Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2002
Representation of somatosensory evoked potentials using discrete wavelet transform.
Somatosensory evoked potentials (SEP) have been shown to be a useful tool in monitoring of the central nervous system (CNS) during anaesthesia. SEP analysis is usually performed by an experienced human operator. For automatic analysis, appropriate parameter extraction and signal representation methods are required. The aim of this work is to evaluate the discrete wavelet transform (DWT) as such a method for an SEP representation. ⋯ The discrete wavelet transformation provides an efficient tool for SEP representation and parameterisation. Depending on the specific problem the DWT, can be adjusted to the desired accuracy, which is important for the subsequent development of automatic SEP analysers.
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J Clin Monit Comput · Apr 2002
Averaging improves the quality of impedance stroke volume measurements during the head up tilt test.
To assess the improvement in quality following averaging data from two or more tilts in the stroke volume (SV) response curve during a head-up tilt test. ⋯ Impedance measurements can be very variable, making the assessment of SV changes during a head-up tilt test difficult. By averaging the data from several tilts one can improved the quality of the SV wavelet sufficiently to identify important postural changes.
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J Clin Monit Comput · Apr 2002
Bilobed splitting of median nerve somatosensory evoked p14 potential under deep hypothermia.
To further elucidate temperature related changes in subcortical components of somatosensory evoked potentials (SEP) in intraoperative monitoring. ⋯ Deep hypothermia may separate presynaptic and postsynaptic electric activity of evoked potentials that overlap at normal body temperature. Such possible phenomena must be kept in mind to correctly interprete monitoring data at very low body temperatures and may help in better understanding the generation of different SEP components.
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J Clin Monit Comput · Feb 2002
Comparative StudyA comparison of two impedance cardiographs using head-up tilting and trend analysis.
To compare the performances of two impedance cardiographs, the RheoCardioMonitor (RCM) and the BoMed NCCOM3, using trend analysis. This involved a series of head-up tilts, a simulation of the stroke volume (SV) and cardiac output (CO) response, calculation of prediction errors and cumulative sums (Cusum). ⋯ Simulation of a physiological response, such as that to head-up tilting, and using a trend analysis based on prediction errors and Cusum, is a useful technique. The trending abilities of the RCM and BoMed were similar.