Medical devices are becoming more important in the health care sector. One of the major issues for companies developing and producing medical devices is to be updated on the regulatory requirements and implement them in the process. This thesis examines the regulatory requirements for medical devices in Argentina, Australia, Brazil, Canada, India, Japan, Mexico, Russia, South Korea and Taiwan and compares them with the requirements in the European Union.
The conclusion of this thesis is that most countries have similar requirements for registration of medical devices and are striving to harmonize with the GHTF guidelines. A company goes far by following the requirements in EU, USA or the GHTF guidelines.
Objective. The aim of this study was to compare clinically relevant performance of: 1) a prototype respiratory sensor based on capnometry with two alternative signal receptor fixations, 2) a fiberoptic humidity sensor and 3) human visual observation. Comparative provocation tests were performed on volunteers at the Post-Anesthesia Care Unit at Västerås Central Hospital. Methods. The experimental tests involved 10 healthy, voluntary test subjects, instructed to intersperse normal breathing with protocol provocations of breath holding, limb and head movements, and nasal oxygen supplement. The signal outputs from the three respiratory monitoring methods were recorded on a personal computer. The signal analysis included visual categorising of the signals and counting breath events. Recognising that none of the methods could act as reference, events were classified as "unanimous," "majority" or "minority" events depending on how many of the three methods that detected a breath. Results. The average total recording time was 37 minutes per subject. The respiratory rates varied from 6.5 to 19 breaths per minute, with a mean value of 11.4 breaths/minute. The breath hold duration ranged from 18 to 50 seconds. Discrepancies between the three methods were found in more than 20% of the marked events. The most frequent majority events were due to events not recorded by the observer who, on the other hand, contributed the least to minority events. The provocations made by the subjects during the measurement did not increase the rates of majority and minority events, compared to periods of no provocation. The fiberoptic device exhibited a large count of minority events but a smaller contribution to majority events than the capnometry prototype. Conclusions. The capnometry and fiberoptic sensors exhibit differences in responses that may be understood from basic principles. The importance of the physical application of the sensor to the patient was clearly observed. The optimum design remains to be found.
A new configuration for a gas sensor is demonstrated. The configuration consists of an electroacoustic element coupled to an acoustic resonator, such as Kundt's tube, exhibiting a resonance frequency that is related to the velocity of sound, which, in turn is a function of the molecular mass of the gas within the resonator. Electrical impedance measurements were performed, whereby a resonance peak attributable to the resonator was identified. Contributing effects to the quality factor, Q, of the resonance, was analyzed. Predictable shifts of the resonance frequency were observed when adding CO2 and He to air, and when varying the resonator length. Linearity within the experimental accuracy was confirmed. The new sensor configuration offers the potential advantages of smaller size, improved dynamic response, and lower cost. © 2001 Elsevier Science B.V. All rights reserved.
The aim of this pilot study was to investigate the possibility to find a correlation between the output from a portable pedobarography system and the walking intensity expressed as walking speed. The system uses shoe insoles with force sensing resistors and wireless transmission of the data via Bluetooth. The force-time integral, at the toe-off phase of the step, for the force sensors in the forward part of the right foot was used to measure impulse data for 10 subjects performing walks in three different walking speeds. This data was then corrected by multiplication with the step frequency. This pilot study indicates that the portable pedobarography system output shows a linear relationship with the walking intensity expressed as walking speed on an individual level.
Over the past few decades, exciting developments have taken place in the field of near-infrared spectroscopy (NIRS). This has been enabled by the advent of robust Fourier transform interferometers and diode array solutions, coupled with complex chemometric methods that can easily be executed using modern microprocessors. The present edited volume intends to cover recent developments in NIRS and provide a broad perspective of some of the challenges that characterize the field. The volume comprises six chapters overall and covers several sectors. The target audience for this book includes engineers, practitioners, and researchers involved in NIRS system design and utilization in different applications. We believe that they will greatly benefit from the timely and accurate information provided in this work.
Having a device with the capability of measure motions from gait produced by a human being, could be of most importance in medicine and sports. Physicians or researchers could measure and analyse key features of a person's gait for the purpose of rehabilitation or science, regarding neurological disabilities. Also in sports, professionals and hobbyists could use such a device for improving their technique or prevent injuries when performing. In this master thesis, I present the research of what technology is capable of today, regarding gait analysis devices. The research that was done has then help the development of a suggested standalone hardware sensor node for a Body Area Network, that can support research in gait analysis. Furthermore, several algorithms like for instance UWB Real-Time Location and Dead Reckoning IMU/AHRS algorithms, have been implemented and tested for the purpose of measuring motions and be able to run on the sensor node device. The work in this thesis shows that a IMU sensor have great potentials for generating high rate motion data while performing on a small mobile device. The UWB technology on the other hand, indicates a disappointment in performance regarding the intended application but can still be useful for wireless communication between sensor nodes. The report also points out the importance of using a high performance micro controller for achieving high accuracy in measurements.
Clothing with conductive textiles for health care applications has in the last decade been of an upcoming research interest. An advantage with the technique is its suitability in distributed and home health care. The present study investigates the electrical properties of conductive yarns and textile electrodes in contact with human skin, thus representing a real ECG-registration situation. The yarn measurements showed a pure resistive characteristic proportional to the length. The electrodes made of pure stainless steel (electrode A) and 20% stainless steel/80% polyester (electrode B) showed acceptable stability of electrode potentials, the stability of A was better than that of B. The electrode made of silver plated copper (electrode C) was less stable. The electrode impedance was lower for electrodes A and B than that for electrode C. From an electrical properties point of view we recommend to use electrodes of type A to be used in intelligent textile medical applications.
Eight ECG beat detection algorithms, from the PhysioNet's WFDB and Cardiovascular Signal toolboxes, were tested on twenty measurements, obtained by the Savvy patch ECG device, for their accuracy in beat detection. On each subject, one measurement is obtained while sitting and one while running. Each measurement lasted from thirty seconds to one minute. The measurements obtained while running were more challenging for all the algorithms, as most of them almost perfectly detected all the beats on the measurements obtained in sitting position. However, when applied on the measurements obtained while running, all the algorithms have performed with decreased accuracy. Considering overall percentage of the faulty detected peaks, the four best algorithms were jqrs, from the Cardiovascular Signal Toolbox, and ecgpuwave, gqrs, and wqrs, from the WFDB Toolbox, with percentages of faulty detected beats 1.7, 2.3, 2.9, and 3, respectively.
The atrial irregular rhythm, often reflected in atrial fibrillation, undulation or flutter, is recognized as one of the major causes of brain stroke and entails an increased risk of thromboembolic events because it increases the likelihood of blood clots formation. Its early detection is becoming an increasingly important preventive measure. The paper presents a simple methodology for the detection of atrial irregular rhythm by ECG body gadget that can perform long-term measurements, e.g. several weeks or more. Multichannel ECG, on the body surface, gives a more detailed insight into the atrial activity in comparison to standard 12-lead ECG. The information from MECG is compared with single-channel patch ECG. The obtained results suggest that the proposed methodology could be useful in treatments of atrial irregular rhythm. One can obtain a reliable information about the time and duration of fibrillation events, or determine arrhythmic focuses and conductive pathways in heart atria, or study the effects of antiarrhythmic drugs on existing arrhythmias and on an eventual development of new types of arrhythmias.