Travel Reference
In-Depth Information
Asthma
Asthma is a disease of the bronchi caused by allergy, exercise, or breathing cold air. In-
haling the substance to which the individual is allergic (the allergen), or inhaling dry or
cold air that irritates the cells lining the airway, increase the secretion of mucus into the
bronchi.Simultaneouslythemusclesinthewallsofthebronchigointospasm,constricting
these air passages. The narrowed bronchi filled with excess mucus obstruct the passage of
air.
Asthmamaybemild,severe,or—rarely—fatal.Althoughafirstattackmayoccuratany
time, most individuals are aware of their susceptibility long before engaging in wilderness
activities.
Asthma isarecurring disease. Mostpeople with this problem have suffered previous at-
tacks and are under the care of a physician who can provide the medications that should be
taken on a trip. Fortunately, individuals with mild asthma are not particularly limited in the
wilderness activities in which they can participate; some may breathe more easily at high
altitude where the air is thinner and freer of allergens and pollutants ( Chapter 25: Altitude
and Common Medical Conditions ) .
The most significant sign of asthma is difficulty in breathing, particularly during ex-
piration. The expiratory phase of respiration is considerably prolonged, is associated with
wheezing, and may require conscious effort.
An incessant, irritating cough is often present. Toward the end of an asthmatic attack,
considerable quantities of very thick mucus may be coughed up. Fever is usually absent,
but the pulse rate may be moderately increased. The respiratory rate is usually faster than
normal in spite of the difficulty in breathing. When the person is examined, the chest may
appearmoreexpandedthannormalattheendofexpiration.Wheezingonexpirationisusu-
ally audible throughout all parts of the lung.
The most important treatment for an acute asthma exacerbation is an albuterol inhaler.
Albuteroloccupiesbeta-receptorsinthesmoothmuscleofthebronchiandmakesthebron-
chial walls relax. It also helps loosen mucus in the airways so that it can be coughed up.
The dose is two puffs (inhalations) every four hours. Side effects of albuterol inhalation
may include an increased heart rate and tremor. Most persons with asthma carry an inhaler
with them. Steroid inhalers also are very effective in treating asthma on a continuing basis.
Formoderateorsevereacuteasthmaticexacerbations,steroidsaregivenorallyorintraven-
ously in addition to inhaled albuterol.
Athighaltitude, asthma mayfurtherlimit theamountofoxygenintheblood,andthere-
fore supplemental oxygen is helpful. At sea level, supplemental oxygen is usually not ne-
cessary for mild or moderate asthma exacerbations.
Onbothshortandextendedtripsasthmaticsshouldcarryadequatemedicationsfortreat-
mentofanexacerbation. Asthmatics ascending toaltitude shouldbeconservative inallow-
ing adequate time for acclimatization. Although some asthmatics do better at altitude, oth-
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