Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 2013
Validation of the new Complior sensor to record pressure signals non-invasively.
The Complior device (Alam Medical, France) has contributed to the rise of arterial stiffness as a measure of cardiovascular risk. In its latest version (Complior Analyse) the sensor records pressure instead of distension waveforms thus allowing the measurement of central pressure and pulse wave analysis. The aim of our study was to verify that the new sensor measures pressure waveforms accurately in both time and frequency domain. ⋯ These differences were of the same magnitude as the beat-to-beat variation of the form factor (3.3 %) and of the absolute area (3.1 mmHg·s(-1)), respectively. The second systolic peak was detectable in 4 subjects, with no statistical difference between invasive and non-invasive values. The new pressure sensor of the Complior Analyse device recorded pressure waveforms accurately and could be used to perform pressure wave analysis.
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J Clin Monit Comput · Dec 2013
Case ReportsMethohexital in total intravenous anesthesia during intraoperative neurophysiological monitoring.
Total intravenous anesthesia (TIVA) is usually recommended during spinal surgery when transcranial motor evoked potentials (tcMEPs) are used to monitor. A shortage of propofol has prompted a search for an alternative sedative-hypnotic agent. We explored the use of methohexital as an alternative. ⋯ TcMEPs and somatosensory evoked potentials were acquired to monitor neurological function and electroencephalogram was used to titrate the methohexital dose. Two cases are presented in which the anesthesia and monitoring that was provided were successful. These cases indicate that methohexital can be a suitable alternative to propofol in some patients.
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J Clin Monit Comput · Dec 2013
The relationship between the area of peripherally-derived pressure volume loops and systemic vascular resistance.
Arterial and photoplethysmographic (PPG) waveforms have been utilized to non-invasively estimate stroke volume from the pulse contour. The ability of these pulse contour devices to accurately predict stroke volume is degraded when afterload changes significantly. There is a need for a non-invasive device capable of identifying when vascular tone has changed. ⋯ There was no meaningful correlation between ΔSVR and either ΔPVA or ΔMAP (based on minute-to-minute changes). Indexed values of PVA are correlated with indexed values of SVR and may serve as a useful monitor for changes in afterload but in their present form do not offer added value above the measurement of MAP. Incorporation of different (e.g. finger, forehead) and redundant (e.g. bilateral) sites may significantly improve the accuracy of this technique.
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J Clin Monit Comput · Dec 2013
Polyvinylidene fluoride film based nasal sensor to monitor human respiration pattern: An initial clinical study.
Design and development of a piezoelectric polyvinylidene fluoride (PVDF) thin film based nasal sensor to monitor human respiration pattern (RP) from each nostril simultaneously is presented in this paper. Thin film based PVDF nasal sensor is designed in a cantilever beam configuration. Two cantilevers are mounted on a spectacle frame in such a way that the air flow from each nostril impinges on this sensor causing bending of the cantilever beams. ⋯ It was observed that any change/alterations in the pattern of RIP is followed by same amount of change/alterations in the pattern of PVDF nasal sensor with k = 0.815 indicating strong agreement between the PVDF nasal sensor and RIP respiratory air-flow pattern. The developed sensor is simple in design, non-invasive, patient friendly and hence shows promising routine clinical usage. The preliminary result shows that this new method can have various applications in respiratory monitoring and diagnosis.
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J Clin Monit Comput · Dec 2013
Survey of muscle relaxant effects management with a kinemyographic-based data archiving system: a retrospective quantitative and contextual quality control approach.
In a retrospective quality control study of muscle relaxant management, we assessed unbiased files provided by an automatic archiving system using quantitative monitoring generated by a kinemyographic transducer and suggest improvements for a possible future design. 200 randomly selected files were double checked to collect the values of twitch height ratio (THr), train of four ratio (TOFr) and TOF count in four periods: references values acquisition (REF), maximal level of paralysis, paralysis maintenance, pre-tracheal extubation residual paralysis assessment (RPA). The parameter values were selected according to period-specific predefined rules. A quantitative quality control was based upon standardized cut-offs values. ⋯ Presence of "difficult to interpret" episodes started with 18 files for the REF period and increased to 42, 86 and 52 in the subsequent ones most of them probably related to the absence of initial calibration procedure. In the real life conditions, a near to optimal quality control is not always observable with the quantitative neuromuscular monitoring studied. To improve the NMT monitoring, the calibration of the sensor should be performed vigorously by the anaesthesia provider and the quality of this calibration must be displayed on the screen of the monitor.