title: [Airflow resistance of shortened tracheal tubes.].
abstract: OBJECTIVE
  Tracheal tube length may be shortened just after the cuff probably without noxious influence on airflow resistance. This study aimed at determining the effects of such shortening under different inspiratory flows.
  
  
  METHODS
  Flow resistance was measured in tubes with internal diameters of 7; 7.5; 8; 8.5; 9 and 9.5 millimeters. Measurements were undertaken on standard tubes and on those shortened just after the cuff level. Flows were 0.07 liters per second (L.s-1), 0.1; 0.2; 0.33; 0.5 and 1 L.s-1.
  
  
  RESULTS
  Resistances were progressively lower for larger internal diameters, but were higher for a same diameter under higher flow, both, in standard and shortened tubes. Shortened tubes showed lower or equal flow resistance as compared to standard tubes with the same diameter.
  
  
  CONCLUSIONS
  Resistance has been lower or comparable on shortened tubes as compared to standard tubes.
authors.affiliation: CET/SBA, HC da FMUSP.
authors.forename: Fernando José Gonçalves do
authors.initials: FJ
authors.lastname: Prado
authors.forename: Joaquim Edson
authors.initials: JE
authors.lastname: Vieira
authors.forename: Fábio Ely Martins
authors.initials: FE
authors.lastname: Benseñor