ALTITUDE AND COMMON MEDICAL CONDITIONS - Medicine for Mountaineering and Other Wilderness Activities - page 380

(5000 m). Altitude illness, especially pulmonary edema, must be carefully avoided. Sim-
ilarly, smoking, lung disease, and other disorders of oxygen transport render the pregnant
woman at altitude more hypoxemic, and physiologically at a higher altitude.
Clinicians concerned about unmasking placental insufficiency at high altitude may find
that having pregnant women breath air with only 15 percent oxygen is a useful but uncal-
ibrated tool. The safety of modest hypoxia on the fetus and mother at different stages of
pregnancy and at different altitudes (different levels of hypoxia), whether persons at risk
foruntowardeffectscanbeidentifiedpriortoexposure,andtheinteractionofhypoxiawith
other stresses such as exercise clearly require more investigation. Studies comparing large
populationsofwomenwithandwithouthigh-altitude exposureduringpregnancywouldbe
particularlyusefulforpregnantlowlanderstryingtomakeinformeddecisionsaboutthepo-
tential risks of altitude.
CHILDREN AT ALTITUDE
In general, children tolerate moderate altitude well. Children born and raised at high alti-
tudesseemtohavenomoreproblemsthanadults.Whethertheincidenceofacutemountain
sickness(AMS)andotheraltitudedisordersininfantsandyoungchildrenisaboutthesame
as adults or somewhat higher is somewhat controversial. In one study fourteen children
aged three to thirty-six months ascended from 5275 feet (1609 m) to 11,440 feet (3488 m).
About 20 percent developed AMS, an incidence comparable to that in adults. As in adults,
the higher the altitude and the faster the ascent, the greater the incidence of AMS. A few
observers have thought that children acclimatize somewhat more slowly.
Identifying children with AMS can be a problem. Children frequently become ill with
vagueviralillnessesthatcreatesymptomssimilartothoseofAMS—headaches,irritability,
loss of appetite, inability to sleep, and fatigue. Infants and young children cannot verbalize
what is bothering them. Parents are advised to avoid high altitudes with children so young.
If they go to such altitudes and their children become ill, parents should assume the chil-
dren have AMS and descend immediately.
Air travel appears safe for children with upper respiratory infections, nasal allergies,
and ear infections. Children may experience pain in flight, but permanent damage from
barotrauma appearstobeextremely rare.Nasalspraysanddecongestants maydecrease the
riskofdiscomfort,butsomestudiessuggesttheseagentshavelimitedeffectivenessinchil-
dren. Middle ear infections seem to protect children from pain because fluid obliterates the
middle ear space and pressure differences cannot develop. Flying is safe for children with
tympanic membrane tubes.
Conventional wisdom recommends nursing infants or giving them bottles during ascent
and descent and when they cry during flight. The rationale is that the infants are crying
because they are experiencing barotrauma or are dehydrated. No data support these recom-