Biomaterial Database

Maximum inspiratory muscle endurance capacity during resistive loading in chronic obstructive pulmonary disease. 1990

C S Sassoon, and R Lodia, and R W Light, and C K Mahutte

Department of Medicine, Veterans Administration Medical Center, Long Beach, Calif.

In 10 patients with stable severe chronic obstructive pulmonary disease (COPD) we evaluated the relationship between the degree of airway obstruction and hyperinflation, and the maximum inspiratory muscle endurance capacity during added inspiratory resistive loading. We measured the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) and airway resistance (Raw) as indices of airway obstruction, and the ratio of functional residual capacity to total lung capacity (FRC/TLC) as an index of hyperinflation. The mean resting transdiaphragmatic pressure to its maximum (Pdi/Pdimax), the tension time index of the diaphragm, and the maximum transdiaphragmatic pressure (Pdimax) were also determined. Following 15 min of resting breathing, the patients breathed through added inspiratory resistances which were progressively increased every 3 min until exhaustion. Maximum endurance capacity (ECmax) was defined as the product of the esophageal pressure - time integral and frequency at the maximum load sustainable for 3 min. ECmax correlated significantly with Raw (r = -0.67, p less than 0.04). The addition of FRC/TLC to the analysis resulted in a significant increase in the correlation coefficient (r = 0.86, p less than 0.01). ECmax did not correlate with FEV1/FVC. Both resting Pdi/Pdimax and Pdimax independently influenced ECmax. In addition, Pdimax correlated significantly with FRC/TLC, and resting Pdi/Pdimax with Raw. We conclude that in stable patients with severe COPD, both airway obstruction and hyperinflation affect maximum inspiratory muscle endurance capacity during inspiratory resistive loading.

UI	MeSH Term	Description	Entries
D008173	Lung Diseases, Obstructive	Any disorder marked by obstruction of conducting airways of the lung. AIRWAY OBSTRUCTION may be acute, chronic, intermittent, or persistent.	Obstructive Lung Diseases,Obstructive Pulmonary Diseases,Lung Disease, Obstructive,Obstructive Lung Disease,Obstructive Pulmonary Disease,Pulmonary Disease, Obstructive,Pulmonary Diseases, Obstructive
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D010807	Physical Endurance	The time span between the beginning of physical activity by an individual and the termination because of exhaustion.	Endurance, Physical,Physical Stamina,Stamina, Physical
D012132	Respiratory Muscles	These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.	Ventilatory Muscles,Respiratory Muscle,Muscle, Respiratory,Muscle, Ventilatory,Muscles, Respiratory,Muscles, Ventilatory,Ventilatory Muscle
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
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000368	Aged	A person 65 years of age or older. For a person older than 79 years, AGED, 80 AND OVER is available.	Elderly
D000403	Airway Resistance	Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow.	Airway Resistances,Resistance, Airway,Resistances, Airway
D014109	Total Lung Capacity	The volume of air contained in the lungs at the end of a maximal inspiration. It is the equivalent to each of the following sums: VITAL CAPACITY plus RESIDUAL VOLUME; INSPIRATORY CAPACITY plus FUNCTIONAL RESIDUAL CAPACITY; TIDAL VOLUME plus INSPIRATORY RESERVE VOLUME plus functional residual capacity; or tidal volume plus inspiratory reserve volume plus EXPIRATORY RESERVE VOLUME plus residual volume.	Lung Capacity, Total,Capacities, Total Lung,Capacity, Total Lung,Lung Capacities, Total,Total Lung Capacities