National Sleep Foundation

Chapter 3: Sleep-Related Breathing Disorders

Assessment and Diagnosis

SRHHS is diagnosed in a sleep disorders laboratory.

SRHS is diagnosed by documenting the presence of hypercapnia during sleep, defined as CO2 levels that exceed 55 mmHg for 10 or more minutes, or CO2 levels that rise to 10 mmHg or more above awake supine level to a value greater than 50 mmHg for 10 or more minutes during sleep.1


  1. Casey KR, Cantillo KO, and LK Brown, “Sleep-Related Hypoventilation/Hypoxemic Syndromes,” Chest 2007;131;1936-1948. DOI 10.1378/chest.06-2334.