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ICSD-2 Classification

II. Sleep Related Breathing Disorders

• Primary Central Sleep Apnea

• Cheyne Stokes Breathing Pattern

• High Altitude Periodic Breathing

• Central Sleep Apnea Due to Medical Condition Not Cheyne Stokes

• Central Sleep Apnea Due to Drug or Substance

• Obstructive Sleep Apnea, Adult

• Sleep Related Nonobstructive Alveolar Hypoventilation, Idiopathic

• Sleep Related Hypoventilation/Hypoxemia Due to Pulmonary Parenchymal or Vascular Pathology

• Sleep Related Hypoventilation/Hypoxemia Due to Lower Airways Obstruction

• Sleep Related Hypoventilation/Hypoxemia Due to Neuromuscular and Chest Wall Disorders

• Other Sleep Related Breathing Disorders

Central Sleep Apneas

Primary Central Sleep Apnea
Cheyne Stokes Breathing Pattern
High Altitude Periodic Breathing
Central Sleep Apnea Due to Medical Condition Not Cheyne Stokes
Central Sleep Apnea Due to Drug or Substance

Primary Central Sleep Apnea (CSA)

• Diagnostic Criteria

– Patient reports at least one of the following

• EDS

• Frequent arousals and awakenings or insomnia

• Awakening SOB

– PSG shows 5 or more central apneas / hr of sleep

– Not better explained by another disorder

• Patients with CSA tend to have low normal PCO2 (<40mmHg) during wakefulness. They are felt to have a high ventilatory response to CO2 which leads to instability of ventilatory control. When the CO2 drops below the apnea threshold, a central apnea occurs.

• Insomnia leads to increased sleep-wake transitions and ventilatory control is unstable during this time.

• PSG reveals:

– fragmented sleep

– increased Stages 1+2

– decreased SWS

– mild hypoxemia following central apneas

– Decreased central apneas during REM sleep

– Cycle length < 45 sec

Cheyne Stokes Breathing Pattern

• Diagnostic Criteria

– PSG shows at least 10 central apneas and hypopneas /hr of sleep in which the hypopnea has a crescendo-decrescendo pattern of tidal volume accompanied by frequent arousals and derangement of sleep structure

– Symptoms are not required to make the diagnosis, but many patients report EDS, fragmented sleep, insomnia, awakening SOB

– Breathing disorder occurs in association with a serious illness such as CHF, stroke or renal failure

• Characteristically occurs during NREM sleep

• Seen in 25-40% of CHF (indicates high risk of cardiac transplantation or death), 10% of stroke

• Tend to occur in pts who chronically hyperventilate (probably due to vagal irritant receptors from pulmonary congestion) and have a PCO2 near the apnea threshold. The crescendo-decrescendo pattern comes from a prolonged lung-to-chemoreceptor circulatory delay (inversely proportional to cardiac output).

• Cycle length typically > 45 sec (vs < 45 sec in CSA)

• PSG similar to CSA except for different respiratory pattern

High Altitude Periodic Breathing

• Diagnostic Criteria

– Recent ascent to at least 4000 m

– PSG demonstrates recurrent central apneas primarily during NREM sleep at a frequency of > 5/hr. The cycle length should be 12-34 sec

• Normal adaptation to altitude

Central Sleep Apnea Due to Medical Condition Not Cheyne Stokes

• Central sleep apnea without a Cheyne Stokes pattern which is believed secondary to a medical disorder

• Brainstem lesions (vascular, neoplastic, degenerative, demyelinating, traumatic), cardiac or renal disease.

Central Sleep Apnea Due to Drug or Substance

• Diagnostic Criteria

– Taking long acting opiate for at least 2 months

– PSG with CAI >= 5/hr or periodic breathing (Cheyne Stokes)

• Respiratory depression from mu-receptor in medulla

• Most described with methadone but also reported with morphine and hydrocodone

Hallmarks of the Central Sleep Apneas:

	Event Index	Symptoms Required?	Cycle Length	Stage Predominence	Comments
Primary CSA	>=5/hr	Yes	< 45 s	NREM
Cheyne Stokes	>=10/hr	No	> 45 s	NREM	Crescendo-decrescendo CHF, renal failure, stroke
High Altitude Periodic Breathing	Not specified	No	12-34 s	NREM	>4000 m
CSA 2 Medical Condition Not CSR					Brainstem lesions > cardiac, renal disease
CSA 2 Drug or Substance	>=5/hr OR CSR >10/hr				Opiates

Obstructive Sleep Apnea, Adult

Diagnostic Criteria (Need A, B, & D or C & D)

at least 1 of the following

• Unintentional sleep episodes, EDS, un-refreshing sleep, fatigue, or insomnia

• Awakens with breath holding, gasping or choking

• Bed partner reports loud snoring, breathing interruptions, or both during sleep

PSG demonstrates:

• Five or more scoreable respiratory events (apneas, hypopneas, or RERAs)

• Evidence of respiratory effort during all or a portion of the respiratory event

PSG demonstrates:

• 15 or more scoreable respiratory events (apneas, hypopneas, or RERAs)

• Evidence of respiratory effort during all or a portion of the respiratory event

Sleep disorder is not better explained by another disorder

Simplified Diagnostic Criteria for OSA:

• RDI >= 5/hr + symptoms

• RDI >= 15/hr +/- symptoms

• RDI = (apneas + hypopneas + RERAs) / hr

• Recommend not categorizing patients with UARS separately from OSA since the pathophysiology is the same!

Sleep hypoventilation syndromes

• Includes:

– Sleep Related Non-obstructive Alveolar Hypoventilation, Idiopathic

– Sleep Related Hypoventilation/Hypoxemia Due to Pulmonary Parenchymal or Vascular Pathology

– Sleep Related Hypoventilation/Hypoxemia Due to Lower Airways Obstruction

– Sleep Related Hypoventilation/Hypoxemia Due to Neuromuscular and Chest Wall Disorders

• All (except idiopathic) are characterized by prolonged periods of hypoxemia (and increase in PCO2 if measured) without an apparent change in breathing

• All can lead to pulmonary HTN, cardiac arrhythmias

Sleep Related Nonobstructive Alveolar Hypoventilation, Idiopathic

• Diagnostic Criteria

– PSG demonstrates shallow breathing for longer than 10 seconds with associated oxygen desaturation, frequent arousals or brady-tachycardia

– No primary lung diseases, skeletal abnormalities or neuromuscular disorder

– Elevated PCO2 at night but may eventually persist into the day

• Is distinguished from CSA/OSA by sustained hypoxemia instead of brief and cyclical (often last several minutes)

Sleep Related Hypoventilation/Hypoxemia

• Diagnostic Criteria for all 3 disorders include:

– At least one of the following:

• SPO2 < 90% for more than 5 minutes and a nadir of at least 85%

• SPO2 < 90% for at least 30% TST

• Sleeping ABG with PCO2 abnormally high or disproportionately increased relative to wakefulness

• “… Due to Pulmonary Parenchymal or Vascular Pathology”

– Presence of lung parenchymal or pulmonary vascular disease

• “… Due to Lower Airways Obstruction”

– Lower airways obstruction with FEV1/FVC ratio < 70

– COPD, bronchiectasis

• “… Due to Neuromuscular and Chest Wall Disorders”

– Presence of neuromuscular or chest wall disease

– Includes Obesity Hypoventilation Syndrome

Reference:

The International Classification of Sleep Disorders, Second Edition. The American Academy of Sleep Medicine Press, 2005. Can be purchased at the AASM store online!