Relevance between the oro-nasal thermistor signal's derivative and the nasal pressure transducer signal in airflow monitoring

Signals of an oro-nasal thermistor (Th) and a nasal air pressure transducer (NP) are widely used as surrogates of airflow for diagnosing sleep-disordered breathing, while the relationships between Th and NP were less discussed. To demonstrate the time derivative of Th is linear correlated with NP, a total of 15,053 epochs (defined 30-s as 1 epoch) clinical data were studied. The correlation coefficients between the time derivative of Th and NP in each epoch were calculated and its mean value is 0.87. It indicated that the time derivative of Th has a linear positive correlation with NP.