title: Effect-site concentration of propofol required for LMA-Supreme™ insertion with and without remifentanil: a randomized controlled trial.
abstract: 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 % (EC50) 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 EC50 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 EC50 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 EC50 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 < 0.0001).
  
  
  CONCLUSIONS
  The propofol requirement for smooth insertion of the LMA-Supreme™ was 60 % less when remifentanil (5 ng.mL(-1)) was co-administered.
  
  
  BACKGROUND
  Identified as NCT01974648 at www.clinicaltrials.gov .
authors.affiliation: Department of Toxicology, Faculty of Medicine, Complutense University, Madrid, Spain. mati@plagaro.net.|Department of Anaesthesiology, Hospital Universitario Gregorio Marañón, Madrid, Spain. mati@plagaro.net.
authors.forename: Matilde
authors.initials: M
authors.lastname: Zaballos
authors.affiliation: Department of Anaesthesiology, Hospital Universitario Gregorio Marañón, Madrid, Spain. emiliabastida@gmail.com.
authors.forename: Emilia
authors.initials: E
authors.lastname: Bastida
authors.affiliation: Department of Anaesthesiology, Hospital Universitario Gregorio Marañón, Madrid, Spain. s.agusti@hotmail.com.
authors.forename: Salomé
authors.initials: S
authors.lastname: Agustí
authors.affiliation: Department of Anaesthesiology, Hospital Universitario Gregorio Marañón, Madrid, Spain. maiteportas@gmail.com.
authors.forename: Maite
authors.initials: M
authors.lastname: Portas
authors.affiliation: Department of Anaesthesiology, Hospital Universitario Gregorio Marañón, Madrid, Spain. consuelojdf@gmail.com.
authors.forename: Consuelo
authors.initials: C
authors.lastname: Jiménez
authors.affiliation: Department of Anaesthesia, Head Department of Anaesthesiology, Hospital Universitario Gregorio Marañón, Madrid, Spain. mlopezgi@yahoo.es.
authors.forename: Maite
authors.initials: M
authors.lastname: López-Gil
mesh_terms: D000328:Adult; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D017214:Laryngeal Masks; D008297:Male; D008875:Middle Aged; D010880:Piperidines / Q000008:administration & dosage*; D015742:Propofol / Q000008:administration & dosage*; D011446:Prospective Studies; D000077208:Remifentanil
chemical_list: D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol