COMPARISON OF ANOXIA WITH AND WITHOUT EBULLISM
Abstract
Water vapor and evolved gases play a unique role in the physiologic responses of animals exposed to a near-vacuum. To identify and compare these responses with those induced by other types of anoxia at higher pressures, three groups of anesthetized dogs were rapidly exposed for 2 minutes to one of three anoxic conditions: (1) 100% N2 at ground-level pressures, (2) reduced pressure of 55 torr (55 mm. Hg absolute), and (3) 2 torr. Measurements included cardiovascular changes, arterial and mixed venous tensions of oxygen and carbon dioxide, hydrogen ion concentration, arterial lactate, pyruvate, and 'excess' lactate. Responses to a near-vacuum were more extreme than with anoxia per se. The nitrogen-exposed group showed the least severe responses, while the responses of the dogs that were decompressed to 55 torr were intermediate, in most respects being closely related to those of the nitrogen-breathing group. Most of the responses resulting from the near-vacuum exposures are associated with the vaporization and ebullition of body fluids and, therefore, can be related to a combination of anoxia, ineffective circulation, and apnea.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1968
- Accession Number
- AD0667790
Entities
People
- Julian P. Cooke
- Richard W. Bancroft
- Stephen M Cain
Organizations
- United States Air Force School of Aerospace Medicine