Biomaterial Database

Pulmonary diffusing capacity in the presence of ventilation inhomogeneity. 1987

G M Saidel, and M Modarreszadeh

Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio.

A model has been developed to quantify the effectiveness of alveolar-capillary transport in the presence of ventilation inhomogeneity. The exhalation dynamics of carbon monoxide (CO), argon (Ar), and lung volume from a single-breath experiment are analyzed simultaneously. A membrane transport coefficient (MTCO) that does not vary with lung volume is evaluated by a two-stage optimization procedure and related to diffusing capacity. Also, the model allows for a decrease in membrane transport rate associated with reduced lung volume. The model is tested by simulation studies and experiments with human subjects having normal or diseased (mainly obstructed) lungs. The MTCO provides a clear distinction between normal and obstructed lungs with respect to alveolar-capillary transport, whereas the semilog slope of the Ar alveolar plateau characterizes the ventilation inhomogeneity. Only when the diffusing capacity is corrected by the Ar slope, DLCO(Ar), do the breathing maneuvers performed from different preinflation volumes (residual volume or functional residual capacity) yield the same results for lungs with ventilation inhomogeneity. The uncorrected DLCO overestimates the effectiveness of alveolar-capillary transport in the presence of ventilation inhomogeneity.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D011653	Pulmonary Diffusing Capacity	The amount of a gas taken up, by the pulmonary capillary blood from the alveolar gas, per minute per unit of average pressure of the gradient of the gas across the BLOOD-AIR BARRIER.	Capacity, Pulmonary Diffusing,Diffusing Capacity, Pulmonary
D012115	Residual Volume	The volume of air remaining in the LUNGS at the end of a maximal expiration. Common abbreviation is RV.	Residual Volumes,Volume, Residual,Volumes, Residual
D003198	Computer Simulation	Computer-based representation of physical systems and phenomena such as chemical processes.	Computational Modeling,Computational Modelling,Computer Models,In silico Modeling,In silico Models,In silico Simulation,Models, Computer,Computerized Models,Computer Model,Computer Simulations,Computerized Model,In silico Model,Model, Computer,Model, Computerized,Model, In silico,Modeling, Computational,Modeling, In silico,Modelling, Computational,Simulation, Computer,Simulation, In silico,Simulations, Computer
D005260	Female		Females
D005541	Forced Expiratory Volume	Measure of the maximum amount of air that can be expelled in a given number of seconds during a FORCED VITAL CAPACITY determination . It is usually given as FEV followed by a subscript indicating the number of seconds over which the measurement is made, although it is sometimes given as a percentage of forced vital capacity.	Forced Vital Capacity, Timed,Timed Vital Capacity,Vital Capacity, Timed,FEVt,Capacities, Timed Vital,Capacity, Timed Vital,Expiratory Volume, Forced,Expiratory Volumes, Forced,Forced Expiratory Volumes,Timed Vital Capacities,Vital Capacities, Timed,Volume, Forced Expiratory,Volumes, Forced Expiratory
D005652	Functional Residual Capacity	The volume of air remaining in the LUNGS at the end of a normal, quiet expiration. It is the sum of the RESIDUAL VOLUME and the EXPIRATORY RESERVE VOLUME. Common abbreviation is FRC.	Capacities, Functional Residual,Capacity, Functional Residual,Functional Residual Capacities,Residual Capacities, Functional,Residual Capacity, Functional