Development and Validation of a Digital Oxygen Flowmeter for Precision Respiratory Rehabilitation

Introduction: For decades, hospitals have relied on traditional oxygen flowmeters to regulate oxygen delivery; however, these analogue devices frequently exhibit poor accuracy, with reported flow deviations ranging from 48% to 185% of nominal values, compromising safe and efficient oxygen therapy. The COVID-19 pandemic further highlighted the need for more accurate, automated, and resource-efficient oxygen delivery systems capable of supporting modern precision-medicine approaches. Materials and Methods: This study aimed to develop and evaluate a digital oxygen flowmeter based on thermal mass flow technology, designed for use within hospital oxygen networks and compliant with ISO 15002:2023 standards, with control software developed in accordance with IEC 62304:2006. A controlled laboratory measurement system analysis was performed comparing the digital flowmeter with conventional Thorpe-tube flowmeters. Both devices were tested under identical conditions using a calibrated flow analyzer (TSI Certifier™) across five clinically relevant flow settings (0.5, 1, 3, 5 and 10 L/min). In addition, the digital flowmeter underwent a performance evaluation using a vital signs simulator (Riegel 370A930) to assess its autonomous response capabilities. Accuracy, precision, repeatability, and compliance with predefined acceptance limits were analysed. Results: The digital flowmeter demonstrated markedly superior performance, achieving an accuracy of approximately 1% compared with 18% for conventional flowmeters. Measurement variability was minimal and independent of operator input. All digital flow measurements complied with predefined accuracy criteria, while a substantial proportion of analogue readings fell outside acceptable limits. Beyond direct control via the device interface, the digital flowmeter supported prescription-based operation and integration with a central system receiving multiple biosignals, including peripheral oxygen saturation, heart rate, and respiratory cycle, enabling automated and adaptive oxygen delivery. Conclusions: The developed digital flowmeter provides precise, automated and biosensor-integrated oxygen control, representing a key technological step toward precision respiratory rehabilitation, although further studies are needed to assess long-term clinical performance.