REPLICATION AND EXTENSION OF RAPID DECOMPRESSION OF CHIMPANZEES TO A NEAR VACUUM
Technical rept., 1 Apr 1965-31 Aug 1966
AEROMEDICAL RESEARCH LAB (6571ST) HOLLOMAN AFB NM
Pagination or Media Count:
Nine chimpanzees were decompressed from 179 mm. Hg breathing 100 oxygen to less than 2 mm. Hg in .8 second and remained at this altitude from 90 to 210 seconds. After recompression with 100 percent oxygen to 179 mm. Hg, the subjects were maintained at this pressure environment for 4 hours post decompression. Results of these tests, which were of replicatory nature, have substantiated previous findings that chimpanzees can survive sudden exposure to a near vacuum and recover within 4 hours to once again satisfactorily perform complex behavioral schedules on which they had extensive training. One subject of questionable fitness expired following a 90-second exposure to a near vacuum. ECG, respiration, and skin temperature were recorded as a standard procedure from all subjects, only two of which were instrumented for EEG. All subjects demonstrated tachycardia immediately following decompression which was regularly followed by a rather sudden bradycardia. There was an initial drop in skin temperature immediately after decompression with an ensuing gradual fall resulting in a total decrease of 1.7 to 2.0C. Visual inspection of the EEG as well as power spectral density computer analysis indicated the expected greater subcortical resistance to anoxia when compared to cortical responses. Evoked responses to stimulation of subcortical areas were used as indicators of excitability.
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