Evaluating cross-sectional area of the trachea in children with Cystic Fibrosis

http://www.ncbi.nlm.nih.gov/pubmed/22326722

Respir Physiol Neurobiol. 2012 Feb 6. [Epub ahead of print]
Evaluation of the trachea and intrathoracic airways by the acoustic reflection method in children with cystic fibrosis.
Leboulanger N, Louis B, Corvol H, Ramirez A, Fodil R, Lofaso F, Fauroux B.
Source
UPMC University Paris 06, France; Otolaryngology-Head and Neck Surgery Department, AP-HP, Armand-Trousseau Children's Hospital, 26 Avenue du Dr Arnold Netter, 75012 Paris, France; INSERM, Unité U955, 94010 Créteil, France; INSERM UMR S-938, 75012 Paris, France.

Abstract
Tracheomalacia has been observed in older patients with cystic fibrosis (CF). The acoustic reflection method (ARM) allows a noninvasive calculation of the longitudinal cross-sectional area of the trachea (MTAv) and the airway resistance (Raw). ARM measurements were performed in 20 CF children and 20 controls during spontaneous breathing (SB), forced inspiration (FI), and forced expiration (FE). The mean MTAv value was comparable in the CF patients and the control subjects during SB, FI, and FE. The Raw was also comparable during SB and FI. However, the Raw during FE was higher in the CF patients than in the control subjects (7.9±2.3 vs 5.0±1.5cmH(2)Ol(-1)s(-1), respectively, p<0.001). In the patients with CF, only the Raw during FE correlated with the predicted forced expiratory volume in 1s (R(2)=0.37, p=0.04). The tracheal cross-sectional area measured by the ARM is normal in children with CF but the increase in Raw during FE suggests an increase in intrathoracic airway distensibility.