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Return to High Altitude Activity After High Altitude Illness

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Military Sports Medicine Fellowship Every Warrior an Athlete Return to High Altitude Activity After High Altitude Illness Kevin deWeber, MD, FAAFP – PowerPoint PPT presentation

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Title: Return to High Altitude Activity After High Altitude Illness


1
Return to High Altitude Activity After High
Altitude Illness
Military Sports Medicine Fellowship
Every Warrior an Athlete
  • Kevin deWeber, MD, FAAFP
  • Director,
  • Primary Care Sports Medicine Fellowship

2
(No Transcript)
3
Objectives
  • Review pathophysiology of high altitude illness
    (HAI)
  • Review the types of HAI and how they are treated
  • Review factors predisposing to HAI
  • Discuss preventive treatment for those with a
    remote history of HAI
  • Discuss factors in return-to-altitude decisions
    after recent HAI

4
Preview
  • Little evidence for recommendations of return to
    altitude activity after HAI
  • Acclimatization and slow ascent are powerful
  • Ascend lt 600 m/day
  • Rest day every 600 1200 m
  • Prophylactic meds advised if unable to comply
  • Consider neuro-psych deficits from moderate
    AMS/HACE and their effect on activity

5
Environment at high altitude(gt1500 m or 4920 ft)
  • Barometric pressure decreases
  • Partial pressure of oxygen decreases
  • RESULT Hypobaric Hypoxia
  • Lower alveolar O2 leads to lower SaO2

6
Ft. Carson, CO, 6500 ft
Pikes Peak, 14,110 ft (4300 m)
US Air Force Academy, 7,000 ft
7
Acclimatization bodys adaptation to hypobaric
hypoxia
8
Acclimatization
  • Immediate (minutes to hours)
  • ? Sympathetic tone ? ? HR CO
  • ? Ventilation ? ? PaO2 and ? PaCO2 ? ? pH
  • Renal bicarbonate diuresis (to balance pH)
  • ? Pulmonary artery pressure ? ? O2 absorption
  • Delayed (days to weeks)
  • Erythropoietin ? ? RBC production
  • Remodeling of pulmonary arterioles

9
Altitude Illnesses (Failure to Acclimatize)
  • Cerebral Syndromes
  • Acute Mountain Sickness (AMS)
  • High Altitude Cerebral Edema (HACE)
  • mild AMS moderate AMS HACE
  • Pulmonary Syndrome
  • High Altitude Pulmonary Edema (HAPE)
  • Importance
  • HACE and HAPE can be fatal

10
Acute Mountain Sickness(AMS)
  • Defined as HEADACHE plus one or more symptom
  • Anorexia, nausea or vomiting
  • Fatigue or weakness
  • Dizziness or lightheadedness
  • Difficulty sleeping

11
Effects of AMS on performance
  • Mild annoyance only
  • Moderate impaired concentration, memory,
    speech, and physical performance
  • Can be disabling
  • Subtle abnormalities visible on MRI
  • Effects can last weeks

12
High Altitude Cerebral Edema(HACE)
  • AMS symptoms plus ALTERED L.O.C. and ATAXIA
  • Other neuro findings possible
  • Coma develops
  • Death results if untreated
  • Pathophysiology
  • altered cerebral vascular permeability
  • leads to brain swelling
  • MRI cerebral edema,
  • lesions of corpus callosum

13
High Altitude Pulmonary Edema(HAPE)
  • Defined by two pulmonary symptoms
  • Cough, dyspnea at rest, exercise intolerance,
    chest tightness/congestion
  • and two pulmonary signs
  • Crackles, wheezing, cyanosis, tachypnea,
    tachycardia
  • Most common cause of death among HAI
  • 50 mortality rate if not treated quickly

14
High Altitude Pulmonary Edema(HAPE)
  • CXR findings
  • Blotchy fluffy infiltrates
  • Pathophysiology
  • Hypoxia
  • ? pulmonary artery hypertension
  • alveolar damage
  • ? edema and hemorrhage into alveoli

15
Risk factors for HAI
  • Rapid gain in altitude
  • Prior history of HAI
  • genetic factors involved
  • Alcohol, sedatives
  • HAPE cold ambient temperature
  • Strenuous exercise

16
HAI Protective Factors
  • Residence at elevation gt900 m (2950 ft)
  • Slow gain in elevation
  • lt600 m (1970 ft) per day in sleeping elevation
  • Genetic factors
  • Vigorous fluid intake
  • Physical fitness NOT protective

17
Treating HAI
  • Rest, halt ascent
  • Descent
  • Moderate AMS gt500 m (1640 ft)
  • HACE gt 1000 m (3280 ft)
  • HAPE 500 1000 m
  • Oxygen if available
  • Keep warm (esp. for HAPE)
  • Portable hyperbaric chambers

18
Portable Altitude Chamber (PAC)
Gamow bag Certec bag
19
Treating HAI (cont.)
  • Acetazolamide
  • Speeds acclimatization
  • 75 effective in preventing AMS
  • Treats moderate AMS HACE
  • Dose 125-250 mg BID

20
Treating HAI (cont.)
  • Dexamethasone
  • Decreases cerebral edema
  • Treats moderate AMS and HACE
  • Prevents AMS, ? HACE
  • Dose
  • 2 mg po/IM/IV QID
  • 4 mg BID

21
Treating HAI (cont.)
  • Nifedipine
  • Decreases pulmonary artery pressure
  • Prevents and treats HAPE
  • Dose 20 30 mg extended release BID

22
Treating HAI (cont.)
  • Salmeterol
  • Decreases alveolar fluid transport
  • Prevents and treats HAPE
  • Dose 125 mcg inhaled BID

23
Considerations for Return to Altitude Activity
after HAI
  • Severity and type of prior HAI
  • Future ascent requirements
  • Feasibility of descent/extra rest days if needed
  • Availability of medical treatments

24
Two scenarios for Return to Altitude Activity
after HAI
  1. Remote history of HAI, fully recovered
  2. Recent HAI, with/without recovery

25
1. Remote history of HAI, fully recovered
  • Proper acclimatization protocols are paramount
  • Ascend no more than 600 m (1970 ft) per day in
    sleeping altitude when gt2500 m (8200 ft)
  • Spend one extra night every 600-1200 m (1970
    3937 ft)
  • Avoid abrupt ascent to gt3000 m (9843 ft)
  • Spend 2-3 nights at 2500-3000 m before ascending
    further

26
Acute mountain sickness influence of
susceptibility, preexposure, and ascent rate
Schneider M et al. Med Sci Sports Exerc 2002
27
Prevention of recurrent AMS
  • Proper acclimatization, slow ascent. If
    not possible
  • Acetazolamide 125-250 mg po BID starting 1 day
    prior to ascent, continuing until at max altitude
    for 2 days. If not possible
  • Alternate Dexamethasone 2 mg po QID or 4 mg BID,
    starting 1 day prior, cont. until at max altitude
    2 days
  • Unknown which is better or if combination therapy
    is indicated

28
Prevention of recurrent HACE
  • (No evidence-based recommendations)
  • Strong recommendation for acclimatization and
    slow ascent.
  • If not possible, or descent/medical treatment not
    possible
  • Prophylaxis with acetazolamide or dexamethasone,
    as for AMS

29
Prevention of recurrent HAPE
  • The power of slow ascent case series
  • 4 climbers with history of 2-4 prior cases of
    HAPE each
  • Made a collective 7 ascents to gt 5000 m (16,400
    ft)
  • Acclimatized fully
  • Ascended only 330-350 m (984-1150 ft) a day
  • RESULT no cases of HAPE (100 effective)

Bärtsch P et al. High altitude pulmonary edema.
Respiration 1997
30
Prevention of recurrent HAPE(cont.)
  • The power of meds 1 R, DB, PC trial comparing
    prophylactic meds
  • Dex 8 mg bid
  • Tadalafil 10 mg bid
  • Dex tad vs placebo
  • P lt 0.001 lt 0.007
  • Dex vs tab not sig
  • Both dex tad reduced pulmonary artery pressure

31
Prophylaxis for recurrent HAPE
  • Strong recommendation for acclimatization and
    slow ascent.
  • If not possible, or descent/medical treatment not
    possible
  • Prophylactic options
  • Tadalafil 10 mg po bid
  • Dexamethasone 8 mg po bid
  • Acetazolamide 125-250 mg po BID
  • Salmeterol 125 mcg inhaled BID
  • Nifedipine 20-30 mg XR BID
  • All beginning 1 day before ascent

No evidence of superiority of one agent or
risks/benefits of combination therapy
32
2. Return to Altitude Activity after Recent HAI
  • Considerations (same as remote HAI hx)
  • Severity and type of prior HAI
  • Future ascent requirements
  • Feasibility of descent/extra rest days if needed
  • Availability of medical treatments
  • Additional considerations for recent HAI
  • Should the patient fully recover before returning
    to altitude/activity?
  • How safe is continued activity at altitude?
  • Should activities be limited?

33
Treatment of Mild AMS
  • Descend gt 500 m (1640 ft) OR
  • Rest 1-2 days at same altitude
  • Oxygen 12-24 hours, if available
  • Consider acetazolamide 125-250 mg po BID
  • Symptomatic treatment with analgesics,
    anti-emetics

34
Return to Altitude Activity during/after Mild AMS
  • (No evidence-based recommendations)
  • Common practice continue activity despite
    symptoms
  • Risks
  • Impaired cognition/performance
  • Progression to moderate AMS or HACE
  • Consider acetazolamide

35
To air is human altitude illness during an
expedition length adventure race
  • 10-day, 238-mile race at elevations of 9,500
    13,500 ft
  • No prophylaxis allowed
  • 33 cases of AMS treated during race
  • 88 were returned to race
  • 58 finished race (compared to 74 overall)
  • CONCLUSION untreated AMS probably reduces
    athletic performance

Talbot TS et al. Wilderness Environ Med 2004
36
Treatment of Moderate AMS
  • Descend gt500 m
  • Rest 1-2 days
  • Do not allow continued ascent/activity
  • Significant performance/cognition decrement
  • Risk of progression to HACE
  • Oxygen 1-2 days, if available
  • Acetazolamide dex as alternate

37
Return to Altitude Activity after recovery from
Moderate AMS
  • (No evidence-based recommendations)
  • Strict adherence to acclimatization and slow
    ascent protocols
  • Ascend no more than 600 m/day
  • Rest day every 600 1200 m
  • Consider acetazolamide (or dex)
  • Counsel on recognition and rapid treatment of
    HACE/HAPE

38
Treatment of HACE
  • Immediate descent gt 1000 m and hospitalize
  • Oxygen to maintain SaO2 gt90
  • Dexamethasone8 mg PO/IM/IV initially followed by
    4 mg QID
  • Portable hyperbaric therapy if descent impossible

39
Treatment of HACE (cont.)
  • Management of coma
  • Bladder catheterization
  • Airway control
  • Diagnostic studies
  • CXR to rule out concurrent HAPE
  • MRI to rule out other conditions

40
Recovery from HACEhighly variable
  • 1-3 days for symptoms to resolve
  • Days to 12 weeks for neuropsychological function
    to normalize
  • 3-4 weeks for papilledema to resolve
  • Days to 5 weeks for MRI to normalize

41
Return to Altitude Activity after recovery from
HACE
  • (No evidence based recommendations)
  • Full recovery highly advised
  • Strict adherence to acclimatization and slow
    ascent protocols
  • Ascend lt 600 m/day
  • Rest day every 600 1200 m
  • Consider prophylaxis
  • Acetazolamide dex as alternate

42
Treatment of HAPE
  • Immediate descent 500-1000 m
  • Oxygen to keep SaO2 gt90.
  • If descent/O2 not immediately available
  • Portable hyperbaric therapy
  • Nifedipine 20-30 mg extended release BID (avoid
    if concomitant HACE) and/or
  • Salmeterol 125 mcg inhaled

43
Treatment of HAPE (cont.)
  • Admit if
  • gt4L/min O2 requirement
  • Elderly, very young
  • Concomitant HACE or co-morbid cardio-pulmonary
    disease
  • Dexamethasone if concomitant HACE
  • Low-flow outpatient O2 for others check daily

44
Recovery from HAPE
  • Variable little evidence in literature
  • May take 2 weeks to recover strength
  • Resume some activity when SaO2 gt 90 without
    supplemental O2
  • Remaining at some altitude fosters
    acclimatization via pulmonary arteriolar
    remodeling

45
Reascent following resolution of high altitude
pulmonary edema (HAPE).
  • Case reports of 3 mountaineers with HAPE
  • Treated with
  • descent to lower altitude
  • oxygen
  • rest 2-3 days
  • Resumed ascent no prophylaxis
  • lt 600 m/day ascent several rest days
  • RESULT all reached peaks w/o HAPE
  • One reached summit of Mt. Everest at 8850 m
    (29,035 ft)

Litch JA, Bishop R. High Alt Med Biol 2001
Spring2(1)53-5
46
Return to Altitude Activity after recovery from
HAPE
  • (No evidence based recommendations)
  • Strict adherence to acclimatization and slow
    ascent protocols
  • Ascend lt 300 - 600 m/day
  • Rest day every 600 1200 m
  • Consider prophylaxis
  • acetazolamide and/or
  • nifedipine or salmeterol
  • (especially if ascent will be gt 600 m/day)

47
Review
  • Little evidence for recommendations of Return to
    Altitude Activity after HAI
  • Acclimatization and slow ascent are powerful
  • Ascend lt 600 m/day
  • Rest day every 600 1200 m
  • Prophylactic meds advised if unable to comply
  • Consider neuro-psych deficits from moderate
    AMS/HACE and their effect on activity

48
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