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Effective Target Plasma Concentrations of Remifentanil to Prevent Tracheal Iutubation Response |
Jinbao Li, M.D. Department of Anesthesiology, Changhai Hospital, Second Military Medical University, Shanghai, China |
Objective To determine the effective target plasma concentrations required to prevent tracheal intubation response in 50% of adult and elderly patients(Cp50 ) anesthetized with etomidate. Methods Forty ASA I or II patients aged 18-80 year with body mass index between 20-30kg/m2 undergoing elective general anesthesia were enrolled in the study. BP, HR and ECG were continuously monitored and recorded before intubation (baseline) and at 1 and 2 min after intubation.Patients were randomly divided into 2 groups (n=20 each) according to their age : adult group(18-65yr) and elderly group(65-80yr). Intubation response was defined as an increase in SBP and/or HR by 15% of the baseline value within 2min.Remifentanil was administered by TCI at a plasma concentration of 6 μg/L for 5 min followed by intravenous etomidate 0.3mg/kg given within 30 seconds.When the patients lost consciousness, intravenous rocuronium 0.6mg/kg was given to facilitate tracheal intubation which was accomplished within 30 seconds. Cp50 was determined by up and down sequential trial. The ratio of two consecutive target plasma concentration was 1.2. Results The Cp50 of remifentanil in adult and elderly group were respectively 4.11 μg/L and 3.37 μg/L. The 95% confidence intervals were respectivelly 3.90-4.34 μg/L and 3.02-3.75 μg/L. Conclusion The Cp50 of remifentanil for suppression of cardiovascular response to tracheal intubation were 4.11μg/L and 3.37μg/L respectively in adult and elderly patients anesthetized with 0.3 mg/kg etomidate. Anesthesiology 2008; 109 A684 |