Peripheral resistance: a link between global airflow obstruction and regional ventilation distribution.
J Appl Physiol (1985)
; 114(4): 504-14, 2013 Feb 15.
Article
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| MEDLINE
| ID: mdl-23123354
Airflow obstruction and heterogeneities in airway constriction and ventilation distribution are well-described prominent features of asthma. However, the mechanistic link between these global and regional features has not been well defined. We speculate that peripheral airway resistance (R(p)) may provide such a link. Structural and functional parameters are estimated from PET and HRCT images of asthmatic (AS) and nonasthmatic (NA) subjects measured at baseline (BASE) and post-methacholine challenge (POST). Conductances of 35 anatomically defined proximal airways are estimated from airway geometry obtained from high-resolution computed tomography (HRCT) images. Compliances of sublobar regions subtended by 19 most distal airways are estimated from changes in regional gas volume between two lung volumes. Specific ventilations (sV) of these sublobar regions are evaluated from 13NN-washout PET scans. For each pathway connecting the trachea to sublobar region, values of R(p) required to explain the sV distribution and global airflow obstruction are computed. Results show that R(p) is highly heterogeneous within each subject, but has average values consistent with global values in the literature. The contribution of R(p) to total pathway resistance (R(T)) increased substantially for POST (P < 0.0001). The fraction R(p)/R(T) was higher in AS than NA at POST (P < 0.0001) but similar at BASE (range: 0.960-0.997, median: 0.990). For POST, R(p)/R(T) range was 0.979-0.999 (NA) and 0.981-0.995 (AS). This approach allows for estimations of peripheral airway resistance within anatomically defined sublobar regions in vivo human lungs and may be used to evaluate peripheral effects of therapy in a subject specific manner.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Asma
/
Resistencia de las Vías Respiratorias
/
Broncoconstricción
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Ventilación Pulmonar
/
Obstrucción de las Vías Aéreas
/
Pulmón
Tipo de estudio:
Diagnostic_studies
/
Observational_studies
/
Prognostic_studies
Límite:
Adult
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
J Appl Physiol (1985)
Asunto de la revista:
FISIOLOGIA
Año:
2013
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos