1. Zhenzheng Lin
NSC 495 Sec 001

2.  Acute exposure to low partial pressure of
oxygen at high altitude
 It commonly occurs above 2,400 meters (8,000
feet)
 Resembling a case of flu or a hangover

3.  The air density or the number of molecules (of
both oxygen and nitrogen) per given level, which
drops as altitude increases
 Dehydration due to the higher rate of water vapor
lost from the lungs at higher altitudes also
contribute to the symptoms of altitude sickness.
 Acclimatization-putting extra red blood cells into
your blood stream
 People can experience similar symptoms during
air travel (Cabin pressurized similar to 3,000
meters)

6.  Digestion
• Lack of appetite, nausea, or vomiting
 Brain
• Fatigue or weakness
• Dizziness or lightheadedness
• Insomnia
• Persistent rapid pulse
 Respiratory
• Shortness of breath upon exertion
• Drowsiness
 Peripheral edema (swelling of hands, feet, and
face).

7.  Ascent graduate. Start the rise below 3000m
 A night of acclimatization every 1000 meters
 Abundant hydration (5 liters/day)
 70-80% carbohydrate diet to achieve higher
blood oxygen levels
• Blood Oxygen Levels vs. blood carbohydrate levels
• Tissues consume oxygen in proportion as they utilize
glucose. Therefore, in the presence of low blood
sugar, the tissues will consume less oxygen and so
suffer an oxygen lack (Wortis, 2001)

8.  Acetazolamide -administered 1 day before
ascent and continued for 2 to 3 days is
effective (Hackett and Roach, 2001)
• A large clinical trail from Nepal showed 125 mg of the
Acetazolamide twice daily is effective and bigger doses
offer no significant benefit (Dasmat et al, 2006)

9.  Acetazolamide
• Carbonic anhydrase (CA) inhibitor
• CO2 + H2O <--CA--> H2CO3 <--> H+ + HCO3-
• Forces the kidneys to excrete bicarbonate, this re-
acidifies the blood, balancing the effects of the
hyperventilation that occurs at altitude in an attempt
to get oxygen.
• It suppress respiratory alkalosis. This re-acidification
acts as a respiratory stimulant

10.  Dexamethasone 8 mg/day in divided doses
may be used (Rock et al, 1989)
• Does not help in acclimatization. Symptoms may occur
after stoppage of drug (Hackett et al, 1988)

11.  Mild AMS
• Discontinue ascent. Rest and acclimatize
• Speed up acclimatization with Acetazolamide 250 mg 12
hourly
• Go down if symptoms continue
 Moderate AMS
• Go down
• Hyperbaric chamber if decent not possible
• Acetazolamide 250 mg 12 hourly or Dexamethasone 8
mg/day

12.  HAPE is due to general vasoconstriction in the pulmonary circulation
which, with constant or increased cardiac output, will leads to increases in
capillary pressures.
 The blood vessels more prone to fluid leakage. This fluid leakage into the
alveoli of the lungs interferes with respiration

13.  Fluid in the lungs
 Symptoms similar to bronchitis
 Persistent dry cough
 Fever
 Shortness of breath even when resting

14.  Immediate Descent, preferably by at least
1000 meters.
 Oxygen should also be given if possible @ 4-
6L/min
 The standard drug treatments for which there
is strong clinical evidence are
• Dexamethasone 8 mg/day
• Nifedipine 15 mg first then 20 to 30 mg every 12 hours
• Phosphodiesterase inhibitors such as Tadalafil (but may
worsen the headache of mountain sickness)

15.  HACE is caused by local vasodilation of
cerebral blood vessels in response to
hypoxia, resulting in greater blood flow
and, consequently, greater capillary pressures

16.  Swelling in the brain
 Headache Gradual loss of consciousness
 Increased nausea
 Retinal hemorrhage

17.  Immediate Descent
 Oxygen administration @ 4-6L/min
 Dexamethasone will also temporarily alleviate
symptoms, which is the necessary life-saving
measure.
 Hyperbaric bags are highly effective in
conjunction with dexamethasone