Figure 1.

Recommendations for sleep studies in patients with LOPD. Isolated nocturnal tachypnea or lone increase of base excess on early-morning blood gas analysis may both be indicative of nocturnal hypoventilation but do not justify ventilatory support. However, both scenarios should give rise to monitor patients in shorter intervals. ^a sleep disruption, morning headache, daytime hypersomnolence; ^b dyspnea, orthopnea; ^c VC < 50% predicted, VC postural drop > 40%, MIP < 60 cm H₂O, SNIP < 40 cm H₂O. VC, vital capacity; RMW, respiratory muscle weakness; paCO₂, carbon dioxide tension; paO₂, oxygen tension; AHI, apnea hypopnea index; SpO₂, oxygen saturation; tcCO₂, transcutaneous carbon dioxide tension; CPAP, continuous positive airway pressure; OSA, obstructive sleep apnea; PSG, polysomnography; SNIP, sniff nasal inspiratory pressure; MIP maximum inspiratory pressure.