Respiratory rate measurement by pressure variation in the high flow nasal cannula-system in healthy volunteers

• Published in: Journal of clinical monitoring and computing 2024-12, Vol.38 (6), p.1397-1404
• Main Authors: Miechels, Jeffrey, Koning, Mark V.
• Format: Article
• Language: English
• Subjects: Adult; Anesthesiology; Apnea - diagnosis; Apnea - physiopathology; Cannula; Critical Care Medicine; Equipment Design; Female; Health Sciences; Healthy Volunteers; Humans; Intensive; Male; Medicine; Medicine & Public Health; Middle Aged; Monitoring; Monitoring, Physiologic - instrumentation; Monitoring, Physiologic - methods; Mouth; Original Research; Position measurement; Pressure; Reproducibility of Results; Respiration; Respiratory Rate; Spirometry - instrumentation; Spirometry - methods; Statistics for Life Sciences; Young Adult
• ISSN: 1387-1307; 1573-2614; 1573-2614
• DOI: 10.1007/s10877-024-01185-8

Purpose This study tests if the pressure variation in the HFNC-system may allow for monitoring of respiratory rate and the pressure difference during breathing may be a marker of respiratory effort. Methods A HFNC system (Fisher & Paykel Optiflow Thrive 950) was modified by adding a GE Healthcare D-Lite spirometry sensor attached to a respiratory module and a pressure transducer. Participants were instructed to breathe regularly, quickly and slowly during 4 different conditions (HFNC flow 30 l/min and 70 l/min and with an open and closed mouth). Respiratory rate was counted based on pressure variation shown on the monitor graphs and compared with the count by observation of the participant. The pressure difference between inspiration and expiration was tested for correlation with the respiratory rate, as a surrogate marker for respiratory effort. Results Twenty five participants were included in this study. False detection of apnea in pressure-based measurements occurred in 10% and 11% of the measurements with open mouth position at 30 l/min and 70 l/min HFNC-flow, respectively, but not with a closed mouth. The 95% Limits of Agreement were − 1.85;1.91, -13.72;9,88, -2.25;2.47, -30.32;19.93 for the conditions of 30 l/min -closed mouth, 30 l/min – open mouth, 70 l/min – closed mouth and 70 l/min – open mouth, respectively. There was a correlation between pressure difference and respiratory effort, except for the condition of 30 l/min with open mouth. Conclusions The pressure variation in the HFNC system allows for respiratory rate and effort monitoring, but requires further development to increase precision. Trial Registration ClinicalTrials.gov (NCT05991843).