Page 63 - Journal of Special Operations Medicine - Winter 2014

The Use of Dexamethasone in Support of
High-Altitude Ground Operations and Physical Performance:

Review of the Literature

Reginald O’Hara, PhD; Jennifer Serres, PhD; William Dodson, MD;
Bruce Wright, PhD; Jason Ordway, BS; Eric Powell, MS; Molly Wade, MS

ABSTRACT
Objective: Military Special Operators (SOs) are exposed high altitudes such as an increase in the dryness of ambi-
environmental conditions that can alter judgment and ent air, reduction of air density, and a diminished partial
physical performance: uneven terrain, dryness of ambi- pressure of oxygen.
ent air, reduction of air density, and a diminished partial
pressure of oxygen. The primary purpose of this review Although individual physiological responses to alti-
was to determine the medical efficacy of dexamethasone tude and acclimatization rates vary dramatically, the
as an intervention for the prevention and treatment of physiological effect of hypobaric high-altitude hypoxia
high-altitude illness. The secondary purpose was to de- (HHH) is ubiquitous. Symptoms of less severe cases
1,2
termine its ability to maintain physical performance of of HHH, occurring within 6 to 24 hours of arrival at
SOs at high altitudes. Methods: A search of the literature altitude, may include irritability, physical weakness,
from 1970 to 2014 was performed, locating 61 relevant decreased appetite, tachycardia, insomnia, dizziness,
articles, with 43 addressing the primary and secondary nausea, headache, and peripheral edema. More severe
3-6
purposes of this literature review. Conclusions: The re- cases of HHH may result in acute mountain sickness
view indicates that dexamethasone is an effective pre- (AMS), high-altitude pulmonary edema (HAPE), and
vention and treatment intervention for high-altitude high-altitude cerebral edema (HACE). Although AMS
illness. Commonly used dosages of either 2mg every 6 is short lived and normally subsides within 2 to 7 days,
hours or 4mg every 12 hours can prevent high-altitude HAPE and HACE are potentially fatal if not treated im-
1,7
illnesses in adults. Currently in USSOCOM operations, mediately by trained personnel. Two key physiological
there is an option to use 4mg every 6 hours (concur- mechanisms exist regarding the oxygen transport sys-
rently with acetazolamide 125mg bid) if ascending tem and altitude acclimatization: (1) there is a reduc-
rapidly to or above 11,500 ft without time for acclimati- tion in the delivery of oxygen to the exercising muscles
zation. Researchers also determined that acute exposure due to changes in peak blood flow and/or distribution of
to high altitude, even in asymptomatic subjects, resulted the amount of blood ejected from the right ventricle of
in small cognitive deficits that could be reversed with the heart every minute, and (2) there is an alteration
dexamethasone. Dexamethasone may also help improve in the diffusion or utilization of oxygen by the active
cognition and maximal aerobic capacity in SOs who are skeletal muscles.
susceptible to high-altitude pulmonary edema.
A literature review was performed using the following
Keywords: high altitude, mountain, performance, strength, sources: PubMed, Defense Technical Information Cen-
endurance, physical, military, Special Operations ter, the Cochran Library, and the Franzello Aeromedical
Library. Search parameters were limited to publications
from 1970 to 2014 using the following keywords alone
or in combination: dexamethasone, high altitude, moun-
Introduction
tain, strength, endurance, physical, military, special
Special Operators (SOs)–Special Operations Forces (SOF) operations, acute mountain sickness (AMS) treatment,
members of all branches–are routinely exposed to a vari- high-altitude pulmonary edema (HAPE) treatment, and
ety of environmental conditions that can alter judgment high-altitude cerebral edema (HACE). This review iden-
and physical performance, potentially affecting mission tified 61 articles; 43 were pertinent for further analy-
success. These situations are further exacerbated by the sis. Each of these 43 studies was analyzed and included
hazardous conditions experienced when ascending to in the dexamethasone review matrix and assigned a

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