HAPE results from the accumulation of fluid on the lungs preventing the effective exchange of oxygen, leading to shortness of breath and a dry cough with a frothy, pink phlegm. This type of altitude illness occurs in 1-2% of people ascending to altitude and typically the symptoms being, to occur on the second night after arrival at altitude.

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The initial symptoms do have a likeness to the natural increase in breathing rate when travelling to altitude, however, someone suffering from HAPE will be unable to catch their breath or to exert themselves.

Other symptoms include: headache, increased heart rate, low grade fever, severe fatigue and weakness, irrational behaviour and tightness of breath.

Furthermore, the sufferers will have a lower oxygen saturation level than non-sufferers at the same altitude.

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There are a number of risk factors associated with HAPE these include; prior diagnosis of HAPE, obesity, the rare absence of a right pulmonary artery and those with an increased blood pressure in the arteries supplying the lungs.

If these symptoms occur the following treatments can be given:

1. As soon as any signs of HAPE occur the patient should be sat upright until further treatments can be arranged.
2. The aim should be to descend at least 1000m, however for a sufferer of HAPE it is important to minimise their amount of exertion so if possible, a vehicle should be used to descend them.
3. Where decent is not possible the use of a hyperbaric bag will provide the same effect. When inflated the hyperbaric bag produces a pressure that is equivalent to a decent of 1000m. This treatment can be used for up to 6 hours for sufferers of HAPE, however it may not be that comfortable for patients as it requires them to lay flat. When signs of improvement occur every effort should be taken to descend the patient.
4. Supplementary oxygen should be given, if possible, to any sufferers of HAPE, for mild HAPE an oxygen flow of 2 to 4 litres per minute is recommended. However, for more severe cases an oxygen flow of 8 to 10 litres per minute is necessary .
5. It is also possible to take Nifedipine, a dosage of 10mg orally, immediately followed by 20mg four times a day, this should only be given for the time taken to evacuate the individual, due to the serious side effects this medication causes. This medication helps to lower pulmonary hypertension.

‍References:

Barry, P.W. and Pollard, A.J. (2003) “Altitude illness”, British Medical Journal, 326(7395), pp.915-919.

Bezruchka, S. (2005) Altitude illness: Prevention & Treatment, Seattle: Mountaineers Books.

Luks, A.M., Auerbach, P.S., Freer, L., Grissom, C.K., Keyes, L.E., McIntosh, S.E., Rodway, G.W., Schoene, R.B., Zafren, K. and Hackett, P.H. (2019) “Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update”, Wilderness & environmental medicine, 30(4), pp.3-18.