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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J Clin Monit Comput · Jan 2000
Comparative StudyComparison of a prototype esophageal oximetry probe with two conventional digital pulse oximetry monitors in aortocoronary bypass patients.
Pulse oximetry (SpO2) is the non-invasive standard for monitoring arterial oxygen saturation in patients undergoing anesthesia, but is subject to external interference by motion artifact, peripheral vasoconstriction, and low cardiac output. We hypothesized that oximetry signals could be acquired from the esophagus when peripheral pulse oximetry is unobtainable. Therefore, we tested an esophageal stethoscope which incorporates transverse oximetry photodetectors and emitters in patients undergoing coronary bypass surgery. ⋯ Digital pulse oximetry failure is common in CABG patients, probably because of marginal cardiac output and peripheral vasoconstriction associated with hypothermia. Our study could not confirm that esophageal technology, which utilizes the esophagus as a site of transflectance oximetry, was superior to conventional digital pulse oximetry.
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J Clin Monit Comput · Jan 2000
Infrared transmission of electronic information via LAN in the operating room.
Recent advances in technology have brought many kinds of monitoring devices into the operating room (OR). The information gathered by monitors can be channeled to the operating ward information system via a local area network (LAN). Connecting patients to monitors and monitors to the LAN, however, requires a large number of cables. ⋯ In our trial, we found no evidence of EMI of IR modems with any of the medical devices we tested. Furthermore, IR modems showed similar performance to a wired system even in an electrically noisy environment. We conclude that IR wireless connectivity can be safely and effectively used in ORs.
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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.