High altitude pulmonary edema


  • Also known as HAPE
  1. Noncardiogenic pulm edema d/t increased microvascular pressure in the pulm circulation
  2. Most lethal of the altitude illnesses
  3. Occurs in <1/10,000 skiers in Colorado; 2-3% of Mt. McKinley climbers
  4. Typical pt is strong and fit; may not have symptoms of AMS before onset of HAPE
  5. Most commonly noticed on the second night at a new altitude

Risk Factors

  • Heavy exertion
  • Rapid ascent
  • Cold
  • Excessive salt ingestion
  • Use of a sleeping medication
  • Preexisting pulmonary HTN
  • Preexisting respiratory infection (children)
  • Previous history of HAPE

Clinical Features

  1. Early
    • Dry cough, decreased exercise performance, dyspnea on exertion, localized rales
    • Resting SaO2 is low for the altitude and drops markedly w/ exertion (aids in the dx)
  2. Late
    • Dyspnea at rest, marked weakness, productive cough, cyanosis, generalized rales
    • Tachycardia and tachypnea correlate with the severity of illness
    • Altered mental status and coma (from severe hypoxemia)
  3. ECG
    • Right strain pattern
  4. CXR
    • Progresses from interstitial to localized-alveolar to generalized-alveolar infiltrates
  5. ABG
    • Hypoxemia with respiratory alkalosis

Differential Diagnosis

High Altitude Illnesses


  • Immediate descent is treatment of choice - minimize exertion
  • If cannot descend use combination of:
    • Supplemental O2 - Can completely resolve the pulmonary edema within 36-72hr
    • Hyperbaric bag
    • Keep pt warm (cold stress elevates pulm artery pressure)
    • Use expiratory positive airway pressure mask
    • Consider the medications listed below that are usually used for prevention


  • Admission
    • Warranted for severe illness that does not respond immediately to descent
  • Discharge
    • Progressive clinical and X-ray improvement and a PaO2 of 60mmHg or SaO2>90%


  • Nifedipine 20mg q8hr while ascending is effective prophylaxis in pts who had HAPE before
  • Tadalafil 10mg BID 24hr prior to ascent
  • Salmeterol inhaled BID

See Also