What is HAPE
What is High Altitude Pulmonary Edema (HAPE)?
HAPE is an accumulation of fluid in the air sacs of the lungs, due to leaky capillaries. It severely inhibits exchange of oxygen in the lungs, and can result in death . HAPE symptoms start gradually within the first 2-4 days at altitude. The earliest symptoms are shortness of breath with exercise, with decreased exercise performance. As more fluid accumulates in the lungs, symptoms progress to severe shortness of breath even at rest, a persistent cough sometimes with blood, chest tightness or congestion, and severe weakness. Untreated patients progress to unconsciousness, coma, and death.
How is HAPE diagnosed?
Lake Louise Criteria for diagnosing HAPE are a combination of symptoms and physical exam findings. At least two of the following symptoms: shortness of breath at rest, cough, weakness and decreased exercise performance, chest tightness or congestion; AND at least two of the following signs on physical exam: fast heart rate, fast breathing, crackles or wheezing heard in the lungs, or low oxygen measured by a device called a pulse oximeter or signs of low oxygen such as dusky or bluish appearance of the skin. Chest X-ray in a HAPE patient confirms fluid in the lungs.
How often do people in Colorado get HAPE?
HAPE is much less common than AMS in Colorado. A survey done in Summit County showed 150 patients diagnosed with HAPE over a three year period. Others estimate it occurs in about one of every 10,000 skiers. Rarely does anyone die of HAPE in Colorado because medical care is readily available. About half of HAPE patients also experience AMS, leaving the other half without the ?warning' symptoms of headache and other AMS symptoms. Because of this, symptoms may be ignored until breathing becomes very difficult.
What happens in the lungs to cause HAPE?
The blood pressure in the lungs rises in response to low oxygen levels. In some areas of the lung, the blood vessels cannot contain high pressure and flow and breakdown of the small vessels causes leaking of fluid across the membranes into the air sacs.
Am I at risk for HAPE?
Risk factors for HAPE include:
- Genetic makeup
- A prior history of HAPE
- Certain preexisting lung and heart conditions
- History of high pulmonary artery pressure
- Men tend to get HAPE more frequently than women
- Coming to high altitude with a respiratory infection, especially children
How is HAPE treated?
- Oxygen and rest are the main treatments for HAPE. Oxygen increases the oxygen in the blood as well as lowers the pressure in the lung blood vessels. Many times oxygen and rest are all a patient needs to get better. In most ski resorts, those with HAPE use an oxygen concentrator machine for 2 to 3 days, the HAPE resolves, and they can then ski.
- Medications such as Viagra®, Cialis® and nifedipine are sometimes used in treatment as they lower the blood pressure in the lungs. Clinical research has yet to demonstrate if they have any value over oxygen alone.
- Descent to a lower altitude may be needed if a patient does not get better with oxygen. When oxygen is not available, descent is mandatory.
- Hyperbaric chambers including portable ones such as the Gamow® bag may be used to lower the altitude if a person is in the backcountry and unable to descend immediately because of weather or injury.