title: [Analysis of changes in the spectrogram following endotracheal intubation].
abstract: OBJECTIVE
  Voice alteration is a common event following endotracheal intubation. The objective of this study is to describe strobolaryngoscopic and spectrogram changes after endotracheal intubation, and attempt to identify a relationship between these changes and also with anaesthetic variables.
  
  
  METHODS
  Thirty-eight patients who underwent endotracheal intubation for otological surgery were studied prospectively. None of these subjects had a history of voice problems or prior cervical surgery, and they did not consume alcohol or tobacco. The patients were studied prior to the operation and 3 hours, 24 hours, and 7 days after surgery. Laryngeal morphology was explored by strobolaryngoscopy. The vocal output was examined by means of the GRABS scale, acoustic analysis and spectrogram.
  
  
  RESULTS
  Strobolaryngoscopy was normal 24 hours after surgery in all but 2 subjects, in whom it later returned to normal. Spectrography, acoustic analysis (jitter and shimmer), and GRABS scale all showed an initial worsening of voice production after surgery when compared to pre-operative values, followed by a recovery of normal values 1 week after surgery. No statistical correlation was found between voice output and anaesthetic variables.
  
  
  CONCLUSIONS
  Although there are temporary voice changes in subjects undergoing endotracheal intubation during the early post-operative period, these recover to normal parameters within 7 days after surgery. These changes occur even in the absence of strobolaryngoscopic changes.
authors.affiliation: Servicio de Otorrinolaringología, Hospital Universitario Puerta de Hierro, Universidad Autónoma de Madrid, Madrid, España. josem.verdaguer@gmail.com
authors.forename: José M
authors.initials: JM
authors.lastname: Verdaguer
authors.forename: Carmen
authors.initials: C
authors.lastname: Górriz
authors.forename: María P
authors.initials: MP
authors.lastname: Prim
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Del Palacio
authors.forename: Javier
authors.initials: J
authors.lastname: Gavilán
authors.forename: Juan I
authors.initials: JI
authors.lastname: de Diego
mesh_terms: D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D007828:Laryngoscopy; D008297:Male; D008875:Middle Aged; D010699:Phonation; D011446:Prospective Studies; D013018:Sound Spectrography / Q000379:methods*; D013060:Speech / Q000502:physiology*