A PHC is not intended to be used as a cure for severe acute mountain sickness. They are designed to stabilize a patient only until they can descend. All patients with HAPE or HACE should descend as soon as possible after being initially stabilized in a PHC.44

For all PHC, the usual treatment protocol is to place the soldier into the bag, pump the bag up until the pressure-relief valve hisses, then keep the pressure up by occasional pumping for the duration of the treatment. Continuous pumping is required to ventilate the bag and remove CO2. PHC treatment durations are generally 1-2 hours every several hours for 4-6 treatments a day as tolerated by patients until symptoms improve or the patient can be evacuated as required. Prolonged care in a PHC is taxing for the provider and patient thus the common use of intermittent therapy. Maximum therapeutic treatment is obtained by adding supplemental oxygen by nasal cannula or mask with the hyperbaric treatments. Hyperbaric treatments can be repeated as necessary until the casualty clinically improves or is able to descend.45

There is presently only anecdotal data to support PHC treatments in the setting of altitude emergencies.45-46

In individuals with AMS without HAPE or HACE The PHC can be used to relieve AMS until the patient can be evacuated or allowed more time for acclimatization. If the patient responds to the PHC, they may cautiously climb back up to the higher altitudes. The climber should be constantly monitored for any recurrence of symptoms of AMS.45-47