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ED50 of desflurane for laryngeal mask airway removal in anaesthetised adults
Author(s) -
Makkar J. K.,
Arora S.,
Jain K.,
Wig J.
Publication year - 2011
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1111/j.1365-2044.2011.06813.x
Subject(s) - medicine , propofol , anesthesia , desflurane , laryngeal mask airway , airway , general anaesthesia , laryngeal masks , nitrous oxide , mascara , ed50 , larynx , surgery , receptor
Summary Previous estimates for the end‐tidal concentration of desflurane that allows removal of the laryngeal mask airway in 50% of anaesthetised adults (ED50) have ranged from 2.1% to 5.3%. To assess which value is correct, we studied 32 female patients (aged 30–50 years) undergoing intracavity caesium implants for cervical carcinoma under general anaesthesia. Anaesthesia was induced with propofol 2–3 mg.kg −1 and maintained with desflurane in a 50% nitrous oxide‐oxygen mixture. At the end of surgery, a predetermined target end‐tidal desflurane concentration (starting at 4%) was maintained for 10 min using Dixon’s up‐down method and the laryngeal mask airway was removed. The target end‐tidal concentration in the next patient was increased or decreased by 0.5% depending upon the response of the previous patient. Removal of the laryngeal mask airway without coughing, clenching, biting, movement or any adverse airway event during or within 1 min after removal was considered to be successful. We found that the laryngeal mask airway can be successfully removed in 50% (ED50) and 95% (ED95) of the anaesthetised adults at end‐tidal desflurane concentrations of 2.4% (95% CI 1.3–2.9) and 3.8% (3.1–9.6), respectively.