Predictive Accuracy of a Model of Volatile Anesthetic Uptake

Kennedy, R. C.; French, Richard A.; Spencer, Chris

doi:10.1097/00000539-200212000-00027

Cited by 30 publications

(26 citation statements)

References 24 publications

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“…In this analysis, the Lerou model was modified to use measured end-tidal concentrations instead of predicted ones as input. The model used Kennedy’s partition coefficients for sevoflurane (22) presented in the table below. Cardiac output, organ blood flow (to include cerebral blood flow), tissue volumes, blood pool compartments, carbon dioxide production, and oxygen uptake were normalized to patient weight and considered constant (23).…”

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confidence: 99%

An Evaluation of Remifentanil-Sevoflurane Response Surface Models in Patients Emerging from Anesthesia

Johnson

Syroid

Gupta³

et al. 2010

Anesthesia &Amp; Analgesia

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Introduction We previously reported models that characterized the synergistic interaction between remifentanil and sevoflurane in blunting responses to verbal and painful stimuli. This preliminary study evaluated the ability of these models to predict a return of responsiveness (ROR) during emergence from anesthesia and a response to tibial pressure when patients required analgesics in the recovery room. We hypothesized that model predictions would be consistent with observed responses. We also hypothesized that under non steady state conditions, accounting for the lag time between effect site (Ce) and end tidal (ET) sevoflurane concentrations would improve predictions. Methods Twenty patients received a sevoflurane, remifentanil, and fentanyl anesthetic. Two model predictions of responsiveness were recorded at emergence: an ET based and a Ce based prediction. Similarly two predictions of a response to noxious stimuli were recorded when patients first required analgesics in the recovery room. Model predictions were compared to observations with graphical and temporal analyses. Results While patients were anesthetized, model predictions indicated a high likelihood that patients would be unresponsive (≥ 99%). However, following termination of the anesthetic, models exhibited a wide range of predictions at emergence (1% to 97%). Although wide, the Ce based predictions of responsiveness were better distributed over a percentage ranking of observations than the ET based predictions. For the ET based model, 45% of the patients awoke within 2 minutes of the 50% model predicted probability of unresponsiveness; 65% awoke within 4 minutes. For the Ce based model, 45% of the patients awoke within 1 minute of the 50% model predicted probability of unresponsiveness; 85% awoke within 3.2 minutes. Predictions of a response to a painful stimulus in the recovery room were similar for the Ce and ET based models. Discussion Results confirmed in part our study hypothesis; accounting for the lag time between Ce and ET sevoflurane concentrations improved model predictions of responsiveness but had no effect on predicting a response to a noxious stimulus in the recovery room. These models may be useful in predicting events of clinical interest but large scale evaluations with numerous patients are needed to better characterize model performance.

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confidence: 99%

An Evaluation of Remifentanil-Sevoflurane Response Surface Models in Patients Emerging from Anesthesia

Johnson

Syroid

Gupta³

et al. 2010

Anesthesia &Amp; Analgesia

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“…UU.). Con los parámetros de edad, peso, talla y sexo se estimó: la concentración objetivo ajustada a la edad 26 , el consumo de oxígeno y volumen minuto 27 y el volumen efectivo pulmonar 28 . La dosis de purga del sistema (circuito-paciente) se administró en el primer minuto.…”

Section: Métodosunclassified

Desempeño predictivo y clínico de un dispositivo target-controlled infusion para sevofluorano en una estación de trabajo convencional: correlación farmacocinética del modelo empleado

Arana¹,

Monzón²,

Gómez³

et al. 2014

Revista Colombiana de Anestesiología

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r e v c o l o m b a n e s t e s i o l . 2 0 1 4;4 2(4):255-264 Revista Colombiana de Anestesiología Colombian Journal of Anesthesiology w w w . r e v c o l a n e s t . c o m . c o Investigación científica y tecnológica Desempeño predictivo y clínico de un dispositivo target-controlled infusion para sevofluorano en una estación de trabajo convencional: correlación farmacocinética del modelo empleado

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“…Zusätzliche zu messende Variablen wären die inspiratorische Narkosegaskonzentration und das Atemminutenvolumen, die unmittelbar aus dem Routinemonitoring der Narkose verfügbar sind. Mehrere pharmakokinetische Modelle der gängigen volatilen Anästhe-tika stehen ebenfalls zur Verfügung [5,73,122] und sind z. T. bereits praktisch erprobt [52,53,74]. Ein derartiges System ist patentiert, wurde als Prototyp 2005 prä-sentiert und steht derzeitig in Bern vor der klinischen Erprobung.…”

Section: Expertensysteme ("Advisory Systems") Zur Dosisoptimierung Vounclassified

Pharmakokinetische/pharmakodynamische Modelle für Inhalationsanästhetika

et al. 2007

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Pharmacokinetic models can be differentiated into two groups: physiological-based models and empirical models. Traditionally the pharmacokinetics of volatile anaesthetics are described using physiological-based models together with the respective tissue-blood distribution coefficients. The compartments of the empirical model have no anatomical equivalents and are merely the product of the mathematical procedure for parameter estimation. The end expiratory concentration of volatile anaesthetics is approximately equal to the arterial concentration and, therefore, the description of the transition between plasma and effect site for volatile anaesthetics plays a central role. The most important parameter here is the k(e0) value which is a time constant and describes the time delay for the transition from the central compartment to the calculated effect compartment. The k(e0) values for sevoflurane and isoflurane are the same but the concentration balance between the end-tidal concentration and the effect compartment occurs twice as quickly with desflurane. In clinical practice volatile anaesthetics are normally combined with N(2)O and/or opioids. This results in an additive interaction between volatile anaesthetics and N(2)O but a synergistic interaction of volatile anaesthetics with opioids. However, there are relatively few investigations on the interactions between the clinically widely used combination of volatile anaesthetics, N(2)O and opioids.

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Predictive Accuracy of a Model of Volatile Anesthetic Uptake

Cited by 30 publications

References 24 publications

An Evaluation of Remifentanil-Sevoflurane Response Surface Models in Patients Emerging from Anesthesia

An Evaluation of Remifentanil-Sevoflurane Response Surface Models in Patients Emerging from Anesthesia

Desempeño predictivo y clínico de un dispositivo target-controlled infusion para sevofluorano en una estación de trabajo convencional: correlación farmacocinética del modelo empleado

Pharmakokinetische/pharmakodynamische Modelle für Inhalationsanästhetika

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