Journal of clinical monitoring and computing
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J Clin Monit Comput · Oct 2016
Changes in cerebral oxygen saturation during transcatheter aortic valve replacement.
Cerebral oxygen saturation (rSO2) is a non-invasive monitor used to monitor cerebral oxygen balance and perfusion. Decreases in rSO2 >20 % from baseline have been associated with cerebral ischemia and increased perioperative morbidity. During transcatheter aortic valve replacement (TAVR), hemodynamic manipulation with ventricular pacing up to 180 beats per minute is necessary for valve deployment. ⋯ Furthermore, baseline rSO2 in this population was at the lower limit of the published normal range. Significant cerebral desaturation during valve deployment may potentially be limited by maximizing rSO2 after anesthetic induction. Future studies should attempt to correlate recovery in rSO2 with recovery of hemodynamics and cardiac function, provide detailed neurological assessments pre and post procedure, determine the most effective method of maximizing rSO2 prior to hemodynamic manipulation, and provide the most rapid method of recovery of rSO2 following valve deployment.
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J Clin Monit Comput · Oct 2016
An adaptive real-time beat detection method for continuous pressure signals.
A novel adaptive real-time beat detection method for pressure related signals is proposed by virtue of an enhanced mean shift (EMS) algorithm. This EMS method consists of three components: spectral estimates of the heart rate, enhanced mean shift algorithm and classification logic. The Welch power spectral density method is employed to estimate the heart rate. ⋯ The parameters of the algorithm are adaptively tuned for ensuring its robustness in various heart rate conditions. The performance of the EMS method is validated with expert annotations of two standard databases and a non-invasive dataset. The results from this method show that the sensitivity (Se) and positive predictivity (+P) are significantly improved (i.e., Se > 99.45 %, +P > 98.28 %, and p value 0.0474) by comparison with the existing scheme from the previously published literature.
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J Clin Monit Comput · Oct 2016
Respiratory modulations in the photoplethysmogram (DPOP) as a measure of respiratory effort.
DPOP is a measure of the strength of respiratory modulations present in the pulse oximetry photoplethysmogram (pleth) waveform. It has been proposed as a non-invasive parameter for the prediction of the response to volume expansion in hypovolemic patients. The effect of resistive breathing on the DPOP parameter was studied to determine whether it may have an adjunct use as a measure of respiratory effort. ⋯ Further, a relationship between DPOP and percent modulation of the pleth waveform was observed. A version of the DPOP algorithm that corrects for low perfusion was implemented which resulted in an improved relationship between DPOP and PPV. Although a limited cohort of seven volunteers was used, the results suggest that DPOP may be useful as a respiratory effort parameter, given that the fluid level of the patient is maintained at a constant level over the period of analysis.