Biomaterial Database

Topographical ventilation and perfusion distribution during IPPB in the lateral posture. 1978

J C Chevrolet, and J G Martin, and R Flood, and R R Martin, and L A Engel

We measured topographical ventilation and perfusion distribution in the gravity field using 133Xe in 5 normal subjects either during natural breathing or during intermittent positive pressure ventilation (IPPB) in the lateral decubitus posture. The ratio of ventilation of upper regions to that of lower regions increased from 0.61 +/- 0.10 (mean +/- SE) during natural breathing to 0.95 +/- 0.08 during IPPB. In contrast, the ratio of regional perfusion was unchanged in the 2 conditions. Consequently, distribution of regional ventilation-perfusion ratios became less homogeneous during IPPB. Whereas during natural breathing the ratio of ventilation-perfusion of upper regions to that of lower regions was 1.09 +/- 0.18, during IPPB this ratio was 1.52 +/- 0.14. Despite the differences in regional ventilation distribution between natural breathing and IPPB, analysis of multiple-breath 133Xe washouts measured at the mouth did not reveal any difference. The results are consistent with the hypothesis that the magnitude of diaphragmatic tension is the main determinant of topographical ventilation distribution in the lateral posture.

UI	MeSH Term	Description	Entries
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
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
D011187	Posture	The position or physical attitude of the body.	Postures
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
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013990	Tidal Volume	The volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are TV or V with subscript T.	Tidal Volumes,Volume, Tidal,Volumes, Tidal
D014692	Ventilation-Perfusion Ratio	The ratio of alveolar ventilation to simultaneous alveolar capillary blood flow in any part of the lung. (Stedman, 25th ed)	Ratio, Ventilation-Perfusion,Ratios, Ventilation-Perfusion,Ventilation Perfusion Ratio,Ventilation-Perfusion Ratios
D014980	Xenon Radioisotopes	Unstable isotopes of xenon that decay or disintegrate emitting radiation. Xe atoms with atomic weights 121-123, 125, 127, 133, 135, 137-145 are radioactive xenon isotopes.	Radioisotopes, Xenon