Abstract
BackgroundDue 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.MethodsSimultaneous 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.ResultsCT 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).ConclusionIn 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.
Highlights
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)
Patient demographics and results of pulmonary function tests are displayed in table 1
According to 3 recently published reference value equations using gender, age, and height as predictors, respective mean DLNO %pred and DLCO %pred for the patient group were: 71 ± 19 and 82 ± 17 %pred [17]; 60 ± 17 and 75 ± 16 %pred [18]; 63 ± 18 and 86 ± 19 %pred [19]
Summary
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 quantified via the diffusing capacity for nitric oxide (DLNO), as opposed to the conventional diffusing capacity for carbon monoxide (DLCO). The results of studies focussing on the diffusing capacity for carbon monoxide (DLCO) in CF are largely contradictory, as a spectrum of elevated, decreased, or normal values has been reported [1,2]. Recent data in children and adults suggest a slightly elevated DLCO in early CF and a reduction only in advanced disease [3,4,5]. Based on these findings, DLCO currently appears to play no role in CF assessment compared to spirometry or computed tomography (CT) [6]. In combination with DLCO, Vc and Dm can be determined in a single maneuver, based on the equation for the serial connection of resistances [8,9]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
