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Available from: Sergio Bevilacqua, Sep 27, 2015
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    ABSTRACT: The aim of this study was to evaluate the effectiveness and safety of carotid endarterectomy (CEA) with conscious sedation under remifentanil (Remifentanil anesthesia - RA) vs conventional loco-regional anesthesia (Conventional-LRA) in the current practice of a vascular surgery unit. We introduced the ''Remifentanil-RA'' in our practice according to a two-step protocol. In the first step we performed a pilot prospective study to assess the procedure's safety and reproducibility in our setting on 60 consecutive patients with symptomatic and/or high-grade (>70%) internal carotid artery stenosis and alternately assigning them either to ''Remifentanil-RA'' or ''Conventional-LRA'' CEA. In the second step we analysed our routine operative records as to effectiveness and safety on 533 patients who consecutively underwent ''Remifentanil-RA'' CEA. We compared them with 533 age- and sex-matched historical controls who underwent ''Conventional-LRA'' CEA. The patients' mean age was 71.2+/-6.8 vs 71.8+/-6.1 (''Remifentanil-RA'' vs ''Conventional-LRA''). About 73% of them were male and 56% had a symptomatic carotid stenosis. Neither the pilot study nor second step comparison showed differences in outcome measures. We found only higher peri-operative nausea/ vomit (3.6% vs 0.4% ''Remifentanil-RA'' vs ''Conventional-LRA'', P<0.0002) and fewer re-operations for post-operative hematomas (3% vs 5.4% respectively, P=0.048). We found that ''Remifentanil-RA'' CEA was safe, effective and satisfactory. Nevertheless, with the potential problems of intubation and those already found with side effects, a randomized control trial (RCT) is needed in order to prove that this method is superior to ''Conventional-LRA'' CEA.
    The Journal of cardiovascular surgery 09/2005; 46(4):431-6. · 1.46 Impact Factor
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    Journal of Vascular Surgery 05/2009; 49(5):S14. DOI:10.1016/j.jvs.2009.02.031 · 3.02 Impact Factor
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    ABSTRACT: The pharmacokinetics and pharmacodynamics of remifentanil were studied in 65 healthy volunteers using the electroencephalogram (EEG) to measure the opioid effect. In a companion article, the authors developed complex population pharmacokinetic and pharmacodynamic models that incorporated age and lean body mass (LBM) as significant covariates and characterized intersubject pharmacokinetic and pharmacodynamic variability. In the present article, the authors determined whether remifentanil dosing should be adjusted according to age and LBM, or whether these covariate effects were overshadowed by the interindividual variability present in the pharmacokinetics and pharmacodynamics. Based on the typical pharmacokinetic and pharmacodynamic parameters, nomograms for bolus dose and infusion rates at each age and LBM were derived. Three populations of 500 individuals each, ages 20, 50, and 80 yr, were simulated base on the interindividual variances in model parameters as estimated by the NONMEM software package. The peak EEG effect in response to a bolus, the steady-state EEG effect in response to an infusion, and the time course of drug effect were examined in each of the three populations. Simulations were performed to examine the time necessary to achieve a 20%, 50%, and 80% decrease in remifentanil effect site concentration after a variable-length infusion. The variability in the time for a 50% decrease in effect site concentrations was examined in each of the three simulated populations. Titratability using a constant-rate infusion was also examined. After a bolus dose, the age-related changes in V1 and Ke0 nearly offset each other. The peak effect site concentration reached after a bolus dose does not depend on age. However, the peak effect site concentration occurs later in elderly individuals. Because the EEG shows increased brain sensitivity to opioids with increasing age, an 80-yr old person required approximately one half the bolus dose of a 20-yr old of similar LBM to reach the same peak EEG effect. Failure to adjust the bolus dose for age resulted in a more rapid onset of EEG effect and prolonged duration of EEG effect in the simulated elderly population. The infusion rate required to maintain 50% EEG effect in a typical 80-yr old is approximately one third that required in a typical 20-yr old. Failure to adjust the infusion rate for age resulted in a more rapid onset of EEG effect and more profound steady-state EEG effect in the simulated elderly population. The typical times required for remifentanil effect site concentrations to decrease by 20%, 50%, and 80% after prolonged administration are rapid and little affected by age or duration of infusion. These simulations suggest that the time required for a decrease in effect site concentrations will be more variable in the elderly. As a result, elderly patients may occasionally have a slower emergence from anesthesia than expected. A step change in the remifentanil infusion rate resulted in a rapid and predictable change of EEG effect in both the young and the elderly. Based on the EEG model, age and LBM are significant demographic factors that must be considered when determining a dosage regimen for remifentanil. This remains true even when interindividual pharmacokinetic and pharmacodynamic variability are incorporated in the analysis.
    Anesthesiology 02/1997; 86(1):24-33. DOI:10.1097/00000542-199701000-00005 · 5.88 Impact Factor
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