Base teórica de “Competitividad”

High Altitude: 5,000-11,500 ft (1500-3500 meters) Very High Altitude: 11,500-17,500 ft (3500-5500 meters) Extreme Altitude: Over 17,500 ft (over 5500 meters)

Acute Mountain Sickness (AMS):

Mild, Moderate, Severe:

Guidelines and Considerations: An acute illness characterized by headache, fatigue, loss of appetite, lightheadedness and irritability. Usually occurs with rapid unacclimatized ascent from below 5,000 ft to above 8,000ft, and especially with abrupt ascent to very high or extreme altitude. • Incidence and severity of AMS depend on speed of ascent, altitude attained, time at altitude, level of exertion at altitude and individual susceptibility.

Signs & Symptoms:

 Headache,  Fatigue,  Loss of appetite,

 Dizziness and irritability (symptoms frequently mimic a bad hangover).

 Dry cough is common.

 Dyspnea at rest is not common and frequently precedes or indicates High Altitude Pulmonary Edema (HAPE).

Caution: Ataxia is not a sign of AMS alone: A person with AMS and ataxia is assumed to have High Altitude Cerebral Edema (HACE) and requires urgent evacuation to a lower altitude and treatment steroids.

Mild AMS: Headache, anorexia, nausea and malaise.

Moderate AMS: Severe headache, vomiting, decreased urine output.

Severe AMS: Dyspnea at rest, ataxia, decreased level of consciousness, pulmonary rales.

Treatment:

Mild AMS:

1. Descend minimum of 1000 ft., rest and acclimatize.

2. Acetazolamide (Diamox) 250mg b.i.d. or 500mg QD (sustained release form).

3. Mild analgesia (Tylenol) for headache or phenergan or zofran for significant nausea.

Moderate AMS:

1. Descend immediately a minimum of 1000 ft.

2. Oxygen 2-4 LPM by mask. Acetazolamide as above.

3. Consider Decadron, 4 mg, PO, IM or IV q. 6 hrs (does not speed acclimatization, but will reduce symptoms).

4. Hyperbaric therapy (Gamow bag or equivalent) if descent is delayed or impossible.

Severe AMS:

1. Same as for moderate, but IMMEDIATE descent is mandatory.

2. If descent is delayed, hyperbaric therapy while awaiting descent or evacuation.

Note 1: DO NOT use sleeping medication or other sedating drugs to treat sleep disturbances at altitude. Use of these medications is thought to increase the incidence of HACE. Sleep

disturbances usually resolve with proper acclimation. Acetazolamide may be helpful.

Note 2: Acetazolamide (Diamox), a carbonic anhydrase inhibitor/diuretic, can speed

mg (extended release) po q24 hours, preferably starting 1-2 days prior to ascent, and continuing for at least one day after ascent. This is a sulfa-based medication, and should not be given to patients allergic to sulfa.

Note 3: Decadron (Dexamethasone) 4 mg PO, IM or IV q. 6 hours may prevent AMS if deployment to altitude is required without time for acclimatization. Note this does NOT speed acclimatization, but reduces the symptoms of AMS. Best used in quick in/out operations where altitude exposure is transient.

High Altitude Cerebral Edema (HACE):

Guidelines and Considerations: A severe form of AMS characterized by alterations of

consciousness, ataxia, confusion, drowsiness, stupor, coma and death. Progression from AMS to HACE usually occurs over 12-72 hrs. HACE and High Altitude Pulmonary Edema (HAPE) can and frequently do appear at the same time in the same patient.

Caution: A person who has symptoms of AMS and develops an altered metal status or ataxia is most likely in the early stages of HACE and requires immediate treatment.

Signs & Symptoms: Similar to severe AMS.

 Ataxia,

 Confusion,

 Impaired mentation and severe lassitude.

 Patients with AMS who are not improving within 24 hours should be suspected of having early HACE.

Differential Diagnosis: Hypothermia, carbon monoxide poisoning, stroke, HAPE, drug ingestion, exhaustion, infection (encephalitis).

Treatment:

1. Emergency descent of a minimum of 1000 ft but preferably more (the lower the better).

2. Hyperbaric bag while awaiting descent or evacuation.

3. Oxygen 2-4 LPM by mask. If an IV is started, run at KVO.

4. Decadron, 8mg IV, IM, PO loading dose, 4 mg PO, IV or IM q 6 hrs.

Warning: Do not delay descent while awaiting evacuation. If possible, have evacuation aircraft meet you at a lower elevation.

High Altitude Pulmonary Edema (HAPE):

Guidelines and Considerations: Mild, Moderate, Severe: HAPE is more common in young and healthy individuals, usually occurring 2-4 days after arriving at altitude, and most commonly on or after the second night at altitude. Rarely occurs below 8,000 ft. Any individual who does not seem to be acclimatizing to altitude, has increasing AMS symptoms after being on the mountain for 36 hrs or more, or is experiencing increasing dyspnea at rest must be suspected of having HAPE.

Signs and Symptoms:

Mild HAPE:

 Dyspnea on exertion, easy fatigability, especially with uphill travel, +/- rales in lung bases.

Moderate HAPE:

 Dyspnea, weak, fatigue with travel on level ground, raspy cough, possible nail bed cyanosis, headache, decreased appetite, +/- rales (usually bilateral).

 Severe HAPE: Dyspnea at rest, productive cough (frothy, occasionally blood tinged sputum), extreme weakness, orthopnea, cyanosis, rales.

Differential Diagnosis: Bronchitis, pneumonia, asthma, AMS, HACE.

Treatment:

1. Oxygen, high flow if possible.

2. Immediate emergency descent.

3. Minimize physical exertion (will worsen HAPE)

4. If there is sufficient oxygen available, and the time, the victim and team might be better off to keep the patient on oxygen overnight, and then descend in the morning when he is somewhat improved.

5. Hyperbaric bag if not able to descend immediately.

Note: Lasix and/or Morphine are not used in HAPE.

Caution: The definitive treatment for HAPE is descent to lower altitude. Descend as soon as the diagnosis is suspected.

Use of Nifedipine in HAPE: Use of the calcium-channel blocker, nifedipine, has been advocated as an adjunct treatment for HAPE. While it appears to be effective, this medication has significant side effects, most notably severe hypotension which may preclude ambulation.

Dose of nifedipine is 10 mg orally, followed by 30 mg of the slow-release formulation every 12-24 hours, or 10 mg orally every 4 hours, titrated to response. Do not use this medication without direct physician order. Nifedipine is an adjunct for treatment of HAPE and does not substitute for oxygen and descent.

UV Keratitis (Snow Blindness):

Ultraviolet burn of the cornea caused by intense UV and reflected UV light at altitude. Can also be caused by prolonged exposure to UV light in an arctic/snow environment.

Signs & Symptoms:

 Pain to the eyes (feels like sand in the eyes), usually starting 4-6 hrs after UV exposure.

 Light sensitivity,

 Tearing,

 Headache.

Differential Diagnosis: Foreign body in eyes, conjunctivitis, acute close-angle glaucoma, iritis.

Treatment:

1. Usually a self-limiting problem resolving within 12-24 hrs.

2. Remove contact lenses if present.

3. Eyes will be very sensitive to light. Protect from light to tolerance.

4. Oral medications for pain control.

Prevention: Wear sunglasses with good UV blocking lenses, preferably with side shields.

Chapter 17: Cold Injuries