Journal of clinical monitoring and computing
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J Clin Monit Comput · Jan 2000
Non-invasive cardiac output monitoring by aortic blood flow measurement with the Dynemo 3000.
The operating principles and methods for the continuous determination of aortic blood flow (ABF) with the Dynemo 3000 system are described in detail. The system uses a novel transesophageal ultrasonic Echo-Doppler probe simultaneously to measure aortic diameter and blood flow velocity at the same anatomic level, in real-time. Non-invasive ABF measurement is combined with vital sign data from standard monitors to provide a composite hemodynamic profile including volume, afterload and contractility data used by the physician to optimize therapy. A review of the clinical validation and comparison to thermodilution measurements showing a significant positive correlation over a wide range of clinical flow situations is also briefly presented.
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This review provides a practical clinical guide to the measurement of pulmonary mechanics. Although these measurements are now commonly available in a variety of clinical settings, there is considerable confusion regarding their interpretation and significance. A basic understanding of the principles involved will help prevent the misuse of this important information.
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J Clin Monit Comput · Jan 2000
Representation and classification of breath sounds recorded in an intensive care setting using neural networks.
Develop and test methods for representing and classifying breath sounds in an intensive care setting. ⋯ Long term monitoring of lung sounds is not feasible unless several barriers can be overcome. Several choices in signal representation and neural network design greatly improved the classification rates of breath sounds. The analysis of transmitted sounds from the trachea to the lung is suggested as an area for future study.
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J Clin Monit Comput · Jan 2000
Influence of tidal volume and thoraco-abdominal separation on the respiratory induced variation of the photoplethysmogram.
The present study was aimed at determining the relative influences of tidal volume and thoraco-abdominal separation (relative thoracic and abdominal contribution to the tidal volume) on the respiratory induced intensity variation (RIIV) of the photoplethysmographic signal. The effects were studied in two body positions. ⋯ The effects on the RIIV signal following changes in thoraco-abdominal separation and tidal volume are of the same order of magnitude. In the supine position, the influence of thoracic versus abdominal contribution to the tidal volume is not as significant as in the sitting position. Photoplethysmography is a promising technique for combined monitoring of several respiratory parameters, including tidal volume. In situations where the relative thoracic and abdominal contributions are likely to vary, the tidal volume information becomes less reliable.
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J Clin Monit Comput · Jan 2000
Determining the artifact sensitivity of recent pulse oximeters during laboratory benchmarking.
This study aimed to investigate and compare the performance of the algorithms contained in the newest generation of pulse oximeters (Masimo SET in IVY2000, Nellcor Oxismart N-3000, Agilent M3 rev. B) against a traditional pulse oximeter (Agilent CMS rel. A.0). ⋯ Very pronounced improvements (between 2.3 and 3.4 fold) on all of the newer devices were found for the pulse rate. The NMC turned out to be a very useful tool for generating a standard signal set for algorithm development and benchmarking purposes that eliminates repetitive clinical testing in early stages. The applicability of its results needs confirmation by clinical live studies.