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Cardiovascular Pressures with Venous Gas Embolism and DecompressionVenous gas embolism (VGE) is reported with decompression to a decreased ambient pressure. With severe decompression, or in cases where an intracardiac septal defect (patent foramen ovale) exists, the venous bubbles can become arterialized and cause neurological decompression illness. Incidence rates of patent foramen ovale in the general population range from 25-34% and yet aviators, astronauts, and deepsea divers who have decompression-induced venous bubbles do not demonstrate neurological symptoms at these high rates. This apparent disparity may be attributable to the normal pressure gradient across the atria of the heart that must be reversed for there to be flow potency. We evaluated the effects of: venous gas embolism (0.025, 0.05 and 0.15 ml/ kg min for 180 min.) hyperbaric decompression; and hypobaric decompression on the pressure gradient across the left and right atria in anesthetized dogs with intact atrial septa. Left ventricular end-diastolic pressure was used as a measure of left atrial pressure. In a total of 92 experimental evaluations in 22 dogs, there were no reported reversals in the mean pressure gradient across the atria; a total of 3 transient reversals occurred during the peak pressure gradient changes. The reasons that decompression-induced venous bubbles do not consistently cause serious symptoms of decompression illness may be that the amount of venous gas does not always cause sufficient pressure reversal across a patent foramen ovale to cause arterialization of the venous bubbles.
Document ID
19980211652
Acquisition Source
Johnson Space Center
Document Type
Reprint (Version printed in journal)
Authors
Butler, B. D.
(Texas Univ. Houston, TX United States)
Robinson, R.
(Texas Univ. Houston, TX United States)
Sutton, T.
(Texas Univ. Houston, TX United States)
Kemper, G. B.
(Texas Univ. Houston, TX United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1995
Publication Information
Publication: Aviation, Space, and Environmental Medicine
Publisher: Aerospace Medical Association
Subject Category
Aerospace Medicine
Report/Patent Number
NASA/CR-1995-205315
NAS 1.26:205315
Funding Number(s)
CONTRACT_GRANT: NAG9-215
CONTRACT_GRANT: F33615-90-D-0606
CONTRACT_GRANT: F33615-90-D-0014
Distribution Limits
Public
Copyright
Public Use Permitted.
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