International journal of clinical monitoring and computing
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Int J Clin Monit Comput · Jan 1985
Computerized monitoring of the EMG and EEG during anesthesia. An evaluation of the anesthesia and brain activity monitor (ABM).
An intraoperative evaluation was made of the electroencephalographic (EEG) and electromyographic (EMG) functions of the Anesthesia and Brain activity Monitor (ABM). This device derives both these measures from a single electrode pair that is typically placed on the mid-forehead and mastoid process. The evaluation consisted of 1) quantifying the zero-crossing frequency (ZXF) of the EEG and mean integrated voltage of both measures (MIVEEG and MIVEMG) that occurred during induction and emergence from general anesthesia in 17 patients and 2) case reports sampled from an additional 41 patients. ⋯ The single channel EEG/EMG display of the ABM seems sufficient to warn the anesthesiologist of pathologic decreases in cerebral electrical activity. Marked depression of cerebral function is associated with accidental anesthetic overdose, hypoxia or global ischemia. Additionally, the device should be useful for monitoring burst-suppression or isoelectric EEG patterns intentionally produced during barbiturate or isoflurane coma for cerebral protection.
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A conceptual framework is proposed for the selection of monitored parameters during anesthesia, and a new device for monitoring the parameters in a unified manner is briefly presented. A 'basic set' of 6 parameters is proposed to cover the needs of most routine anesthesia: Blood Pressure, ECG/Heart Rate, Temperature, FiO2, FetCO2, and, Cortical Activity (by EEG spectral analysis). Additional parameters are added in accordance with specified factors such as patient status and complexity of the surgical procedure. An initial version of a new monitor, 'Cerebro Trac', designed for neurosurgery and cardiovascular surgery, is briefly presented, along with planned future capabilities and directions for its use.
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Int J Clin Monit Comput · Jan 1984
Computer application for respiratory data processing in closed circuit anesthesia.
A computerized respiratory monitor system for closed circuit anesthesia is described. The system consists of a mass spectrometer, a hot-wire respiratory flow meter, a microcomputer, a central display and a recorder. Respiratory parameters obtained by the computerized system include O2 consumption, carbon dioxide production, expiratory minute volume and respiratory rate. ⋯ Closed circuit anesthesia is being used with increasing frequency in recent years. The patient's condition must be monitored continuously during the closed circuit anesthesia to maintain optimal depth of anesthesia and to prevent hypoxia or hypercarbia; however, monitoring of the respiratory gas exchange is difficult. We have developed a computerized respiratory monitor system for the closed circuit anesthesia.
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Int J Clin Monit Comput · Jan 1984
Case ReportsPractical aspects of differential ventilation with selective peep in acute respiratory failure.
Hypoxaemia in association with acute respiratory failure continues to be a severe problem in some intensive care patients. Among strategies proposed, we want to focus attention on differential ventilation with selective PEEP, administered in the lateral position. ⋯ The rationale of this concept is briefly presented in this paper, where the main emphasis is laid on the practical aspects of its clinical application. Two case reports are included as examples of our experiences.
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A review of the literature and of our recent data (obtained by computer-based analysis of multiple inert gas elimination) re-emphasizes the significant gas exchange disturbances found to occur during general anesthesia which develop for probably several reasons. In this report we suggest firstly that the reduction in functional residual capacity (FRC) may well be an effect of anesthesia just as is abnormal gas exchange. In other words, the reduction in FRC is not per se the cause of gas exchange disturbances, but rather occurs alongside them. ⋯ Such factors include altered hypoxic vasoconstriction, a change in airway secretions and clearance of those secretions, changes in bronchomotor tone, changes in surfactant activity, and alveolar volume loss due to rapid uptake of soluble anesthetic gases like nitrous oxide. To qualitatively and quantitatively distinguish amongst these various potential factors will require experimental protocols and techniques of a highly controlled and accurate nature. That in 1983 we still do not understand the basic mechanisms behind abnormal gas exchange during anesthesia attests to the difficulty of mounting such an experiment.