title: Resistance of tracheal tubes 3.0 and 3.5 mm internal diameter. A comparison of four commonly used types.
abstract: The resistance of RAE, Rüsch, Mallinckrodt paediatric and Portex plain nasal and oral tracheal tubes with internal diameters 3.0 mm and 3.5 mm was calculated at air flows of 1 to 10 litres per minute. The flow resistance profiles of RAE and Rüsch tracheal tubes was generally higher than those of Mallinckrodt paediatric and Portex plain tubes. All RAE and Rüsch nasotracheal tubes of size 3.0 mm internal diameter and orotracheal tubes 3.0 mm internal diameter had a flow resistance exceeding 3.0 kPa litres/second at an air flow of 4 litres/minute. It is concluded that these tracheal tubes ought only to be used with assisted or controlled ventilation.
mesh_terms: D004867:Equipment Design; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007442:Intubation, Intratracheal / Q000295:instrumentation*; D012212:Rheology