hypoxia altitude simulation test (HAST)

Indications

• used to predict in-flight hypoxia during air travel in patient with COPD or other cardiopulmonary disorder
• pO2 on room air at sea level < 70 mm Hg is an indication for HAST
• since supplemental oxygen should be provided to air travelers with an SaO2 < 92%

Contraindications

• patient on supplemental oxygen therapy

Clinical significance

• simulates oxygen content of air at an altitude of 8000 feet (2500 meters)

Procedure

• the patients breaths hypoxic gas for 20 minutes
  • inhalation of 15% oxygen - 85% nitrogen
  • determination of SaO2 (pulse oximetry) vs pO2 (ABG)
  • if pO2 during HAST decreases to < 50 mm Hg or SaO2 decreases to < 92%, supplmental oxygen indicated for air travel
  • measurement of pO2 during activity may be performed
  • may include supplemental oxygen titration

More general terms

• clinical procedure

Additional terms

• air travel