title: Comparison of the effects of the laryngeal mask airway and endotracheal intubation on vocal function.
abstract: We have compared changes in vocal function produced after insertion of a laryngeal mask airway (LMA) with those produced by tracheal intubation in 20 patients. Using acoustic waveform analysis, we computed amplitude variability (AV), pitch variability (PV), harmonics-to-noise ratio (HNR) and additive noise level (ANL) before anaesthesia and at 1, 4, and 24 h after tracheal extubation. There were no significant changes in vocal function after extubation except for HNR ratio (P = 0.046) at 4 h in the LMA group. There were differences in all four variables at 1 h, 4 h, or both, after tracheal extubation compared with baseline in the tracheal tube group. In both groups, all variables were the same as baseline values 24 h after extubation. We observed significant differences in AV (4 h), PV and ANL (1, 4 h) values between the two groups. These observations suggest that the LMA causes less vocal change than tracheal intubation.
authors.affiliation: Department of Anaesthesiology, Chonbuk National University Medical School, Republic of Korea.
authors.forename: S K
authors.initials: SK
authors.lastname: Lee
authors.forename: K H
authors.initials: KH
authors.lastname: Hong
authors.forename: H
authors.initials: H
authors.lastname: Choe
authors.forename: H S
authors.initials: HS
authors.lastname: Song
mesh_terms: D000328:Adult; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects; D017214:Laryngeal Masks / Q000009:adverse effects; D007828:Laryngoscopy; D013997:Time Factors; D014831:Voice / Q000502:physiology*