Patient ventilator asynchrony and sleep disruption during non-invasive ventilation

Sleep disordered breathing is common in patients with chronic respiratory failure. Respiratory failure results from an imbalance between the loads placed upon the respiratory system and its capacity to compensate for that load. To balance the load on the respiratory system in patients with respiratory disease, neural respiratory drive is elevated to activate and recruit muscle to increase the operational capacity from the respiratory muscle pump. Overnight, the natural fall in neural respiratory drive during sleep, particularly in rapid eye movement (REM) sleep exacerbates the respiratory muscle load-capacity imbalance. This occurs in combination with muscle hypotonia of the upper airway musculature and a blunted hypercapnic ventilatory response predisposing to alveolar hypoventilation and respiratory failure (1,2). Sleep disordered breathing frequently develops as an early sign of underlying respiratory failure leading to sleep fragmentation as the patient awakes to augment neural respiratory drive and daytime somnolence (3,4)