This study is looking at two different treatments for obstructive sleep apnea (OSA) in children. OSA is a sleep condition where breathing repeatedly stops and starts during sleep, which can affect a child's health, behavior, learning, and quality of life.

Children with moderate-to-severe OSA who cannot be treated with surgery are often prescribed Continuous Positive Airway Pressure (CPAP). CPAP uses a mask worn during sleep to deliver pressurized air and keep the airway open. Although CPAP is effective, many children have difficulty using it regularly because it can feel uncomfortable or hard to tolerate.

This study compares CPAP with another treatment called High-Flow Nasal Cannula (HFNC). HFNC delivers warm, humidified air through soft nasal prongs and may be more comfortable and easier for children to use while still helping keep the airway open during sleep.

Children aged 2 to 18 years with moderate-to-severe OSA will be randomly assigned to use either CPAP or HFNC at home during sleep for 3 months. The study will measure how much each treatment is used, how well it improves sleep-related symptoms and quality of life, how comfortable it is for children, and how it affects caregivers.

The goal of this study is to find out whether HFNC is a comfortable and effective alternative to CPAP for treating obstructive sleep apnea in children.

Obstructive sleep apnea (OSA) is a common pediatric condition characterized by repeated episodes of upper airway obstruction during sleep. These episodes disrupt normal sleep patterns and oxygenation and are associated with significant short- and long-term health consequences. In children, untreated moderate-to-severe OSA has been linked to impaired quality of life, behavioral and emotional difficulties, impaired learning and school performance, cardiovascular and metabolic effects, and increased caregiver stress and health care utilization.

For many children, adenotonsillectomy is the first-line treatment; however, a substantial proportion continue to experience residual OSA after surgery or are not suitable surgical candidates. In these cases, Continuous Positive Airway Pressure (CPAP) therapy is the standard treatment. CPAP delivers pressurized air through a mask worn during sleep to keep the airway open. While CPAP is effective under optimal conditions, real-world effectiveness in pediatric populations is limited by low tolerance and adherence. Common challenges include discomfort related to the mask interface, claustrophobia, air pressure intolerance, and family burden associated with nightly device use.

High-Flow Nasal Cannula (HFNC) therapy has emerged as a potential alternative for treating pediatric OSA. HFNC delivers warmed, humidified air at high flow rates through soft nasal prongs and can generate positive airway pressure that supports upper airway patency. Compared with CPAP, HFNC may be perceived as less intrusive and more comfortable, which could improve adherence and overall treatment effectiveness. Preliminary physiologic studies and small clinical trials suggest that HFNC can reduce OSA severity; however, there is limited evidence comparing HFNC and CPAP in children, particularly over extended periods of use in home settings.

The CHOSA Trial was designed to address this evidence gap by directly comparing CPAP and HFNC in children with moderate-to-severe OSA who require non-surgical therapy. The study evaluates the real-world use of these therapies in the home environment, with a focus on treatment adherence as well as patient- and family-centered outcomes. By embedding the intervention within routine clinical care across multiple centers, the study aims to reflect typical pediatric sleep medicine practice and enhance the generalizability of its findings.

Participants receive comprehensive education and support to promote safe and effective use of their assigned therapy. Device setup, fitting, and optimization are performed by trained respiratory therapists, and treatment is titrated using standard sleep study procedures to ensure appropriate therapeutic settings. During the home treatment period, participants and caregivers receive ongoing clinical support consistent with usual care, including troubleshooting for comfort and usability concerns.

The primary focus of the study is adherence to therapy, assessed using objective device data. Secondary aspects of the study evaluate the broader impact of treatment on sleep-related symptoms, quality of life, comfort, psychosocial functioning, caregiver burden, and health economic outcomes using validated instruments. These outcomes were selected to capture not only physiological effectiveness, but also the acceptability and practicality of each treatment from the perspective of children and families.

A qualitative component is incorporated to provide a deeper understanding of participant and caregiver experiences. Through semi-structured interviews, the study explores perceived benefits and challenges of CPAP and HFNC, factors influencing nightly use, strategies families employ to support adherence, and the impact of therapy on daily routines and well-being. This qualitative information complements quantitative findings and helps contextualize adherence and outcome data.

Both CPAP and HFNC are commonly used non-invasive respiratory therapies with established safety profiles in pediatric care. Safety monitoring is conducted throughout the study, and adverse events are documented in accordance with ethical and regulatory requirements. Participation is voluntary, and families may withdraw at any time without affecting the child's clinical care.

By comparing CPAP and HFNC in a large, diverse pediatric population using real-world home use conditions, the CHOSA Trial aims to inform clinical decision-making and guideline development. The results are expected to clarify whether HFNC offers a more acceptable or effective alternative for children who struggle with standard CPAP therapy and to support evidence-based expansion of treatment options for pediatric obstructive sleep apnea.

Inclusion Criteria:

• Aged 2 to 18 years
• Diagnosed with moderate to severe obstructive sleep apnea, defined as an obstructive apnea-hypopnea index (OAHI) ≥5 events/hour, confirmed by an in-laboratory polysomnography within the previous 6 months
• Deemed to require Continuous Positive Airway Pressure (CPAP) therapy as part of usual clinical care
• Ability of the participant and/or parent or legal guardian to provide informed consent (and assent when applicable)

Exclusion Criteria:

• Predominant or pathological central sleep apnea (central apnea-hypopnea index ≥5 events/hour)
• Chronic respiratory failure or medical conditions requiring ventilatory support with a set respiratory rate (e.g., neuromuscular disease requiring bilevel ventilation with a backup rate)
• Hypoventilation requiring non-invasive ventilation with a set respiratory rate
• History of pneumothorax or pneumomediastinum
• Uncontrolled gastroesophageal reflux and/or recurrent vomiting
• Uncontrolled oral secretions
• Prior use of CPAP or High-Flow Nasal Cannula therapy for treatment of obstructive sleep apnea within the previous 12 months

Individual participant data (IPD) that are de-identified will be shared upon reasonable request and subject to approval by the study investigators, applicable institutional policies, and data-sharing agreements. IPD sharing may be limited or delayed to protect participant privacy, respect consent provisions, and allow for completion of planned primary and secondary analyses. Data will only be shared for scientifically sound research proposals and in accordance with ethical, legal, and regulatory requirements.

Participants, caregivers, and care providers are not masked due to the visible and distinct nature of the assigned devices (CPAP vs High-Flow Nasal Cannula). Outcome assessment of the primary endpoint (therapy adherence) is conducted using objective device-generated data, and investigators are blinded to adherence results during the intervention period. No additional parties are masked.