Journal of clinical monitoring and computing
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J Clin Monit Comput · Jan 2000
Limits of corrected flow time to monitor hemodynamic status in children.
Doppler corrected flow time (i.e., corrected left ventricular ejection time) as a noninvasive tool for assessing hemodynamic changes has been previously reported for adult patients. Its use in paediatrics seems to be worthwhile but no data concerning its accuracy are presently available in this population. The purpose of this work was to study the relationships between corrected flow time (FT) and indices of systemic vascular resistance (SVR) and of myocardial contractility in healthy children. ⋯ These results show that the use of Bazett's formula correct FT could lead to hemodynamic misinterpretations, because it does not rule out all the heart rate effect. Moreover, in healthy children corrected FT appears as an inaccurate index to monitor physiological afterload alterations, because of the involvment of other hemodynamic factors such as contractility in its variation.
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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
Computerisation and decision making in neonatal intensive care: a cognitive engineering investigation.
This paper reports results from a cognitive engineering study that looked at the role of computerised monitoring in neonatal intensive care. A range of methodologies was used: interviews with neonatal staff, ward observations, and experimental techniques. ⋯ Factors that seemed to affect staff use of the computer were the lack (or shortage) of training on the system, the specific clinical conditions involved, and the availability of alternative sources of information. These findings have relevant repercussions for the design of computerised decision support in intensive care and suggest ways in which computerised monitoring can be enhanced, namely: by systematic staff training, by making available online certain types of clinical information, by adapting the user interface, and by developing intelligent algorithms.
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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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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.