Pulse wave amplitude reduction: A surrogate marker of micro-arousals associated with respiratory events occurring under non-invasive ventilation?

SummaryIntroductionRespiratory events occurring under non-invasive ventilation (NIV) may produce sleep fragmentation. Alternatives to polysomnography (PSG) should be validated for providing simple monitoring tools for patients treated at home with NIV.ObjectivesTo study the value of pulse wave amplitude (PWA) reduction as a surrogate marker of cortical micro-arousals associated with respiratory events occurring during NIV.Methods27 PSG tracings under NIV recorded in 9 stable patients with Obesity Hypoventilation Syndrome (OHS), under 3 different ventilator modes (no back-up rate, low or high back-up rate) were analyzed. For all respiratory events (obstructive, central, or mixed event), the association with EEG-micro-arousals, PWA reduction of more than 30% and the presence of associated SpO2 desaturation ≥4% was recorded.Results2474 respiratory events during NREM sleep were analyzed. 73.6% were associated with an EEG-MA, 91.4% with a ≥4% decrease in SpO2, and 74.9% with a significant PWA reduction. Sensitivity of PWA for the detection of an EEG-micro-arousal related to a respiratory event was 89.1% [95%CI: 76.7–95.3]. Positive predictive value (PPV) was 87.0% [95%CI: 75.0–94.0]. Sensitivity of PWA was highest in the S mode, compared to both other S/T modes, p = <0.001. Sensitivity of PWA was also higher for central and mixed events, compared to obstructive respiratory events, p =