title: Patency of paediatric endotracheal tubes for airway instrumentation.
abstract: BACKGROUND
  Airway exchange catheters (AEC) and fiberoptic bronchoscopes (FOB) for tracheal intubation are selected so that there is only a minimal gap between their outer and inner diameter of endotracheal tube (ETT) to minimize the risk of impingement during airway instrumentation. This study aimed to test the ease of passage of FOBs and AECs through paediatric ETT of different sizes and from different manufacturers when using current recommendations for dimensional equipment compatibility taken from text books and manufacturers information.
  
  
  METHODS
  Twelve different brands of cuffed and uncuffed ETT sized ID 2.5 to 5.0 mm were evaluated in an in vitro set-up. Ease of device passage as well as the locations of an impaired passage within the ETT were assessed. Redundant samples were used for same sized ETT and all measurements were triple-checked in randomized order.
  
  
  RESULTS
  In total, 51 paired samples of uncuffed as well as cuffed paediatric ETT were tested. There were substantial differences in the ease of ETT passage concordantly for FOBs and AECs among different manufacturers, but also among the product lines from the same manufacturer for a given ID size. Restriction to passage most frequently was found near the endotracheal tube tip or as a gradually increasing resistance along the ETT shaft.
  
  
  CONCLUSIONS
  Current recommendations for dimensional equipment compatibility AECs and FOBs with ETTs do not appear to be completely accurate for all ETT brands available. We recommend that specific equipment combinations always must be tested carefully together before attempting to use them in a patient.
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Zurich, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Elfgen
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Zurich, Switzerland.
authors.forename: P K
authors.initials: PK
authors.lastname: Buehler
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Zurich, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Thomas
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Zurich, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Kemper
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Zurich, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Imach
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Zurich, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Weiss
mesh_terms: D020680:Bronchoscopes; D057785:Catheters; D002648:Child; D004867:Equipment Design; D005336:Fiber Optic Technology; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation*