The hypoxic ventilatory response and arousal burden predict the magnitude of ventilatory long‐term facilitation in humans with obstructive sleep apnoea

The magnitude of progressive augmentation (PA) and ventilatory long-term facilitation (vLTF) are two forms of respiratory plasticity that are enhanced in some humans with obstructive sleep apnoea (OSA). This response might be linked to repeated nocturnal exposure to intermittent hypoxia or other traits connected to OSA. A meta-analysis was completed using data from 91 OSA participants who completed one of two mild intermittent hypoxia protocols during wakefulness. Two iterations of a subset regression analysis were completed to identify the best model that predicted the magnitude of PA or vLTF. Novel (e.g., arousal and hypoxic burden) or standard indicators of sleep apnoea (e.g., apnoea/hypopnoea index), anthropometric variables, protocol elements and physiological variables measured during wake and sleep were included as independent variables. After model selection, a multiple linear regression analysis was used to identify the most impactful variables in the model. The hypoxic ventilatory response (HVR) alone (R = 0.589, P < 0.001) or in combination with the arousal index (R = 0.625, P < 0.015 for both variables) predicted the magnitude of PA, whilst the HVR in combination with the arousal burden (R = 0.602, P < 0.001) or arousal index (R = 0.593, P < 0.002 for all variables) predicted the magnitude of vLTF. The HVR and markers of arousal are strong predictors of the magnitude of PA and vLTF. In contrast, markers of apnoea severity, including the hypoxic burden, did not add to the ability to predict the magnitude of PA or vLTF.