Accession Number : ADA019291

Title :   The Effect of Transversely Applied Acceleration on Lung Mechanics in Man,


Personal Author(s) : Glaister,D. H. ; Ironmonger,M. R. ; Lisher,B. J.

Report Date : MAY 1975

Pagination or Media Count : 51

Abstract : Argon boluses were used to study the distribution of ventilation in subjects exposed to acceleration up to 5G whilst lying in prone, supine and left and right lateral postures. Transpulmonary pressure was also recorded. Closing volume was increased in prone and supine postures and, at any given volume, lung compliance decreased. In lateral decubitus, acceleration produced a step in the expired argon plateau at about 50% VC which coincided with a flatter part of a complex pressure-volume curve. It is argued that the weight of mediastinal structures causes a discontinuity in the vertical gradient of transpulmonary pressure of some 5 cm water per G, and at higher levels of acceleration the two lungs ventilate sequentially. A two compartment model was used to demonstrate that all observations could be accounted for on the basis of increased lung weight, with no change in the mechanical properties of individual units.

Descriptors :   *Acceleration, *Biomechanics, *Pulmonary function, Aviation medicine, Lung, Humans, Transverse, Argon, Pulmonary blood circulation, Posture(Physiology), Ventilation(Physiology), Body weight, Pressure gradients, Lung function tests, Tracer studies, Mechanical properties, Males, Centrifugal force, Volume, Great Britain

Subject Categories : Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE