Somnoscreen plus rc

Polysomnography is performed with the SOMNOscreen™ plus RC (Somnomedics, Randersacker, Germany) using the following montage: one EEG channel (Fp2-A1, 512 Hz), two EOG channels (1 cm below and 1 cm lateral of the outer right canthus as well as 1 cm above and 1 cm lateral of the outer left outer canthus, 512 Hz), one EMG channel (Chin1-Chin2, 512 Hz), one ECG channel (modified lead II, 512 Hz), thoracic respiratory effort channel (inductance plethysmography belt, 32 Hz), finger photoplethysmography (non-dominant arm, 128 Hz), body position (stored every 30 s), movement (32 Hz), and ambient light (stored every 30 s). Relevant skin areas are prepared with Nuprep (Weaver & Co., Aurora, CO, USA) before electrode placement to reduce skin impedance. Although this montage does not comply with AASM standards [128 ], the use of a single channel EEG, two EOG channels, and one EMG channel has been shown to have good validity when assessing sleep stages [129 (link)].

Polygraphy (SOMNOscreen™ plus RC, SOMNOmedics, Randersacker, Germany) will be performed within 3 days after PCI and repeated at the 12-week follow-up visit in both treatment groups (Fig. 1). Polygraphy evaluation includes breathing parameters (such as pressure cannula, snoring, thoracic and abdominal respiratory effort measures), oxygen saturation, ECG (including estimates of systolic and diastolic blood pressure based on the pulse-transit time method using validation references), recording of body position and light detection as well as a patient marker.
All polygraphy data are analysed by a central scoring lab to ensure consistency and quality. Each centre will send three respiratory recordings to the central lab for checking and validation as part of quality control. Apnoeas and hypopnoeas will be scored according to American Academy of Sleep Medicine (AASM) 2012 criteria by one experienced sleep technician blinded to the clinical data [22 (link)]. SDB is defined as an apnoea-hypopnoea index (AHI) ≥ 15/h (based on total recording time) and is categorised as predominantly OSA (≥ 50% of apnoeas obstructive) or predominantly CSA (< 50% of apnoeas obstructive).