Abstract
Introduction The current gold standard sensors to measure airflow in apnoea and hypopnoea detection are the oronasal thermal airflow sensor and the nasal pressure transducer, respectively.1 Due to the contact nature of these sensors in the nasal region, they are poorly tolerated by children. In a recent audit, we found that 50% of children refused the nasal pressure sensor due to its invasiveness, and of those that accepted it, 64% removed the prongs over the course of the night.
The aim of the current study was to evaluate a non-contact method to monitor respiration by developing infrared thermal imaging, whereby temperature fluctuations associated with respiration are measured and correlated with airflow.
Methods 11 healthy adult volunteers participated following University Ethics. Respiratory signals were recorded over four simulated apnoea scenarios resembling normal respiration; central; obstructive and hypopnoeic pauses. Simulated apnoeas were measured via nasal pressure cannula and respiratory inductance bands [SOMNOtouchTM RESP; SOMNOmedics, Germany] versus thermal imaging techniques.
Results 70% of the apnoea episodes correlated with airflow sensor readings (Example trace in figure 1). In 16% of recordings the subject’s head position did not allow correct identification of the region of interest (i.e. the nostrils). For the remaining 14% of cases there was partial agreement between the thermal measurements and nasal pressure readings.
Sample characteristics and the CSHQ scores
Discussion These results indicate thermal imaging may be valuable as a detection tool for sleep apnoea, particularly in the case of paediatric patients whose tolerance for contact nasal sensors is poor.
Reference
Berry RB, Albertario CL, Harding SM, et al. for the American Academy of Sleep Medicine. The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications. Version 2.5. Darien, IL: American Academy of Sleep Medicine, 2018.
