High Altitude Pulmonary Edema Response to Continuous Airway Positive Pressure: A Randomized Controlled Trial: The HAPER CAPER Trial

Background: Morbidity and mortality in cardiogenic pulmonary edema have been reduced by noninvasive positive-pressure airway maneuvers. The value of continuous positive airway pressure (CPAP) for the treatment of high-altitude pulmonary edema (HAPE) is uncertain. The purpose of this study was to evaluate the efficacy and speed of CPAP for HAPE resolution. Methods: A prospective, investigator-initiated, multicenter, randomized, double-blind controlled trial of high-flow oxygen with CPAP versus sham CPAP with high-flow oxygen (oxygen-only group) was conducted. Sixty-four dyspneic adults with maximum oxygen saturation < 85%, recent arrival at high altitude, and noncardiogenic pulmonary edema on chest radiography were randomized to receive CPAP treatment plus usual care or usual care (oxygen-only) delivered through a sham CPAP mask. The primary endpoint was the clinical resolution of HAPE. Results: HAPE resolution in the CPAP plus high FiO2 group and the high flow oxygen alone group was similar. However, this finding should be interpreted cautiously due to this study being slightly underpowered. There was no significant difference in time to resolution (CPAP ~158 min vs. oxygen ~178 min, p = 0.297). Both therapies were effective, with a mean time to resolution of HAPE of approximately 2.5 to 3 h. No treatment-related adverse outcomes, intubations, or mortality were observed in either group. Conclusion: Both CPAP with high-flow oxygen and high-flow oxygen alone are highly effective for the treatment of HAPE. CPAP conferred no improvement in the time to resolution of HAPE. High-flow oxygen therapy requires significantly less resource utilization for similar benefits in the treatment of HAPE. Trial registration: ClinicalTrials.gov identifier: NCT04186598.