Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2008
Non-invasive automated measurement of cardiac output during stable cardiac surgery using a fully integrated differential CO(2) Fick method.
To re-evaluate the accuracy and precision of a non-invasive method for measurement of cardiac output based on the differential CO(2) Fick approach using an automated change in respiratory rate delivered by a ventilator under control by a prototype measurement system. ⋯ Acceptable agreement with thermo- dilution during surgery was found, particularly where the ventilatory change involved an increase in respiratory rate from a lower baseline. This approach has potential to be readily integrated into modern anesthesia delivery platforms, allowing routine non-invasive cardiac output measurement.
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J Clin Monit Comput · Aug 2008
Computerized recording of neuromuscular monitoring and the risk of residual paralysis at the time of extubation.
We tested whether a newly installed neuromuscular monitoring device (NMT) with a computerized anesthesia recording system, incorporated in all anesthesia stations, could enhance the commitment to objective neuromuscular monitoring in a teaching hospital anesthesia department. ⋯ Despite the presence of quantitative objective neuromuscular monitoring in all operating rooms, and the automatic data recording system, the rate of monitoring neuromuscular blockade was not high enough to rule out the potential risk of residual paralysis at the time of extubation.
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J Clin Monit Comput · Aug 2008
Noninvasive detection of the hemodynamic stress of exercise using the photoplethysmogram.
Exercise induced hemodynamic stress has been studied extensively using a wide range of physiological sensors. While athletes can modulate their training intensity using EKG-based heart rate monitors, there are currently no noninvasive monitors that can be used to ascertain with a high degree of certainty the hemodynamic stress an individual is experiencing because of fatigue or an underlying pathology. We propose that cardiac stress will result in detectable changes in skin blood flow. ⋯ As volitional fatigue approached, the low frequency (f = 0.05-0.2 Hz) amplitude modulation observed in the PPG became more pronounced; then, within several seconds of the cessa- tion of the protocol, they disappeared. Using a software-based detector, these distinct waves are reliably detected, with a low incidence of false positives, in all subjects before the onset of volitional fatigue. We hypothesize that the low frequency waves observed in the PPG of individuals exercising to volitional fatigue provide a mechanism for noninvasively detecting hemodynamic stress to the human vascular system.
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J Clin Monit Comput · Aug 2008
A measure of confidence in Bland-Altman analysis for the interchangeability of two methods of measurement.
Bland-Altman (B-A) analysis has largely replaced the correlation coefficient as the predominant tool for evaluating the interchangeability of two methods of clinical measurement. However, we contend that B-A analysis might lead to erroneous conclusions when the data range is small. We provide an example to illustrate this and explore a possible analysis technique to address this limitation.
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J Clin Monit Comput · Jun 2008
Accuracy of continuous central venous oxygen saturation monitoring in patients undergoing cardiac surgery.
Continuous assessment of central venous oxygen saturation (S(cevox)O(2)) with the CeVOX device (Pulsion Medical Systems, Munich, Germany) was evaluated against central venous oxygen saturation (S(cv)O(2)) determined by co-oximetry. ⋯ In adult patients during and after cardiac surgery, the current version of the CeVOX device might not be the tool to replace S(cv)O(2) determined by co-oxymetry, although sensitivity and specificity of S(cevox)O(2 )to predict substantial changes in S(cv)O(2) were acceptable.