Page 104 - 2022 Ranger Medic Handbook

Altitude Medical Emergencies
Altitude Illnesses
Acute Mountain Sickness (AMS): Typically occurs at altitudes > 8,000 ft (2,500 meters). Onset typically occurs 6–12
hours after ascent but can occur as quickly as 3 hours after ascent. The key to prevention is prophylactic acetazolamide
and a combination of slow, graded ascent and staged ascent. A slow, graded ascent is no more than 1,650 ft/day (500
meter) when above 10,000 ft (3,000 meters), and limit sleeping altitude to 1,000 ft above previous night’s altitude. A
staged ascent is spending 2–3 days at moderate altitude 8,000–10,000 ft (2,500–3,000 meters).
High Altitude Cerebral Edema (HACE): Rare below 11,500 ft. Headache is common at altitude. Ataxia and altered
mental status at altitude are HACE until proven otherwise.
High Altitude Pulmonary Edema (HAPE): Caused by the hypoxia of altitude, HAPE is the most common cause of death
from altitude illness. Usually occurs above 8,000 ft. Respiratory distress at high altitude is HAPE until proven otherwise.
SECTION 3 HACE AND HAPE MAY COEXIST IN THE SAME PATIENT!

Signs/Symptoms
S/Sx: AMS is generally benign and self-limiting, but symptoms may become debilitating. Worsening condition should
prompt consideration of a more life-threatening condition (HAPE or HACE). AMS Diagnosis: recent ascent > 8,000 ft
(2,500 meter), plus a headache AND at least of the following: anorexia, nausea, vomiting, insomnia, dizziness, lighthead-
edness, lassitude, weakness, or fatigue. No correlation with fitness level (likely genetic predisposition).
HACE: Unsteady, wide, and unbalanced (ataxic) gait and altered mental status are hallmark signs.
HAPE: Dyspnea at rest is the hallmark sign. Other symptoms may include cough, crackles upon auscultation, tachypnea,
tachycardia, fever, central cyanosis, or decreased physical exercise tolerance. Measure SpO 2 % and compare to other
people around. If measured SpO 2 % is less than others’ and the patient has symptoms, then descent must be initiated.
Initial Management & Extended Management
1. Halt ascent. Immediately descend at least 1,500 ft for HACE, HAPE, or refractory AMS if tactically feasible.
2. If AMS Symptoms Present: Acetazolamide 250mg PO bid UNLESS PATIENT IS ALLERGIC TO SULFA or is already
taking as prophylaxis. Dexamethasone 4mg PO/IV/IM q6hr if patient is allergic to sulfa. If dexamethasone is adminis-
tered, no further ascent until asymptomatic for 18 hours after last dexamethasone dose. Descend if symptoms worsen.
3. If HACE Symptoms Present: Ataxia or Altered Mental Status: Dexamethasone 10mg IV/IM STAT, then 4mg IV/
IM q6hr. Individuals with HACE should not be left alone and especially not be allowed to descend alone. Administer
supplemental oxygen, if available.
4. If HAPE Symptoms Present: Shortness of Breath at Rest: Nifedipine 10mg PO/SL STAT; then 20mg q6hr if blood
pressure is stable. For extended management, consider sildenafil 50mg q8hr OR Tadalafil 10mg q12hr (do not use
in HACE; the drop in blood pressure will worsen the symptoms of this disease). Administer supplemental oxygen, if
available. Consider salmeterol 2 inhalations q12hr. OR albuterol 2 inhalations q6hr.
5. Minimize patient exertion during descent for HAPE since this will exacerbate symptoms.
6. Treat per Pain Management Protocol but avoid the use of narcotics since they may depress respiratory drive and
worsen high altitude illness. Treat per Nausea and Vomiting Protocol.
7. For signs or symptoms of either HAPE or HACE, if immediate descent is not tactically feasible and a GAMOW bag
is available, use a GAMOW bag in 1-hour treatment sessions with bag inflated to a pressure of 2 psi (approximately
100mmHg) above ambient pressure. Four or five sessions are typical for effective treatment. GAMOW BAG TREAT-
MENT IS NOT A SUBSTITUTE FOR DESCENT.
8. Treat per Dehydration Protocol.
DISPOSITION: Most cases of AMS are relatively mild, resolve in 2–3 days, and do not require evacuation. Avoid vigorous
activity for 3–5 days. Priority evacuation for AMS patients who worsen despite therapy. Urgent evacuation for patients
with suspected HACE or HAPE. Individuals who have recovered from HACE or HAPE should not re-ascend without
medical officer clearance.
Prophylaxis & Pretreatment
AMS Emergency Rapid Ascent/HAF Insertion at Altitude > 11,500 ft: With prior medical officer approval, consider
pretreatment of unit personnel with acetazolamide 125mg PO bid OR dexamethasone 4mg PO/IV/IM q6hr (for operations
< 48 hours). Dexamethasone prevents symptoms but does not help with acclimation.
AMS Prevention/Pretreatment: Acetazolamide 125mg PO bid, started 24 hours before ascent to altitude > 8,000 ft.
Takes 8 hours after the first dose to have efficacy. Cease pretreatment after 2–3 days at target altitude or during descent.
If true sulfa allergy, do not use acetazolamide and supplement with dexamethasone. If sulfa ABX allergy, continue to use
acetazolamide with medical officer approval. For personnel who have a history of previous HAPE, nifedipine, acetazol-
amide, sildenafil, tadalafil, salmeterol, and albuterol may be used (individually or in combination).
90 SECTION 3 TACTICAL MEDICAL EMERGENCY PROTOCOLS (TMEPs) & SICK CALL