The oxygenated room was used as a dormitory for two subjects and a double blind study showed that they had an improved quality of sleep by both objective and subjective measurements, had fewer symptoms of acute mountain sickness the following day and, most interesting of all, had higher levels of oxygen in their arterial blood the following day when they were breathing ambient air. The explanation of this last finding may be that their control of ventilation was altered following reduction of their sleep disordered breathing during the night as a result of the oxygen enrichment. The rationale for these numbers is as follows. The objective was to determine the feasibility of measuring the effects of oxygen enrichment on cognitive function at a simulated altitude of 5000 m using the WMRS facility. Initially we planned to provide the nitrogen enrichment in the WMRS lab from liquid nitrogen tanks.
Special valves allow the nitrogen to be vented at the appropriate rate.
This is similar to the arrangement used in one of the facilities in north Chile where oxygen enrichment is being carried out with liquid oxygen tanks. However, Dr. John Severinghaus of UCSF came up with the idea of reversing the AirSep machines to provide nitrogen instead of oxygen. There is no convenient attachment for the nitrogen-rich effluent when the molecular sieves are being purged. However, in effect, we placed the AirSep machines in the room and vented the oxygen that they produced to the outside. In fact, the machines were not actually in the room but in a gas-tight box just outside the room, and the box was connected to the room with large ports and fans.