Journal of clinical monitoring and computing
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J Clin Monit Comput · Jan 2000
Estimation of jugular venous O2 saturation from cerebral oximetry or arterial O2 saturation during isocapnic hypoxia.
Near-infrared spectroscopy (NIRS) has the potential for providing valuable information about oxygen delivery to the brain. However, questions have been raised about the accuracy of these measurements. This study was undertaken to compare noninvasive cerebral saturation measurements to jugular venous saturation under conditions of hypoxia and hypercapnia. ⋯ Cerebral oxygen saturation measured by cerebral oximetry compares well to the measured SjvO2 in normal subjects, despite multiple physiological reasons for differences. The closer relationship of SjvO2 to rSO2 than SaO2 under the conditions of these experiments indicates that the measurement reflects primarily intracranial saturation. However, outcome studies under clinical conditions are needed to determine the clinical utility of cerebral oximetry.
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J Clin Monit Comput · Jan 2000
Hierarchical rule-based monitoring and fuzzy logic control for neuromuscular block.
The important task for anaesthetists is to provide an adequate degree of neuromuscular block during surgical operations, so that it should not be difficult to antagonize at the end of surgery. Therefore, this study examined the application of a simple technique (i.e., fuzzy logic) to an almost ideal muscle relaxant (i.e., rocuronium) at general anaesthesia in order to control the system more easily, efficiently, intelligently and safely during an operation. ⋯ The results showed that a hierarchical rule-based monitoring and fuzzy logic control architecture can provide stable control of neuromuscular block despite the considerable individual variation in neuromuscular block required among patients. Also, there was less variation in T1% error compared with that of previous study on mivacurium. Meanwhile, the consistent medium CV of the MIR of both rocuronium and mivacurium indicated a good controller activity which is able to withstand noise, diathermy effect, artifacts and surgical disturbances.
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J Clin Monit Comput · Jan 2000
Clinical TrialMonitoring of respiratory rate in postoperative care using a new photoplethysmographic technique.
Photoplethysmography (PPG) is a non-invasive optical technique that measures variations in skin blood volume and perfusion. The PPG signal contains components that are synchronous with respiratory and cardiac rhythms. We undertook this study to evaluate PPG for monitoring patients' respiratory rate in the postoperative care unit, using a new prototype device. We compared it with the established technique, transthoracic impedance (TTI). ⋯ Our results indicate that PPG has the potential to be useful for monitoring respiratory rate in the postoperative period.
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J Clin Monit Comput · Jan 2000
Randomized Controlled Trial Clinical TrialSpecific elements of a new hemodynamics display improves the performance of anesthesiologists.
We tested the hypothesis that a monitoring display proposed by Blike et al. improves the performance of anesthesiologists. We measured the performance of anesthesiologists using the new display and compared it to their performance with a traditional display. We studied three different displays on how they affected recognition and differentiation of five etiologies of shock-anaphylaxis, bradycardia, hypovolemia, ischemia and pulmonary embolus. ⋯ The new display with "emergent features" can improve the diagnostic performance of clinicians.
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To develop and test a method for standardized calibration of pulse oximeters. ⋯ The tests have shown the capabilities of a spectral light modulator for use as a possible calibration standard for pulse oximeters. If some improvements of the current prototype can be achieved we conclude from the experience with the device that this novel concept for the calibration of pulse oximeters is feasible and that it could become an important tool for assessing the performance of pulse oximeters.