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Vol 51, No 1 (2017)
- Year: 2017
- Articles: 16
- URL: https://journals.rcsi.science/0006-3398/issue/view/14604
Theory and Design
Visual and Robotic Guidance Systems for Transcatheter Implantation of Heart Value Prostheses
Abstract
Transcatheter heart valve prosthesis implantation (TCHVPI) is a complex method whose results depend on each of the components of the biotechnological system, such that complications cannot always be avoided. New medical technologies, namely robot systems (RS) and visual guidance systems (VGS) have been developed to counter these problems and make the procedure less dependent on the human factor. This review discusses the main current and potential VGS and RS technologies; the role of their integration is discussed and the main requirements for next-generation TCHVPI RS are evaluated.
1-5
Article
An Electric Stimulator for Intraoperative Verification and Monitoring of the State of the Facial Nerve and the Muscles of Expression
Abstract
An electric stimulator for pre-operative electrical diagnosis and intraoperative verification of nerves and muscles in the maxillofacial area is described. A block diagram of the apparatus is presented and the parameters of the output impulses and stimulation programs used at the pre-operative and intraoperative stages are described. Use of the instrument in neurosurgical operations increases the effectiveness of assessments of the physiological state of nerves and decreases the risk of traumatization. Results were obtained without using neuromonitoring instrumentation based on recording electrical activity in nerves and muscles.
6-10
Use of High-Tech Electrosurgical Instruments to Increase the Efficacy and Safety of Operations on the Thyroid Gland
Abstract
This article describes the use of nanostructured zirconium dioxide to provide high performance characteristics for novel electrosurgical instruments. Design solutions providing major functional improvements are described. A clinical study evaluated the effectiveness of using the new electrosurgical instruments with a special high-frequency generator in surgical operations on the thyroid gland.
11-15
Spectral Studies of Biodegradation and Hemolysis Caused by Contact of Bulk and Film Nanocomposites with Biological Fluids
Abstract
The paper discusses the possibility of use of nanocomposites obtained by laser structuring of single-walled (SWCNTs) and multi-walled (MWCNTs) carbon nanotubes in bovine serum albumin matrix as tissue-engineering scaffolds for blood vessel network sprouting in the process of biodegradation of the nanocomposite implant. The lowest rate of biodegradation was obtained in bulk and film nanocomposites based on SWCNTs immersed in NaCl solution: 2.45 and 9.77% weight loss after 14 days, respectively. Analysis of the dynamics of changes in the optical density of NaCl solution showed intense biodegradation of nanocomposites after six days of immersion. Spectral studies showed that contact of blood with bulk and film nanocomposites based on SWCNTs did not lead to hemolysis (hemolysis level ≤ 0.5%).
16-19
Use of Dual Energy X-Ray Absorptiometry for Assessment of Fracture Risk in Dialysis Patients
Abstract
The aim of the present work was to demonstrate the ability of dual energy X-ray absorptiometry (DEXA) to predict the overall risk of fractures in dialysis patients. A prospective study of 522 patients (271 men, 251 women) receiving long-term hemodialysis in dialysis centers in St. Petersburg was carried out. Cox stepwise multivariate regression analysis showed that a combination of measures of bone mineral density in the lumbar vertebrae and the distal bones of the forearm and the duration of kidney replacement therapy provided the best prediction of overall fracture risk. Conclusions: DEXA is a convenient tool for assessing facture risk in patients on hemodialysis.
20-23
Prediction of the Risk of Osteoporotic Fractures Using Bayesian Belief Networks
Abstract
Assignment of patients to fracture risk groups helps to select the optimum treatment strategy and decrease the probability of osteoporotic fractures. This article presents a novel approach to assessment of the risk of osteoporotic fractures using Bayesian networks. Results obtained using this approach are presented.
24-27
Regulation of the Functional State of the Human Brain by Real-Time Frequency−Phase Synchronization of Sensory Stimuli with the EEG Rhythm
Abstract
A method providing real-time digital EEG filtration in selected leads and assessment of the instantaneous amplitude and phase of the background rhythm to generate control signals for the presentation of sensory stimuli at specified phases of the dominant biorhythm is presented. Examples of phase-dependent rearrangements in EEG characteristics in humans detected using this method are given.
28-32
Performance of a Right Ventricular Assist Rotary Pump in the Process of Biventricular Mechanical Circulatory Support
Abstract
Performance of a right ventricular assist rotary pump in the process of biventricular mechanical circulatory support was studied using a cardiovascular system model. Three modifications of the rotary pump and their pressure−flow curves were considered. It was shown that a normal pressure level and right ventricular unloading without collapse could be achieved using pumps with pressure−flow curves scaled to the pressure difference specific to pulmonary circulation.
33-36
A System for Regular Artificial Moistening of Eyeballs by Dosed Application of a Medicinal Mixture
Abstract
A biotechnical system for regular artificial moistening of eyeballs by dosed application of a medicinal mixture was developed. A special self-adjusting dispenser is used to measure out doses of a liquid medicinal mixture applied to the area of the conjunctival cavities of the eyes. Clinical trials of the system revealed stabilization of functional and clinical parameters in all patients.
37-40
41-45
A Method and a Device for Diagnostics of the Functional State of Peripheral Vessels of the Upper Limbs
Abstract
The article suggests a method and a device for diagnostics of the functional state of peripheral vessels of the upper limbs, which provide identification of angiospastic disorders with a lower probability of false-negative result, allowing thereby the quality of diagnostics to be improved. The suggested approach is based on combined application of laser Doppler flowmetry and contact thermometry during an occlusion test. The obtained results can be used in various fields of medicine for the development of multi-functional non-invasive diagnostic systems for the diagnosis and prevention of diseases associated with changes in the functional state of peripheral vessels.
46-51
A Device and a Method for Determining the Rate of Oxygen Consumption by an Isolated Perfused Rat Liver
Abstract
The goal of this work was to suggest a method for measuring the total rate of oxygen consumption by an isolated perfused rat liver. This method involves calculation of the rates of oxygen consumption by the blood stream and through the liver surface. The two independently determined values are then summed up to determine the total consumption rate. Experimental results obtained by this method are in good agreement with the results obtained previously using the manometric method of measurement of the oxygen consumption rate.
52-55
Methods for Compensation of Coil Misalignment in Systems for Inductive Transcutaneous Power Transfer to Implanted Medical Devices
Abstract
The problem of variation of the output characteristics (voltage, current, power) of inductive powering systems for implantable medical devices is considered. The variation is primarily caused by relative misalignment of transmitting and receiving coils. A classification of misalignments is proposed. Main approaches to coil misalignment compensation are: mechanical fixation of the coils; evaluation of the relative position of the coils for elimination of misalignment or further tuning of the transmitting part of the system; optimization of the coil geometry providing stability within the given misalignment range; tuning the working frequency of the transmitting part of the system. It is shown that the compensation method should be selected with due regard to the implantable device parameters (first of all, the coil implantation site and the power consumption of the device).
56-60
A System for Remote-controlled Intelligent Monitoring of the Health Status in Humans
Abstract
The structure of a system for remote monitoring health status in humans is discussed, consisting of a mobile monitor, mobile device, a server in a healthcare institution, and a family doctor’s mobile computer. An algorithm for remote intelligent monitoring of patients, adjusting the operating mode and signal recording channel characteristics is presented, along with an algorithm for the processing and analysis of diagnostic information when there are changes in the patient’s ongoing physiological status from the individual norm.
61-65
Use of the CompactRIO Platform with the LabView Programming Environment for Simultaneous Recording and Processing of Different Types of Bioelectrical Signals
Abstract
A data collection system for simultaneous recording of electroencephalogram and other bioelectrical signals based on the CompactRIO platform (National Instruments, USA), consisting of a chassis with 32-channel NI-9205 modules for recording biological signals, is described. A virtual instrument running EEG signal processing algorithms was developed in the LabVIEW environment for calculation of the amplitudes of the main rhythms, frequency-amplitude, and frequency-time spectra of EEG signals in different leads.
66-71
A Method for Investigation of the Acoustic Reflex on the Basis of Impedance Measurements
Abstract
A method for investigation of the acoustic reflex on the basis of impedance measurements was suggested. The method involves evaluation of the tympanic membrane response to sound stimulation by measuring the acoustic impedance of the external auditory canal. The capabilities of the method were assessed both by physical modeling using a Helmholtz resonator and by a full-scale study in volunteer subjects.
72-76