Journal of clinical monitoring and computing
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J Clin Monit Comput · Feb 2002
Time-variant investigation of quadratic phase couplings caused by amplitude modulation in electroencephalic burst-suppression patterns.
Several studies suggest that parameters derived from bispectral analysis of the EEG can be used to characterize specific cortical activation states represented by non linear interaction between brain electrical oscillations. For example, it was shown that so-called bispectral indices can be used to assess the depth of sedation. The methods applied so far are based on interval-related procedures of bispectral analysis. Consequently, the use of the resulting parameters for on-line monitoring or investigations of signal properties during transition periods, e.g., when entering burst-suppression periods, is restricted. The objective of this paper is to provide the methodological basis for a time-continuous (on-line) investigation of quadratic phase coupling induced by amplitude modulation. ⋯ It was found that these periods are associated with increasing DAM compared with the baseline conditions.
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J Clin Monit Comput · Feb 2002
Enamel nail polish does not interfere with pulse oximetry among normoxic volunteers.
To determine if enamel nail polish interferes with pulse oximetry. ⋯ Enamel finger nail polish pigments do not interfere with pulse oximetry as previously reported, the A660-A940 difference must be greater than 1.88 +/- 0.23 SD AU in order to affect pulse oximetry.
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J Clin Monit Comput · Feb 2002
Comparative StudyComparative provocation test of respiratory monitoring methods.
The aim of this study was to compare clinically relevant performance of: 1) a prototype respiratory sensor based on capnometry with two alternative signal receptor fixations, 2) a fiberoptic humidity sensor and 3) human visual observation. Comparative provocation tests were performed on volunteers at the Post-Anesthesia Care Unit at Västerås Central Hospital. ⋯ The capnometry and fiberoptic sensors exhibit differences in responses that may be understood from basic principles. The importance of the physical application of the sensor to the patient was clearly observed. The optimum design remains to be found.
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J Clin Monit Comput · Feb 2002
A computerized method to measure systolic pressure variation (SPV) in mechanically ventilated patients.
Intrathoracic pressure variation during mechanical ventilation has different effects on cardiac preload and stroke volume in both ventricles. Changes in left ventricle stroke volume are reflected by fluctuations of the arterial pressure waveform or Systolic Pressure Variation (SPV). SPV has been proposed as a way to evaluate vascular volume status in mechanically ventilated patients as well as responsiveness of the left ventricle stroke volume to volume loading. ⋯ The automated SPV measurement requires less time as well as human errors compared to the manual method; this makes SPV calculation a competitive alternative to methods for the measurements of stroke volume variations as arterial thermodilution technique and transesophageal echocardiography, which require sophisticated equipment and specific experience.