Sleep-related hypoventilation is a sleep disorder related to progressive respiratory impairment. When this disorder occurs comorbidly with other disorders (e.g., COPD, neuromuscular disorders, obesity), disease severity reflects the severity of the underlying condition, and the disorder progresses as the condition worsens.
Polysomnography demonstrates episodes of decreased respiration associated with elevated CO2 levels.
The disturbance is not better explained by another current sleep disorder.
Specify if:
Severity is graded according to the degree of hypoxemia and hypercarbia present during sleep and evidence of end organ impairment due to these abnormalities (e.g., right sided heart failure). The presence of blood gas abnormalities during wakefulness is an indicator of greater severity.
Congenital central alveolar hypoventilation usually manifests at birth with shallow, erratic, or absent breathing. This disorder can also manifest during infancy, childhood, and adulthood because of variable penetrance of the PHOX2B mutation.
Pulmonary hypertension, cor pulmonale, cardiac dysrhythmias, polycythemia, neurocognitive dysfunction, and worsening respiratory failure can be the cause of sleep-related hypoventilation. The disorder severity corresponds with increasing severity of blood gas abnormalities.
Sleep-related hypoventilation is diagnosed using polysomnography showing sleep-related hypoxemia and hypercapnia that is not better explained by another breathing-related sleep disorder.
The documentation of increased arterial pC02 levels to greater than 55 mmHg during sleep or a 10 mmHg or greater increase in pC02 levels (to a level that also exceeds 50 mmHg) during sleep in comparison to awake supine values, for 10 minutes or longer, is the gold standard for diagnosis. However, obtaining arterial blood gas determinations during sleep is impractical, and non-invasive measures of pC02 have not been adequately validated during sleep and are not widely used during polysomnography in adults.
Prolonged and sustained decreases in oxygen saturation (oxygen saturation of less than 90% for more than 5 minutes with a nadir of at least 85%, or oxygen saturation of less than 90% for at least 30% of sleep time) in the absence of evidence of upper airway obstruction are often used as an indication of sleep-related hypoventilation; however, this finding is not specific, as there are other potential causes of hypoxemia, such as that due to lung disease.