gms | German Medical Science

Introduction: Respiratory Effort-Related Arousals (RERAs) are common phenomena during sleep in patients with sleep related breathing disorders. They destroy the physiological sleep architecture, consequently they are responsible for daytime sleepiness. Therefore it is of special interest to detect RERAs easily. It would be very helpful for the daily clinical work to be able to identify respiratory effort-related arousals without the need of oesophageal pressure measurements or without the detection of arousal activity in the electroencephalogram (EEG).

Nasal cannula/pressure transducer systems generate an indirect flow signal that allows the detection of reduced flow amplitude and changes in the flow shape.

The aim of this study was to evaluate the accuracy of using the shape and amplitude of a single flow channel (the microMESAM device, a linearized nasal cannula/pressure transducer) to detect RERAs.

Method: Twenty-five patients with a sleep apnea syndrome and/or excessive daytime sleepiness were included in this prospective study. All underwent a fully attended polysomnography (PSG) and a simultaneous measurement with the microMESAM system. The polysomnographies were analyzed with regard to apneas, hypopneas and RERAs. The microMESAM detection of apneas, hypopneas and RERAs was performed using an automatic algorithm.

Results: MicroMESAM and PSG generated hypopnea- and apnea-indices correlated highly (r=0.795 and r=0.974 respectively). The detection of RERAs showed an average correlation (r=0.58).

Conclusion: MicroMESAM can be used to detect RERAs reliably. The automatic detection of RERAs is statistically significant but needs to be further improved for the daily clinical work. An additional registration of an arousal indicator e.g. heart rate or pulse transit time may improve the detection of RERAs without measuring the cortical arousal activity in EEG or the registration of intrathoracic pressure which both are complex measurements.