Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2002
Clinical TrialCorrelation beween AAI-index and the BIS-index during propofol hypnosis: a clinical study.
To determine the degree of linearity and correlation between the anaesthetic depth indices BIS and AAI over a wide range of hypnotic depth using propofol. ⋯ The AAI-index correlates with the BIS-index during propofol hypnosis in the absence of surgical stimulation. Neither the BIS-index, heart rate, nor systemic blood pressure were influenced by the acoustical stimulation from the A-line monitor. Both indices decreased in relation to increasing doses of propofol, but the AAI-index was lower both before becoming unconscious, during transition to unconsciousness, and during the deeper levels of sedation. The AAI-index lacks linearity at both very low and higher levels of propofol sedation with a nearly on-off behaviour for wakefulness vs hypnosis.
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J Clin Monit Comput · Aug 2002
Temporal patient state characterization using Iterative Order and Noise (ION) estimation: applications to anesthesia patient monitoring.
As more sensors are added to increasingly technology-dependent operating rooms (OR), physicians such as anesthesiologists must sift through an ever-increasing number of patient parameters every few seconds as part of their OR duties. To the extent these many parameters are correlated and redundant, manually monitoring all of them may not be an optimal physician strategy for assessing patient state or predicting future changes to guide their actions. ⋯ This paper illustrates the use of ION to improve significantly the performance of PCA in the efficient representation of patient state and in improving the performance of linear predictors of clinically significant parameters.
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J Clin Monit Comput · Aug 2002
Randomized Controlled Trial Clinical TrialBiasing effect of the electromyogram on BIS: a controlled study during high-dose fentanyl induction.
A biasing effect of the electromyogram (EMG) on the Bispectral Index (BIS) may explain discrepancies in previous studies assessing BIS in the presence of neuromuscular activity. Our aims were: to evaluate variations of BIS in the presence of high EMG activity associated with muscular rigidity after administration of high-dose fentanyl; to compare muscular rigidity, as measured by the EMG variable of the BIS monitor, in patients who were administered two different dosages of fentanyl at induction of cardiac anaesthesia. ⋯ During fentanyl-induced muscular rigidity BIS recordings reflect EMG variations. When assessing BIS in the absence of neuromuscular blockade, it is necessary to evaluate the effect of EMG on BIS before making conclusions about depth of sedation. Fentanyl-induced rigidity appears to be a dose-related phenomenon which the EMG variable of BIS 3.4 is able to quantify.
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J Clin Monit Comput · Aug 2002
Clinical TrialA better landmark for positioning a central venous catheter.
Improper positioning of central venous catheters (CVCs) can lead to erosion through the superior vena cava (SVC) or right atrium (RA) and pericardial tamponade. It is widely recommended that the tip of CVCs be placed above the heart or the pericardial reflection. The purpose of this study was to identify an easily recognized landmark to allow identification of the proximal extent of the pericardial reflection on a routine chest radiograph (CXR). ⋯ The distal half of the SVC lies within the pericardial reflection, and the upper limit of the pericardial reflection is slightly above the level of the carina. These landmarks are useful for determining proper position of the tip of a CVC on CXR.
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J Clin Monit Comput · Aug 2002
Closed-loop control if the inspired fraction of oxygen in mechanical ventilation.
Supplemental oxygen treatment of patients on mechanical ventilation is crucial in maintaining the patients' oxygen levels in the normal range. The purpose of this study was to evaluate the effectiveness of a closed-loop controller for automatic adjustment of the fraction of inspired oxygen, FIO2. More specifically, the aim of the study was to assess the robustness of the controller in correcting hypoxemia as well as its effectiveness in prevention of hyperoxemia and oxygen toxicity. ⋯ The results of the study attest to the reliability of the proposed closed-loop control scheme for automatic adjustment of FIO2. Further evaluation of the controller will require testing the effectiveness of the system on different patient groups.