title: Detection of positional airway obstruction in neonates by acoustic reflection.
abstract: In neonates intubated with an uncuffed endotracheal tube (ETT), positional changes of the head may induce obstruction (side position-related ETT obstruction [SPRO]) due to abutment of the beveled distal ETT orifice against the tracheal wall. We studied whether the acoustic reflection (ACR) method, a 4-s measurement that maps cross-sectional area as a function of the distance along the ETT and the airways, could detect SPRO. Eleven preterm newborns intubated with 2.5-mm ETTs and clinically suspected of having SPRO were studied with the head oriented to the left and to the right. In all patients there was a marked decrease in the ACR-measured area beyond the distal tip of the ETT in the presence of obstruction (decrease = 38 +/- 22% [mean +/- SD] of the ETT inside area), while the ACR-measured area increased markedly in the absence of obstruction (increase = 49 +/- 17%). For six of the 11 infants, we also recorded the maximal flow produced by a set mechanical inflation pressure. This maximal flow decreased in the presence of obstruction (decrease = 47 +/- 18%), and was constantly associated with a decrease in ACR-measured area beyond the ETT. In conclusion, ACR measurement is an efficient method for diagnosing positional ETT obstruction in intubated newborns.
authors.affiliation: Service de Médecine Néonatale de Port-Royal, Centre Hospitalier Universitaire Cochin, Assistance Publique-Hôpitaux de Paris-Université Paris V, Paris, France. pierre-henri.jarreau@cch.ap-hop-paris.fr
authors.forename: P H
authors.initials: PH
authors.lastname: Jarreau
authors.forename: B
authors.initials: B
authors.lastname: Louis
authors.forename: L
authors.initials: L
authors.lastname: Desfrère
authors.forename: P W
authors.initials: PW
authors.lastname: Blanchard
authors.forename: D
authors.initials: D
authors.lastname: Isabey
authors.forename: A
authors.initials: A
authors.lastname: Harf
authors.forename: G
authors.initials: G
authors.lastname: Moriette
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D000402:Airway Obstruction / Q000175:diagnosis* / Q000209:etiology; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007442:Intubation, Intratracheal / Q000009:adverse effects*; D011187:Posture