Journal of clinical monitoring and computing
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J Clin Monit Comput · Feb 2008
Comparative Study Clinical TrialNear-infrared spectroscopy to monitor peripheral blood flow perfusion.
Non-invasive evaluation of peripheral perfusion may be useful in many contexts including peri-operative monitoring. We validated a novel non-invasive spectroscopy technique to assess peripheral perfusion. This method, which is based on the measurement of tissue saturation variations after an ischemic period, was compared to strain gauge plethysmography and radionuclide plethysmography. The technique uses near-infrared spectroscopy (NIRS) to determine the rate of change of forearm tissue saturation during reactive hyperemia. ⋯ The NIRS technique appears well suited for the non-invasive evaluation of limb perfusion.
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J Clin Monit Comput · Feb 2008
ReviewEvaluations of physiological monitoring displays: a systematic review.
The purpose of this paper is to present the findings from a systematic review of evaluation studies for physiologic monitoring displays, centered on empirical assessments across all available settings and samples. The findings from this review give readers the opportunity to examine past work across studies and set the stage for the design and conduct of future evaluations. ⋯ The advent of integrated graphical displays ushered a new era into physiological monitoring display designs. All but one study reported significant differences between traditional, numerical displays and novel displays; yet we know little about which graphical displays are optimal and why particular designs work. Future authors should use a theoretical model or framework to guide the study design, focus on other clinical study participants besides anesthesiologists, employ additional research methods and use more realistic and complex tasks and settings to increase external validity.
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J Clin Monit Comput · Feb 2008
Comparative StudyCan photoplethysmography variability serve as an alternative approach to obtain heart rate variability information?
Heart rate variability (HRV), extracted from an electrocardiogram, is known to be a noninvasive indicator reflecting the dynamic interplay between perturbations to cardiovascular function and the dynamic response of the cardiovascular regulatory system. Photoplethysmography (PPG) is a noninvasive method to monitor arterial oxygen saturation on a continuous basis. Given the rich cardiovascular information in the PPG signal, and the ubiquity and simplicity of pulse oximetry, we are investigating the feasibility of acquiring dynamics pertaining to the autonomic nervous system from PPG waveforms. ⋯ We compare PPGV to HRV by computing time and frequency domain parameters often associated with HRV measurements, as well as approximate entropy calculations. Our results demonstrate that the parameters of PPGV are highly correlated with the parameters of HRV. Thus, our results indicate that PPGV could be used as an alternative measurement of HRV.
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J Clin Monit Comput · Dec 2007
Using Bland-Altman to assess agreement between two medical devices--don't forget the confidence intervals!
The limits of agreement approach of Bland and Altman is by far the most popular method for investigating statistical agreement between two measurement devices. This work presents the dangers of relying exclusively on the limits of agreement alone and argues that authors should always provide confidence intervals to assess the variability in the estimated limits.