Evaluation of the FreeO2 System for Oxygen Weaning After Acute Hypoxemic Respiratory Failure

Evaluation of the FreeO2 System for Oxygen Weaning After Acute Hypoxemic Respiratory Failure

Acute hypoxemic respiratory failure (AHRF) is a common condition associated with substantial morbidity, mortality, and healthcare resource utilization. Although advances in oxygen therapy, particularly high-flow nasal oxygen (HFNO), have improved the management of AHRF, the transition from HFNO to conventional low-flow oxygen therapy remains an important and understudied phase of patient care.

During oxygen weaning, oxygen flow is usually adjusted manually by healthcare professionals according to a target oxygen saturation (SpO₂). Because oxygen saturation is often assessed intermittently outside continuously monitored settings, patients may experience episodes of hypoxemia or hyperoxia before oxygen flow is adjusted.

FreeO2 is an automated oxygen titration system that continuously adjusts oxygen flow according to the patient's SpO₂. Its safety and effectiveness have been demonstrated in several clinical settings, but its use during oxygen weaning after HFNO has not been specifically evaluated.

The objective of this study is to assess whether the use of the FreeO2 system during oxygen weaning after HFNO in patients recovering from acute hypoxemic respiratory failure improves oxygen saturation control and facilitates the weaning process compared with standard oxygen therapy.

Inclusion Criteria:

• Age ≥18 years
• Acute hypoxemic respiratory failure requiring high-flow nasal oxygen therapy for at least 12 hours
• Fraction of inspired oxygen (FiO₂) ≤35%
• Peripheral oxygen saturation (SpO₂) ≥ the predefined lower target threshold:
• 88% in patients at risk of hypercapnia
• 94% in patients without risk of hypercapnia
• Women of childbearing potential must use an effective contraceptive method (oral contraceptives, injectable contraceptives, intrauterine device, double-barrier method, contraceptive patch); women must be postmenopausal for at least 24 months or surgically sterilized
• Patient's oral agreement and absence of written refusal to participate, indicating that the participant has understood the study objectives and required procedures and agrees to participate and comply with study-related requirements and restrictions
• Affiliation with or beneficiary of the French social security system

Exclusion Criteria:

• Age <18 years
• Uncontrolled acute respiratory acidosis requiring invasive or non-invasive mechanical ventilation
• Unstable peripheral oxygen saturation (SpO₂)
• Excessive bronchial secretions
• Carbon monoxide poisoning
• Severe cardiocirculatory failure (mean arterial pressure <65 mmHg without fluid resuscitation and/or requiring vasopressors, and/or severe arrhythmia)
• Acute neurological failure (Glasgow Coma Scale <15, or new-onset sensorimotor deficit)
• Acute kidney injury requiring renal replacement therapy
• Known untreated severe obstructive sleep apnea