Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2002
Mycardial ischemia and determined chaos in integral homeostatic regulation.
This study was devoted to the problem of homeostatic stability loss caused by myocardial ischemia, induced by stress testing. It involved 55 patients with different variants of coronary heart disease and 15 practically healthy volunteers as controls. Routine bicycle ergometry and nonstop monitoring of the cardiac-interval duration were conducted simultaneously. ⋯ Determined chaos was shown to be the main property of these dynamics in all cases. The original method of measuring the cardiac rhythm entropy chaotisity level is presented. It is suggested that the newly revealed phenomenon of a sharp rise in the cardiac entropy trajectory chaotisity level and followed by a decrease, which happens in the multidimensional phase space, may be used as an additional criterion of myocardial ischemia development for the verification of dubious stress-testing results.
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J Clin Monit Comput · Apr 2002
Monitoring pulmonary function with superimposed pulmonary gas exchange curves from standard analyzers.
A repetitive graphic display of the single breath pulmonary function can indicate changes in cardiac and pulmonary physiology brought on by clinical events. Parallel advances in computer technology and monitoring make real-time, single breath pulmonary function clinically practicable. We describe a system built from a commercially available airway gas monitor and off the shelf computer and data-acquisition hardware. ⋯ This paper describes a real-time, single breath pulmonary monitoring system that displays three parameters graphed against time: expired flow rate, oxygen uptake and carbon dioxide production. This system allows for early and rapid recognition of treatable conditions that may lead to adverse events without any additional patient measurements or invasive procedures. Monitoring systems similar to the one described in this paper may lead to a higher level of patient safety without any additional patient risk.
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J Clin Monit Comput · Apr 2002
A prototype device for standardized calibration of pulse oximeters II.
There is no commonly accepted in vivo calibration method for pulse oximeters available up to now. On the basis of a prototype device for the calibration of pulse oximeters which was introduced recently, a second approach based on the same concept was tackled in order to design a reliable method for standardized calibration of pulse oximeters. ⋯ Compared to the first prototype the current version is simpler and less expensive in production. Many of previously existing problems are solved and the applicability to a large variety of pulse oximeters and sensors is given. The novel concept for the calibration of pulse oximeters is a tool for assessing the performance of pulse oximeters.
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J Clin Monit Comput · Apr 2002
Comparative StudyComparison of endotracheal tube and hookwire electrodes for monitoring the vagus nerve.
Monitoring the vagus nerve and the recurrent laryngeal nerve during surgical procedures may reduce the probability of significant nerve injury. As such, a number of methods to monitor these nerves have been devised including placing electrodes directly into the vocal cords or recording from surface electrodes. In direct comparison, monitoring the identical muscles, bipolar hookwire electrodes displayed approximately one order of magnitude greater amplitude, of both spontaneously occurring and evoked electrical activity than double wire endotracheal tube electrodes. The enhanced sensitivity of the hookwire electrodes, despite the technical difficulties with placement, suggests their use when maximum sensitivity is required.
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J Clin Monit Comput · Apr 2002
Real-time pulse oximetry artifact annotation on computerized anaesthetic records.
Adoption of computerised anaesthesia record keeping systems has been limited by the concern that they record artifactual data and accurate data indiscriminately. Data resulting from artifacts does not reflect the patient's true condition and presents a problem in later analysis of the record, with associated medico-legal implications. This study developed an algorithm to automatically annotate pulse oximetry artifacts and sought to evaluate the algorithm's accuracy in routine surgical procedures. ⋯ The real-time artifact detection algorithm developed in this study was more accurate than anaesthetists who post-operatively reviewed records produced by an existing computerised anaesthesia record keeping system. Algorithms have the potential to more accurately identify and annotate artifacts on computerised anaesthetic records, assisting clinicians to more correctly interpret abnormal data.