Technology and health care : official journal of the European Society for Engineering and Medicine
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A new automatic wheeze detection method which is based on image processing techniques applied to the sonagram was developed here. In the calculation of the sonagram, autoregressive and FFT spectrum estimation methods were compared. The method was validated in four wheezing asthmatic patients by a pulmonary physician. ⋯ Very short wheezes were not detected. The false positive amount of wheezing in control subjects was only about 1%. The method extracts also information about the frequency, duration, flow and volume associated with the wheezes.
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Technol Health Care · Dec 1997
Distribution of Marcaine in an in vitro model of the subarachnoid space conforming to actual spinal column geometries.
To study factors influencing the distribution of local anaesthetics in the subarachnoid space, an in vitro model is constructed which takes into account the natural curvature of the spinal column and the volume occupation of spinal cord and nerve fibres to resemble the in vivo situation. Three Marcaine solutions of different baricity (1003, 1008, 1030 kg/m3) are injected with a 22 G, a 27 G Quincke point needle and a 18 G multiport catheter into three models of non-pathological spinal columns with injection flow speeds of 0.6, 0.2 or 0.1 ml/s. Methylene blue is added for visual and qualitative assessment of drug distribution. ⋯ For all other variables, no significant difference is found after ten minutes, though the initial distribution may differ according to the geometry used. A hypobaric solution yields a remarked difference between fast and slower injections. The position of the catheter should be controlled.
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Technol Health Care · Dec 1996
Validation and clinical application of a continuous P0.1 measurement using standard respiratory equipment.
The airway occlusion pressure, P0.1, is the negative airway pressure generated during the first 100 msec of an occluded inspiration. P0.1 is a parameter for the neuro-muscular activation of the respiratory system, which is an important determinant for the work of breathing. It has been shown to be a good predictor for successful weaning from mechanical ventilation. ⋯ This correlation was significant (r = 0.99, p < 0.01). From these data we conclude that the described method for continuous P0.1 measurement provides reliable values with the advantage of a maneuver-free, breath-by-breath measurement technique. It thereby opens the possibility for monitoring the neuro-muscular activation of the respiratory system at the bedside, which is shown as an example for a patient during weaning from mechanical ventilation.
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Technol Health Care · Sep 1996
The nightmare of FDA clearance/approval to market: perception or reality?
Over the last few years the Center for Device Evaluation and Research (CDRH) at the Food and Drug Administration (FDA) has received annually over 16 thousand submissions related to medical devices. Over 10,000 of these are major submissions which include applications to conduct clinical trials and applications to market medical devices for a specified indication for use. Each application is carefully considered. ⋯ In addition, FDA assists applicants through the development of guidance documents, which discuss the type of information that would be beneficial to include in a submission. The Division of Small Manufacturers Assistance at FDA is dedicated to helping interested persons understand the clearance/approval process. This paper will discuss the role of FDA in the regulation of medical devices, with an emphasis on the pathway to obtaining permission to market medical devices in the United States.
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Keeping the oxygenation status of newborn infants within physiologic limits is a crucial task in intensive care. For this purpose several vital parameters are supervised routinely by monitors, such as electrocardiograph, transcutaneous partial oxygen pressure monitor and pulse oximeter. Each monitor issues an alarm signal whenever an upper or lower limit of the parameter(s) measured is exceeded. ⋯ The data and video were analysed off line with the help of an experienced neonatologist. His judgement was compared to the analysis of the Fuzzy Logic system. The results show that it is possible to improve the reliability of the monitored data with the aid of an evaluation strategy based on Fuzzy Logic and hence distinguish between real alarm situations and movement artefacts to the extent that an application in an intensive care unit under routine conditions becomes conceivable.