Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 1999
Clinical TrialSelective versus non-selective neural stimulation in the monitoring of muscular relaxation during general anesthesia.
The depth of muscular relaxation during general anesthesia is monitored through the analysis of the contraction evoked by selective electrical stimulation of a peripheral nerve. The aim of this study was to compare the method of selective stimulation (SS) to a new method based on non-selective electrical stimulation (NSS) delivered over the muscle. ⋯ NSS is equivalent to SS for muscular relaxation monitoring during general anesthesia. This has important implications to simplify muscular relaxation monitor design.
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J Clin Monit Comput · Aug 1999
New approaches for the detection and analysis of electroencephalographic burst-suppression patterns in patients under sedation.
An automatic EEG pattern detection unit was developed and tested for the recognition of burst-suppression periods and for the separation of burst from suppression patterns. The median, standard deviation and the 95% edge frequency were computed from single channels of the EEG within a moving window and completed by the continuous computation of frequency band power via an adapted Hilbert resonance filter. These parameters were given to the inputs of two hierarchically arranged artificial neural networks (NNs). ⋯ A group-related training of the NNs was realized. For the group-related trained NNs EEG data for 6 patients were used for training and the data of 6 other patients for testing the classification performance of the pattern recognition units. Additionally, the reliability of the detection algorithm was tested with data of two patients with convulsive state, resistant to treatment, and burst-suppression like pattern EEC.
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J Clin Monit Comput · Aug 1999
Ergonomic automated anesthesia recordkeeper using a mobile touch screen with voice navigtion.
To develop an ergonomically designed computerized recordkeeping tool for anesthesiologists that allows the clinician to maintain visual contact with the patient while performing recordkeeping. ⋯ An EARK system was designed to allow the user to maintain visual contact with the patient while performing recordkeeping tasks. The combination of a mobile touch screen and voice response/recognition facilitated the design goals of the system. Although the system has enjoyed universal clinical acceptance, the voice functions remain too limited to satisfy the needs of a completely handsfree user interface. Enhancements to voice recognition technology will offer the potential for improved functionality. Additional research is also needed to better define the relationship between vigilance and visual contact with the patient.
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J Clin Monit Comput · Aug 1999
Partial CO2 rebreathing cardiac output--operating principles of the NICO system.
The partial rebreathing method of cardiac output estimation is reviewed with a particular focus on its application for continuous monitoring, rebreathing and implementations and from both a historical and technical perspective. The assumptions of the method are discussed as well as the various implementations. ⋯ Compared to conventional cardiac output methods, the partial CO2 rebreathing technique is non-invasive, can easily be automated and can provide real-time and continuous cardiac output monitoring. Taking advantage of modern sophisticated sensor and signal processing technology and integrating multiple monitored physiological variables the NICO monitor is the first commercially available cardiac output system making use of the partial rebreathing of CO2.
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J Clin Monit Comput · Aug 1999
Comparative StudyMicrostream capnograpy technology: a new approach to an old problem.
Significant technical limitations inherent in black-body infrared technology used in conventional sidestream and mainstream capnography have hindered the acceptance and growth of capnography as a monitoring tool outside the operating room environment. We describe a new technology (Microstream) for CO2 monitoring, based on molecular correlation spectroscopy, which results in a highly efficient and selective emission of a spectrum of discrete wavelengths exactly matching those for CO2 absorption. The CO2 specific emissions allow for an extremely small sample cell (15 microl), which in turn, permits the use of a very low sample flow rate (50 ml/min) without compromising waveform integrity or end-tidal CO2 accuracy. Design and technology features of the CO2 emission source, sample cell, and breath sampling circuits are described.