title: A pillow of 8 cm height did not improve laryngeal view and alignment of airway axes but increased anesthesiologist discomfort compared to a pillow of 4 cm height during tracheal intubation in adult patients.
abstract: BACKGROUND
  Neck flexion by head elevation using an 8 to 10 cm thick pillow and head extension has been suggested to align the laryngeal, pharyngeal and oral axis and facilitate tracheal intubation. Presently, the laryngeal view and discomfort for tracheal intubation were evaluated according to two different degrees of head elevation in adult patients.
  
  
  METHODS
  This prospective randomized, controlled study included 50 adult patients aged 18 to 90 years. After induction of anesthesia, the Cormack Lehane grade was evaluated in 25 patients using a direct laryngoscope while the patient's head was elevated with a 4 cm pillow (4 cm group) and then an 8 cm pillow (8 cm group). In the other 25 patients, the grades were evaluated in the opposite sequence and tracheal intubation was performed. The success rate and anesthesiologist's discomfort score for tracheal intubation, and laryngeal, pharyngeal and oral axes were assessed.
  
  
  RESULTS
  There were no differences in the laryngeal view and success rate for tracheal intubation between the two groups. The discomfort score during tracheal intubation was higher in the 8 cm group when the patient's head was elevated 4 cm first and then 8 cm. The alignment of laryngeal, pharyngeal and oral axes were not different between the two degrees of head elevation.
  
  
  CONCLUSIONS
  A pillow of 8 cm height did not improve laryngeal view and alignment of airway axes but increased the anesthesiologist discomfort, compared to a pillow of 4 cm height, during tracheal intubation in adult patients.
authors.affiliation: Department of Anesthesiology and Pain Medicine, National Medical Center, Seoul, Korea.
authors.forename: Hyo Ju
authors.initials: HJ
authors.lastname: Hong
authors.affiliation: Department of Anesthesiology and Pain Medicine, National Medical Center, Seoul, Korea.
authors.forename: Mijung
authors.identifier: 0000-0001-5838-4893
authors.initials: M
authors.lastname: Yun
authors.affiliation: Department of Anesthesiology and Pain Medicine, National Medical Center, Seoul, Korea.
authors.forename: Sung Hoon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jung Won
authors.initials: JW
authors.lastname: Hwang
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Hyung Chul
authors.initials: HC
authors.lastname: Lee
keywords: Airway management; Intratracheal intubation; Laryngoscope; Vocal cords