My best review slide from Tintin ed7 เอาไว้ประกอบการดูรายการ 7summits

1. HIGH-ALTITUDE MEDICAL PROBLEMS
Priya Kantanon
review from tintinelli ed7

2. High altitude
is a hypoxic environment
[>2440 m (>8000 ft)]

3. •Intermediate altitude, 1520 to 2440 m (5000 to
8000ft)
Exercise performance
Increased alveolar ventilation
without major impairment in arterial oxygen transport
•Acute mountain sickness (AMS) occurs at and above
2130 to 2440 m (7000 to 8000 ft) and sometimes at
lower altitudes in particularly susceptible individuals.

4. •High altitude, 2440 to 4270 m (8000 to 14,000 ft)
decreased arterial oxygen saturation (SaO2)
marked hypoxemia may occur during exercise and sleep
•Very high altitude, 4270 to 5490 m (14,000 to 18,000 ft)
visitors to the mountainous regions of South America and the Himalayas
•Extreme altitude, >5490 m (>18,000 ft)
complete acclimatization generally is not possible
accompanied by severe hypoxemia and hypocapnia.

7. PHYSIOLOGY OF ALTITUDE
ACCLIMATIZATION
• Ventilation
• Blood
• Fluid Balance
• Cardiovascular System
• Exercise Capacity
• Limitations to Acclimatization
• Sleep at High Altitude?

8. VENTILATORY ACCLIMATIZATION
• After 4 to 7 days
• Primary initial adaptation is maintenance of
alveolar PO2 through increased ventilation
• Respiratory depressants or stimulants

9. Hypoxia Hyperventilation Respiratory alkalosis
Renal excretion of HCO3
Central chemoreceptors reset
to progressively lower PaCO2
pH returns normal
ventilation continues to increase
Acetazolamide

11. BLOOD
•Erythropoietin level increases (2hrs)
•Increased red cell mass over days to weeks
•Shifts in the oxyhemoglobin dissociation curve are thought
to be minimal
2,3-diphosphoglyceric acid --> right
Respiratory alkalosis --> left

13. Peripheral venous
constriction
increase in central
blood volume
baroreceptors
decreaseADH&
aldosterone
diuresis
decreased plasma volume and
hyperosmolality
FLUID
BALANCE
Antidiuresis
is a hallmark
of AMS.

14. CARDIOVASCULAR SYSTEM
• SV HR.
• BP
• Pulmonary circulation constrict
• pulmonary pressure
• CBF. O2 delivery to brain
• ICP

15. EXERCISE CAPACITY
• Drops dramatically
• 10% for each 1000-m
(3280-ft) altitude gain
above 1500 m (4920 ft)

16. SLEEP AT HIGH ATTITUDE
• Sleep stages III and IV are
reduced at altitude, whereas
sleep stage I is increased

17. ABNORMAL SLEEP
• Increase in arousals
• Only slightly less rapid eye
movement time
• Cheyne-Stokes respiration
• Intervals of apnea of >20
seconds
Quality of sleep and arterial oxygenation during sleep improve
with acclimatization and with acetazolamide.

18. HIGH-ALTITUDE SYNDROMES
• Acute hypoxia
• AMS
• Pulmonary edema
• Cerebral edema
• Retinopathy
• Peripheral edema
• Sleeping problems
All fundamental mechanism
All same setting of rapid ascent
in unacclimatized persons
All same essential therapy:
descent and oxygen
administration.

19. ACUTE HYPOXIA

20. S&S
• Dizziness
• Light-headedness
• Dimmed vision
• Loss of consciousness
Treatment
• Oxygen, rapid descent, and
correction of the underlying
cause

21. AMS
ACUTE MOUNTAIN SICKNESS
• More gradual and less severe hypoxic insult than in acute
hypoxia syndrome
• Headache
• GI disturbances
• Dizziness or light-headedness
• Sleep disturbance

22. Factors
Rate of ascent
Sleeping altitude
Inherent factors
Obesity
Not correlate : age,sex,physical fitness

23. Clinical Features
• 1 and 6 hours later, but sometimes are delayed for 1 or 2
days
• Especially after a night's sleep
• Mild AMS similar to alcohol hangover
• Headaches, GI symptoms , constitutional symptoms
• Irritable and often wants to be left alone

25. • SaO2 is typically normal for a given altitude
Correlates poorly with the diagnosis of AMS
• Duration : 15-94hr at 3000m
• At higher sleeping altitudes :
• May last much longer, up to
weeks if untreated
• More likely to progress to
pulmonary or cerebral edema

26. Differential diagnosis
• Hypothermia
• Carbon monoxide poisoning
• Pulmonary or CNS infection
• Dehydration
• Migraine
• Exhaustion

27. Treatment
• Descent and Oxygen
• The three principles of treatment are
1)Do not proceed to a higher sleeping altitude in the presence of
symptoms
2)Descend if symptoms do not abate or become worse despite
treatment
3)Descend and treat immediately in the presence of a change in
consciousness, ataxia, or pulmonary edema.

29. Treatment
Oxygen supplementation
• Promptly relieves headache, dizziness, and most other
symptoms, although ataxia may resolve more slowly
• Nocturnal administration of low-flow oxygen
(0.5 to 1 L/min)

30. MedicalTherapy
Acetazolamide
• Carbonic anhydrase inhibitor
• Should be avoided by individuals with a history of
anaphylaxis to sulfa antibiotics
• Alters the flavor of beer and other drinks

31. Indications for acetazolamide
1) History of altitude illness
2) Abrupt ascent to >3000 m (>9840 ft)
3) AMS requiring treatment
4) Bothersome periodic breathing during sleep.
5 mg/kg/d PO in two or three divided doses is sufficient for
prevention or treatment
125 mg PO twice daily is effective for prevention

33. Symptomatic treatment
Headache
• Aspirin is effective for prophylaxis
Nausea and vomiting
• Ondansetron orally disintegrating tablets, 4 to 8 mg every 4
to 6 hours
Frequent wakening
• Short-acting benzodiazepine
• Newer nonbenzodiazepine
• Diphenhydramine 25 to 50 mg

34. Prevention
• Graded ascent with adequate time for acclimatization
• Spend a night at an intermediate altitude of 1500 to 2000 m,
before sleeping at altitudes >2500 m
• Avoiding overexertion, alcohol, and respiratory depressants
• Acetazolamide : started 24 hours before the ascent and
should be continued for the first 2 days at altitude.
• Dexamethasone, 4 milligrams PO every 12 hours, starting the
day of ascent and continuing for the first 2 days at altitude.

37. High altitude Cerebral edema
HACE
• Altered mental status, ataxia, stupor, and progression to coma
if untreated.
• Headache, nausea, and vomiting are not always present.
• Because of raised ICP, focal neurologic signs, such as third and
sixth cranial nerve palsies, may result.
HACE = progressive neurologic deterioration in someone with AMS or HAPE

38. Treatment
• Descent is the highest
priority.
• Oxygen supplementation,
descent, and steroid therapy.
• In acutely ill patients who cannot
descend, of steroids, supplemental
oxygen, and a hyperbaric bag
• Acetazolamide may be used as an
adjunct

39. • Ataxic or confused after
descent should be admitted
to hospital.
• Coma may persist for days,
even for weeks, after
evacuation to lower altitude,
yet the patient may still
recover.

40. • reversible white matter edema

42.
High altitude pulmonary edema
HAPE
• Most lethal of the altitude illnesses
• Risk factors
• Heavy exertion
• Rapid ascent
• Cold
• Excessive salt ingestion
• Use of a sleeping medication
• Previous history indicating
inherent individual susceptibility
Pulmonary hypertension
• Intracardiac shunts (atrial septal
defect
• Patent ductus arteriosus (patent
foramen ovale)
• Drug-induced pulmonary
hypertension (phentermine)
• Chronic venous thrombotic
disease.

44. PATHOPHYSIOLOGY
• High microvascular pressure
• Venous constriction and Uneven arterial vasoconstriction
overperfusion of some areas of the lung vasculature
Noncardiogenic pulmonary edema

45. CLINICAL FEATURES
• Dry cough
• Decreased exercise performance
• Dyspnea on exertion
• Increased recovery time from exercise
• Localized rales, usually in the right mid-lung field
• Late : tachycardia, tachypnea, dyspnea at rest, marked weakness,
productive cough, cyanosis, and more generalized rales develop,
altered mental status and eventually coma develop
Decreased exercise performance
and Dry cough are enough to raise the
suspicion of early HAPE

46. CLINICALS
• Strong and fit
• May or may not have
symptoms of AMS before
• Second night at a new
altitude
• Sign of acute pulmonary
hypertension

47. TERATMENT
• Early recognition!!!
• Exertion by the patient must
be minimized
• Oxygen supplementation
• Bed rest, keep warm
• CPAP, Bi-PAP
Immediate descent is the
treatment of choice

48. MEDICATION. (WHEN OXYGEN IS UNAVAILABLE)
• Nifedipine (10) , (30) for treatment
• Nifedipine SL(20)1 tab q 8hr for prophylaxis
• Nitric oxide
• Phosphodiesterase 5 inhibitors, sildenafil and
tadalafil blunt hypoxic pulmonary vasoconstriction
• Tadalafil(10) 1x2 ,24 hours prior to ascent
• Inhaled salmeterol bid
None of these agents is as effective as
oxygen administration or descent, which
still remain the treatments of choice

49. • Hospitalization
• Adequate discharge criteria
progressive clinical and radiographic
improvement
PaO2 of 60 mm Hg or
SaO2 of >90%
• An episode of HAPE is not
a contraindication to
subsequent ascent

50. PERIPHERAL EDEMA
• Face and distal extremities
• 18% of trekkers at 4200 m
(13,800 ft) in Nepal
• Twice as common in women
• Often was associated with AMS
but not in all cases
• Thorough examination for
pulmonary and cerebral edema

51. HIGH-ALTITUDE RETINOPATHY
• Retinal edema, tortuosity and dilatation
of retinal veins, disc hyperemia, retinal
hemorrhage, and, rarely, cotton-wool
exudates.
Retinal hemorrhages
• Macular hemorrhages
• Resolve spontaneously in 10 to 14 days.
• Hemorrhages are common at sleeping
altitudes of >5000 m (>16,400 ft)

52. HIGH-ALTITUDE PHARYNGITIS
AND BRONCHITIS
• Dry, hacking cough.
• Purulent bronchitis and a painful pharyngitis
• Not infection
• Bronchospasm
• Severe coughing spasms --> cough fracture of the ribs

53. • Fast-acting agonists,
such as albuterol, MDI
relief coughing spasms
• Prophylactic use of
long-acting agonists
and inhaled steroids

54. ULTRAVIOLET KERATITIS
(SNOW BLINDNESS)
• UVA and UVB
• Less cloud cover, less water
vapor, and less particulate
matter in the air
• Radiation increases roughly 5%
for every 300 m (9800 ft)
gained and is exacerbated by
reflection back from snow

55. SYMPTOMS
• May not become apparent for 6 to 12 hours.
• Severe pain, a foreign-body or gritty sensation, photophobia,
tearing, marked conjunctival erythema, chemosis, and eyelid
swelling
TREATMENT
• UV keratitis generally is self-limited and heals within 24
hour
• Systemic analgesics. , cold compresses with eye patches

56. SUNGLASSES
• should transmit <10% of UVB light.
• Side shields and polarizing lenses
• "Eskimo sunglasses"

57. CHRONIC MOUNTAIN
POLYCYTHEMIA/CHRONIC
MOUNTAIN SICKNESS
• Monge disease
• Excessive polycythemia
• Phlebotomy, relocation to a
lower altitude, or home
oxygen use

58. INDIVIDUALS WITH ILLNESSES
AGGRAVATED BY HIGH ALTITUDE
• Chronic lung disease
• Atherosclerotic heart disease
• Sickle cell disease
• Pregnant Women

59. EXPOSURETO
HIGH ALTITUDE
RECOMENDATION

60. !ank y"

61. DESCENT AND OXYGEN!!!

64. AMS HACE HAPE
S&S
Headache
GI disturbances
Dizziness or light-headedness
Sleep disturbance
progressive neurologic
deterioration in someone
with AMS or HAPE
decrease exercise
performance,Dry
cough,DOE
acute PHTN
risk factor
Rate of ascent
Sleeping altitude
Inherent factors
Obesity
not known
Heavy exertion,Rapid ascent,Cold,
Excessive salt ingestion,Use of a
sleeping medication,Previous history
indicating inherent individual
susceptibility,PulHTN
prevention
Acetazolamide,Dexa,grad
ual ascend none
gradual
ascend,tadalafil,nifedipine,ac
etazolamide
treatment
oxygen & descend
Acetazolamide,dexa hyperbaric bag,dexa
Nifedipine,NTG,tadalafil,rest,
hyperbaric bag
HIGH-ALTITUDE ILLNESS