Biomaterial Database

Maximal activation of the human diaphragm but not inspiratory intercostal muscles during static inspiratory efforts. 1988

D K McKenzie, and B L Plassman, and S C Gandevia

Unit of Clinical Neurophysiology, Prince Henry Hospital, Sydney, N.S.W., Australia.

It is widely held that transdiaphragmatic pressure is a reliable index of the extent of central activation of the diaphragm but the maximal voluntary transdiaphragmatic pressure is lower during inspiratory than expulsive efforts. To determine whether the diaphragm is fully activated during the two manoeuvres supramaximal stimuli were delivered to both phrenic nerves during maximal efforts. No discernible twitch was evoked during 30-55% of attempted maximal efforts with either voluntary manoeuvre. Thus the difference in maximal transdiaphragmatic pressure between the manoeuvres must reflect changes in chest-wall geometry or mechanics rather than in the phrenic motor outflow. Inspiratory intercostal muscle activity was consistently submaximal during maximal inspiratory efforts.

UI	MeSH Term	Description	Entries
D007366	Intercostal Muscles	Respiratory muscles that arise from the lower border of one rib and insert into the upper border of the adjoining rib, and contract during inspiration or respiration. (From Stedman, 25th ed)	Intercostal Muscle,Muscle, Intercostal,Muscles, Intercostal
D007384	Intermittent Positive-Pressure Breathing	Application of positive pressure to the inspiratory phase of spontaneous respiration.	IPPB,Inspiratory Positive-Pressure Breathing,Intermittent Positive Pressure Breathing (IPPB),Breathing, Inspiratory Positive-Pressure,Breathing, Intermittent Positive-Pressure,Inspiratory Positive Pressure Breathing,Intermittent Positive Pressure Breathing,Positive-Pressure Breathing, Inspiratory,Positive-Pressure Breathing, Intermittent
D008297	Male		Males
D010791	Phrenic Nerve	The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm.	Nerve, Phrenic,Nerves, Phrenic,Phrenic Nerves
D011175	Positive-Pressure Respiration	A method of mechanical ventilation in which pressure is maintained to increase the volume of gas remaining in the lungs at the end of expiration, thus reducing the shunting of blood through the lungs and improving gas exchange.	Positive End-Expiratory Pressure,Positive-Pressure Ventilation,End-Expiratory Pressure, Positive,End-Expiratory Pressures, Positive,Positive End Expiratory Pressure,Positive End-Expiratory Pressures,Positive Pressure Respiration,Positive Pressure Ventilation,Positive-Pressure Respirations,Positive-Pressure Ventilations,Pressure, Positive End-Expiratory,Pressures, Positive End-Expiratory,Respiration, Positive-Pressure,Respirations, Positive-Pressure,Ventilation, Positive-Pressure,Ventilations, Positive-Pressure
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
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man