Discusses illnesses you may experience at high altitude.

1. High Altitude Illnesses

2. TLO
• Given a simulated casualty, treat altitude
illnesses in accordance with the references.

3. ELO
• Choose from a given list the correct
definition of acute mountain sickness.
• Choose the most common and prominent
symptom of acute mountain sickness.

4. ELO
• Select from a given list the field management of
Acute Mountain Sickness.
• Select from a given list five of the seven high
altitude health preventive measures.
• Choose the correct definition of high altitude
cerebral edema.
• Choose from a given list five of the symptoms of
high altitude cerebral edema.

5. ELO
• Choose the field management of high altitude
cerebral edema.
• Choose the correct definition of high altitude
pulmonary edema.
• Choose from a list three of the nine symptoms of
high altitude pulmonary edema.
• Choose the field management of high altitude
pulmonary edema from a given list.
• Choose from a list the most important treatment of
HACE and HAPE.

6. Physiology of
Acclimatization
• “This malady only
attacks strangers; the
people of Tibet know
nothing of it, nor do
their doctors know
why it attacks
strangers.”
- 14th
Century Mongol
Chieftain

7. Acclimatization
• April 15, 1875, the
Zenith, a hot air
balloon manned by
three scientists
attempted to go over
28,000 ft……..

8. Acclimatization
• “I wanted to cry out
‘We are at 8000m’ but
my tongue was
paralyzed. Suddenly I
closed my eyes and
fell inert, entirely
losing consciousness.”

9. Acclimatization
• “my two companions
were crouched in the
basket, their heads
covered….Sivel’s face
was black, his eyes
dull, his mouth open
and full of blood.
Croce’s eyes were half
shut and his mouth
bloody”

10. Acclimatization
• One hundred years
later in 1978, Reinhold
Messner and Peter
Habeler climbed Mt
Everest (29,035 ft)
without the aid of
oxygen

11. Acclimatization
• Two expeditions- two vastly different
outcomes-
• What is the major factor which determined
the ultimate outcome?

12. Factors in Acclimatization
• Altitude
• Depends on rate of ascent.
• Individual Variation

13. Acclimatization
• Hypoxia due to
decreased barometric
pressure
• Sea level: 760mmHg
• 8,000 ft: 559mmHg
• 14,000ft: 445mmHg
• 18,000ft: 370mmHg
• 29,000ft: 253mmHg

14. Acclimatization
• Starts at 5000 ft

15. Hypoxic Ventilatory
Response
• Hypoxia triggers carotid body.
• Central respiratory center stimulated.
• Ventilation increases.

16. Respiratory Changes
• Increased respiratory
rate will cause oxygen
levels to rise and
carbon dioxide levels
to fall
• Any consequences?

17. Price to be Paid
• Carbon dioxide is the principle and most
effective mediator of blood acidity therefore
when the levels drop – the pH rises above
acceptable levels.
• This respiratory alkalosis causes a brake to
be placed on further ventilation.

18. Renal
• Responds to alkalosis
with bicarbonate
diuresis
• pH levels can now be
maintained
• Brake on increased
respiration is relaxed
• RR can increase once
again

19. Pulmonary
• Unlike other areas of
the body- the
pulmonary vasculature
is under local control
rather than messages
from the central
nervous system

20. Pulmonary
• Whenever the oxygen
pressure in alveoli are
low then the
pulmonary artery
pressure rises
• Average PAP at
12,000 ft is 22 torr
(5-10 torr at sea level)

21. Cardiac
• Increased heart rate to
compensate for
hypoxia
– With moderate
altitudes – will return
to baseline levels with
acclimatization
• Little effect on blood
pressure

22. Cerebral Circulation
• Hypoxia causes
vasodilation
• Hypocapnea causes
vasoconstriction
• Vasodilation
outweighs
vasoconstriction
• Increase of cerebral
blood flow by 20-40%

23. Hemopoietic Response
• Erythropoeitin levels
increase within two
hours of ascent
• New RBC’s seen
within 4-5 days
• 80% at 2 weeks
• 95% at 6 weeks

24. Dehydration Risk Factors
• Increased respiratory losses
• Bicarbonate Diuresis
• Cold Diuresis
• Difficulty in procuring water
• Decreased Intake

25. Sleep Patterns
• Stage 1 increased, stage 2 unaffected.
• Stages 3, 4 and REM decreased.
• Due to nocturnal periodic breathing
– ^respiration
– ^pH
– Apnea
– O2 sat declines, CO2 rises
– Ventilatory rate rises

26. Acute Mountain Sickness
• “travellers have to
climb over Mount
Greater Headache,
Mount Lesser
Headache, and the
Fever Hills”
- warning from
Chinese general to his
emperor

27. AfterAction Report from
Afghanistan

28. Acute Mountain Sickness
(AMS)
• Definition: AMS is a self limiting illness
which results when an unacclimatized
individual ascends rapidly to high altitude

29. Pathophysiology
• Poor HVR
• Mild AMS: Cerebral vasodilation
• Severe AMS/HACE: Blood brain barrier
compromised; cerebral edema

30. Signs and Symptoms
• Prominent Symptoms:
– Headache
– Nausea
– Vomiting

31. Signs and Symptoms
• Secondary Symptoms
– Dizziness
– Anorexia
– Malaise
– Insomnia
– Weakness

32. AMS Lake Louise
Consensus Criteria
• Headache PLUS
• One of the following signs or symptoms:
– Nausea
– Vomiting
– Dizziness
– Anorexia
– Malaise
– Insomnia
– Weakness

33. AMS Headache
• Throbbing
• Bitemporal or occipital
• Worse at night/early morning
• Worse with Valsalva

34. AMS
• “At 13,000 ft, my
partner begged to
descend before the
alien clawing at the
inside of his skull
found its way out”
- AMS sufferer on Mt
Ranier

35. Similar Syndromes
• Dehydration
• Hangover
• Viral Syndrome
• Exhaustion
• Medication
• Carbon Monoxide
Poisoning

36. Field Management of AMS
• Stop further ascent

37. Field Management of AMS
• Symptomatic Treatment:
– Headache
• Motrin
• Aspirin
– Nausea
• Compazine
• Phenergan
– AMS Medications

38. Field Management of AMS
• Evacuation and
Descent

39. Field Management of AMS
• AMS Medications:
– Diamox (Acetazolamide)
– Decadron (Dexamethasone)

40. Diamox
• Carbonic Anhydrase
Inhibitor- causing
bicarbonate diuresis-
decreasing pH
• Stimulates Respiration
• Decreases CSF Production
• Maintains oxygenation
during sleep
• Dose is 125-250mg

41. Diamox
• Contraindicated in
sulfa allergy and
G6PD deficiency
• May cause peripheral
paresthesias and
altered taste of
carbonated beverages
• May cause bone
marrow suppression,
blurred vision, nausea

42. Diamox
• WARNINGS:
– Dehydration
– Will prevent altitude
illnesses but will not
increase physical
endurance

43. Dexamethasone
• Mechanism of Action: Unknown- reduce
brain-blood volume, prevents blood-brain
barrier leaks
• Effects evident in 2-8 hrs
• Prevention: 2 mg q6h or 4mg q12h PO
• Tx AMS: 4 mg q6h PO
• Side Effects: Psychosis, hyperglycemia,
dyspepsia, rebound on withdrawal

44. AMS Medications
• Diamox preferred over Decadron
– Lower side effect profile
– Aids acclimatization
• Use Decadron with Sulfa Allergy and
G6PD
• Combination is superior to single treatment

45. AMS Treatment
• All patients must be evaluated for HAPE
and HACE

46. Incidence
• 6765 ft – <1%
(MWTC)
• 7000-9000ft- 22%
• 10000ft – 42%
(Colorado ski
resorts)

47. AMS- Risk Factors
• Prior ascents without AMS is no guarantee
against AMS in the future.
• Those with prior AMS are at increased risk
of reoccurrence.

48. Prevention
• Conservative Ascent
Profile:
– Begin operations at
7,000ft or below
– 3000ft/day below 14K
– 1000ft/day above 14K
– Extra day of
acclimatization for
every 4,000 ft gain

49. Prevention
• Increase fluid intake –
will only prevent
dehydration not AMS

50. Prevention
• Work high
• Sleep low

51. Prevention
• Avoid overexertion

52. Prevention
• Avoid alcohol and
sedatives (at the very
least the first two
nights)
• Affects the ventilatory
response

53. Prevention
• Diet
– High in carbohydrates
– 70% or greater

54. Prevention
• Prophylaxis
– Diamox
– Decadron

55. Prophylaxis
• In setting of forced ascent
• Previous history of altitude related illness
• Diamox 125 mg PO BID, 24 hours prior to
ascent and 48 hours afterwards; also 500mg
QD

57. High Altitude Cerebral
Edema
HACE
• High altitude illness
characterized by
swelling of the brain

58. Pathophysiology of HACE
• Poor HVR
• Increased vascular permeability (not well
understood)
• Fluid moves from intravascular to
extravascular space (white matter edema)
• Resulting increased intracranial pressure
• Same process occurs in AMS to a lesser
extent

59. Signs and Symptoms
• Hallmarks of HACE: ataxia and altered
mental status.

60. Signs and Symptoms
• Altered Mental Status
– Personality Changes
– Poor decision making
– Irritability
– Hallucinations
– Difficulty with concentration
– Decreasing level of alertness
– Unconscious
– Coma

61. Signs and Symptoms
• Ataxia
– Tandem gait: most reliable test for both medical
and practical reasons

64. Treatment
• DESCENT
– Only definitive
treatment
– Patients are unstable
and can die shortly
after the onset

65. Treatment
• Decadron
(dexamethasone)
• Effects evident in 2-8
hours
• TX: HACE: 8-10mg
IV/IM/PO followed by
4mg q6h

66. Treatment
• Oxygen

67. Treatment
• Reduce brain edema
• Renal Diuretics
– Lasix
– Diamox
• Osmotic Diuretics
– Glycerol
– Mannitol
• Hyperventilation
– With care as patient is
already alkalotic

68. Treatment
• Gamow Bag
– “Portable hyperbaric
chamber”
– Can descend
2psi/105mmHg
– At 14,000 ft will take pt
down to 7,000’
– Weight 14 lbs
– Recommendations:
• HAPE 2-4 hrs
• HACE 4-6 hrs

69. Incidence
• 12K-14K is the dividing line for the
increase in risk
• Incidence at less than 10K is very rare.

70. Risk Factors
• Same as for AMS

71. Prevention
• Same preventive measures as AMS

72. High Altitude Pulmonary
Edema
• “….they suddenly
encountered a cold wind
which made them shiver
and unable to speak.
Hwuy-Ring could not go
any farther. A white froth
came from his mouth and
he said “I cannot live any
longer. Do you
immediately go away, that
we do not all die here”;
and with these words he
died” – Buddhist
missionary 330AD

73. High Altitude Pulmonary
Edema (HAPE)
• A high altitude illness which is
characterized by filling of the lungs with
fluid.

74. Pathophysiology
• Maladaptive Hypoxic Pulmonary
Vasoconstrictor Response (HPVR)
– beneficial in certain situations at low altitude
i.e. pneumonia.
• Increased pulmonary artery pressure.
• Edema secondary to leakage from increased
hydrostatic pressure.
• Impaired oxygenation.

75. Symptoms of HAPE
• Weakness/Decreased
Exercise Performance
• Cough
• Chest Tightness
• Dyspnea at rest

76. Signs of HAPE
• Crackles/Wheezing in
at least one lung field
• Increased RR
• Increased HR
• Central Cyanosis
(Note: Reset baselines
for RR and HR)

77. Other Signs of HAPE
• Orthopnea
• Cough productive of
pink frothy sputum is
a late sign
• Pulse Oximetry
– Denali 14K- 80-87%
HAPE < 75%
- Reset baselines

78. Lake Louise Criteria
• Symptoms: Any two of the following:
• Dyspnea at rest
• Cough
• Weakness/Decreased Exercise Performance
• Chest tightness
PLUS:

79. Lake Louise Criteria
• Signs: Any two of the following:
• Crackles/Wheezing in at least one lung field
• Increased RR
• Increased HR
• Central cyanosis

80. HAPE Treatment
• DESCENT- Definitive treatment
• High flow O2.
– Triage Tool- Place patient on high flow oxygen.
Should see improvement in five minutes. Decrease PAP
30-50%
• Gamow Bag as a temporizing measure
• Elevate head
• Rest/Warmth
• Medications

81. HAPE Treatment
• Rest and warmth
– Decrease blood flow to pulmonary arteries and
therefore decreases pulmonary artery pressure
– Incidences of sudden death with exertion in
cases of HAPE
– Cold increases pulmonary artery pressure
therefore keep patients warm

82. HAPE Treatment
• Nifedipine 10/20 mg
PO followed by:
• Procardia 30 mg q24h
or Adalat 20mg q6h
• Pulmonary Artery
Vasodilator – decrease
PAP by 30%

83. HAPE Treatment
• Albuterol
• Unknown mechanism-
Na-ATPase Pump vs
Pulmonary
Vasodilator

84. Treatment Consideration
• HACE and HAPE often run together
• Root Cause: Poor HVR
• Unconscious patient with HAPE?
– Treat both HACE and HAPE

85. Incidence
• Incidence at lower than 10K is rare

86. Risk Factors
• Cold
• URI
• Otherwise same risk
factors as for AMS

87. HAPE Prevention
• If HAPE suceptible:
– Salmeterol
– Nifedipine
• Otherwise employ
same preventative
measures as for AMS

88. Experimental Treatments
• Nitric Oxide
• Inhaled Iloprost
(prostacyclin)
• Viagra
• Garlic
• Intermittent Hypoxia
• Ginko
• Diamox/Decadron

89. Sickle Cell Trait
• Splenic Syndrome-
severe left upper
quadrant pain upon
exertion
• Prevention
• Identification
• Hydration

90. Miscellaneous High Altitude
Illnesses

91. Visual
• RK – Effects starting
at 10K
• PRK- Safe
• LASIK- Nearsighted
at 14-20K

92. High Altitude Deterioration
• Weight loss
• Lethargy, Weakness
• Poor sleep
• Headache
• Polycythemia

93. Systemic Edema
• Edema of the hands, face, ankles
• Screen for other high altitude illnesses
• Can treat with Lasix or Diamox

94. High Altitude
Pharyngitis/Bronchitis
• Sore throat, chronic cough, dry nasal
passages
• Treatment- hydration, lozenges, antitussive
agent (codeine), steam inhalation, nasal
saline spray, topical nasal ointment
(vaseline)

95. Insomnia
• Periodic breathing-
• Treatments:
– Diamox 62.5 mg qhs

96. GI Distress
• Difficulty with digestion at high altitudes
(fats)
• Treat with
– Antacids
– H2 Blockers
– Small frequent meals (carbs)

97. Miscellaneous
• High Altitude Retinal Hemorrhages
• Hypertension
• Coronary Artery Disease
• Asthma
• Immune Suppression
• Impaired Wound Healing
• Thrombosis/Focal Neurological Findings
• Subacute Mountain Sickness
• Chronic Mountain Sickness

98. Questions ???