Title: Return to High Altitude Activity After High Altitude Illness
1Return 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)
3Objectives
- 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
4Preview
- 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
5Environment 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
6Ft. Carson, CO, 6500 ft
Pikes Peak, 14,110 ft (4300 m)
US Air Force Academy, 7,000 ft
7Acclimatization bodys adaptation to hypobaric
hypoxia
8Acclimatization
- 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
9Altitude 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
10Acute Mountain Sickness(AMS)
- Defined as HEADACHE plus one or more symptom
- Anorexia, nausea or vomiting
- Fatigue or weakness
- Dizziness or lightheadedness
- Difficulty sleeping
11Effects 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
12High 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
13High 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
14High Altitude Pulmonary Edema(HAPE)
- CXR findings
- Blotchy fluffy infiltrates
- Pathophysiology
- Hypoxia
- ? pulmonary artery hypertension
- alveolar damage
- ? edema and hemorrhage into alveoli
15Risk factors for HAI
- Rapid gain in altitude
- Prior history of HAI
- genetic factors involved
- Alcohol, sedatives
- HAPE cold ambient temperature
- Strenuous exercise
16HAI 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
17Treating 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
18Portable Altitude Chamber (PAC)
Gamow bag Certec bag
19Treating HAI (cont.)
- Acetazolamide
- Speeds acclimatization
- 75 effective in preventing AMS
- Treats moderate AMS HACE
- Dose 125-250 mg BID
20Treating HAI (cont.)
- Dexamethasone
- Decreases cerebral edema
- Treats moderate AMS and HACE
- Prevents AMS, ? HACE
- Dose
- 2 mg po/IM/IV QID
- 4 mg BID
21Treating HAI (cont.)
- Nifedipine
- Decreases pulmonary artery pressure
- Prevents and treats HAPE
- Dose 20 30 mg extended release BID
22Treating HAI (cont.)
- Salmeterol
- Decreases alveolar fluid transport
- Prevents and treats HAPE
- Dose 125 mcg inhaled BID
23Considerations 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
24Two scenarios for Return to Altitude Activity
after HAI
- Remote history of HAI, fully recovered
- Recent HAI, with/without recovery
251. 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
26Acute mountain sickness influence of
susceptibility, preexposure, and ascent rate
Schneider M et al. Med Sci Sports Exerc 2002
27Prevention 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
28Prevention 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
29Prevention 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
30Prevention 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
31Prophylaxis 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
322. 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?
33Treatment 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
34Return 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
35To 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
36Treatment 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
37Return 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
38Treatment 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
39Treatment of HACE (cont.)
- Management of coma
- Bladder catheterization
- Airway control
- Diagnostic studies
- CXR to rule out concurrent HAPE
- MRI to rule out other conditions
40Recovery 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
41Return 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
42Treatment 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
43Treatment 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
44Recovery 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
45Reascent 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
46Return 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)
47Review
- 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
48Thank you!