absorb the nitrogen when air is pumped through them at high pressure. The oxygen is then added
to the ventilation of a room thus raising the oxygen concentration above its normal value of 21%.
The result is that the effective altitude of the occupants is decreased. For every 1% of oxygen
enrichment, for example from 21 to 22%, the effective altitude is reduced by about 300 m. In a
typical facility at an altitude of 4300 m, maintaining an oxygen concentration of 25% in the room
reduces the effective altitude to 3000 m. In practice the technique is easy to use and it has been
shown to improve productivity, reduce fatigue, and generally improve the quality of life. One
telescope facility at an altitude of 5050 m with a room oxygen concentration of 27% has been
working well for the past 5 years. Three other telescopes at altitudes of 4200 or 5050 m are
planning oxygen enriched rooms. The technique is a major advance in improving productivity
and working conditions at high altitude.
248.
ALLEVIATING THE HYPOXIA OF PASSENGERS ON THE PROPOSED GOLMUD-
LHASA RAILROAD. John West
1
. University of California San Diego
1
.
The Golmud-Lhasa railroad presently under construction is over 1100 km long and 75% of it
will be above an altitude of 4000 m. This creates a major challenge for passengers particularly if
they have no prior acclimatization to high altitude. Presumably the trip will take at least 12 hours.
One possible way of alleviating the hypoxia is to raise the oxygen concentration in the cars as is
presently being done in rooms at high altitude for astronomers. Each car could have its own
oxygen concentrators and there is probably ample electrical power available. However the large
number of passengers per car and the consequent high ventilation and large volume of oxygen to
be generated would be a challenge that is not seen in high-altitude rooms. Another potential
problem is variation in altitude of the track but it should be possible to choose an oxygen
concentration that is both efficacious and safe. It might also be feasible to automatically alter the
oxygen concentration in the cars depending on the altitude. Another possibility would be to
pressurize the passenger cars as in aircraft cabins. This would mean a very different design from
conventional railroad cars, for example for the windows and doors. Finally oxygen from masks
could be made available for each passenger but it would hardly be feasible to use these for such
long periods. However they should be available for people who develop acute mountain sickness.
Perhaps there could be two types of cars, one for people with high-altitude acclimatization, and
another for people without. The latter could be charged a supplement for the privilege of
breathing higher PO2.
249.
PERIODIC BREATHING AND ARTERIAL BLOOD OXYGENATION IN TIBETANS AND
HAN STUDIED IN HYPOBARIC CHAMBER AT SIMULATED ALTITUDE OF 5000M.
Tianyi Wu
1
, Robert Pywaczewski
2
, Xiang Wung
1
, Cheng Hani-Wei
1
, Paweliwiski
2
, Jan Zieliski
2
.
High Altitude Medical Research Institute, Xining, P.R.China
1
, Institute of TB and Lung Diseases,
Warsaw, Poland
2
.
Aim of our study was to investigate periodic breathing (PB) and arterial blood oxygenation in
Tibetans and Han at simulated altitude of 5000m. We studied 8 Tibetans, mean age 26.6±7.4
years, and 6 Han, mean age 30.5±4.5 years. Two PSG were performed, 1st at ambient altitude
2261m, the 2nd during acute exposure to altitude of 5000m (split night design). Results are
shown in table 1 and 2. Table 1. Periodic breathing and arterial blood oxygenation in Tibetans
and Han at the elevation of 2261 m, means±SD.
PB % of
sleep time
SaO2
mean (%)
SaO2 min
(%)
SaO2
mean REM
(%)
SaO2 mean
non-REM (%)
Tibet
ans
0.04± 0.01
91.9± 1.6
87.5± 2.5
92.6± 1.6
91.7± 1.8
Han
0.003
±0.005
92± 0.9
85± 3.5
92.5± 0.8
91.7± 1.0
