Journal of clinical monitoring and computing
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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.
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J Clin Monit Comput · Oct 2006
ReviewIntraoperative motor evoked potential monitoring: overview and update.
Amidst controversy about methodology and safety, intraoperative neurophysiology has entered a new era of increasingly routine transcranial and direct electrical brain stimulation for motor evoked potential (MEP) monitoring. Based on literature review and illustrative clinical experience, this tutorial aims to present a balanced overview for experienced practitioners, surgeons and anesthesiologists as well as those new to the field. ⋯ The many advances in motor system assessment achieved in the last two decades undoubtedly improve monitoring efficacy without unduly compromising safety. Future studies and experience will likely clarify existing controversies and bring further advances.
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J Clin Monit Comput · Dec 2004
ReviewPulse transit time by R-wave-gated infrared photoplethysmography: review of the literature and personal experience.
Pulse transit time (PTT) is the time it takes a pulse wave to travel between two arterial sites. A rela tively short PTT is observed with high blood pressure (BP), aging, arteriosclerosis and diabetes mellitus. Most methods used for measuring the PTT are cumbersome and expensive. In contrast, the interval between the peak of the R-wave on the electrocardiogram and the onset of the corresponding pulse in the finger pad measured by photoplethysmography can be easily measured. We review herein the literature and impart the experience at our institution on clinical applications of R-wave-gated photo-plethysmography (RWPP) as measurement of PTT. ⋯ In clinical practice, sleep-apnea may be accurately monitored by RWPP. RWPP seems to reflect autonomic influences and may be particularly well-suited for the study of vascular reactivity. Thus, further descriptions of disease-specific cardiovascular reactivity patterns may be possible with techniques based on RWPP. Other clinical uses of RWPP are investigational.
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Fetal pulse oximetry shares many problems with traditional pulse oximetry, but also poses unique challenges that may compromise accurate SpO2 determination and data availability. The purpose of this review is to characterize the factors that may influence fetal pulse oximetry and their relationship to sensor design. A review of the literature of pulse oximetry identifies the factors that have been shown to influence fetal pulse oximetry performance, as well as other factors from traditional pulse oximetry that may also be expected to have an effect. ⋯ The factors influencing fetal pulse oximetry may be categorized as follows: fetal physiology, tissue characteristics at the monitoring site, sensor-tissue interface, and external influences. Monitoring site selection is of paramount importance in reducing the impact of interfering factors on fetal pulse oximetry performance. Many factors of importance in traditional pulse oximetry have yet to be characterized as far as their potential for interference in fetal pulse oximetry.