Effect-site concentration of propofol required for LMA-Supreme? insertion with and without remifentanil: a randomized controlled trial

摘要

Background A new supraglottic device, the LMA-Supreme?, has recently become available for clinical use. Information on anaesthetic and co-adjuvant requirements for insertion of the LMA-Supreme? is limited. The present study aimed to evaluate the optimal effect-site concentration of propofol in 50?% (EC ₅₀ ) of adults necessary for successful insertion of the LMA-Supreme? and to examine remifentanil’s effect on propofol requirements. Methods Fifty-eight elective patients (aged 18–60 years; ASA (American Society Anaesthesiologists) physical status classification I and II) scheduled for day surgery were randomly assigned to one of two groups: propofol with saline or propofol with remifentanil. Anaesthesia was induced by target-controlled infusion according to predetermined effect-site concentrations of propofol and remifentanil (5?ng.mL ?1 ). The EC ₅₀ was calculated using Dixon’s up-and-down method. Ten minutes following drug administration, LMA-Supreme? insertion was attempted without the use of muscle relaxant drugs. Results In the propofol?+?saline group, the EC ₅₀ of propofol required for LMA-Supreme? insertion was 6.32?±?0.67?μg.mL ?1 (95?% CI, 5.69–6.94?μg.mL ?1 ). With the addition of remifentanil at an effect-site concentration of 5?ng.mL ?1 , the EC ₅₀ of propofol required for LMA-Supreme? insertion was 2.50?±?0.80?μg.mL ?1 (95?% CI, 1.82–3.17?μg.mL ?1 ; p? Conclusions The propofol requirement for smooth insertion of the LMA-Supreme? was 60?% less when remifentanil (5?ng.mL ?1 ) was co-administered. Clinical trial registration Identified as NCT01974648 at www.clinicaltrials.gov .