Biomaterial Database

Flow and age dependence of airway closure and dynamic compliance. 1975

R Begin, and A D Renzetti, and A H Bigler, and S Watanabe

The influence of expiratory flow rate and age on the results of measurement of closing volume (CV) of the lung have been studied by a nitrogen single-breath method in 66 asymptomatic lifetime nonsmoking normal subjects between 20 and 82 yr of age. Normal was defined as having values for spirometric measurements within a 95% tolerance interval of reported predicted normal mean values. For the CV determination, inspiratory flow rate was held constant at 0.51/s and studies were carried out at expiratory flow rates of 0.25, 0.5, 1.0, and 1.5 1/s. Our results show that CV expressed as a percentage of vital capacity (VC) and the slope of the alveolar plateau increases with increasing flow rate and age. Dynamic compliance (Cdyn) at frequencies corresponding to peak flow rates of 0.5 and 1.5 1/s was also measured and correlated well with the CV results. Frequency dependence of compliance with aging was demonstrated. Nine smokers with normal spirometric measurements and abnormal CV %VC were also studied. Since the results of Cdyn measurement differentiated only two-thirds of the smokers from the normal population, we suggest that the CV method is probably more sensitive than the Cdyn method for the detection of small airway obstruction.

UI	MeSH Term	Description	Entries
D008170	Lung Compliance	The capability of the LUNGS to distend under pressure as measured by pulmonary volume change per unit pressure change. While not a complete description of the pressure-volume properties of the lung, it is nevertheless useful in practice as a measure of the comparative stiffness of the lung. (From Best & Taylor's Physiological Basis of Medical Practice, 12th ed, p562)	Compliance, Lung,Compliances, Lung,Lung Compliances
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D009584	Nitrogen	An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.
D010993	Plethysmography, Whole Body	Measurement of the volume of gas in the lungs, including that which is trapped in poorly communicating air spaces. It is of particular use in chronic obstructive pulmonary disease and emphysema. (Segen, Dictionary of Modern Medicine, 1992)	Whole Body Plethysmography,Body Plethysmographies, Whole,Body Plethysmography, Whole,Plethysmographies, Whole Body,Whole Body Plethysmographies
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D012123	Pulmonary Ventilation	The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.	Respiratory Airflow,Ventilation Tests,Ventilation, Pulmonary,Expiratory Airflow,Airflow, Expiratory,Airflow, Respiratory,Test, Ventilation,Tests, Ventilation,Ventilation Test
D012129	Respiratory Function Tests	Measurement of the various processes involved in the act of respiration: inspiration, expiration, oxygen and carbon dioxide exchange, lung volume and compliance, etc.	Lung Function Tests,Pulmonary Function Tests,Function Test, Pulmonary,Function Tests, Pulmonary,Pulmonary Function Test,Test, Pulmonary Function,Tests, Pulmonary Function,Function Test, Lung,Function Test, Respiratory,Function Tests, Lung,Function Tests, Respiratory,Lung Function Test,Respiratory Function Test,Test, Lung Function,Test, Respiratory Function,Tests, Lung Function,Tests, Respiratory Function
D005069	Evaluation Studies as Topic	Works about studies that determine the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies.	Critique,Evaluation Indexes,Evaluation Methodology,Evaluation Report,Evaluation Research,Methodology, Evaluation,Pre-Post Tests,Qualitative Evaluation,Quantitative Evaluation,Theoretical Effectiveness,Use-Effectiveness,Critiques,Effectiveness, Theoretical,Evaluation Methodologies,Evaluation Reports,Evaluation, Qualitative,Evaluation, Quantitative,Evaluations, Qualitative,Evaluations, Quantitative,Indexes, Evaluation,Methodologies, Evaluation,Pre Post Tests,Pre-Post Test,Qualitative Evaluations,Quantitative Evaluations,Report, Evaluation,Reports, Evaluation,Research, Evaluation,Test, Pre-Post,Tests, Pre-Post,Use Effectiveness
D005260	Female		Females