title: Flexion compromises ventilation with the laryngeal tube suction II in children.
abstract: BACKGROUND
  There are insufficient data as to the influence of the head and neck flexion, extension, and rotation on the ventilation with laryngeal tube suction II (LTS II). The purpose of this study was to investigate the influence of the head and neck position on oropharyngeal sealing pressure (primary outcome) and ventilation score (secondary outcome) during ventilation with the LTS II in children.
  
  
  METHODS
  We studied 33 children scheduled for elective surgery. Oropharyngeal sealing pressure and ventilation score were measured with the head and neck in a neutral position, flexed, extended and rotated to the right. The ventilation score was scored from 0 to 3 based on three items (no leakage with an airway pressure of 15 cmH2O, bilateral chest excursion, and a square wave capnogram; each item scored 0 or 1 point). Peak inspiratory pressure (PIP) at a tidal volume of 10 ml x kg(-1) and fiberoptic laryngeal views were also assessed in each position.
  
  
  RESULTS
  Although the sealing pressure was lower in the extended position [22 (8) cmH2O] than that in the neutral position [25 (7) cmH2O], there was no significant leakage during ventilation with a tidal volume of 10 ml x kg(-1). In the neutral, extended and rotated positions, the median ventilation scores were better (3 point respectively) than that with the head and neck flexed (1 point). PIP was decreased with the head and neck extended or rotated but was significantly increased in flexion position. During fibreoptic examination, the vocal cords were more easily seen in extension and right rotation, compared with the neutral position and flexion.
  
  
  CONCLUSIONS
  Although oropharyngeal sealing pressure is decreased with the head and neck extended, effective ventilation with LTS II can be performed like in the neutral position or the rotated position. While the sealing pressure is maintained with the head and neck flexed, flexion compromises the ventilation with LTS II in children.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Jongnogu, Seoul, Korea.
authors.forename: Jin-Tae
authors.initials: JT
authors.lastname: Kim
authors.forename: Hyo-Seok
authors.initials: HS
authors.lastname: Na
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Bae
authors.forename: Hyun-Jeong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Hwa-Yong
authors.initials: HY
authors.lastname: Shin
authors.forename: Hee-Soo
authors.initials: HS
authors.lastname: Kim
authors.forename: Chong-Sung
authors.initials: CS
authors.lastname: Kim
authors.forename: Seong-Deok
authors.initials: SD
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D017558:Elective Surgical Procedures; D004867:Equipment Design; D005260:Female; D006257:Head; D006801:Humans; D017214:Laryngeal Masks / Q000009:adverse effects*; D008297:Male; D009333:Neck; D011187:Posture / Q000502:physiology*; D011312:Pressure; D012107:Research Design; D012121:Respiration, Artificial / Q000295:instrumentation* / Q000379:methods; D013396:Suction; D016896:Treatment Outcome