Accession Number : AD0467142


Title :   PULMONARY FUNCTION IN MAN DURING PROLONGED ACCELERATION. I. DIFFUSING CAPACITY AND BLOOD FLOW.


Descriptive Note : Phase rept.,


Corporate Author : NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA AVIATION MEDICAL ACCELERATION LAB


Personal Author(s) : Power, Gordon G , Jr ; Hyde, Richard W ; Sever, Raymond J


Report Date : 30 Jun 1965


Pagination or Media Count : 14


Abstract : This report discusses the possible causes of the decreased arterial oxygen saturation seen when a subject is accelerated in a centrifuge by measuring simultaneously the pulmonary diffusing capacity, and the pulmonary capillary blood flow, using breathholding techniques with carbon monoxide and acetylene. After one minute of forward acceleration at eight times normal gravity, 8G, average capillary diffusing capacity decreased 35% from an initial control of 33.7 to 21.5 m1/min x mm Hg in four subjects. Although this decrease was statistically significant (p0.01) the values observed were not low enough to indicate that impaired diffusion was a prime cause of arterial unsaturation. Average Qc decreased 35% during acceleration from an initial control value of 12.9 to 8.2 L/min, also a significant change (p0.01). These values may have indicated that total pulmonary blood flow was reduced, but a more likely explanation is that a large portion of pulmonary flow perfused non-ventilated regions. Capillary diffusing capacity and Qc returned toward initial control levels within 8 minutes after acceleration in most instances. (Author)


Descriptors :   *ACCELERATION , PHYSIOLOGY , BLOOD CIRCULATION , LUNG , AVIATION MEDICINE , DIFFUSION , CAPILLARIES(ANATOMY) , POSTURE(PHYSIOLOGY) , PRESSURE BREATHING , ACETYLENE , RESPIRATION


Distribution Statement : APPROVED FOR PUBLIC RELEASE