title: Lung diffusing capacity for nitric oxide and carbon monoxide in relation to morphological changes as assessed by computed tomography in patients with cystic fibrosis.
abstract: BACKGROUND
  Due to large-scale destruction, changes in membrane diffusion (Dm) may occur in cystic fibrosis (CF), in correspondence to alterations observed by computed tomography (CT). Dm can be easily quantified via the diffusing capacity for nitric oxide (DLNO), as opposed to the conventional diffusing capacity for carbon monoxide (DLCO). We thus studied the relationship between DLNO as well as DLCO and a CF-specific CT score in patients with stable CF.
  
  
  METHODS
  Simultaneous single-breath determinations of DLNO and DLCO were performed in 21 CF patients (mean +/- SD age 35 +/- 9 y, FEV1 66 +/- 28%pred). Patients also underwent spirometry and bodyplethysmography. CT scans were evaluated via the Brody score and rank correlations (rS) with z-scores of functional measures were computed.
  
  
  RESULTS
  CT scores correlated best with DLNO (rS = -0.83; p < 0.001). Scores were also related to the volume-specific NO transfer coefficient (KNO; rS = -0.63; p < 0.01) and to DLCO (rS = -0.79; p < 0.001) but not KCO. Z-scores for DLNO were significantly lower than for DLCO (p < 0.001). Correlations with spirometric (e.g., FEV1, IVC) or bodyplethysmographic (e.g., SRaw, RV/TLC) indices were weaker than for DLNO or DLCO but most of them were also significant (p < 0.05 each).
  
  
  CONCLUSIONS
  In this cross sectional study in patients with CF, DLNO and DLCO reflected CT-morphological alterations of the lung better than other measures. Thus the combined diffusing capacity for NO and CO may play a future role for the non-invasive, functional assessment of structural alterations of the lung in CF.
authors.affiliation: Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, Ludwig-Maximilians-University, Ziemssenstr, 1, D-80336 München, Germany. Holger.Dressel@med.uni-muenchen.de
authors.forename: Holger
authors.initials: H
authors.lastname: Dressel
authors.forename: Laura
authors.initials: L
authors.lastname: Filser
authors.forename: Rainald
authors.initials: R
authors.lastname: Fischer
authors.forename: Katharina
authors.initials: K
authors.lastname: Marten
authors.forename: Ullrich
authors.initials: U
authors.lastname: Müller-Lisse
authors.forename: Dorothea
authors.initials: D
authors.lastname: de la Motte
authors.forename: Dennis
authors.initials: D
authors.lastname: Nowak
authors.forename: Rudolf M
authors.initials: RM
authors.lastname: Huber
authors.forename: Rudolf A
authors.initials: RA
authors.lastname: Jörres
mesh_terms: D000328:Adult; D002248:Carbon Monoxide / Q000378:metabolism*; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000503:physiopathology; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D010993:Plethysmography, Whole Body; D011653:Pulmonary Diffusing Capacity / Q000502:physiology*; D012189:Retrospective Studies; D013147:Spirometry; D014057:Tomography, X-Ray Computed
chemical_list: D009569:Nitric Oxide; D002248:Carbon Monoxide