Few studies have specifically addressed the role of back-up respiratory rate (BURR) in noninvasive ventilation (NIV), and clinical practice is often empirical. There are potentially complex interactions between BURR settings and respiratory centers: absence of BURR may be associated with central respiratory events and can contribute to upper airway instability in patients prone to obstructive hypopnea or apnea. Conversely, use of a BURR can contribute to improved efficacy of NIV and arterial blood gases in obesity-hypoventilation and is strongly recommended in patients with neuromuscular disorders.