Immediate Management of High‑Altitude Pulmonary Edema (HAPE)

First‑Line Therapy

• Supplemental oxygen is the primary treatment for HAPE and produces rapid clinical improvement within minutes. The American College of Cardiology/American Heart Association (ACC/AHA) guideline recommends immediate administration of enriched inspired O₂ for all patients with HAPE. [1][2]
• Immediate descent to a lower altitude together with supplemental oxygen is recommended for both adults and children with HAPE. Descent is considered definitive therapy and should be initiated as soon as feasible. [3][4]

Oxygen Delivery Parameters

• Deliver oxygen via a non‑rebreather (reservoir) mask at 15 L/min when SpO₂ is below 85 %. This flow rate reliably achieves target saturations. [6][7]
• Aim for a peripheral oxygen saturation of 94–98 % in previously healthy patients without chronic lung disease. Maintaining this range supports rapid reversal of hypoxic pulmonary vasoconstriction. [6][7]

Pharmacologic Adjuncts (when descent is delayed)

• Nifedipine (extended‑release) may be used as an adjunctive agent if immediate descent is not possible. It lowers pulmonary artery pressure through selective pulmonary vasodilation. [3][1]
• Acetazolamide is indicated for prevention of HAPE, not for acute treatment. It should be started before ascent and continued for 3–4 days after arrival; it is not appropriate for patients already in respiratory failure. [3][2]
• Dexamethasone is not recommended as primary acute therapy for established HAPE. Guidelines prioritize oxygen and descent over corticosteroid use in the acute setting. [3][2]
• The American Heart Association/American Thoracic Society guidelines do not mention diuretics (e.g., furosemide) in the HAPE treatment algorithm, reflecting their lack of benefit for this non‑cardiogenic edema. [3][4]

Monitoring and Response Assessment

• Patients should demonstrate rapid clinical improvement (within minutes to a few hours) after oxygen therapy. Lack of improvement warrants evaluation for alternative diagnoses such as pneumonia, asthma, or other causes of pulmonary hypertension. [1][3]
• Do not postpone oxygen administration to obtain additional diagnostic studies; immediate oxygen is a medical emergency in HAPE. [1][2]

Critical Pitfalls to Avoid

• Avoid reliance on pharmacologic agents alone without oxygen or descent; medications are adjuncts only. [1][4]
• Do not combine acetazolamide with other diuretics at altitude, as this can cause excessive dehydration and electrolyte disturbances. 5

All facts are drawn from guideline‑based sources (Circulation, Thorax) and reflect current evidence‑based recommendations for the acute management of high‑altitude pulmonary edema.