Physiological measurement
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Physiological measurement · Jun 2017
Global and regional assessment of sustained inflation pressure-volume curves in patients with acute respiratory distress syndrome.
Static or quasi-static pressure-volume (P-V ) curves can be used to determine the lung mechanical properties of patients suffering from acute respiratory distress syndrome (ARDS). According to the traditional interpretation, lung recruitment occurs mainly below the lower point of maximum curvature (LPMC) of the inflation P-V curve. Although some studies have questioned this assumption, setting of positive end-expiratory pressure 2 cmH2O above the LPMC was part of a 'lung-protective' ventilation strategy successfully applied in several clinical trials. The aim of our study was to quantify the amount of unrecruited lung at different clinically relevant points of the P-V curve. ⋯ Our results confirm the notion of ongoing lung recruitment at pressure levels above LPMC for all investigated model equations and highlight the importance of a regional assessment of lung recruitment in patients with ARDS.
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Physiological measurement · Jun 2017
Regional ventilation redistribution measured by electrical impedance tomography during spontaneous breathing trial with automatic tube compensation.
Automatic tube compensation (ATC) was developed to overcome the flow resistance of endotracheal tube and decrease the imposed work of breathing. Although ATC is used as an evidence-based strategy to predict successful weaning from assisted ventilation, the changes in regional ventilation distribution induced by this technique are not known. We hypothesized that continuous positive airway pressure plus ATC (CPAP + 100%ATC) could reactivate the respiratory muscles in patients with prolonged mechanical ventilation (PMV) more effectively than volume assist-control mandatory ventilation (ACMV). ⋯ Dorsal redistribution of ventilation and reduction of ventilation delay as identified by EIT indicate that CPAP + 100%ATC was effective in reactivating the respiratory muscles in the PMV patients of the present study.
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Physiological measurement · Jun 2017
Comparative StudyComparative study of separation between ex vivo prostatic malignant and benign tissue using electrical impedance spectroscopy and electrical impedance tomography.
Currently no efficient and reliable technique exists to routinely assess surgical margins during a radical prostatectomy. Electrical impedance spectroscopy (EIS) has been reported as a potential technique to provide surgeons with real-time intraoperative margin assessment. In addition to providing a quantified measure of margin status, a co-registered electrical impedance tomography (EIT) image presented on a surgeon's workstation could add value to the margin assessment process. ⋯ The results presented in this paper corroborate our previous studies and present the strongest evidence yet that an intraoperative-capable impedance probe can be used to distinguish benign from malignant prostate tissues. An in vivo study with a large cohort will be necessary to definitively determine the preferred approach and to show the clinical effectiveness of using this technology for margin assessment.
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Physiological measurement · Apr 2017
Development of an improved wearable device for core body temperature monitoring based on the dual heat flux principle.
In this paper, a miniaturized wearable core body temperature (CBT) monitoring system based on the dual heat flux (DHF) principle was developed. ⋯ This system has the potential for reliable continuous CBT measurement in rest and can reflect CBT variations during exercise.
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Physiological measurement · Feb 2017
Improved spectrum analysis in EEG for measure of depth of anesthesia based on phase-rectified signal averaging.
The definition of the depth of anesthesia (DOA) is still controversial and its measurement is not completely standardized in modern anesthesia. Power spectral analysis is an important method for feature detection in electroencephalogram (EEG) signals. Several spectral parameters derived from EEG have been proposed for measuring DOA in clinical applications. ⋯ Especially for raw EEG contaminated by artifacts, when the BIS index is used to indicate the consciousness level, the improvement is 7.37% (p < 0.05), 9.04% (p < 0.05), 18.46% (p < 0.05), 27.73% (p < 0.05), 14.65% (p < 0.05), 2.52%, 5.38% and 6.24% (p < 0.05) for relative alpha and beta power, power ratio, total power, MF, SEF, RE and SE, respectively. However, when the EACL is used to indicate the consciousness level, the improvement is 3.30% (p < 0.05), 16.69% (p < 0.05), 15.08% (p < 0.05), 34.83% (p < 0.05), 27.78% (p < 0.05), 5.89% (p < 0.05), 26.05% (p < 0.05) and 23.42% (p < 0.05). Spectral parameters derived from PRSA are more useful to measure the DOA in noisy cases.