Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 1998
Reflectance pulse oximetry--principles and obstetric application in the Zurich system.
Transmission and reflectance are the two main modes of pulse oximetry. In obstetrics, due to the absence of a transilluminable fetal part for transmission oximetry, the only feasible option is the reflectance mode, in which sensor and detector are located on the same surface of the body part. ⋯ We have designed, developed, constructed and tested a reflectance pulse oximeter with the possibility to adjust the electronic circuits and signal processing in order to determine the effects of various parameters on signal amplitude and wave-form and to optimize the sensitivity and spatial arrangement of the optical elements. Following an explanation of the principles of reflectance pulse oximetry, we report our experience with the design, development, construction and field-testing of an in-house reflectance pulse oximetry system for obstetric application.
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Mixtures of helium and oxygen are regaining a place in the treatment of obstruction of the upper and lower respiratory tract. The parenchymal changes during the course of IRDS or ARDS may also benefit from the reintroduction of helium/oxygen. In order to monitor and document the effect of low-density gas mixtures, we evaluated the Datex AS/3 Side Stream Spirometry module with D-lite (Datex-Engstrom Instrumentarium Corporation, Finland) against two golden standards. ⋯ Measurements with the D-lite using low-density gases are satisfactorily contained in best-fit equations with a standard deviation of less than 5% during all ventilatory modes and mixtures.
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J Clin Monit Comput · Aug 1998
A real-time algorithm to improve the response time of a clinical multigas analyser.
An algorithm to improve the response time of a clinical respiratory multigas analyser is presented. ⋯ The algorithm provides an improvement on the relatively slow response times of the clinical gas analyser for breath-by-breath time-dependent applications. The same algorithm can also be applied to other instruments which have slow response times.
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J Clin Monit Comput · Aug 1998
Accuracy of volume measurements in mechanically ventilated newborns: a comparative study of commercial devices.
Ventilatory measurements in ventilated newborns are increasingly used to monitor and to optimize mechanical ventilation. The aim of this study was to compare the accuracy of volume measurements by different instruments using standardized laboratory conditions. ⋯ Most of the currently available neonatal spirometry devices allow sufficiently accurate volume measurements in the range of 10-60 ml and at frequencies between 30-60/min provided that an increased FIO2 is taken into account.
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J Clin Monit Comput · Aug 1998
In vivo evaluation of a closed loop monitoring strategy for induced paralysis.
Reliable closed loop infusion systems for regulating paralysis level can be a great convenience to the anesthesiologists in automating their task. This paper describes the in vivo performance evaluation of a self-tuning controller that is designed to accommodate large variations in patient drug sensitivity, drug action delays and environmental interfering noise. ⋯ The system adapted to a large variation in the sample subject drug sensitivity. It remained stable despite large amplitude disturbances and maintained the paralysis at the desired level following the removal of the disturbances.