrane, UK Centre for Reviews and Dissemination, Canadian Agency for Drugs and Technologies in Health databases have been interrogated for articles between 1998 and 2008. 146 scientific articles were found. 56 articles focus on patient treatment, 23 are reviews, 3 are to be considered as both patient treatment papers and reviews, 53 are either technical reports, system descriptions or analyses of new approaches; 8 are general discussion on telerehabilitation. The present paper draw the scenario of the first ten years of telerehabilitation, focussing on clinical applications and technologies. Basically, it confirms the lack of comprehensive studies providing evidence for supporting decision and policy-makers in adopting telerehabilitation technologies in the clinical practice. An overall lack of standardisation in the used terminology also results from the analysis of keywords, which is typical of quite recent fields of application.
Neurorehabilitation 01/2010; 27(4):287-304. · 1.63 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This work focuses on the evaluation of the potential use of electrospun poly(epsilon-caprolactone) (PCL) micrometric and/or sub-micrometric fibrous membranes for rat hippocampal astrocyte (HA) and rat cerebro-microvascular endothelial cell (CEC) cultures. Both mats supported cell adhesion, proliferation, cellular phenotype and spreading. Microfibrous mats allowed cellular infiltration, while both HAs and CECs were unable to migrate within the sub-micrometric fibrous mat, leaving an acellularized inner region. This finding was correlated to the presence of larger voids within electrospun PCL microfibrous mats, suggesting that the morphology should be accurately selected for the realization of a cell environment-mimicking mat. Based on our results, the proper fiber architecture can be regarded as a crucial issue to be considered in order to deal with suitable polymeric mats tailored for specific in vitro application.
Journal of Materials Science Materials in Medicine 12/2009; 21(4):1353-62. · 2.32 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Two innovative surgical approaches addressing systemic venous anomalies in single-ventricle patients are evaluated.
Between 2003 and 2007, 7 patients underwent a unifocal bilateral bidirectional cavopulmonary anastomosis, and 5 patients underwent a hepatoazygos venous connection associated with a previous (n = 4) or concomitant (n = 1) Kawashima operation. Computational fluid dynamics simulations allowed investigation of 2 sets of comparative models: (1) bifocal versus unifocal bilateral bidirectional cavopulmonary anastomosis and (2) classic hepatic vein-pulmonary artery channel versus hepatoazygos direct anastomosis for Fontan completion after or combined with the Kawashima operation.
There was 1 hospital death in the unifocal bilateral bidirectional cavopulmonary anastomosis group. At a mean follow-up of 15.6 +/- 7.40 months after a unifocal bilateral bidirectional cavopulmonary anastomosis and of 38.7 +/- 13.2 months after direct hepatoazygos venous connection, respectively, all 11 survivors are in New York Heart Association class I with functional anastomoses. Computational assessment of bifocal bilateral bidirectional cavopulmonary anastomosis demonstrated weak perfusion between caval veins against symmetric and steady bilateral flow fields in the unifocal arrangement. In the classic post-Kawashima Fontan completion model, the hepatic venous flow to the pulmonary artery was held back by means of preponderant opposite flow, whereas in the direct hepatoazygos venous connection model, the hepatic venous flow merged smoothly into the azygos vein. Power-loss calculation showed no significant difference between bifocal and unifocal bilateral bidirectional cavopulmonary anastomosis topology, whereas the hepatoazygos connection clearly had better energy preservation than the classical connection.
This limited clinical and computational fluid dynamics assessment suggests the efficacy of this new rationale to reduce the additional thrombotic risks produced by systemic venous anomalies in single-ventricle patients.
The Journal of thoracic and cardiovascular surgery 08/2009; 138(5):1154-9. · 3.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In the past 30 years, ultrasound has become a very powerful imaging modality, due mainly to its unique temporal resolution, low cost, non-ionising characteristics and portability. Understanding the physical details of the acoustic wave–tissue interaction is necessary to realise the full potential of ultrasound techniques, which have steadily improved in terms of quality and range of applications in recent years. In this paper, we give an overview of the fundamentals of diagnostic ultrasound and a brief summary of its applications and methods aimed at tissue characterisation. Besides more conventional techniques such as A-mode, B-mode and M-mode, recent successful advances such as harmonic imaging, three-dimensional visualisation, elasticity imaging and the use of contrast agents are discussed. With these technological improvements, ultrasound techniques will be able to provide high-quality diagnostic tools in everyday clinical practice.
Paediatrics and Child Health. 01/2009; 19.
-
[show abstract]
[hide abstract]
ABSTRACT: The implantation of cardiovascular devices such as prosthetic heart valves, even though very common in the clinical domain, is still not free from complications. Thromboembolic events and hemolysis are the major clinical problems that can occur, upon implantation. In this paper, we analyze the role of the particular fluid dynamics associated to such devices, in relation to the clinical outcome. A major issue, still debated, is the way to correlate the experimental findings with blood damage. The availability of advanced techniques such as LDA or PIV is necessary to evaluate the hemodynamical performance of a given implantable device at the local level and to draw reliable conclusions about potentially adverse clinical effects.
Engineering in Medicine and Biology Society, 2008. EMBS 2008. 30th Annual International Conference of the IEEE; 09/2008
-
[show abstract]
[hide abstract]
ABSTRACT: The main purpose of this study is to reproduce in silico the dynamics of a bileaflet mechanical heart valve (MHV; St Jude Hemodynamic Plus, 27mm characteristic size) by means of a fully implicit fluid-structure interaction (FSI) method, and experimentally validate the results using an ultrafast cinematographic technique. The computational model was constructed to realistically reproduce the boundary condition (72 beats per minute (bpm), cardiac output 4.5l/min) and the geometry of the experimental setup, including the valve housing and the hinge configuration. The simulation was carried out coupling a commercial computational fluid dynamics (CFD) package based on finite-volume method with user-defined code for solving the structural domain, and exploiting the parallel performance of the whole numerical setup. Outputs are leaflets excursion from opening to closure and the fluid dynamics through the valve. Results put in evidence a favorable comparison between the computed and the experimental data: the model captures the main features of the leaflet motion during the systole. The use of parallel computing drastically limited the computational costs, showing a linear scaling on 16 processors (despite the massive use of user-defined subroutines to manage the FSI process). The favorable agreement obtained between in vitro and in silico results of the leaflet displacements confirms the consistency of the numerical method used, and candidates the application of FSI models to become a major tool to optimize the MHV design and eventually provides useful information to surgeons.
Journal of Biomechanics 07/2008; 41(11):2539-50. · 2.43 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Electrospinning is a valuable technique to fabricate fibrous scaffolds for tissue engineering. The typical nonwoven architecture allows cell adhesion and proliferation, and supports diffusion of nutrients and waste products. Poly(epsilon-caprolactone) (PCL) electrospun membranes were produced starting from 14% w/v solutions in (a) mixture 1:1 tetrahydrofuran and N,N-dimethylformamide and (b) chloroform. Matrices made up of randomly arranged uniform fibers free of beads were obtained. The average fiber diameters were (a) 0.8 +/- 0.2 microm and (b) 3.6 +/- 0.8 microm. PCL matrices showed the following tensile mechanical properties: tensile modulus (a) 5.0 +/- 0.7 MPa (b) 6.4 +/- 0.2 MPa, yield stress (a) 0.55 +/- 0.06 MPa (b) 0.43 +/- 0.02 MPa, and ultimate tensile stress (a) 1.7 +/- 0.2 MPa and (b) 0.8 +/- 0.1 MPa. The ultimate strain ranged between 300% and 400%. Cytotoxicity of electrospun membranes was continuously evaluated by means of electric cell-substrate impedance sensing technique using human umbilical vein endothelial cells (HUVEC). PCL matrices resulted free of toxic amounts of contaminants and/or process by-products. In vitro studies performed by culturing HUVEC on micrometric and submicrometric fibrous mats showed that both structures supported cell adhesion and spreading. However, cells cultured on the micrometric network showed higher vitality and improved interaction with the polymeric fibers, suggesting an increased ability to promote cell colonization.
Journal of Biomedical Materials Research Part A 06/2008; 89(4):1028-39. · 2.63 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The implantation of cardiovascular devices such as prosthetic heart valves, even though very common in the clinical domain, is still not free from complications. Thromboembolic events and hemolysis are the major clinical problems that can occur, upon implantation. In this paper, we analyze the role of the particular fluid dynamics associated to such devices, in relation to the clinical outcome. A major issue, still debated, is the way to correlate the experimental findings with blood damage. The availability of advanced techniques such as LDA or PIV is necessary to evaluate the hemodynamical performance of a given implantable device at the local level and to draw reliable conclusions about potentially adverse clinical effects.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 02/2008; 2008:1419-22.
-
[show abstract]
[hide abstract]
ABSTRACT: Currently implanted prosthetic heart valves, both mechanical or biological ones, are used to restore the proper blood hemodynamics when the native valves fail. However, these medical devices are not free from drawbacks, such as hemolysis or calcification, also presenting the relevant disadvantage of being unable to growth, repair and remodel. An improvement could be represented by bioresorbable polymeric tissue-engineered heart valves. In this paper a poly(epsilon -caprolactone) (PCL) heart valve prosthesis, realized by means of electrospinning, and its in vitro functional characterization in a pulse duplicator, resembling pulmonary conditions, is presented. Morphological examination revealed polymeric micrometric fibers randomly oriented with an average porosity of about 90 percent. Pulse duplicator testing highlighted that leaflets opened synchronously and showed a correct coaptation in the diastolic phase, even if a slight rotation of the leaflets was visualized. In silico study by numerical simulation of the closed phase predicted the stress distribution within the leaflet, showing that peak levels are reached at the commissures and sustained by the structure without failure. The present study highlighted the technical feasibility to produce polymeric bioresorbable functional heart valves by means of electrospinning. Further studies and design changes are needed in order to optimize the final scaffold to bear arterial hemodynamic conditions.
Annali dell'Istituto superiore di sanita 01/2008; 44(2):178-86. · 0.94 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To propose a novel quantitative method for measuring the torque acting on mechanical heart valve prostheses subjected to a high static magnetic field in a MR scanner.
Torque measurements were performed with a torsion balance, implemented with a copper wire. The reaction torque exerted by the static magnetic field on the device was measured optically from the deflection angle of a laser beam spot on a graduate scale. Three different types of mechanical valves (two bileaflet and one monoleaflet) were tested at different locations of a small bore 4.7 tesla system.
The method proved to be particularly sensitive (detectability limit lower than 10(-6) N x m), reliable and yielded quantitative reproducible results. The equivalent force of the torque measured for the three valves was at least 10(3)-fold lower than the force exerted by the beating heart.
The proposed method provides a quantitative evaluation of the torque induced on prosthetic device by a MR scanner operating at high magnetic field.
Journal of Magnetic Resonance Imaging 12/2007; 26(5):1368-74. · 2.70 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The main purpose of the study was to verify if helical flow, widely observed in several vessels, might be a signature of the blood dynamics of vein graft anastomosis. We investigated the existence of a relationship between helical flow structures and vascular wall indexes of atherogenesis in aortocoronary bypass models with different geometric features. In particular, we checked for the existence of a relationship between the degree of helical motion and the magnitude of oscillating shear stress in conventional hand-sewn proximal anastomosis. The study is based on the numerical evaluation of four bypass geometries that are attached to a simplified computer representation of the ascending aorta with different angulations relative to aortic outflow. The finite volume technique was used to simulate realistic graft fluid dynamics, including aortic compliance and proper aortic and graft flow rates. A quantitative method was applied to evaluate the level of helicity in the flow field associated with the four bypass models under investigation. A linear inverse relationship (R = -0.97) was found between the oscillating shear index and the helical flow index for the models under investigation. The results obtained support the hypothesis that an arrangement of the flow field in helical patterns may elicit damping in wall shear stress temporal gradients at the proximal graft. Accordingly, helical flow might play a significant role in preventing plaque deposition or in tuning the mechanotransduction pathways of cells. Therefore, results confirm that helical flow constitutes an important flow signature in vessels, and its strength as a fluid dynamic index (for instance in combination with magnetic resonance imaging flow visualization techniques) for risk stratification, in the activation of both mechanical and biological pathways leading to fibrointimal hyperplasia.
Journal of Biomechanics 02/2007; 40(3):519-34. · 2.43 Impact Factor
