CO2 Supplement for Treatment of Acute Mountain Sickness

CO2 Supplement for Prophylaxis and Treatment of Acute Mountain Sickness Using Novel Device

It was reported that up to 76% people who rapidly ascend to the altitude higher than 4500 m without sufficient acclimatization will have AMS which often develops 6-8 hours after reaching at high altitude. AMS could be improved if there is no continuous ascent although central sleep apnea may persist much longer. It has also been well documented that exercise capacity was impaired at high altitude. Oxygen inhalation is the most effective treatment method, but it is impractical for outdoor activities because of the large volume required. There are some drugs such as acetazolamide, and ibuprofen for relieving AMS but side effects and inconsistent treatment effect made them to be difficulty for routine use. It is noted that adding CO2 might be useful for improvement of hypoxia and exercise ability and eliminating CSA. There is no available device which can accurately supply constant CO2 and is functionally free of dead space. We innovated a portable device with a special mask for supplement of CO2 for prophylaxis and treatment of AMS.

Study Overview

• Status: Completed
• Conditions: Acute Mountain Sickness; High Altitude; Inhalation; Gas
• Intervention / Treatment: Device: Breathing with CO2 during daytime and night at high altitude; Device: Sleep and doing exercise test under inhalation of air

Detailed Description

Objective: To determine whether, after rapid ascent to high altitude the device could reduce the incidence and severity of AMS as defined by AMS scores, improve sleep quality and reduce central sleep apnea events.

Methods: A randomized placebo-controlled study will be performed in 36 healthy adults with no history of travelling to high altitude (>1000m) a year before the study. Subjects will be randomly and blindly given either CO2 mixed with air or air alone during daytime and sleep. Blood gases will be measured 30 minutes after inhalation of air or CO2. SaO2, heart rate, and respiratory rate will be recorded every two hours. AMS (Lake Louise Acute Mountain Sickness Score) will be recorded before and after sleep. PSG including diaphragm EMG would be recorded under CO2 or air. Exercise time, ventilation heart rate, respiratory rate, and SaO2 will be recorded and maximal load and peak ventilation will be measured during incremental cycle exercise with inhalation of CO2 or ambient air.

• Study Type: Interventional
• Enrollment (Actual): 46
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China
      • Guangzhou Medical University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. BMI less than 25kg/m2
2. normal lung function.
3. Healthy lowlanders (<500m) who have no history to travel to high altitude (>1000m) a year before the study.

Exclusion Criteria:

1. insomnia,
2. moderate or severe OSA based on PSG at sea level (AHI> 15 events/hr).
3. visited to an altitude >2500 m in the preceding year.
4. Currently using medicines for diabetes, hypertension et al.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Breathing with CO2 during daytime and night at high altitude; Subjects will sleep and perform exercise tests under inhalation of low concentration of CO2 supplied by a novel device at high altitude.	Device: Breathing with CO2 during daytime and night at high altitude; Subjects wear the mask connecting to low dose CO2 supplied by a novel device during daytime and sleep dependent on the randomization once arriving high altitude.; Other Names: Sleep and doing exercise test under inhalation of CO2
Placebo Comparator: Breathing with air during daytime and night at high altitude; Subjects will sleep and perform exercise tests under inhalation of air at high altitude.	Device: Sleep and doing exercise test under inhalation of air; Subjects wear the mask connecting to air supplied by the novel device during daytime and sleep dependent on the randomization once arriving high altitude.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence rate of acute mountain sickness (AMS)	Incidence rate of AMS based on Louis's scores under inhalation of CO2 and ambient air. The maximum score is 12 points, and a score greater than 3 indicates the presence of AMS.	72 hours
The severity of AMS	The severity of AMS based on Louis's scores under inhalation of CO2 and ambient air. A score of 3-5 indicates mild AMS, a score of 6-9 indicates moderate AMS and a score of 10-12 indicates severe AMS.	72 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Central sleep apnea index based on PSG	Changes of central sleep apnea index under inhalation of CO2 and ambient air.	72 hours
Sleep quality based on PSG	Changes of sleep quality under inhalation of CO2 and ambient air.	72 hours
Workload in the incremental ergometer test	Changes of workload in the incremental ergometer test under inhalation of CO2 and ambient air.	72 hours
Exercise duration in the incremental ergometer test	Changes of exercise duration in the incremental ergometer test under inhalation of CO2 and ambient air.	72 hours

Collaborators and Investigators

• Sponsor: State Key Laboratory of Respiratory Disease
• Investigators: Principal Investigator: Yuanming Luo, PhD, Guangzhou Medical University

Study record dates

Study Major Dates

• Study Start (Actual): June 7, 2024
• Primary Completion (Actual): July 15, 2024
• Study Completion (Actual): September 2, 2024

Study Registration Dates

• First Submitted: April 20, 2024
• First Submitted That Met QC Criteria: April 26, 2024
• First Posted (Actual): May 1, 2024

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: December 14, 2024
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Keywords: central sleep apnea; Acute mountain sickness; CO2 inhalation
• Additional Relevant MeSH Terms: Pathologic Processes; Respiratory Tract Diseases; Respiration Disorders; Respiratory Aspiration; Altitude Sickness
• Other Study ID Numbers: 2020 037

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The data will be shared after the paper of this study publishing.
• IPD Sharing Time Frame: The data will be shared after the paper of this study publishing.
• IPD Sharing Access Criteria: After the paper of this study publishing
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No