title: Determination of EC95 of remifentanil for smooth emergence from propofol anesthesia in patients undergoing transsphenoidal surgery.
abstract: BACKGROUND
  In patients undergoing pituitary surgery using a transsphenoidal approach, anesthesia emergence should be smooth with minimal coughing. Recent studies demonstrated that a target-controlled infusion of remifentanil effectively suppresses coughing induced by the endotracheal tube. We investigated the EC95 of remifentanil for smooth emergence without coughing from propofol anesthesia in patients undergoing transsphenoidal hypophysectomy.
  
  
  METHODS
  A total of 41 patients undergoing transsphenoidal hypophysectomy, aged 20 to 65 years, with an ASA physical status of I or II, were enrolled. For all participants, anesthesia was induced and maintained with a target-controlled infusion of remifentanil and propofol using predicted effect-site concentration (Ce). A biased coin design up-and-down sequential allocation and isotonic regression method were used to determine the remifentanil EC95 to prevent emergence coughing. In addition, we observed recovery profiles after anesthesia.
  
  
  RESULTS
  According to the study design, 19 patients received remifentanil 2.6 ng/mL Ce and 22 patients received a lower Ce, ranging from 1.0 to 2.2 ng/mL. The EC95 of remifentanil to prevent coughing was estimated as 2.51 ng/mL (95% confidence interval, 2.28-2.57 ng/mL). Despite the exclusion of 1 case because of delayed emergence, 17 of 18 patients receiving 2.6 ng/mL of remifentanil had bradypnea (<10 breaths/min) until 3 minutes after extubation. However, end-tidal carbon dioxide was maintained below 55 mm Hg during anesthetic emergence and respiratory rate recovered within 20 minutes of admission to the postanesthetic care unit.
  
  
  CONCLUSIONS
  The EC95 of remifentanil for smooth emergence from anesthesia was 2.51 ng/mL after transsphenoidal hypophysectomy.
authors.affiliation: Departments of *Anesthesiology and Pain Medicine ‡Neurosurgery, Neuro-Oncology Clinic, Severance Hospital, Yonsei University College of Medicine †Biostatistics Collaboration Unit, Gangnam Medical Research Center, Seoul, Korea.
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Choi
authors.forename: Kyeong Tae
authors.initials: KT
authors.lastname: Min
authors.forename: Jeong-Rim
authors.initials: JR
authors.lastname: Lee
authors.forename: Kwan Woong
authors.initials: KW
authors.lastname: Choi
authors.forename: Kyung-Hwa
authors.initials: KH
authors.lastname: Han
authors.forename: Eui Hyun
authors.initials: EH
authors.lastname: Kim
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Oh
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000465:Algorithms; D000762:Anesthesia Recovery Period; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007016:Hypophysectomy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010880:Piperidines / Q000008:administration & dosage*; D010911:Pituitary Neoplasms / Q000601:surgery; D015742:Propofol; D000077208:Remifentanil; D013100:Sphenoid Bone / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol