The Experts below are selected from a list of 95823 Experts worldwide ranked by ideXlab platform
Cyrill Hornuss - One of the best experts on this subject based on the ideXlab platform.
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time course of expiratory Propofol after bolus injection as measured by ion molecule reaction mass spectrometry
Analytical and Bioanalytical Chemistry, 2012Co-Authors: Cyrill Hornuss, Dirk Wiepcke, Siegfried Praun, Michael E Dolch, Christian C Apfel, Gustav SchellingAbstract:Propofol in exhaled breath can be detected and monitored in real time by ion molecule reaction mass spectrometry (IMR-MS). In addition, Propofol concentration in exhaled breath is tightly correlated with Propofol concentration in plasma. Therefore, real-time monitoring of expiratory Propofol could be useful for titrating intravenous anesthesia, but only if concentration changes in plasma can be determined in exhaled breath without significant delay. To evaluate the utility of IMR-MS during non-steady-state conditions, we measured the time course of both expiratory Propofol concentration and the processed electroencephalography (EEG) as a surrogate outcome for Propofol effect after an IV bolus induction of Propofol. Twenty-one patients scheduled for routine surgery were observed after a bolus of 2.5 mg kg−1 Propofol for induction of anesthesia. Expiratory Propofol was measured using IMR-MS and the cerebral Propofol effect was estimated using the bispectral index (BIS). Primary endpoints were time to detection of expiratory Propofol and time to onset of Propofol’s effect on BIS, and the secondary endpoint was time to peak effect (highest expiratory Propofol or lowest BIS). Expiratory Propofol and changes in BIS were first detected at 43 ± 21 and 49 ± 11 s after bolus injection, respectively (P = 0.29). Peak Propofol concentrations (9.2 ± 2.4 parts-per-billion) and lowest BIS values (23 ± 4) were reached after 208 ± 57 and 219 ± 62 s, respectively (P = 0.57). Expiratory Propofol concentrations measured by IMR-MS have similar times to detection and peak concentrations compared with Propofol effect as measured by the processed EEG (BIS). This suggests that expiratory Propofol concentrations may be useful for titrating intravenous anesthesia.
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real time monitoring of Propofol in expired air in humans undergoing total intravenous anesthesia
Anesthesiology, 2007Co-Authors: Cyrill Hornuss, Siegfried Praun, Michael E Dolch, Johannes Villinger, Albert Dornauer, Patrick Moehnle, Ernst Weninger, Alexander Chouker, Christian Feil, J BriegelAbstract:Background: The physicochemical properties of Propofol could allow diffusion across the alveolocapillary membrane and a measurable degree of pulmonary Propofol elimination. The authors tested this hypothesis and showed that Propofol can be quantified in expiratory air and that Propofol breath concentrations reflect blood concentrations. This could allow real-time monitoring of relative changes in the Propofol concentration in arterial blood during total intravenous anesthesia. Methods: The authors measured gas-phase Propofol using a mass spectrometry system based on ion-molecule reactions coupled with quadrupole mass spectrometry which provides a highly sensitive method for on-line and off-line measurements of organic and inorganic compounds in gases. In a first sequence of experiments, the authors sampled blood from neurosurgery patients undergoing total intravenous anesthesia and performed Propofol headspace determination above the blood sample using an auto-sampler connected to the mass spectrometry system. In a second set of experiments, the mass spectrometry system was connected directly to neurosurgery patients undergoing target-controlled infusion via a T piece inserted between the endotracheal tube and the Y connector of the anesthesia machine, and end-expiratory Propofol concentrations were measured on-line. Results: A close correlation between Propofol whole blood concentration and Propofol headspace was found (range of Pearsonr, 0.846-0.957;P < 0.01; n = 6). End-expiratory Propofol signals mirrored whole blood values with close intraindividual correlations between both parameters (range of Pearson r, 0.784-0.985; n = 11). Conclusion: Ion-molecule reaction mass spectrometry may allow the continuous and noninvasive monitoring of expiratory Propofol levels in patients undergoing general anesthesia.
Siegfried Praun - One of the best experts on this subject based on the ideXlab platform.
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time course of expiratory Propofol after bolus injection as measured by ion molecule reaction mass spectrometry
Analytical and Bioanalytical Chemistry, 2012Co-Authors: Cyrill Hornuss, Dirk Wiepcke, Siegfried Praun, Michael E Dolch, Christian C Apfel, Gustav SchellingAbstract:Propofol in exhaled breath can be detected and monitored in real time by ion molecule reaction mass spectrometry (IMR-MS). In addition, Propofol concentration in exhaled breath is tightly correlated with Propofol concentration in plasma. Therefore, real-time monitoring of expiratory Propofol could be useful for titrating intravenous anesthesia, but only if concentration changes in plasma can be determined in exhaled breath without significant delay. To evaluate the utility of IMR-MS during non-steady-state conditions, we measured the time course of both expiratory Propofol concentration and the processed electroencephalography (EEG) as a surrogate outcome for Propofol effect after an IV bolus induction of Propofol. Twenty-one patients scheduled for routine surgery were observed after a bolus of 2.5 mg kg−1 Propofol for induction of anesthesia. Expiratory Propofol was measured using IMR-MS and the cerebral Propofol effect was estimated using the bispectral index (BIS). Primary endpoints were time to detection of expiratory Propofol and time to onset of Propofol’s effect on BIS, and the secondary endpoint was time to peak effect (highest expiratory Propofol or lowest BIS). Expiratory Propofol and changes in BIS were first detected at 43 ± 21 and 49 ± 11 s after bolus injection, respectively (P = 0.29). Peak Propofol concentrations (9.2 ± 2.4 parts-per-billion) and lowest BIS values (23 ± 4) were reached after 208 ± 57 and 219 ± 62 s, respectively (P = 0.57). Expiratory Propofol concentrations measured by IMR-MS have similar times to detection and peak concentrations compared with Propofol effect as measured by the processed EEG (BIS). This suggests that expiratory Propofol concentrations may be useful for titrating intravenous anesthesia.
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real time monitoring of Propofol in expired air in humans undergoing total intravenous anesthesia
Anesthesiology, 2007Co-Authors: Cyrill Hornuss, Siegfried Praun, Michael E Dolch, Johannes Villinger, Albert Dornauer, Patrick Moehnle, Ernst Weninger, Alexander Chouker, Christian Feil, J BriegelAbstract:Background: The physicochemical properties of Propofol could allow diffusion across the alveolocapillary membrane and a measurable degree of pulmonary Propofol elimination. The authors tested this hypothesis and showed that Propofol can be quantified in expiratory air and that Propofol breath concentrations reflect blood concentrations. This could allow real-time monitoring of relative changes in the Propofol concentration in arterial blood during total intravenous anesthesia. Methods: The authors measured gas-phase Propofol using a mass spectrometry system based on ion-molecule reactions coupled with quadrupole mass spectrometry which provides a highly sensitive method for on-line and off-line measurements of organic and inorganic compounds in gases. In a first sequence of experiments, the authors sampled blood from neurosurgery patients undergoing total intravenous anesthesia and performed Propofol headspace determination above the blood sample using an auto-sampler connected to the mass spectrometry system. In a second set of experiments, the mass spectrometry system was connected directly to neurosurgery patients undergoing target-controlled infusion via a T piece inserted between the endotracheal tube and the Y connector of the anesthesia machine, and end-expiratory Propofol concentrations were measured on-line. Results: A close correlation between Propofol whole blood concentration and Propofol headspace was found (range of Pearsonr, 0.846-0.957;P < 0.01; n = 6). End-expiratory Propofol signals mirrored whole blood values with close intraindividual correlations between both parameters (range of Pearson r, 0.784-0.985; n = 11). Conclusion: Ion-molecule reaction mass spectrometry may allow the continuous and noninvasive monitoring of expiratory Propofol levels in patients undergoing general anesthesia.
Michael E Dolch - One of the best experts on this subject based on the ideXlab platform.
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time course of expiratory Propofol after bolus injection as measured by ion molecule reaction mass spectrometry
Analytical and Bioanalytical Chemistry, 2012Co-Authors: Cyrill Hornuss, Dirk Wiepcke, Siegfried Praun, Michael E Dolch, Christian C Apfel, Gustav SchellingAbstract:Propofol in exhaled breath can be detected and monitored in real time by ion molecule reaction mass spectrometry (IMR-MS). In addition, Propofol concentration in exhaled breath is tightly correlated with Propofol concentration in plasma. Therefore, real-time monitoring of expiratory Propofol could be useful for titrating intravenous anesthesia, but only if concentration changes in plasma can be determined in exhaled breath without significant delay. To evaluate the utility of IMR-MS during non-steady-state conditions, we measured the time course of both expiratory Propofol concentration and the processed electroencephalography (EEG) as a surrogate outcome for Propofol effect after an IV bolus induction of Propofol. Twenty-one patients scheduled for routine surgery were observed after a bolus of 2.5 mg kg−1 Propofol for induction of anesthesia. Expiratory Propofol was measured using IMR-MS and the cerebral Propofol effect was estimated using the bispectral index (BIS). Primary endpoints were time to detection of expiratory Propofol and time to onset of Propofol’s effect on BIS, and the secondary endpoint was time to peak effect (highest expiratory Propofol or lowest BIS). Expiratory Propofol and changes in BIS were first detected at 43 ± 21 and 49 ± 11 s after bolus injection, respectively (P = 0.29). Peak Propofol concentrations (9.2 ± 2.4 parts-per-billion) and lowest BIS values (23 ± 4) were reached after 208 ± 57 and 219 ± 62 s, respectively (P = 0.57). Expiratory Propofol concentrations measured by IMR-MS have similar times to detection and peak concentrations compared with Propofol effect as measured by the processed EEG (BIS). This suggests that expiratory Propofol concentrations may be useful for titrating intravenous anesthesia.
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real time monitoring of Propofol in expired air in humans undergoing total intravenous anesthesia
Anesthesiology, 2007Co-Authors: Cyrill Hornuss, Siegfried Praun, Michael E Dolch, Johannes Villinger, Albert Dornauer, Patrick Moehnle, Ernst Weninger, Alexander Chouker, Christian Feil, J BriegelAbstract:Background: The physicochemical properties of Propofol could allow diffusion across the alveolocapillary membrane and a measurable degree of pulmonary Propofol elimination. The authors tested this hypothesis and showed that Propofol can be quantified in expiratory air and that Propofol breath concentrations reflect blood concentrations. This could allow real-time monitoring of relative changes in the Propofol concentration in arterial blood during total intravenous anesthesia. Methods: The authors measured gas-phase Propofol using a mass spectrometry system based on ion-molecule reactions coupled with quadrupole mass spectrometry which provides a highly sensitive method for on-line and off-line measurements of organic and inorganic compounds in gases. In a first sequence of experiments, the authors sampled blood from neurosurgery patients undergoing total intravenous anesthesia and performed Propofol headspace determination above the blood sample using an auto-sampler connected to the mass spectrometry system. In a second set of experiments, the mass spectrometry system was connected directly to neurosurgery patients undergoing target-controlled infusion via a T piece inserted between the endotracheal tube and the Y connector of the anesthesia machine, and end-expiratory Propofol concentrations were measured on-line. Results: A close correlation between Propofol whole blood concentration and Propofol headspace was found (range of Pearsonr, 0.846-0.957;P < 0.01; n = 6). End-expiratory Propofol signals mirrored whole blood values with close intraindividual correlations between both parameters (range of Pearson r, 0.784-0.985; n = 11). Conclusion: Ion-molecule reaction mass spectrometry may allow the continuous and noninvasive monitoring of expiratory Propofol levels in patients undergoing general anesthesia.
J Briegel - One of the best experts on this subject based on the ideXlab platform.
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real time monitoring of Propofol in expired air in humans undergoing total intravenous anesthesia
Anesthesiology, 2007Co-Authors: Cyrill Hornuss, Siegfried Praun, Michael E Dolch, Johannes Villinger, Albert Dornauer, Patrick Moehnle, Ernst Weninger, Alexander Chouker, Christian Feil, J BriegelAbstract:Background: The physicochemical properties of Propofol could allow diffusion across the alveolocapillary membrane and a measurable degree of pulmonary Propofol elimination. The authors tested this hypothesis and showed that Propofol can be quantified in expiratory air and that Propofol breath concentrations reflect blood concentrations. This could allow real-time monitoring of relative changes in the Propofol concentration in arterial blood during total intravenous anesthesia. Methods: The authors measured gas-phase Propofol using a mass spectrometry system based on ion-molecule reactions coupled with quadrupole mass spectrometry which provides a highly sensitive method for on-line and off-line measurements of organic and inorganic compounds in gases. In a first sequence of experiments, the authors sampled blood from neurosurgery patients undergoing total intravenous anesthesia and performed Propofol headspace determination above the blood sample using an auto-sampler connected to the mass spectrometry system. In a second set of experiments, the mass spectrometry system was connected directly to neurosurgery patients undergoing target-controlled infusion via a T piece inserted between the endotracheal tube and the Y connector of the anesthesia machine, and end-expiratory Propofol concentrations were measured on-line. Results: A close correlation between Propofol whole blood concentration and Propofol headspace was found (range of Pearsonr, 0.846-0.957;P < 0.01; n = 6). End-expiratory Propofol signals mirrored whole blood values with close intraindividual correlations between both parameters (range of Pearson r, 0.784-0.985; n = 11). Conclusion: Ion-molecule reaction mass spectrometry may allow the continuous and noninvasive monitoring of expiratory Propofol levels in patients undergoing general anesthesia.
Samuel H.h. Chan - One of the best experts on this subject based on the ideXlab platform.
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Concentration and regional distribution of Propofol in brain and spinal cord during Propofol anesthesia in the rat.
Neuroscience letters, 1995Co-Authors: Ming-hwang Shyr, Tung-hu Tsai, Peter P. C. Tan, Chieh-fu Chen, Samuel H.h. ChanAbstract:Abstract We evaluated the pharmacokinetics and regional distribution of Propofol in the brain and spinal cord during Propofol anesthesia in Sprague-Dawley rats, using high-performance liquid chromatographic determination of Propofol concentration in brain, whole blood and plasma. We found that the concentration of Propofol in the brain increased and decreased expeditiously during and after a 15-min and 30-min period of i.v. infusion of an anesthetic dose (60 mg/kg per h) of Propofol. Furthermore, Propofol was evenly distributed in the brain and spinal cord during infusion, with a significant inter-individual variation. Upon the establishment of anesthesia 15 and 30 min following intravenous infusion of Propofol, the concentration of Propofol in the brain, whole blood and plasma was respectively 15.7 ± 1.9 and 39.4 ± 2.7 μg/g, 4.5 ± 1.2 and 13.6 ± 1.3 μg/ml and 1.8 ± 0.5 and 5.1 ± 0.9 μg/ml (mean ± SEM, n = 6 or 7). These high brain/blood and brain/plasma ratios during anesthesia suggest that Propofol manifests a pharmacokinetic profile that is different from at least thiopental.
