title: Pulse transit time as a measure of inspiratory effort in children.
abstract: OBJECTIVE
  The current criterion standard for measuring inspiratory effort, esophageal manometry, is an invasive procedure that young patients find intolerable. Inspiratory effort can also be assessed noninvasively by measuring the pulse transit time (PTT). PTT is the time the pulse wave (PW) takes to travel between two arterial sites (normally heart to finger). The speed at which the PW travels is directly proportional to arterial BP. When BP rises, PTT shortens. Conversely, when BP falls, PTT lengthens. In this study, we investigated PTT as a measure for evaluating inspiratory effort in children.
  
  
  METHODS
  We studied 15 healthy children (age range, 5 to 12 years; mean age [+/- SD], 8.3 +/- 2.74; 9 male children) selected from patients referred to our pediatric center for routine assessment.
  
  
  RESULTS
  We assessed changes in the PTT during breathing against known resistances in awake children. Resistance was applied to the nose and mouth with a modified, two-way, nonrebreathing facemask. Our data show a good correlation between the induced inspiratory effort and the amplitude of PTT variations.
  
  
  CONCLUSIONS
  PTT should be a useful method for quantifying changes in inspiratory effort due to augmented upper airway resistance in awake children.
authors.affiliation: Department of Pediatrics, II Faculty S. Andrea University of Rome La Sapienza, Italy. jacopo.pagan@uniroma1.it
authors.forename: Jacopo
authors.initials: J
authors.lastname: Pagani
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Villa
authors.forename: Giovanni
authors.initials: G
authors.lastname: Calcagnini
authors.forename: Arianna
authors.initials: A
authors.lastname: Alterio
authors.forename: Rosa
authors.initials: R
authors.lastname: Ambrosio
authors.forename: Federica
authors.initials: F
authors.lastname: Censi
authors.forename: Roberto
authors.initials: R
authors.lastname: Ronchetti
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D001239:Inhalation / Q000502:physiology*; D008297:Male; D011674:Pulse / Q000379:methods*; D013997:Time Factors