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
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 · 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 · Jan 1999
Case ReportsIntraoperative diagnosis of aortic pseudoaneurysm with transesophageal echocardiography.
A pseudoaneurysm of the ascending aorta is a rare complication of aortic valve endocarditis that requires prompt diagnosis. Several imaging strategies can be used; however, transesophageal echocardiography (TEE) has been utilized more frequently due to its superior resolution in detection of aortic valve complications. This case presents a patient with prosthetic valve dysfunction in which intraoperative TEE was used to diagnose a previously undetected aortic pseudoaneurysm, thus leading to a change in surgical management.
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J Clin Monit Comput · Jan 1999
Clinical investigation of a new combined pulse oximetry and carbon dioxide tension sensor in adult anaesthesia.
To test the accuracy of a new combined oxygen saturation and cutaneous carbon dioxide tension (SPO2-PCO2) sensor in a routine adult clinical environment. This probe provides a non-invasive and continuous monitoring of the arterial oxyhaemoglobin saturation, arterial carbon dioxide tension and pulse rate at the ear lobe. The sensor is intended to measure both relevant respiration/ventilation parameters in one single probe. ⋯ During general anaesthesia, postoperative recovery and critical care treatment, both monitoring of oxygenation and ventilation is important. Since pulse oximetry estimates only arterial oxygen saturation, periodic blood sampling is still necessary to determine the patient's arterial carbon dioxide status. We could demonstrate that the difference between cutaneous and arterial PCO2 was clinically unimportant, and therefore we conclude that the two methods of estimating the patient's carbon dioxide status may be used interchangeably. Our results demonstrated that 3 min after sensor placement, the new SpO2-PCO2 sensor prototype proved to be a reliable tool for continuous non-invasive monitoring of oxygenation and ventilation.