Effect of Hi-OxSR for the Treatment of Post COVID Condition (RECLAIM-HiOxSR)

RECLAIM: Recovering From COVID-19 Lingering Symptoms Adaptive Integrative Medicine Trial - Effect of Hi-OxSR for the Treatment of Post COVID Condition (RECLAIM-HiOxSR)

The RECLAIM study platform will be used to explore whether the use of the Hi-OxSR device improves the symptoms of post covid cognitive dysfunction. Carbon dioxide (CO2) has been proposed as a potential treatment for persistent immune activation as there is evidence that CO2 has antioxidant, anti-inflammatory, and anti-cytokine effects. We conducted a pilot study assessing the open label use of re-breathing CO2 (using Hi-OxSR) twice a day for 14 days, for the treatment of post-COVID cognitive dysfunction. Significant improvements were found in multiple cognitive assessments using TestMyBrain cognitive tests and brain fog (MSNQ) and fatigue scores. This phase 2 clinical trial seeks to build on current findings to determine the optimal effective dose of treatment (i.e. length of use, oxygen concentration, without or without CO2 rebreathing) and the safety of using Hi-OxSR in this patient population.

Study Overview

• Status: Recruiting
• Conditions: Long COVID; Post Acute Sequelae of COVID-19; Post COVID-19 Condition
• Intervention / Treatment: Device: Hi-OxSR device; Device: Hi-Ox device

Detailed Description

This is a Sub-Protocol to the Core Clinical Study Protocol titled: REcovering from COVID-19 Lingering symptoms Adaptive Integrative Medicine (RECLAIM)

• Study Type: Interventional
• Enrollment (Estimated): 120
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Suzanne Cohen; Phone Number: 1-866-673-2524; Email: RECLAIM@uhn.ca

Study Locations

• Canada
  • Alberta
    • Edmonton, Alberta, Canada
      • Not yet recruiting
      • Kaye Edmonton Clinic
      • Contact: Karina Kaur; Email: pkaur5@ualberta.ca
  • Ontario
    • Toronto, Ontario, Canada, M5G 2C4
      • Recruiting
      • University Health Network
      • Contact: Suzanne Cohen; Phone Number: 1-866-673-2524; Email: RECLAIM@uhn.ca
  • Quebec
    • Sherbrooke, Quebec, Canada
      • Not yet recruiting
      • Centre Hospitalier Universitaire de Sherbrooke
      • Contact: Christine Coordinator; Email: christine.rioux-perreault.ciussse-chus@ssss.gouv.qc.ca

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age ≥18 years;
2. Positive COVID-19 test by nasopharyngeal swab RT-PCR (reverse transcription polymerase chain reaction) test, antibody or antigen tests at least 3 months prior to randomization; OR Presumed COVID-19 assessed by the site investigator (no positive COVID-19 test) with acute illness after October 15, 2019.
3. Patients should be treated with standard of care therapies (as discussed in the study manual) for at least 4 weeks prior to entry into trial.
4. Lingering COVID-19 symptoms beyond 3 months from onset of acute COVID and symptoms have lasted at least 2 months. The onset of COVID is considered the earliest of two dates: the date of positive test or the date of first symptoms;
5. Lingering symptoms from COVID-19 present at the time of randomization. "Lingering symptoms of Long COVID" must include self-reported cognitive dysfunction symptoms.
6. Female patients of childbearing potential (as assessed by the overseeing Investigator) who are sexually active must agree to practice true abstinence or use effective methods of contraception while on study treatment. Effective methods of contraception must be discussed and approved by the overseeing Investigator.
7. Must be able to provide informed consent and both willing and able to comply with study requirements.
8. Oxygen saturation on room air ≥92% at screening measured by pulse oximeter.

Exclusion Criteria:

1. Patients who had mechanical ventilation or extracorporeal membrane oxygen (ECMO) for COVID-19;
2. Current end-organ failure, organ transplantation, or current hospitalization in acute care hospital;
3. Contraindications to all of the study interventions;
4. Co-enrolment in another interventional trial (co-enrolment in an observational study is permitted);
5. Currently pregnant or breastfeeding.
6. Known physician diagnosis of cognitive dysfunction prior to COVID infection
7. Use of an investigational drug/device or other interventions within 30 days of screening
8. Use of home oxygen (O2) at baseline
9. History of pulmonary hypertension
10. Interstitial pulmonary fibrosis
11. Moderate to severe chronic obstructive pulmonary disease (COPD)
12. History of narcolepsy
13. Presence of a condition or abnormality that in the opinion of the investigator would compromise the safety of the participant or the quality of the data.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 1; Use of Hi-OxSR for 30 minutes twice a day at low oxygen flow (0.5-3 liters per minute) for 2 weeks.	Device: Hi-OxSR device; The Hi-OxSR device consists of the Hi-Ox mask connected to a portable oxygen concentrator, with added tubing serving as a reservoir for rebreathed exhaled breath.
Experimental: Group 2; Use of Hi-OxSR for 30 minutes twice a day at low oxygen flow (0.5-3 liters per minute) for 4 weeks.	Device: Hi-OxSR device; The Hi-OxSR device consists of the Hi-Ox mask connected to a portable oxygen concentrator, with added tubing serving as a reservoir for rebreathed exhaled breath.
Active Comparator: Group 3; Use of Hi-Ox for 30 minutes twice a day at high oxygen flow (5 liters per minute) for 2 weeks.	Device: Hi-Ox device; The Hi-Ox mask is connected to a portable oxygen concentrator.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Simple reaction time (SRT) task from the TestMyBrain (TMB) Digital Neuropsychology Toolkit On-line survey tool	TestMyBrain was developed as a tool to collect large, population-based samples for understanding the relationship between cognition, emotion, social functioning, and health. This test will take about 5 minutes to complete and will assess reaction time.	Baseline/Start of intervention to two months
Verbal paired associates (VPA) task from the TestMyBrain (TMB) Digital Neuropsychology Toolkit On-line survey tool	TestMyBrain was developed as a tool to collect large, population-based samples for understanding the relationship between cognition, emotion, social functioning, and health. This test will take about 5 minutes to complete and will assess memory.	Baseline/Start of intervention to two months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood samples	Blood samples will be used in correlative studies using advanced multi-omic and machine learning methods to better understand our results so as to identify phenotypes that will benefit from specific therapies	Baseline/start of intervention and 2 months
All cognitive performance tasks (measured by the TESTMYBRAIN.org (TMB) neuropsychology toolkit	TestMyBrain was developed as a tool to collect large, population-based samples for understanding the relationship between cognition, emotion, social functioning, and health. This test battery will take about 20 minutes to complete and will assess: verbal, episodic and working memory, attention, processing speed, basic psychomotor response speed, and cognitive control.	Baseline/start of intervention to 2 weeks, 1, 2 and 6 months
Brain Fog Questionnaire	(Adapted from MSNQ) This is a self-administered 15-item questionnaire that assesses neurocognitive function. It takes approximately less than 5 minutes to complete	Baseline/start of intervention to 2 weeks, 1, 2 and 6 months
Brief Fatigue Inventory	The self-administered Brief Fatigue Inventory is composed of 9 items evaluated on a 10-point scale, assessing severity of fatigue and impact of fatigue on daily life. It takes approximately 2-3 minutes to complete.	Baseline/start of intervention to 2 weeks, 1, 2 and 6 months
Short Form (SF)-36	Mental health related quality of life, measured by the Mental Composite Score (MCS), and physical health-related quality of life, measured by the Physical Component Score (PCS) of the SF-36 (v.1)	Baseline/start of intervention to 2 weeks, 1, 2 and 6 months
Safety, adverse events and serious adverse events	Safety of the Hi-OxSR device will be reported through Adverse Events (AEs) and Serious Adverse Events (SAEs) throughout the study period.	Baseline/start of intervention to 6 months
Symptom Checklist	Symptom Checklist (adapted from the De Paul Symptom Questionnaire (DSQ2), the World Health Organization Global COVID-19 Clinical Platform's Post COVID-19 case report form (CRF) and the Symptom Burden Questionnaire for Long COVID): to track symptom trajectory.	Baseline/start of intervention to 2 and 6 months
The DePaul Symptom Post-Exertional Malaise Short Form DSQ-PEM	The self-administered DSQ-PEM is comprised of two sections assessing post-exertional malaise (PEM): (i) frequency and severity of PEM (5 questions), (ii) consequences, symptoms and recovery (5 questions).	Baseline/start of intervention to 2 weeks, 1, 2 and 6 months
Dyspnea	Assessed using the Borg Dyspnea scale. This short assessment tool assesses perceived shortness of breath on exertion using a 10 point scale as assessed by the patient.	Baseline/start of intervention to 2 and 6 months
Mental Health - General Anxiety Assessment Form (GAD-7)	The GAD-7 is a valid and efficient tool for screening for generalized anxiety disorder and assessing its severity in clinical practice and research. It is an easy-to-use, self-administered patient questionnaire that can be completed in minutes.	Baseline/start of intervention to 2 and 6 months
Mental Health - Patient Health Questionnaire (PHQ-9)	The PHQ-9 is a validated, multipurpose instrument for screening, diagnosing, monitoring and measuring the severity of depression. It incorporates Diagnostic and Statistical Manual IV (DSM-IV) depression diagnostic criteria with other leading major depressive symptoms into a brief self-report tool. The PHQ-9 is brief and useful in clinical practice.	Baseline/start of intervention to 2 and 6 months
Mental Health -Post-traumatic Stress Disorder Checklist (PCL-5)	The PCL-5 is a validated, reliable, 20-item self-report measure that assesses the 20 Diagnostic and Statistical Manual 5 (DSM-5) symptoms of Post-Traumatic Stress Disorder (PTSD). It takes approximately 5-10 minutes to complete.	Baseline/start of intervention to 2 and 6 months
Reintegration to Normal Living Index (RNLI)	This short self-administered assessment tool will determine the degree to which participants reintegrate into normal social activities such as recreation, mobility in the community and interaction in family and other relationships. This tool has been validated in community living adults with mobility limitations.	Baseline/start of intervention to 2 and 6 months
Fatigue Scale (adapted from the De Paul Symptom Questionnaire (DSQ2)	The Fatigue Scale was adapted from the De Paul Symptom Questionnaire (DSQ2)'s 38 questions assessing medical history of Myalgia encephalomyelitis/chronic fatigue syndrome (ME/CFS), comorbidities, medications, impact on quality of life and daily activities, etc.	Baseline/start of intervention to 2 weeks, 1, 2 and 6 months

Collaborators and Investigators

• Sponsor: University Health Network, Toronto
• Investigators: Principal Investigator: Angela m Cheung, MD, PhD, University Health Network, Toronto

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2025
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: April 11, 2025
• First Submitted That Met QC Criteria: April 11, 2025
• First Posted (Actual): April 15, 2025

Study Record Updates

• Last Update Posted (Estimated): September 15, 2025
• Last Update Submitted That Met QC Criteria: September 11, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Post-Infectious Disorders; COVID-19; Pathologic Processes; Chronic Disease; Disease Attributes; Respiratory Tract Infections; Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Lung Diseases; Pneumonia, Viral; Pneumonia; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; Pathological Conditions, Signs and Symptoms; Post-Acute COVID-19 Syndrome
• Other Study ID Numbers: 21-6203-HiOxSR

Drug and device information, study documents

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