Biomaterial Database

Effects of ventilator resistance and compliance on phrenic nerve activity in spontaneously breathing cats. 1996

A Schulze, and A Jonzon, and P Schaller, and G Sedin

Children's Hospital, University of Dresden, Carl Gustav Carus Faculty of Medicine, Germany.

This study investigates the effects of respiratory mechanical loading and unloading on phrenic nerve activity and ventilation. Ten adult cats were anesthetized, intubated, and connected to a servocontrolled infant ventilator while breathing spontaneously in continuous positive airway pressure mode. The ventilator was then set to decrease the pressure at the airway opening in proportion to the inspiratory airflow or the volume of spontaneous breathing (resistive or elastic loading) or to increase the pressure at the airway opening accordingly (resistive or elastic unloading, also called proportional assist ventilation). When compared with continuous positive airway pressure, both resistive and elastic loading increased the number of phrenic nerve impulses per breath and the mean frequency of impulses (p < 0.01, ANOVA). In contrast, elastic unloading decreased phrenic nerve activity significantly in normal and injured lungs. Resistive unloading in normal lungs did not change phrenic nerve activity significantly. The compensatory response in phrenic nerve activity was not large enough to completely offset effects of loading and unloading on ventilation: elastic and resistive loading decreased ventilation. Unloading had the opposite effect on ventilation, particularly in injured lungs. We conclude that respiratory mechanical loading and unloading have statistically significant, opposite effects on phrenic nerve activity and opposite effects on ventilation.

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
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
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
D012121	Respiration, Artificial	Any method of artificial breathing that employs mechanical or non-mechanical means to force the air into and out of the lungs. Artificial respiration or ventilation is used in individuals who have stopped breathing or have RESPIRATORY INSUFFICIENCY to increase their intake of oxygen (O2) and excretion of carbon dioxide (CO2).	Ventilation, Mechanical,Mechanical Ventilation,Artificial Respiration,Artificial Respirations,Mechanical Ventilations,Respirations, Artificial,Ventilations, Mechanical
D012128	Respiratory Distress Syndrome	A syndrome characterized by progressive life-threatening RESPIRATORY INSUFFICIENCY in the absence of known LUNG DISEASES, usually following a systemic insult such as surgery or major TRAUMA.	ARDS, Human,Acute Respiratory Distress Syndrome,Adult Respiratory Distress Syndrome,Pediatric Respiratory Distress Syndrome,Respiratory Distress Syndrome, Acute,Respiratory Distress Syndrome, Adult,Respiratory Distress Syndrome, Pediatric,Shock Lung,Distress Syndrome, Respiratory,Distress Syndromes, Respiratory,Human ARDS,Lung, Shock,Respiratory Distress Syndromes,Syndrome, Respiratory Distress
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D004548	Elasticity	Resistance and recovery from distortion of shape.
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
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia