Effect of acceleration on the distribution of ventilation in man
Glaister, D.H.
Journal of Gravitational Physiology a Journal of the International Society for Gravitational Physiology 1(1): P37-P40
1994
ISSN/ISBN: 1077-9248 PMID: 11538756 Document Number: 6609
The Symposium 'High G and the Lungs' looks at the physiological and potentially pathophysiological effects of the high-G aerospace environment on the lungs of human subjects and experimental animals. It is logical, therefore, to start off with a brief description of that environment and how sustained inertial forces affect pulmonary function. It is concluded that acceleration is the major factor determining the pattern of ventilation in the lung and, in particular, the occurrence and distribution of airway closure. It acts simply through the associated gradient in transpulmonary pressure and has no specific effect on the mechanical properties of lung tissue. Associated ventilation/perfusion irregularities and right-toleft shunting of venous blood consequent upon airway closure lead to arterial oxygen desaturation. Any attempt to correct this by prebreathing 100% 02 will lead to absorptional atelectasis and render the desaturation persistant. All these factors merit consideration in the design of G-protection systems.
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