1,721,137 research outputs found
A simple and innovative way to measure ventricular volume in a mechanical mock of the left ventricle
No full textOngoing innovations in mechanical devices to improve the heart's performance (e.g. left ventricular assist devices, LVAD) require numerical simulations and a bench validation before animal and clinical testing of the device. One of the major requirements of mechanical mocks of the cardiovascular system is the correct evaluation of the parameters of interest (pressure, volumes, flows). This paper presents a new optical method to measure the volume changes of a generic elastic camera through videos acquisition and analysis (using Simpson integration and Matlab software). We tested our proposal with a simple syringe mock of the cardiovascular system under different conditions of simulation dynamics and varying the stroke volumes (SV). We compared our results with those obtained with a standard electromagnetic flowmeter, in terms of instantaneous volume and total SV: the curves presented the same trends (squared Pearson's coefficients greater than 0.9) with a mean difference less than 5%. The proposed optical method is simple and inexpensive and yields results comparable with those of a standard method
A medical instrumentation laboratory dedicated to cardiovascular nurse training
No full textThere has been an ongoing technological evolution and impact of
medical instrumentation on cardiovascular patient care during the last
fifty years, and it is now impossible to manage the diagnostic and therapeutic
process without adequate instrumental support. This trend has
radically modified the professional activity of most healthcare personnel
but it has not always been flanked by appropriate professional training.
In particular, professional nursing schools are resistant to open their
courses to technological aspects and in the rare cases of interest, have
major difficulties finding qualified teachers with clinical experience
and an aptitude for instrumental procedure
Calibrated Hydraulic Resistance Adjuncts for Carbon Dioxide Angiography Optimization
Full text linkAbstract: Background: Despite the growing interest in CO2 angiography, some mechanical aspects related to CO2 injection still need to be deepened, and some improvements are still possible. This work explores the possibility of optimizing gas injection into small-sized arteries. Since the image quality depends on how the gas fills the vessel and is strongly dependent on injection flow, the possibility of controlling the flow is mandatory to obtain good results. To better control the flow, we propose to adjunct small tubes with known hydraulic resistances in parallel to the injection catheter, allowing the generation of the desired injection flow by modulating the injection pressure. Methods: Using a mechanical mock of the cardiovascular system, we measured pressures and flows of interest and acquired the optical images of the vessel during gas injections. We performed a simulation with four different calibrated adjunct resistances in various injection pressure conditions, with and without saline flushing. Results: Our tests demonstrated that the optimized injection of the gas maintains the same procedure durations and reduces the gas volume and the local pressure increase, avoiding the local gas “explosion” in the injection site. Conclusions: Our proposal appears effective and paves the way for research into optimizing clinical CO2 angiography procedures
A Portable Optical Recording Device Simulating CO2 Angiography for Training Purposes
No full textno abstract availabl
DOSE EVALUATION IN INTERVENTIONAL RADIOLOGY EMPLOYING NUMERICAL MODELS
No full textInterventional radiology, among guided RX procedures, is a methodology characterized by high level of doses, both for the patient and for the medical staff. The aim of the present study is to estimate the dose associated to coronary angiography procedures by means of numerical models (simplified and anthropomorphic) and MCNP Monte Carlo code. Numerical estimates were supported by measurement performed with a Dose Area Product meter that is commonly employed in such kind of studies. In the present work the main considerations and the preliminary results are presented
Automated carbon dioxide digital angiography for lower-limb arterial disease evaluation: safety assessment and comparison with standard iodinated contrast media angiography
No full textCarbon dioxide (CO2) has been validated as a contrast agent in a large series of studies. A particular advantages of CO2 over iodinated contrast medium (ICM) is the absence of nephrotoxicity and allergic reactions. One of the limitations of CO2 angiography is the difficulty of CO2 manual injection due to its compressibility. The manual gas injection does not permit optimal control of the gas output. Development of an automated CO2 injector has overcome these problems
X-ray Spectroscopy with a portable Compton Selection chamber: detector design and results.
No full textIn this paper a practical solution to perform spectral analysis of diagnostic X-ray beams is described, based on a miniaturized Compton selection chamber (CSC) using a Si-PIN detector. Results are compared with those obtained with a first prototype of CSC based on nitrogen cooled high purity germanium (HPGe) detector. With this method, the direct X-ray spectrum is Compton scattered inside the CSC, collected by a solid-state detector and reconstructed using a simplified scattering matrix experimentally determined. The results obtained will be compared with a reference standard, represented by direct spectra acquired with an HPGe detector in a laboratory facility, not applicable for on-field measurements
Wireless Endocardial Atrial (and Ventricular) Sensing with no Implanted Power Source: a Proposal
No full textCardiac electrical activity is mainly evaluated by monitoring the electrical biosignals. This requires a long-lasting power supply to make implantable devices cost-effective and efficient. Since the current trend is to implant catheter-free stand-alone electrodes (implantable cardiac monitors), the need for smaller devices is at odds with the need for long-life batteries. To avoid these problems, we propose a passive endocardial sensor able to monitor the movement of the considered chamber based on a permanent magnet shaped for implantation in the internal chamber of the heart (i.e. the right atrium) and an external gauss meter unit to measure sensor-induced magnetic field variations. Since the magnet is permanent, no replacement is needed after the first implant, thereby reducing the risks linked to invasive procedures, and the battery in the external device can be substituted more easily. To test our idea we used a permanent magnet mounted on the tip of a commercial catheter for heart mapping together with a dedicated gauss meter built in our laboratory. The device was tested in vitro and the magnetic field variations were acquired and measured in different conditions of movement and distances. The results demonstrate the feasibility of our approach and open an interesting new scenario where permanent magnets can be used to monitor the mechanical behaviour of the heart
Cold pressor test using strain-gauge plethysmography
No full textThis laboratory activity is designed to teach students how to measure forearm muscle blood flow (FBF) to describe the mechanisms of peripheral blood flow thermal regulation in healthy subjects. The cold pressor test (CPT) is the clinical procedure used in the experiment to induce arterial vasoconstriction. Strain-gauge plethysmography is applied on the patient's forearm to noninvasive monitor vasoconstriction effects on local blood perfusion and physiological parameters such as blood pressure (BP) and heart rate (HR). Patients with an altered peripheral vascular resistance (e.g., in hypertension) have different responses to the CPT from healthy subjects. To date, experimental evidence remains unexplained, as we do not know if the BP and HR increase is caused by a decrease in flow rate or an increase in peripheral vascular resistance during the test. To clarify this situation, we have to quantify the parameter we assume is being conditioned by the regulatory physiological intervention, i.e., peripheral vascular resistance. Peripheral vascular resistance quantification can be calculated as the ratio between muscle flow and mean arterial pressure. Students will learn how to apply the instrumental procedure to collect and analyze data before, during, and after the CPT and to describe the physiological responses of the peripheral vascular system to external stressors. They will also learn how to distinguish healthy from pathological responses on the basis of how sympathetic nervous system reactions influence the biomechanics of peripheral vessels
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