Journal of clinical monitoring and computing
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J Clin Monit Comput · Feb 1999
Randomized Controlled Trial Clinical TrialThe effect of maintaining a constant preload or a constant degree of thumb abduction in the isometric twitch force of the thumb.
To investigate the effects of maintaining a constant preload and of maintaining a constant degree of thumb abduction on the isometric twitch force during mechanomyography of the thumb, we monitored neuromuscular function in patients anaesthetized without the use of a neuromuscular blocking agent. In addition, we studied the relationship between the degree of thumb abduction, twitch force and preload. ⋯ Changes in length of the contracting muscle fibres and creep phenomena in the connective tissue of the muscles, both leading to changes in the sarcomere length of the muscle fibres, may explain the observations in this study. In general, a stabilized preload at a constant degree of abduction seems to be required in order to obtain a stable twitch force.
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J Clin Monit Comput · Feb 1999
A strategy for developing practice guidelines for the ICU using automated knowledge acquisition techniques.
To implement practice guideline entry tools in a reminder system in order to provide decision support to health care workers in clinical care and emergency care environments. To design a knowledge acquisition environment that enables physicians to formulate, update, and verify guidelines without the assistance of a knowledge engineer. ⋯ These first results demonstrate that this bottom-up knowledge acquisition strategy, implemented by the automated knowledge acquisition tools, enables medical specialists to improve the quality of computer support in an ICU without assistance of a knowledge engineer.
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J Clin Monit Comput · Feb 1999
Evaluation of a new advanced thoracic bioimpedance device for estimation of cardiac output.
This study is an evaluation of a new thoracic bioimpedance cardiac output monitoring system which incorporates a modified form of the Kubicek equation and a method of estimating the left ventricular ejection time from the time derivative bioimpedance signals. ⋯ The results from the porcine study show that the new system performed well over a wide range of cardiac outputs, comparing favorably with data from other new bioimpedance cardiac output devices currently available in the market.
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J Clin Monit Comput · Feb 1999
Work of breathing-tidal volume relationship: analysis on an in vitro model and clinical implications.
Work of breathing (WoB) is currently employed to assess the afterload on the respiratory muscles and to estimate the energy expenditure for breathing. Since WoB depends on the ventilated tidal volume (TV), WoB*L(-1), the indicized form of WoB has been employed as a measure of WoB which is independent of TV. Actually, the independence of WoB*L(-1) from the ventilated TV has never been demonstrated. The aim of this study was to verify the predicted TV-independence of WoB*L(-1) on an in vitro model. ⋯ These results demonstrate the TV-dependence of WoB*L(-1) and suggest that WoB*L(-1), if TV changes, cannot be considered as an index of respiratory muscle afterload and should not be used as a guide for weaning patients from the mechanical ventilation. Finally, we introduced a new parameter (WoB1L) which seems to be a more TV-independent measure of respiratory work.
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J Clin Monit Comput · Jan 1999
Comparative StudyComparison of statistical methods to predict the time to complete a series of surgical cases.
We present a statistical model for predicting the time to complete a series of successive, elective surgical cases. The use of sample means of case times and turnover times when scheduling cases does not minimize the operating room labor costs associated with errors in predicting times to complete series of cases. ⋯ The independent variables are the numbers of cases in each series that are in various categories (i.e., combinations of scheduled procedures and surgeons). Although the computational method is preferred on theoretical grounds to that involving sample means, application of both methods shows that the more practical method is to use the sample means of previous case times and turnovers.