The optimal exhaled concentration of sevoflurane for intubation without neuromuscular blockade using clinical bolus doses of remifentanil

Abstract

Background:The aim of this study was to investigate the optimal exhaled sevoflurane concentration that produces adequate endotracheal intubation conditions when sevoflurane is combined with the different bolus doses of remifentanil used in clinical practice.Methods:The patients were randomized to 3 groups (groups 1.0, 1.5, and 2.0), receiving remifentanil bolus doses of 1.0, 1.5, and 2.0 μg/kg, respectively. For each group, the concentration of sevoflurane used for each consecutive patient was increased or decreased using the “up-and-down” method based on the success or failure to achieve adequate conditions for intubation in the previous patient. The remifentanil bolus dose was administered 90 s before intubation and after the target sevoflurane concentration was achieved.Results:In groups 1.0, 1.5, and 2.0, the effective concentration in 50% (EC50) of the sevoflurane concentration required to perform successful intubation was 3.0, 2.0, and 1.29 vol% and the effective concentration in 95% was 3.45, 2.91, and 1.89 vol%, respectively. When sevoflurane was administered for the induction, the increase in heart rate (HR) of group 1.0 was the highest among the groups. The highest number of adverse events occurred in group 2.0, including vocal cord rigidity, hypotension, and bradycardia.Discussion:The EC50 of the sevoflurane concentration was 3.0, 2.0, and 1.29 vol% when it was combined with a bolus dose of remifentanil of 1.0, 1.5, and 2.0 μg/kg, respectively. Of the 3 different bolus doses of remifentanil, the dose of 1.5 μg/kg was least associated with changes in the HR/mean blood pressure during intubation without increasing adverse effects.

Effects of remifentanil with or without midazolam pretreatment on the 95% effective dose of propofol for loss of consciousness during induction

“…[ 3 , 4 , 6 ] Pretreatment with remifentanil during induction has some advantages. The optimal dosage of remifentanil pretreatment can offer hemodynamic stability during maneuvers in the induction period, including laryngoscopy and intubation, [ 9 , 10 ] and it was also shown to have protective effects on organs in animal studies. [ 13 – 15 ] In addition, it is reported that remifentanil pretreatment can prevent pain caused by propofol injection.…”

“…Pretreatment with remifentanil can decrease injection pain [ 8 ] and provide hemodynamic stability during the induction period. [ 9 , 10 ] However, the required bolus dose of propofol for loss of consciousness during induction in patients who receive pretreatment with remifentanil or midazolam remains unclear. Furthermore, the effects of premedication with remifentanil or midazolam on the patient's hemodynamics have not been elucidated.…”

Minimum Alveolar Concentration-Awake of Sevoflurane is Decreased in Patients with Parkinson’s Disease: An Up-and-Down Sequential Allocation Trial

“… 5 The time required to reach an equilibrium between alveolar and target organ concentrations is 9–12 minutes. 9 , 17 Thus, we maintained the end-tidal sevoflurane concentration for 15 minutes before we assessed the response of subjects. Many factors influence the efficacy of inhaled anesthetics, including age, 18 , 19 temperature, 20 hypotension, acid-base status, 21 diabetes, 22 and sepsis.…”

LncRNA Rik-203 contributes to anesthesia neurotoxicity via microRNA-101a-3p and GSK-3β-mediated neural differentiation

“…According to the previous studies, the mice received the 3% sevoflurane anesthesia 2 hours daily at 6, 7, 8 day after birth to mimic the clinical several times anesthesia 14,35,36 ,which is reported to induce the neurotoxicity and further cognitive function defect 2,37 . 3% is also the clinical concentration of sevoflurane for anesthesia 38 . The hippocampus tissues of mice were harvested at the end of the sevoflurane anesthesia administration.…”