title: Changes in pulmonary mechanics with increasing disease severity in children and young adults with cystic fibrosis.
abstract: As forced expiratory volume in 1 second (FEV(1)) is a major predictor of outcome in patients with cystic fibrosis (CF), we investigated the effect of FEV(1) on pulmonary mechanics in children and young adults with CF. We measured respiratory rate; tidal volume; minute ventilation; arterial blood gases; sniff esophageal pressure; dynamic lung compliance; total pulmonary resistance; intrinsic positive end expiratory pressure; and total, elastic, and resistive work of breathing in 32 patients (FEV(1) range: 12-49% predicted). We observed correlations between FEV(1) and Pa(O(2)) (r = 0.76, p < 0.0001) and Pa(CO(2)) (r = -0.70, p < 0.0001), FEV(1) and respiratory rate/tidal volume (r = -0.41, p = 0.02), FEV(1) and dynamic lung compliance (r = 0.64, p < 0.0001), and FEV(1) and total work of breathing (r = -0.52, p = 0.002) and elastic work of breathing (r = -0.60. p = 0.0003). No correlations were observed between FEV(1) and sniff esophageal pressure (p = 0.5), minute ventilation (p = 0.9), total pulmonary resistance (p = 0.3), intrinsic positive end expiratory pressure (p = 0.3), or resistive work of breathing (p = 0.1). As FEV(1) declines in children and young adults with CF, there is an increase in the elastic load and work of breathing, resulting in a rapid shallow breathing pattern, that is associated with further impairment of gas exchange.
authors.affiliation: Pediatric Pulmonary Department, Armand Trousseau Hospital-AP-HP INSERM E 0213, Paris.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Hart
authors.forename: Michael I
authors.initials: MI
authors.lastname: Polkey
authors.forename: Annick
authors.initials: A
authors.lastname: Clément
authors.forename: Michèle
authors.initials: M
authors.lastname: Boulé
authors.forename: John
authors.initials: J
authors.lastname: Moxham
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lofaso
authors.forename: Brigitte
authors.initials: B
authors.lastname: Fauroux
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003550:Cystic Fibrosis / Q000503:physiopathology*; D018450:Disease Progression; D005541:Forced Expiratory Volume; D006801:Humans; D016014:Linear Models; D011659:Pulmonary Gas Exchange; D015656:Respiratory Mechanics; D014939:Work of Breathing