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
Clinical TrialA preliminary evaluation of a new derived EEG index monitor in anesthetized patients.
An electroencephalogram (EEG) monitoring device, recently developed by Nicolet Biomedical, analyzes both high and low EEG frequencies. A processed derivative is obtained and displayed graphically and numerically on a monitor and may be used during anesthesia to indicate anesthetic "depth." However, radio-frequency interference from electrical equipment typically used in the operating room has the potential to interfere with the analysis of the high frequency components of the EEG. ⋯ The derived EEG Index monitoring system evaluated in this study functioned satisfactorily in the operating room setting in patients undergoing general anesthesia. Interference from ESU, facial nerve stimulation, and movement of the electrode wires caused brief interruptions of the derived EEG Index display and did not affect its utility in monitoring brain activity during anesthesia.
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J Clin Monit Comput · Jul 2002
Comparative StudyActivated clotting time systems vary in precision and bias and are not interchangeable when following heparin management protocols during cardiopulmonary bypass.
Our aim was to test the hypothesis that new activated clotting time (ACT) technology, with modifications to instruments and reagents designed to detect earlier clot formation, would be associated with more precise but lower results. A secondary objective was to evaluate the potential impact of any change in ACT measurement on heparin requirements during cardiopulmonary bypass (CPB). ⋯ Our results support the hypothesis that the modified technology (Actalyke) is associated with more precise but lower ACT results. We estimated these lower values would lead to increased heparin dosing during CPB. The impact of this increase on bleeding after cardiac surgery with CPB is controversial and requires further study.
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J Clin Monit Comput · Jul 2002
Bispectral Index in ICU: correlation with Ramsay Score on assessment of sedation level.
The assessment of sedation level in critically ill patient remains a challenge for the intensivists in order to avoid over- or under-sedation phenomena. Scoring systems commonly used still show some limitation; the introduction of Bispectral Index (an EEG parameter) could bring potential advantages in monitoring sedation. According to the reports, Bispectral Index correlates with levels of sedation on the Ramsay Scale. We report our personal experience in this topic. ⋯ The results of the study are consistent with those found in the literature on this topic of study. In fact, this study demonstrates the utility of BIS to track levels of consciousness in ICU patients while still maintaining the use of the score systems to care for ICU patients.
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J Clin Monit Comput · Jul 2002
Pulmonary blood flow (cardiac output) and the effective lung volume determined from a short breath hold using the differential Fick method.
This work attempts to show how pulmonary blood flow (Qp), cardiac output (CO(Fick)) and the lung volume of effective gas exchange (ELV) can be determined from breath-by-breath measurements of the tidal exhaled CO2 elimination V (litre/min) and the end tidal CO2 concentration P (%) using the differential Fick method. The measurements are made during steady state ventilation and when the CO2 balance in the lungs changes subsequent to a perturbation of the gas exchange conditions. ⋯ With a single breath perturbation, the differential Fick method can yield cardiopulmonary information using 2-3 breaths only and with a minimum of interference with the patient. Complete data analysis results in multiple determinations of the Qp and ELV values which improve the attainable precision. Our investigation points to the possibility to determine Qp, CO(Fick) and ELV also during spontaneous breathing, by using the natural tidal variations of V and P.