Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2013
Randomized Controlled TrialThe effect of atropine on the bispectral index response to endotracheal intubation during propofol and remifentanil anesthesia.
Atropine has been reported to increase the propofol requirements for the induction of anesthesia during continuous infusion of propofol. We investigated the influence of atropine on the bispectral index (BIS) response to endotracheal intubation during anesthetic induction with propofol and remifentanil target controlled infusion (TCI). Fifty-six patients aged 18-50 years undergoing general anesthesia, were enrolled. ⋯ From 2 to 5 min after tracheal intubation, BIS was significantly higher in the atropine group than in the control group (p = 0.043, 0.033, 0.049, and 0.001, respectively). When compared with baseline values (immediately before intubation), BIS showed a significant increase at 1 min after intubation in both groups, without intergroup differences, whereas it decreased significantly from 4 to 5 min after intubation only in the control group. This study demonstrated that atropine maintained BIS increases in response to endotracheal intubation during anesthetic induction with propofol and remifentanil TCI, although the maximal response did not differ between the groups.
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J Clin Monit Comput · Apr 2013
Parameter selection in permutation entropy for an electroencephalographic measure of isoflurane anesthetic drug effect.
The permutation entropy (PE) of the electroencephalographic (EEG) signals has been proposed as a robust measure of anesthetic drug effect. The calculation of PE involves the somewhat arbitrary selection of embedding dimension (m) and lag (τ) parameters. Previous studies of PE include the analysis of EEG signals under sevoflurane or propofol anesthesia, where different parameter settings were determined using a number of different criteria. ⋯ Further comparison with previously suggested PE measures, as well as other unrelated EEG measures, indicates the superiority of the NPEI. The PE can be utilized to indicate the dynamical changes of EEG signals under isoflurane anesthesia. In this study, the NPEI measure that combines the PE with m = 3, τ = 2 and that with m = 3, τ = 3 is optimal.
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J Clin Monit Comput · Apr 2013
Comparative StudyComparing hemodynamic effects with three different measurement devices, of two methods of external leg compression versus passive leg raising in patients after cardiac surgery.
External leg compression (ELC) may increase cardiac output (CO) in fluid-responsive patients like passive leg raising (PLR). We compared the hemodynamic effects of two methods of ELC and PLR measured by thermodilution (COtd), pressure curve analysis Modelflow™ (COmf) and ultra-sound HemoSonic™ (COhs), to evaluate the method with the greatest hemodynamic effect and the most accurate less invasive method to measure that effect. We compared hemodynamic effects of two different ELC methods (circular, A (n = 16), vs. wide, B (n = 13), bandages inflated to 30 cm H2O for 15 min) with PLR prior to each ELC method, in 29 post-operative cardiac surgical patients. ⋯ Bland-Altman and polar plots showed lower limits of agreement with changes in COtd for COmf than for COhs. The circular leg compression increases CO more than bandage compression, and is able to increase CO as in PLR. The less invasive Modelflow™ can detect these changes reasonably well.
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J Clin Monit Comput · Apr 2013
Comparative StudyCardiac output measured by uncalibrated arterial pressure waveform analysis by recently released software version 3.02 versus thermodilution in septic shock.
To evaluate the 3.02 software version of the FloTrac/Vigileo™ system for estimation of cardiac output by uncalibrated arterial pressure waveform analysis, in septic shock. Nineteen consecutive patients in septic shock were studied. FloTrac/Vigileo™ measurements (COfv) were compared with pulmonary artery catheter thermodilution-derived cardiac output (COtd). ⋯ Eighty-five percent of the measurements were within the 30°-330° of the polar axis. COfv with the latest software still underestimates COtd at low SVR in septic shock. The tracking capacities of the 3.02 software are moderate-good when clinically relevant changes are considered.
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J Clin Monit Comput · Apr 2013
Identification of apnea during respiratory monitoring using support vector machine classifier: a pilot study.
To determine the use of photoplethysmography (PPG) as a reliable marker for identifying respiratory apnea based on time-frequency features with support vector machine (SVM) classifier. The PPG signals were acquired from 40 healthy subjects with the help of a simple, non-invasive experimental setup under normal and induced apnea conditions. Artifact free segments were selected and baseline and amplitude variabilities were derived from each recording. ⋯ Classification accuracy of 97.22 % was obtained for the combination of power ratio and reflection index features using SVM classifier. The pilot study indicates that PPG can be used as a cost effective diagnostic tool for detecting respiratory apnea using a simple, robust and non-invasive experimental setup. The ease of application and conclusive results has proved that such a system can be further developed for use in real-time monitoring under critical care conditions.