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Seung Ho Choi - One of the best experts on this subject based on the ideXlab platform.
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efficacy of intraoperative dexmedetomidine Infusion on visualization of the surgical field in endoscopic sinus surgery
Korean Journal of Anesthesiology, 2015Co-Authors: Sang Hee Ha, Seung Ho ChoiAbstract:In endoscopic sinus surgery, visualization of the surgical field is a major concern, as surgical bleeding is the cause of many complications. The purpose of this study was to compare the effects of dexmedetomidine and remifentanil on the visualization of the surgical field in endoscopic sinus surgery.Forty-three patients were prospectively enrolled and randomly allocated to the dexmedetomidine or remifentanil group and general anesthesia was induced and maintained using a propofol Target-Controlled Infusion. In the dexmedetomidine group, dexmedetomidine was loaded for 5 min and a continuous Infusion was administered. In the remifentanil group, a remifentanil Target-Controlled Infusion was used. After completion of the operation, the satisfaction with the visualization of the surgical field was assessed on a numeric rating scale, from 0 (= worst) to 10 (= best). The mean blood pressure, heart rate, recovery profiles, and postoperative pain score were recorded.Satisfaction score for visualization by numeric rating scale was not significantly different between the two groups (P = 0.95). There were no differences in the mean blood pressure and heart rate. The extubation time was significantly shorter in the dexmedetomidine group (8.4 ± 1.8 min) than in the remifentanil group (11.9 ± 5.4 min) (P = 0.04). Except for the extubation time, the recovery profiles of the two groups were comparable.Continuous Infusions of dexmedetomidine provide a similar visualization of the surgical field and hemodynamic stability as remifentanil Target-Controlled Infusions in patients undergoing endoscopic sinus surgery.
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efficacy of intraoperative dexmedetomidine Infusion on visualization of the surgical field in endoscopic sinus surgery
Korean Journal of Anesthesiology, 2015Co-Authors: Sang Hee Ha, Seung Ho ChoiAbstract:In endoscopic sinus surgery, visualization of the surgical field is a major concern, as surgical bleeding is the cause of many complications. The purpose of this study was to compare the effects of dexmedetomidine and remifentanil on the visualization of the surgical field in endoscopic sinus surgery.Forty-three patients were prospectively enrolled and randomly allocated to the dexmedetomidine or remifentanil group and general anesthesia was induced and maintained using a propofol Target-Controlled Infusion. In the dexmedetomidine group, dexmedetomidine was loaded for 5 min and a continuous Infusion was administered. In the remifentanil group, a remifentanil Target-Controlled Infusion was used. After completion of the operation, the satisfaction with the visualization of the surgical field was assessed on a numeric rating scale, from 0 (= worst) to 10 (= best). The mean blood pressure, heart rate, recovery profiles, and postoperative pain score were recorded.Satisfaction score for visualization by numeric rating scale was not significantly different between the two groups (P = 0.95). There were no differences in the mean blood pressure and heart rate. The extubation time was significantly shorter in the dexmedetomidine group (8.4 ± 1.8 min) than in the remifentanil group (11.9 ± 5.4 min) (P = 0.04). Except for the extubation time, the recovery profiles of the two groups were comparable.Continuous Infusions of dexmedetomidine provide a similar visualization of the surgical field and hemodynamic stability as remifentanil Target-Controlled Infusions in patients undergoing endoscopic sinus surgery.
Michel Struys - One of the best experts on this subject based on the ideXlab platform.
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dexmedetomidine pharmacokinetic pharmacodynamic modelling in healthy volunteers 1 influence of arousal on bispectral index and sedation
BJA: British Journal of Anaesthesia, 2017Co-Authors: Michel Struys, Anthony Absalom, Laura N Hannivoort, Douglas J Eleveld, Koen Reyntjens, Hugo Vereecke, Pieter ColinAbstract:Abstract Background Dexmedetomidine, a selective α 2 -adrenoreceptor agonist, has unique characteristics, such as maintained respiratory drive and production of arousable sedation. We describe development of a pharmacokinetic–pharmacodynamic model of the sedative properties of dexmedetomidine, taking into account the effect of stimulation on its sedative properties. Methods In a two-period, randomized study in 18 healthy volunteers, dexmedetomidine was delivered in a step-up fashion by means of Target-Controlled Infusion using the Dyck model. Volunteers were randomized to a session without background noise and a session with pre-recorded looped operating room background noise. Exploratory pharmacokinetic–pharmacodynamic modelling and covariate analysis were conducted in NONMEM using bispectral index (BIS) monitoring of processed EEG. Results We found that both stimulation at the time of Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale scoring and the presence or absence of ambient noise had an effect on the sedative properties of dexmedetomidine. The stimuli associated with MOAA/S scoring increased the BIS of sedated volunteers because of a transient 170% increase in the effect-site concentration necessary to reach half of the maximal effect. In contrast, volunteers deprived of ambient noise were more resistant to dexmedetomidine and required, on average, 32% higher effect-site concentrations for the same effect as subjects who were exposed to background operating room noise. Conclusions The new pharmacokinetic–pharmacodynamic models might be used for effect-site rather than plasma concentration Target-Controlled Infusion for dexmedetomidine in clinical practice, thereby allowing tighter control over the desired level of sedation. Clinical trial registration NCT01879865.
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development of an optimized pharmacokinetic model of dexmedetomidine using target controlled Infusion in healthy volunteers
Anesthesiology, 2015Co-Authors: Laura N Hannivoort, Anthony Absalom, Douglas J Eleveld, Johannes H Proost, Koen Reyntjens, Hugo Vereecke, Michel StruysAbstract:Background: Several pharmacokinetic models are available for dexmedetomidine, but these have been shown to underestimate plasma concentrations. Most were developed with data from patients during the postoperative phase and/or in intensive care, making them susceptible to errors due to drug interactions. The aim of this study is to improve on existing models using data from healthy volunteers. Methods: After local ethics committee approval, the authors recruited 18 volunteers, who received a dexmedetomidine Target-Controlled Infusion with increasing target concentrations: 1, 2, 3, 4, 6, and 8ng/ml, repeated in two sessions, at least 1 week apart. Each level was maintained for 30min. If one of the predefined safety criteria was breached, the Infusion was terminated and the recovery period began. Arterial blood samples were collected at preset times, and NONMEM (Icon plc, Ireland) was used for model development. Results: The age, weight, and body mass index ranges of the 18 volunteers (9 male and 9 female) were 20 to 70 yr, 51 to 110kg, and 20.6 to 29.3kg/m(2), respectively. A three-compartment allometric model was developed, with the following estimated parameters for an individual of 70 kg: V1 = 1.78 l, V2 = 30.3 l, V3 = 52.0 l, CL = 0.686 l/min, Q2 = 2.98 l/min, and Q3 = 0.602 l/min. The predictive performance as calculated by the median absolute performance error and median performance error was better than that of existing models. Conclusions: Using Target-Controlled Infusion in healthy volunteers, the pharmacokinetics of dexmedetomidine were best described by a three-compartment allometric model. Apart from weight, no other covariates were identified.
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the performance of compartmental and physiologically based recirculatory pharmacokinetic models for propofol a comparison using bolus continuous and target controlled Infusion data
Anesthesia & Analgesia, 2010Co-Authors: Eric Mortier, Kenichi Masui, Tomiei Kazama, Richard N Upton, Anthony G Doufas, Johan F Coetzee, Michel StruysAbstract:BACKGROUND: With the growing use of pharmacokinetic (PK)-driven drug delivery and/or drug advisory displays, identifying the PK model that best characterizes propofol plasma concentration (Cp) across a variety of dosing conditions would be useful. We tested the accuracy of 3 compartmental models and 1 physiologically based recirculatory PK model for propofol to predict the time course of propofol Cp using concentration-time data originated from studies that used different Infusion schemes. METHODS: Three compartmental PK models for propofol, called the "Marsh," the "Schnider," and the "Schuttler" models, and 1 physiologically based recirculatory model called the "Upton" model, were used to simulate the time course of propofol Cp. To test the accuracy of the models, we used published measured plasma concentration data that originated from studies of manual (bolus and short Infusion) and computer-controlled (Target-Controlled Infusion [TCI] and long Infusion) propofol dosing schemes. Measured/predicted (M/P) propofol Cp plots were constructed for each dataset. Bias and inaccuracy of each model were assessed by median prediction error (MDPE) and median absolute prediction error (MDAPE), respectively. RESULTS: The M/P propofol Cp in the 4 PK models revealed bias in all 3 compartmental models during the bolus and short Infusion regimens. In the long Infusion, a worse M/P propofol Cp at higher concentration was seen for the Marsh and the Schuttler models than for the 2 other models. Less biased M/P propofol Cp was found for all models during TCI. In the bolus group, after 1 min, a clear overprediction was seen for all 3 compartmental models for the entire 5 min; however, this initial error resolved after 4 min in the Schnider model. The Upton model did not predict propofol Cp accurately (major overprediction) during the first minute. During the bolus and short Infusion, the Marsh model demonstrated worse MDPE and MDAPE compared with the 3 other models. During short Infusion, MDAPE for the Schnider and Schuttler models was better than the Upton and the Marsh models. All models showed similar MDPE and MDAPE during TCI simulations. During long Infusion, the Marsh and the Schuttler models underestimated the higher plasma concentrations. CONCLUSION: When combining the performance during various Infusion regimens, it seems that the Schnider model, although still not perfect, is the recommended model to be used for TCI and advisory displays. (Anesth Analg 2010;111:368-.79)
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Comparison of plasma compartment versus two methods for effect compartment-controlled Target-Controlled Infusion for propofol
Anesthesiology, 2000Co-Authors: Michel Struys, Steven L Shafer, Tom De Smet, Birgit Depoorter, Linda Versichelen, Eric Mortier, Frank J E Dumortier, Georges RollyAbstract:Background: Target-Controlled Infusion (TCI) systems can control the concentration in the plasma or at the site of drug effect. A TCI system that targets the effect site should be able to accurately predict the time course of drug effect. The authors tested this by comparing the performance of three control algorithms: plasma-control TCI versus two algorithms for effect-site control TCI, Methods: One-hundred twenty healthy women patients received propofol via TCI for 12-min at a target concentration of 5.4 mu g/ml, In all three groups, the plasma concentrations mere computed using pharmacokinetics previously reported. In group I, the TCI device controlled the plasma concentration. In groups II and III, the TCI device controlled the effect-site concentration. In group II, the effect site was computed using a half-life for plasma effect-site equilibration (t(1/2) k(eo)) of 3.5 min. In group m, plasma effect-site equilibration rate constant (k(eo)) was computed to yield a time to peak effect of 1.6 min after bolus injection, yielding a t(1/2), k(eo) of 34 s, the time course of propofol was measured using the bispectral index, Blood pressure, ventilation, and time of loss of consciousness were measured. Results The time course of propofol drug effect, as measured by the bispectral index, was best predicted in group III. Targeting the effect-site concentration shortened the time to loss of consciousness compared with the targeting plasma concentration without causing hypotension. The incidence of apnea was less in group III than in group II. Conclusion: Effect compartment-controlled TCI can be safely applied in clinical practice. A biophase model combining the Marsh kinetics and a time to peak effect of 1.6 min accurately predicted the time course of propofol drug effect.
Ankuo Chou - One of the best experts on this subject based on the ideXlab platform.
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target controlled Infusion vs manually controlled Infusion of propofol with alfentanil for bidirectional endoscopy a randomized controlled trial
Endoscopy, 2013Co-Authors: Minhsien Chiang, Chiahsun You, Yichun Chiu, Chinwei Kao, Kunchen Lin, Kuanhung Chen, Pengchih Wang, Ankuo ChouAbstract:BACKGROUND AND STUDY AIMS The best anesthesia methods for analgesia and sedation during gastrointestinal endoscopy are still debated. The aim of this study was to compare the recovery time, clinical presentations, and satisfaction between Target-Controlled Infusion (TCI) and manually controlled Infusion (MCI) in same-day bidirectional endoscopy (esophagogastroduodenoscopy followed by colonoscopy). PATIENTS AND METHODS A total of 220 patients with American Society of Anesthesiology physical status 1 or 2 were enrolled and randomized into the TCI or MCI groups. The clinical presentations, vasoactive drug demand, propofol consumption, and adverse events were recorded for both groups peri-procedurally. The concentrations of propofol in the plasma (Cp) and at the site of drug effect (Ce) by computerized simulation were also monitored in both groups. Finally, the satisfaction of patients, endoscopists, and nurse anesthetists was assessed by questionnaire after the examinations. RESULTS Compared with the MCI group, the TCI group had a faster recovery time (17.91 ± 7.72 minutes vs. 14.58 ± 8.55 minutes; P = 0.002), less moderate hypotension (7.37 ± 15.46 % vs. 1.82 ± 5.15 %; P < 0.001), and shorter period of bradypnea (13.81 ± 15.92 % vs. 9.18 ± 12.00 %; P = 0.013). In addition, the TCI group reduced the relative risk of moderate desaturation by 50 % compared with the MCI group (30.9 % vs. 15.5 %; 95 % confidence interval 1.191-3.360; P = 0.007). CONCLUSIONS The study demonstrated that TCI of propofol combined with alfentanil was associated with a faster recovery time, and better hemodynamic and respiratory stability than MCI in same-day bidirectional endoscopy. CLINICAL TRIAL REGISTRATION CGMH IRB Identifier 97-0969B.
Sang Hee Ha - One of the best experts on this subject based on the ideXlab platform.
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efficacy of intraoperative dexmedetomidine Infusion on visualization of the surgical field in endoscopic sinus surgery
Korean Journal of Anesthesiology, 2015Co-Authors: Sang Hee Ha, Seung Ho ChoiAbstract:In endoscopic sinus surgery, visualization of the surgical field is a major concern, as surgical bleeding is the cause of many complications. The purpose of this study was to compare the effects of dexmedetomidine and remifentanil on the visualization of the surgical field in endoscopic sinus surgery.Forty-three patients were prospectively enrolled and randomly allocated to the dexmedetomidine or remifentanil group and general anesthesia was induced and maintained using a propofol Target-Controlled Infusion. In the dexmedetomidine group, dexmedetomidine was loaded for 5 min and a continuous Infusion was administered. In the remifentanil group, a remifentanil Target-Controlled Infusion was used. After completion of the operation, the satisfaction with the visualization of the surgical field was assessed on a numeric rating scale, from 0 (= worst) to 10 (= best). The mean blood pressure, heart rate, recovery profiles, and postoperative pain score were recorded.Satisfaction score for visualization by numeric rating scale was not significantly different between the two groups (P = 0.95). There were no differences in the mean blood pressure and heart rate. The extubation time was significantly shorter in the dexmedetomidine group (8.4 ± 1.8 min) than in the remifentanil group (11.9 ± 5.4 min) (P = 0.04). Except for the extubation time, the recovery profiles of the two groups were comparable.Continuous Infusions of dexmedetomidine provide a similar visualization of the surgical field and hemodynamic stability as remifentanil Target-Controlled Infusions in patients undergoing endoscopic sinus surgery.
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efficacy of intraoperative dexmedetomidine Infusion on visualization of the surgical field in endoscopic sinus surgery
Korean Journal of Anesthesiology, 2015Co-Authors: Sang Hee Ha, Seung Ho ChoiAbstract:In endoscopic sinus surgery, visualization of the surgical field is a major concern, as surgical bleeding is the cause of many complications. The purpose of this study was to compare the effects of dexmedetomidine and remifentanil on the visualization of the surgical field in endoscopic sinus surgery.Forty-three patients were prospectively enrolled and randomly allocated to the dexmedetomidine or remifentanil group and general anesthesia was induced and maintained using a propofol Target-Controlled Infusion. In the dexmedetomidine group, dexmedetomidine was loaded for 5 min and a continuous Infusion was administered. In the remifentanil group, a remifentanil Target-Controlled Infusion was used. After completion of the operation, the satisfaction with the visualization of the surgical field was assessed on a numeric rating scale, from 0 (= worst) to 10 (= best). The mean blood pressure, heart rate, recovery profiles, and postoperative pain score were recorded.Satisfaction score for visualization by numeric rating scale was not significantly different between the two groups (P = 0.95). There were no differences in the mean blood pressure and heart rate. The extubation time was significantly shorter in the dexmedetomidine group (8.4 ± 1.8 min) than in the remifentanil group (11.9 ± 5.4 min) (P = 0.04). Except for the extubation time, the recovery profiles of the two groups were comparable.Continuous Infusions of dexmedetomidine provide a similar visualization of the surgical field and hemodynamic stability as remifentanil Target-Controlled Infusions in patients undergoing endoscopic sinus surgery.
Isabelle Constant - One of the best experts on this subject based on the ideXlab platform.
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influence of depth of hypnosis on pupillary reactivity to a standardized tetanic stimulus in patients under propofol remifentanil target controlled Infusion a crossover randomized pilot study
Anesthesia & Analgesia, 2018Co-Authors: Nada Sabourdin, Nicolas Louvet, Jeanbaptiste Peretout, Eliane Khalil, Marielaurence Guye, Isabelle ConstantAbstract:BACKGROUND Pupillometry allows the measurement of pupillary diameter variations in response to nociceptive stimuli. This technique has been used to monitor the balance between analgesia and nociception. Under general anesthesia, the amplitude of pupillary dilation is related to the amount of administered opioids. The objective of this study was to determine whether at a constant Infusion rate of opioids, the pupillary response was influenced by depth of hypnosis assessed by the bispectral index (BIS). METHODS Twelve patients (14-20 years) anesthetized for orthopedic surgery were included. Under propofol-remifentanil Target-Controlled Infusion, remifentanil effect site target concentration was fixed at 1 ng/mL. Two measures of pupillary reflex dilation were performed on each patient in a randomized order: one at BIS 55 and one at BIS 25. These levels of BIS were obtained by adjusting propofol target concentration and maintained for 10 minutes before each measure. For each measure, we applied a standardized tetanic stimulation on the patient's forearm (60 mA, 100 Hz, 5 seconds). All measures were performed before the beginning of surgery. RESULTS Pupillary dilation was significantly greater at BIS 55 than at BIS 25: 32.1% ± 5.3% vs 10.4% ± 2.5% (mean difference estimate [95% confidence interval]: 21.8% [12.9-30.6], P < .001), without carryover effect (P = .30) nor period effect (P = .52). Hemodynamic parameters and BIS were not modified by the stimulation. CONCLUSIONS In patients receiving a constant Infusion of remifentanil at a target concentration of 1 ng/mL, pupillary dilation after a standardized tetanic stimulation was influenced by depth of hypnosis assessed by the BIS.
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the relationship between bispectral index and propofol during target controlled Infusion anesthesia a comparative study between children and young adults
Anesthesia & Analgesia, 2008Co-Authors: Agnes Rigouzzo, Laure Girault, Nicolas Louvet, Frederique Servin, Tom Desmet, Veronique Piat, Robert Seeman, Isabelle Murat, Isabelle ConstantAbstract:BACKGROUND: In this prospective study, we compared the relationship betweenpropofol concentrations and bispectral index (BIS) in children versus young adultsanesthetized with Target-Controlled Infusion (TCI) of propofol.METHODS: Forty-five prepubertal subjects (children) and 45 postpubertal subjects(adults) were studied. All patients were anesthetized with TCI of propofol, basedon the Kataria et al.’s model for children and on the Schnider et al.’s model foradults. All data from the BIS and the TCI system were continuously recorded usingRugloop software. Remifentanil was continuously administered throughout thestudy (0.25 g kg
