Journal of clinical monitoring and computing
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Monitoring of aortic blood flow, conducting large portions of the cardiac output (CO), allows conclusions on the global hemodynamic status of patients. For this purpose, transesophageal Doppler (TED) devices have been developed, which interrogate the descending aorta and calculate aortic blood flow velocity using the Doppler principle. The recorded velocity-time curve can be used to estimate CO as well other advanced hemodynamic parameters such as preload, afterload and myocardial contractility. ⋯ However, several assumptions are needed to translate the measured Doppler frequency shift to hemo- dynamic variables and discrepancies between the assumed and the actual condition may introduce a considerable risk for erroneous calculations. A correct interpretation of the displayed parameters requires profound knowledge on the technical basis of this method as well as its technical limitations. Our review focuses on these technical aspects which the clinician should be familiar with to allow proper use of TED monitoring devices.
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J Clin Monit Comput · Oct 2009
ReviewSpinal cord stimulation: principles of past, present and future practice: a review.
Electric energy have been in use for the treatment of various ailments, including pain, since the time of Pharaohs. The theoretical basis of electrotherapy of pain was provided by the Gate Control Theory of Melzak and Wall. ⋯ The indications for SCS is growing and the technology involved in this is rapidly advancing, however, high level of scientific evidence is still lacking to support this form of therapy due to difficulties in blinding and comparing with control groups. Future developments in SCS could include, combined SCS-drug delivery system, bio feedback and closed loop systems.
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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
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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The use of processed electroencephalography (EEG) using a simple frontal lead system has been made available for assessing the impact of anesthetic medications during surgery. This review discusses the basic principles behind these devices. The foundations of anesthesia monitoring rest on the observations of Guedel with ether that the depth of anesthesia relates to the cortical, brainstem and spinal effects of the anesthetic agents. ⋯ Using mathematical processing techniques, commercial EEG devices create an index usually between 0 and 100 to characterize this drug effect. Critical aspects of memory formation occur in the frontal lobes making EEG monitoring in this area a possible method to assess risk of recall. Integration of processed EEG monitoring into anesthetic management is evolving and its ability to characterize all of the anesthetic effects on the CNS (in particular awareness and recall) and improve decision making is under study.