Page 22 - Journal of Special Operations Medicine - Spring 2015

rapid decrease in atmospheric pressure. Even recently, limb numbness were most commonly noted in 133 cases
the US Air Force has encountered severe DCS with high­ of altitude DCS Type II reviewed by Wirjosemito and
altitude operations involving the U­2 airframe. 4 colleagues at the US Air Force School of Aerospace
Medicine. Of these cases, 94.7% were due to altitude­
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DCS results when dissolved gases (particularly nitro­ chamber training. In US Navy divers, 0.5% of Type
gen) in the blood and tissues come out of solution due II cases presented with unconsciousness. Rapidity of
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to a state of decreased partial pressure surrounding the symptom onset following decompression is not related
body. These gases form bubbles, which result in a typi­ to the differentiation of Type I versus Type II DCS but is
cal constellation of symptoms depending on their loca­ related to severity of illness. Denial is common and ca­
tion (Table 1). sualties will often attribute their symptoms to anything
but DCS. Three­quarters of DCS casualties develop
Table 1 Signs and Symptoms of Decompression Sickness clinical symptoms within 1 hour of decompression, and
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Fatigue overall 90% will develop symptoms within 12 hours.
Pruritus Very few develop symptoms more than 24 hours after
decompression.
Skin rash (usually macular)
Musculoskeletal pain (often of the joints) Risk factors for DCS have been best studied in the under­
Lymphadenopathy water diving community and are listed in Table 2. 9,10 DCS
*Headache risk is increased in divers who either dive at an elevated
*Vertigo/lightheadedness altitude or ascend to altitude following their dive. Div­
ers should wait at least 12 hours before flying if making
*Numbness/tingling
only one dive per day. Those who require decompression
*Extremity paralysis stops during the dive or who participate in multiple dives
*Dyspnea should wait at least 48 hours before flying. 8,11
*Pharyngeal irritation (“chokes”)
Table 2 Decompression Sickness Risk Factors
*Hemoptysis
*Chest pain Short decompression time (rapid exposure)
*Memory loss Vigorous exercise following exposure
*Changes in affect, speech, or personality Higher body­fat content
*Ataxia (“staggers”) Dehydration
*Visual disturbances Alcohol consumption
*Loss of sphincter control (particularly bladder) Increasing age
*Unconsciousness Male sex
*Death Inexperience (for divers)
Note: *Items are more likely to correlate with a diagnosis of type II Repetitive exposures to pressure change
decompression sickness. Diving at attitude
Ascending to altitude after diving
Golding and colleagues introduced the traditional clas­
sification system in 1960. Type I DCS is defined as
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involving the skin, lymphatics, or musculoskeletal sys­ It should be noted that DCS is technically a separate en­
tem. Type I symptoms are most commonly associated tity from air or gas embolism (AGE), whereby gas bub­
with DCS in the at­risk population. Indeed, joint pains bles form in the blood and may occlude venous return
were the predominating symptom in 60% to 70% of or arterial flow, depending on their location in the body.
altitude DCS cases. Type I DCS does not necessarily re­ This technical difference from DCS, where bubbles may
quire recompression and is not generally considered life form in the tissues themselves, is not particularly rel­
threatening. evant to the treating provider in the field. The presenta­
tion of the casualty may be very similar to DCS and the
By contrast, Type II DCS is typically viewed as more seri­ treatment is the same. Often, these diseases are clustered
ous, with organ involvement such as pulmonary or neu­ under the category of dysbarisms.
rologic manifestations that require urgent and aggressive
intervention. Between 10% and 15% of DCS cases are Case Continued
categorized as type II. While divers typically are affected
in the spinal cord, aviators are more likely to have cere­ Nursing disrobed the patient and placed him in a gown.
bral manifestations. Headache, visual disturbance, and They applied the cardiac monitor, pulse oximeter, and

12 Journal of Special Operations Medicine Volume 15, Edition 1/Spring 2015