Biomaterial Database

Pressure-flow effects on endurance of inspiratory muscles. 1986

F D McCool, and D R McCann, and D E Leith, and F G Hoppin

We examined the effects of varying inspiratory pressures and flows on inspiratory muscle endurance. Four normal subjects performed voluntary forced breathing with various assigned inspiratory tasks. Duty cycle, tidal volume, and mean lung volume were the same in all tasks. Mean esophageal pressure, analogous to a pressure-time integral (PTes), was varied over a wide range. In each task the subject maintained an assigned PTes while breathing on one of a range of inspiratory resistors, and this gave a range of inspiratory flows at any given PTes. Inspiratory muscle endurance for each task was assessed by the length of time the task could be maintained (Tlim). For a given resistor, Tlim increased as PTes decreased. At a given PTes, Tlim increased as the external resistance increased and therefore as mean inspiratory flow rate (VI) decreased. Furthermore, for a given Tlim, PTes and VI were linearly related with a negative slope. We conclude that inspiratory flow, probably because of its relationship to the velocity of muscle shortening, is an independent variable importantly influencing endurance of the inspiratory muscles.

UI	MeSH Term	Description	Entries
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
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
D010827	Physiology	The biological science concerned with the life-supporting properties, functions, and processes of living organisms or their parts.
D011312	Pressure	A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Pressures
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
D012143	Respiratory Physiological Phenomena	Physiological processes and properties of the RESPIRATORY SYSTEM as a whole or of any of its parts.	Respiratory Physiologic Processes,Respiratory Physiological Processes,Respiratory Physiology,Physiology, Respiratory,Pulmonary Physiological Phenomena,Pulmonary Physiological Phenomenon,Pulmonary Physiological Process,Pulmonary Physiological Processes,Respiratory Physiological Concepts,Respiratory Physiological Phenomenon,Respiratory Physiological Process,Concept, Respiratory Physiological,Concepts, Respiratory Physiological,Phenomena, Pulmonary Physiological,Phenomena, Respiratory Physiological,Phenomenas, Pulmonary Physiological,Phenomenas, Respiratory Physiological,Phenomenon, Pulmonary Physiological,Phenomenon, Respiratory Physiological,Phenomenons, Pulmonary Physiological,Phenomenons, Respiratory Physiological,Physiologic Processes, Respiratory,Physiological Concept, Respiratory,Physiological Concepts, Respiratory,Physiological Phenomena, Pulmonary,Physiological Phenomena, Respiratory,Physiological Phenomenas, Pulmonary,Physiological Phenomenas, Respiratory,Physiological Phenomenon, Pulmonary,Physiological Phenomenon, Respiratory,Physiological Phenomenons, Pulmonary,Physiological Phenomenons, Respiratory,Physiological Process, Pulmonary,Physiological Process, Respiratory,Physiological Processes, Pulmonary,Physiological Processes, Respiratory,Process, Pulmonary Physiological,Process, Respiratory Physiological,Processes, Pulmonary Physiological,Pulmonary Physiological Phenomenas,Pulmonary Physiological Phenomenons,Respiratory Physiological Concept,Respiratory Physiological Phenomenas,Respiratory Physiological Phenomenons
D003964	Diaphragm	The musculofibrous partition that separates the THORACIC CAVITY from the ABDOMINAL CAVITY. Contraction of the diaphragm increases the volume of the thoracic cavity aiding INHALATION.	Respiratory Diaphragm,Diaphragm, Respiratory,Diaphragms,Diaphragms, Respiratory,Respiratory Diaphragms
D004947	Esophagus	The muscular membranous segment between the PHARYNX and the STOMACH in the UPPER GASTROINTESTINAL TRACT.
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man