Evaluating the Utility of Continuous Positive Airway Pressure in the Treatment of High Altitude Pulmonary Edema

Study Overview
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Brief Summary
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The primary objective is to evaluate the efficacy of continuous positive pressure on resolution of high-altitude pulmonary edema vs high flow oxygen. The secondary objective is to derive an incidence of high-altitude pulmonary edema based on the elevation and timing from which the subject arrives. Additionally, in a convenience sample of the base study population, an ultrasound evaluation for the presence of B lines in the lungs will be conducted after 2 hours.

Detailed Description
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Multicenter, double-blinded, randomized control trial. Enrollment is based on presentation to one of the treating facilities with clinical signs and symptoms of high-altitude pulmonary edema with a recent arrival at high altitude, an oxygen saturation below 85%, and radiographic evidence of noncardiogenic pulmonary edema. A total of 264 patients will be randomized 1:1 across 2 study arms: a CPAP mask set to 15cm H2O and an altered CPAP mask in which the pressure valve has been modified to deliver no positive pressure. All patients will be treated with 30mg nifedipine XR. Except for the application of positive pressure, all other interventions are performed in the context of everyday clinical practice, and thus will be equivalent for participants in both arms. Patients will be evaluated every 30 minutes for their ability to maintain an oxygen saturation of 92% with a normal respiratory rate and no signs of increased work of breathing on 2 liters of nasal cannula oxygen for a total of up to a maximum treatment length of 2 hours. The primary efficacy endpoint will be assessed every 30 minutes for 2 hours.

Official Title
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Multicenter Randomized Double-Blind Control Trial Evaluating the Utility of Continuous Positive Airway Pressure (CPAP) in the Treatment of High Altitude Pulmonary Edema (HAPE)

Conditions
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Continuous Positive Airway Pressure, High Altitude Pulmonary Edema

Intervention / Treatment
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* Device: CPAP mask system
* Drug: Nifedipine 30 MG
* Device: CPAP mask system without PEEP


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female, age 18 years or greater Oxygen saturation below 85% Recent arrival to high altitude Dyspnea and cough Xray revealing non-cardiogenic pulmonary edema Exclusion Criteria: Pregnancy Age below 18 Patients with respiratory failure requiring intubation Patients with altered mental status Patients with impaired decision-making capacity Patients with a history of congestive heart failure, CAD, COPD, asthma, known current pneumonia Extreme facial hair precluding application of CPAP

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Experimental: CPAP<br>Participants will be treated with CPAP. All patients will be treated with nifedipine unless there is a contraindication like hypotension and bradycardia. | Device: CPAP mask system<br>* Intervention group will receive 15cm of H2O of positive end expiratory pressure<br>Drug: Nifedipine 30 MG<br>* All participants will receive this intervention<br>|
| Placebo Comparator: Control: High flow oxygen<br>Participants will be treated with an altered CPAP mask that will deliver high flow oxygen. All patients will be treated with nifedipine unless there is a contraindication like hypotension and bradycardia. | Drug: Nifedipine 30 MG<br>* All participants will receive this intervention<br>Device: CPAP mask system without PEEP<br>* Placebo group will receive high flow oxygen via altered CPAP mask system without providing any positive end expiratory pressure<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to resolution of HAPE | The amount of time it took to maintain oxygen saturation over 92% on 2L NC oxygen | 2 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Presence or absence of ultrasound detectable B lines | A convenience sample of the total study population will have a bedside pulmonary ultrasound at time zero and two hours | 2 hours | 
| Characterization of time at altitude to development of HAPE | A descriptive measurement of the time since the patient arrived at altitude until the development of HAPE | 2 hours | 
| Incidence of HAPE by native altitude and reported sleeping altitude | Data will be collected and analyzed to seek a relationship between the subjects home altitude and the altitude of their sleep while at high altitude | 2 hours |