title: Ultrasonographic assessment of the diaphragm in chronic obstructive pulmonary disease patients: relationships with pulmonary function and the influence of body composition - a pilot study.
abstract: BACKGROUND
  Skeletal muscle weakness with loss of fat-free mass (FFM) is one of the main systemic effects of chronic obstructive pulmonary disease (COPD). The diaphragm is also involved, leading to disadvantageous conditions and poor contractile capacities.
  
  
  OBJECTIVE
  We measured the thickness of the diaphragm (TD) by ultrasonography to evaluate the relationships between echographic measurements, parameters of respiratory function and body composition data.
  
  
  METHODS
  Thirty-two patients (23 males) underwent (1) pulmonary function tests, (2) echographic assessment of TD in the zone of apposition at various lung volumes, i.e. TD at residual volume (TDRV), TD at functional residual capacity (TDFRC) and TD at total lung capacity (TDTLC), and (3) bioelectrical body impedance analysis. The BMI and the BODE (BMI-Obstruction-Dyspnea-Exercise) index values were reported.
  
  
  RESULTS
  TDRV, TDFRC and TDTLC measured 3.3, 3.6 and 6 mm, respectively, with good intraobserver reproducibility (0.97, 0.97 and 0.96, respectively). All the TDs were found to be related to FFM, with the relationship being greater for TDFRC (r(2) = 0.39 and p = 0.0002). With regard to lung volumes, inspiratory capacity (IC) was found to be closely related to TDTLC (r(2) = 0.42 and p = 0.0001). The difference between TDTLC and TDRV, as a thickening value (TDTLCRV), was closely related to FVC (r(2) = 0.34 and p = 0.0004) and to air-trapping indices (RV/TLC, FRC/TLC and IC/TLC): the degree of lung hyperinflation was greater and the TDTLCRV was less. Finally, we found a progressive reduction of both thicknesses and thickenings as the severity of IC/TLC increased, with a significant p value for the trend in both analyses (p = 0.02).
  
  
  CONCLUSIONS
  Ultrasonographic assessment of the diaphragm could be a useful tool for studying disease progression in COPD patients, in terms of lung hyperinflation and the loss of FFM. © 2014 S. Karger AG, Basel.
authors.affiliation: Pulmonary Medicine Department, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Smargiassi
authors.forename: Riccardo
authors.initials: R
authors.lastname: Inchingolo
authors.forename: Linda
authors.initials: L
authors.lastname: Tagliaboschi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Di Marco Berardino
authors.forename: Salvatore
authors.initials: S
authors.lastname: Valente
authors.forename: Giuseppe Maria
authors.initials: GM
authors.lastname: Corbo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D003964:Diaphragm / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000209:etiology / Q000503:physiopathology; D009929:Organ Size; D010865:Pilot Projects; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012129:Respiratory Function Tests; D014463:Ultrasonography