Travel Reference
In-Depth Information
Auscultationofthelung,althoughitrequirespracticeandexperience,isnottoodifficult
to learn and can be a valuable diagnostic aid, particularly in a remote wilderness situation.
CHRONIC LUNG DISEASE
The most common forms of chronic lung disease are asthma, chronic bronchitis, and em-
physema. All these are obstructive disorders characterized by increased resistance to air-
flow.
Chronicbronchitisandemphysemaareoftenassociatedwithcigarettesmoking.Chronic
bronchitis is characterized by a chronic productive cough due to irritation of the airways.
Emphysema, which is characterized by progressive destruction of lung tissue, results in
loss of alveoli for exchange of oxygen and carbon dioxide. Asthma may occur in both
younger and older persons and is characterized by intermittent episodes of increased air-
way obstruction clinically apparent as coughing, wheezing, and decreased exercise capa-
city. Cold air, exercise, or allergens in the environment may trigger asthma. (The treatment
for acute episodes of asthma is described later in this chapter.) The first sign of chron-
ic obstructive pulmonary disease (COPD) is a decreased forced expiratory volume in one
second.
Another type of chronic lung disease is that caused by fibrosis or scarring. This form of
lung disease is characterized by a decreased forced vital capacity.
Most individuals with severe chronic lung disease do not venture into the wilderness.
Individuals with mild or moderate lung disease, however, may pursue such activities, and
respiratorysymptomsmayoccurduringexertionorataltitudebecausechroniclungdisease
reduces the extra breathing capacity that is needed in these situations. In addition, chron-
ic lung disease reduces the extra breathing capacity that may be required when the body
is stressed by infection, trauma, or shock. Persons who know they have impaired respirat-
ory reserve should be cautious about ascending to altitude, particularly about exercising at
high altitude, and should seek the advice of a physician before wilderness trips (
Chapter
DISORDERS OF BREATHING RHYTHM
Sleep Periodic Breathing at High Altitude
Sleep periodic breathing is almost universal at altitudes above 13,100 feet (4000 m) and
may occur at moderate altitudes above 6600 feet (2000 m). The typical pattern begins with
a few shallow breaths; increases in depth to very deep, sighing respirations; and then falls
low breaths resume and the pattern is repeated and can lead an observer to fear that the
person is not breathing at all.
During the period when breathing has stopped, the person often becomes restless and
sometimes awakens with a sense of suffocation. Acetazolamide eliminates sleep periodic
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