Continuous non-invasive measurement of tidal volume and minute ventilation using a smart nasal cannula

The Flow Regulated Nasal Delivery System (FRNDS) is a novel smart nasal cannula platform developed to enable noninvasive, continuous monitoring of tidal volume (VT) and detection of abnormal breathing events. Combined with peripheral capillary oxygen saturation (SpO₂) data modulation of oxygen flow can be accomplished. In a cohort of 57 adults, FRNDS-derived VT and minute ventilation were compared to reference measurements from respiratory inductance plethysmography (RIP) across a range of oxygen flow rates. While the cannula system tended to overestimate inspiratory and underestimate expiratory VT-especially at higher flow rates-these errors were substantially reduced by applying machine learning regression models trained on anatomical and physiological features, achieving strong agreement with RIP averaging a 53.5 mL error, 78.2 mL root-mean error, and is within ~ 11% of the actual value. The system also demonstrated robust performance in classifying clinically relevant breathing patterns, including apneic spells and mouth breathing, suggesting utility for real-time respiratory surveillance and sleep apnea detection. These results support FRNDS as a promising, adaptable solution for individualized respiratory monitoring in both clinical and home environments.