Concentrations of Desflurane and Propofol That Suppress Response to Command in Humans

Chortkoff, Ben S.; Eger, Edmond I.; Crankshaw, D. P.; Gonsowski, Charles T.; Dutton, Robert C.; Ionescu, Pompi

doi:10.1097/00000539-199510000-00014

Cited by 62 publications

(19 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With this technique the induction times in both groups were longer than in routine clinical practice but a more precise target concentration could be achieved at the induction end-point. Target concentrations for induction were similar in both groups and comparable with those found by other investigators [20]. This resulted in the use of normal induction doses of propofol as no other drugs or premedication were given [21].…”

Section: Discussionsupporting

confidence: 79%

Clinical usefulness of the bispectral index for titrating propofol target effect-site concentration

et al. 1998

View full text Add to dashboard Cite

SummaryThe bispectral index, a new processed electroencephalographic parameter which may give information on depth of anaesthesia, was used in 58 patients undergoing outpatient gynaecological surgery in order to study if the addition of bispectral index monitoring to standard clinical monitoring could improve the titration of target propofol concentration when using effect-site target-controlled propofol infusion for sedation. In Group 1 (n ¼ 30), the bispectral index was recorded but the anaesthetist was unaware of the readings and therefore only classical signs of depth of anaesthesia were used to guide the anaesthetist in controlling the effect-site concentration. In Group 2 (n ¼ 28), bispectral index readings were available to the anaesthetist and effect-site concentration was adjusted to ensure that bispectral index was maintained between 40 and 60. Similar propofol induction and maintenance doses, blood and effect-site concentrations and mean bispectral index were found in the two groups. A greater percentage of bispectral index readings lying outside the target range (i.e. < 40 or > 60) and more movement at incision and during maintenance were found in Group 1. There was a trend towards more implicit awareness in patients in Group 1. Bispectral index was found to be useful for measuring depth of sedation when using propofol target-controlled infusion. Propofol dosage could not be decreased but a more consistent level of sedation could be maintained due to a more satisfactory titration of target effectsite concentration. For many years, anaesthetists have tried to correlate the pharmacokinetics and pharmacodynamics of propofol in order to achieve the most appropriate dosage schemes for continuous intravenous infusion [1]. Recently, a pharmacokinetically based technique for the administration of propofol (target-controlled infusion, TCI) has proved to have many advantages [2]. The concept underlying TCI techniques is to apply the three-compartmental pharmacokinetic model for propofol [3] and to predict by calculation its concentration in one of the compartments, e.g. the central (blood) compartment or the theoretical effect-site compartment [4]. Target-controlled infusion devices will rapidly achieve and maintain the desired predicted concentration in the chosen compartment [5]. Effect compartment modelling is motivated by the observed dissociation between the measured blood concentrations of the drug and the currently measured indices of drug effect, e.g. the processed electro-encephalogram (EEG). The hysteresis between pharmacokinetics and pharmacodynamics can be quantified by a rate constant, k e1 . The time course of a drug effect is found to parallel the time course of the effect compartment modelling. It therefore becomes appealing to be able to control quantitatively the drug concentration in the effect compartment rather than in the central compartment [6,7]. This method can provide a better prediction of anaesthetic drug effect [8].

show abstract

Section: Discussionsupporting

confidence: 79%

Clinical usefulness of the bispectral index for titrating propofol target effect-site concentration

et al. 1998

View full text Add to dashboard Cite

show abstract

“…Because the BIS values did not differ between the low-flow group and the other treatment groups, inadequate emergence did not seem to occur. All the end-tidal desflurane concentrations were lower at these timepoints than the minimum alveolar concentrations at which an anaesthetized patient responds appropriately to spoken commands reported by Song et al 12 and Chortkoff et al 13 This is likely to be due to the effect of remifentanil, as opioids can reduce minimum alveolar concentration values via interaction with inhaled anaesthetics. [14][15][16] Because the administration of inhaled anaesthetic should be terminated early in clinical applications, there was concern about whether patients would be more aware than would usually be expected.…”

Section: Discussionmentioning

confidence: 57%

Comparison of emergence times with different fresh gas flow rates following desflurane anaesthesia

et al. 2014

View full text Add to dashboard Cite

Objective: To investigate emergence times with different fresh gas flow rates, following desflurane anaesthesia. Methods: Patients undergoing surgery with desflurane anaesthesia were randomly assigned to receive fresh gas flow rates of 100% oxygen during emergence of 2 l/min (group D2), 4 l/min (group D4) or 6 l/min (group D6). Time to eye opening, spontaneous movement and extubation (emergence time) were assessed after desflurane discontinuation. The end-tidal concentration of desflurane and bispectral index were recorded at each of these timepoints. Results: A total of 105 patients were included in the study, with 35 in each of the three groups. Mean times to extubation were 17.6 min, 9.9 min and 9.1 min in groups D2, D4 and D6, respectively. Times to eye opening, spontaneous movement and extubation in group D2 were significantly longer than in groups D4 and D6. Conclusions: These results suggest that there is the potential to predict emergence time based on fresh gas flow rate following desflurane anaesthesia. It should therefore be possible to use a lowflow technique during the emergence period, in addition to the maintenance period, without delaying recovery if the inhaled anaesthetic is stopped at the predicted time before the end of surgery.

show abstract

“…It would also reduce the anesthesiologists workload, save time and resources, and allow for safer patient recovery [2] . Some studies of ROC show large variations (0.8-2.7 μg/mL) in propofol C e producing ROC from anesthesia [3,4] , making it difficult to predict the minimum concentration for effective sedation and the concentration of propofol during emergence.…”

Section: Introductionmentioning

confidence: 99%

A pharmacodynamic analysis of factors affecting recovery from anesthesia with propofol-remifentanil target controlled infusion

et al. 2012

View full text Add to dashboard Cite

Aim: To examine individual patient's demographic parameters and clinical variables related to return of consciousness (ROC) and the pharmacodynamic relationship between propofol effect-site concentration (C e ) and ROC from propofol-remifentanil anesthesia. Methods: Ninety-four patients received propofol-remifentanil anesthesia using the effect-site target-controlled infusion (TCI) system. All clinical events were noted, and variables possibly related to propofol C e at ROC were examined using linear correlation analyses. Pharmacodynamic modeling incorporating covariates was performed using NONMEM (Nonlinear Mixed Effects Modeling) VII software. Results:The C e values of propofol at loss of consciousness (LOC) and ROC were 4.4±1.1 μg/mL and 1.1±0.3 μg/mL, respectively. Age was negatively correlated with propofol C e at ROC (r=-0.48, P<0.01). Including age as a covariate in C e50 (the effect-site concentration associated with 50% probability of return of consciousness) and λ (the steepness of the concentration-versus-response relationship) significantly improved the performance of the basic model based on the likelihood ratio test, with a significant decrease in the minimum value of the objective function. The C e50 in 25-, 50-, and 75-year-old patients was predicted to be 1.38, 1.06, and 0.74 μg/mL, respectively. The λ in 25-, 50-, and 75-year-old patients was predicted to be 12.23, 8.70, and 5.18, respectively. Conclusion: Age significantly affects the relationship between propofol C e and ROC, and pharmacodynamic modeling including age could lead to better predictions of ROC during emergence from propofol-remifentanil anesthesia.

show abstract

Concentrations of Desflurane and Propofol That Suppress Response to Command in Humans

Cited by 62 publications

References 22 publications

Clinical usefulness of the bispectral index for titrating propofol target effect-site concentration

Clinical usefulness of the bispectral index for titrating propofol target effect-site concentration

Comparison of emergence times with different fresh gas flow rates following desflurane anaesthesia

A pharmacodynamic analysis of factors affecting recovery from anesthesia with propofol-remifentanil target controlled infusion

Contact Info

Product

Resources

About