Diagnosis of Sleep-disordered Breathing
The American Academy of Sleep Medicine (AASM) strongly recommends using
objective testing to diagnose the entire spectrum sleep-disordered
breathing and not relying solely on screening questionnaires, tools and
prediction algorithms.29
Using oximetry alone is not valid for diagnosing sleep-disordered
breathing as it will not diagnose hypercapnia and can underestimate the
severity of sleep-disordered breathing.33 Actigraphy,
which measures sleep parameters and the average motor activity over a
period of days to weeks using a noninvasive accelerometer, shows
evidence of poor and fragmented sleep in CF but does not allow for the
diagnosis of nocturnal hypoxia, OSA, or nocturnal
hypoventilation34. Home sleep apnea tests are not
recommended in the CF population because they are limited to assessing
the sleep-wake pattern but do not reveal other sleep disturbances.
The gold standard diagnostic test for sleep-disordered breathing in the
CF population is an overnight, attended, in-laboratory polysomnography
(PSG).33 A PSG is a noninvasive diagnostic test that
monitors EEG to determine sleep staging, oronasal airflow and
abdominal/chest wall movement to determine the presence of sleep
disordered breathing, end-tidal or transcutaneous carbon dioxide
(CO2) monitoring to determine the presence of
hypoventilation, in addition to several limb leads to evaluate for
periodic limb movements (PLMs).30 In addition, there
is video monitoring to evaluate for sleep movement
disorders.30
The AASM recommends that PSG be used in patients with underlying
cardiopulmonary disease, respiratory muscle weakness, hypoventilation,
and/or chronic opioid use to diagnose sleep-disordered
breathing.29 PSG will allow for the diagnosis of
nocturnal hypoxia, obstructive sleep apnea, and nocturnal
hypoventilation. Therefore, CF patients will benefit the most from PSG
when sleep-disordered breathing is suspected.