Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2014
Improved spatial resolution and electrogram wave direction independence with the use of an orthogonal electrode configuration.
To improve spatial resolution in recordings of intra-cardiac electrograms we characterized the utility of a novel configuration of two recording electrodes arranged perpendicularly to the endocardial surface. We hypothesized that this configuration denoted as orthogonal close unipolar (OCU) would combine advantages of conventional unipolar and contact bipolar (CBP) configurations. Electrical excitation was simulated in a computational model as arising from dipole current or from multi-wavelet reentry sources. ⋯ The difference between the actual dominant frequency in the tissue and that recorded by the electrodes was 0.44 ± 0.33 Hz for OCU, 0.58 ± 0.40 Hz for unipolar, and 0.62 ± 0.46 Hz for CBP. OCU confers improved spatial resolution compared with both unipolar and CBP electrode configurations. Unlike the case with CBP, OCU recordings are independent of excitation wave-front direction.
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J Clin Monit Comput · Apr 2014
Controlled Clinical TrialEntropy correlates with Richmond Agitation Sedation Scale in mechanically ventilated critically ill patients.
Sedation is routinely used in intensive care units. However due to absence of objective scoring systems like Bispectral Index and entropy our ability to regulate the degree of sedation is limited. This deficiency is further highlighted by the fact that agitation scores used in intensive care units (ICU) have no role in paralyzed patients. ⋯ There was a statistically significant correlation between the state entropy (SE) and RASS [Spearman's rho/rs = 0.334, p\0.0001]; response entropy (RE) and RASS [Spearman's rho/rs = 0.341, p\0.0001]). For adequate sedation as judged by a RASS value of 0 to -3, the mean SE was 57.86 ± 16.50 and RE was 67.75 ± 15.65. The present study illustrates that entropy correlates with RASS (between scores 0 and -3) when assessing the level of sedation in mechanically ventilated critically ill patients.
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J Clin Monit Comput · Apr 2014
Comparative StudyPeripheral tissue oximetry: comparing three commercial near-infrared spectroscopy oximeters on the forearm.
Estimation of regional tissue oxygenation (rStO2) by near infrared spectroscopy enables non-invasive end-organ oxygen balance monitoring and could be a valuable tool in intensive care. However, the diverse absolute values and dynamics of different devices, and overall poor repeatability of measurements are a problem. The aim of the present study is to test the hypothesis that INVOS 5100C, FORE-SIGHT and NONIN EQUANOX 7600 have similar properties concerning absolute values, repeatability, and sensitivity to changes in rStO2. ⋯ Two measures of signal-to-noise were similar among devices. This suggests that good repeatability comes at the expense of low sensitivity to changes in oxygenation. Values of rStO2 on the forearm from INVOS, NONIN and FORE-SIGTH cannot be used interchangeably.
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J Clin Monit Comput · Apr 2014
Comparative StudyElevated preoperative blood pressure predicts the intraoperative loss of SSEP neuromonitoring signals during spinal surgery.
Intraoperative neuromonitoring of somatosensory evoked potentials (SSEPs) can allow identification of evolving neurologic deficit. However, SSEP deterioration is not always associated with postoperative deficit. Transient physiologic changes, including a decrease in blood pressure (BP), can result in signal deterioration, defined as a decrease in waveform amplitude of[50 %seen without neurologic deficit. ⋯ While the presence of preoperative elevated BP predicts SSEP abnormality (p = 0.0039), a diagnosis of hypertension does not. Elevated BP, not a hypertension diagnosis, is associated with intraoperative loss of SSEP signals. This effect of elevated BP on SSEPs may be due to the larger associated intraoperative BP decline.
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J Clin Monit Comput · Apr 2014
Practice guidelines for the supervising professional: intraoperative neurophysiological monitoring.
The American Society of Neurophysiological Monitoring (ASNM) was founded in 1988 as the American Society of Evoked Potential Monitoring. From the beginning, the Society has been made up of physicians, doctoral degree holders, technologists, and all those interested in furthering the profession. The Society changed its name to the ASNM and held its first Annual Meeting in 1990. ⋯ Adherence to a literature-based, formalized process characterizes the construction of all ASNM guidelines. The guidelines covering the Professional Practice of intraoperative monitoring were established by a committee of nearly 30 total participants and ultimately endorsed by the Board of Directors of ASNM on January 24th 2013. That document follows.