Abstract
Obesity hypoventilation syndrome (OHS) is defined by the combination of obesity (body
mass index [BMI] ≥30 kg/m2), sleep-disordered breathing, and daytime hypercapnia (arterial carbon dioxide tension
[PaCO2] ≥45 mm Hg at sea level) during wakefulness occurring in the absence of an alternative
neuromuscular, mechanical, or metabolic explanation for hypoventilation. Patients
with OHS can be classified by phenotypes depending on whether or not they have obstructive
respiratory events: hypoventilation and no or not significant obstructive sleep apnea
(OSA) and hypoventilation and significant OSA; we also add a third phenotype, which
is the hospitalized patient with acute-on-chronic respiratory failure. We describe
the mid- and long-term outcomes with and without positive airway pressure (PAP) by
these three phenotypes.
Keywords
obesity hypoventilation syndrome - apnea - positive airway pressure - CPAP - non-invasive
ventilation