ALTITUDE AND COMMON MEDICAL CONDITIONS - Medicine for Mountaineering and Other Wilderness Activities - page 381

mendations, and feeding may make the infants more uncomfortable. Air in the intestines
expands 20 percent during flight. Sucking and eating introduces more air. Infants probably
should be fed no more often when flying than when at home.
One study has suggested that the lower oxygen pressure in airliner cabins at cruising
altitudesmaybehazardoustoinfants.Whenfortyinfantsweresubjecttotheoxygenlevels
found at about 6000 feet (1800 m) in aircraft, four developed irregular breathing and such
decreased blood oxygen levels that the study was interrupted. However, these studies were
carried out in a laboratory. Millions of infants travel on airliners without apparent adverse
effects.
ALCOHOL AT ALTITUDE
Alcohol ingestion at altitude is widespread. A recent epidemiological study indicated that
64 percent of tourists ingest alcohol during the first few days at 9240 feet (2800 m). Two
questions regarding alcohol are frequently asked: (1) Does alcohol affect acclimatization?
(2) Does altitude potentiate the effects of alcohol?
In regard to acclimatization, determination of blood gases in ten individuals one hour
after ingestion of 50 gm of alcohol (equivalent to 1 liter of beer) at 550 feet (171 m) and
again after four hours at 10,000 feet (3000 m) disclosed that alcohol had no effect on
ventilation at the low altitude. However, at higher altitude alcohol depressed ventilation as
gauged by a decreased arterial oxygen pressure (from 69 to 64 mm Hg) and increased car-
bon dioxide pressure (from 32.5. to 34 mm Hg).
Whether this amount of ventilatory depression would contribute to AMS and whether
repeated doses would have greater effect was not tested. Nonetheless, alcohol might im-
pede ventilatory acclimatization and should be used with caution at high altitude (as else-
where).
Conventional wisdom proffers an additive effect of altitude and alcohol on brain func-
tion. However, in a variety of studies mostly related to aviation, no influence by altitude
was detectable.
The possibility of interactions between alcohol and altitude deserves more study. The
limited data on blood gases at altitude after alcohol ingestion support the popular notion
that alcohol may slow ventilatory acclimatization. Considerable data, however, refute the
belief that at least up to 12,000 feet (3660 m) altitude increases the effect of alcohol. How
altitude and alcohol might interact at higher altitudes is unknown.
FUTURE DIRECTIONS
Assessing the effect ofhighaltitude onmyriad medical conditions isadifficult task requir-
ing multiple approaches. The most fruitful avenue of research would be a large, ongoing