Background:~Swenson described HAPE in 2002, as a form of hydrostatic acute pulmonary edema with an alteration of alveolar-capillary permeability. Overall prevalence of AMS is 10-20% while incidence of HAPE, HACE or mixed incidence is 2-3%. Highest reported incidence of HAPE among Indian soldiers climbing to Siachen glacier is 15.5%. At 1500-2400m, A series of 52 patients admitted for HAPE over a period of 9 years was reported in literature..~Scientific rationale:~Positive pressure has been used to increase altitude tolerance since the 1940s under simulated altitudes. PEEP applied via face mask increased SpO2 and decreased AMS symptoms. CPAP was used after ascent to 3205 m on Mount Cook in New Zealand where it improved SpO2 and reduced symptoms of HAPE. A CPAP helmet providing 15 cmH20 CPAP improved SpO2 in a single HAPE patient (at 5300 m) from 56% to 74%.-1st case report. A study at Thorang La pass (5416 m) in October 2010 in the Nepal Himalaya found that nasal continuous positive airway pressure (CPAP) is useful as an additional modality to treat presumed high altitude pulmonary edema (HAPE)- 2nd case report.
High altitude pulmonary edema (HAPE) is mostly treated with supplemental oxygen, nifedipine 30mg twice a day, rest, limiting cold exposure and descent (simulated or actual) Gamow Bag provides simulated descent and buy time for actual descent. CPAP is claimed to be effective in many case reports to treat HAPE temporarily until actual descent is taken place. This study aims to evaluate the role of CPAP in treating HAPE at those high altitude stations where Gamow bag is not available and immediate descent is not possible.