Sleep related disorders

1. Sleep related disorders
Amr Abdullah Elsyed
Lecturer of critical care
Alexandria university of medicine

2. Sleep Disordered Breathing refers to an
abnormal respiratory pattern (i.e., apneas,
hypopneas, or respiratory effort related
arousals) or abnormal reductions in gas
exchange (i.e., hypoventilation).
Hypoxemia can also occur, which is
unrelated to either respiratory pattern
abnormalities or alveolar hypoventilation.
Daytime symptoms and signs of disturbed
sleep may result, with or without organ
system dysfunction.

3. EVENTS — Several types of breathing abnormalities may
be detected during sleep, including apnea, hypopnea,
respiratory effort related arousals, and hypoventilation.
Apnea — Apnea is the cessation, or near cessation, of
airflow. It exists when airflow is less than 20 percent of
baseline for at least ten seconds in adults.
Types:
Obstructive apnea
Central apnea
mixed

4. Hypopnea —
Hypopnea is an abnormal reduction of
airflow to a degree that is insufficient to
meet the criteria for an apnea.
Although criteria for a hypopnea vary
among sleep laboratories, a common
definition is 30 percent reduction of
thoracoabdominal breathing movements
or airflow lasting at least ten seconds, with
4 percent oxyhemoglobin desaturation

5. Respiratory effort related
arousals
Respiratory effort related arousals (RERAs) are
episodes during which inspiratory airflow or tidal
volume is maintained at the expense of
increased respiratory effort, suggesting
increased upper airway resistance.
Patients with RERAs tend to have frequent
microarousals, defined as
electroencephalographic activation lasting three
seconds or less.
As a consequence, patients tend to have daytime
sleepiness, fatigue, or inattention despite the
absence of apneas or hypopneas.

6. Hypoventilation
Hypoventilation during sleep is defined as
an increase in the arterial carbon dioxide
(pCO2) of at least 10 mm Hg during sleep,
compared with an awake supine value.

7. Apnea-Hypopnea Index
The Apnea–Hypopnea Index (AHI) is the total
number of apneas and hypopneas per hour of
sleep.
The AHI is most commonly calculated per hour of
total sleep.
However, an AHI is occasionally calculated per
hour of non-REM sleep, per hour of REM sleep,
or per hour of sleep in a certain position to
provide insight into the sleep stage dependency
or sleep position dependency of the Sleep
Disordered Breathing.

8. Respiratory Disturbance Index
The Respiratory Disturbance Index (RDI) is
the total number of events (e.g., apneas,
hypopneas, and RERAs) per hour of
sleep.
The RDI is generally larger than the AHI,
because the RDI considers the frequency
of RERA, while the AHI does not.

9. Desaturation
Oxygen desaturation is a frequent sequelae of
apnea and hypopnea.
Several measures are used to quantify the severity
of desaturation.
The desaturation index (DI) is the number of times
that the oxygen saturation falls by more than
three to four percent per hour of sleep.

10. Arousal Index
The Arousal Index (ArI) is the total number
of arousals per hour of sleep.
It is generally lower than the AHI or RDI
because approximately 20 percent of
apneas or hypopneas are not
accompanied by arousals.

11. Obstructive Sleep Apnea-
Hypopnea
Obstructive Sleep Apnea-Hypopnea (OSAH) is
defined as either:
More than 15 apneas, hypopneas, or RERAs per
hour of sleep in an asymptomatic patient, OR
More than five apneas, hypopneas, or RERAs per
hour of sleep in a patient with symptoms (e.g.,
sleepiness, fatigue and inattention) or signs of
disturbed sleep (e.g., snoring, restless sleep,
and respiratory pauses).

12. Central Sleep Apnea Syndrome
Central Sleep Apnea Syndrome (CSAS)
exists when symptoms or signs of
disturbed sleep are accompanied by more
than five central apneas plus hypopneas
per hour of sleep, and normocarbia during
wakefulness.

13. Cheyne-Stokes respiration
Cheyne-Stokes respiration refers to a cyclic
pattern of central apneas and crescendo-
decrescendo tidal volumes.
It is considered a type of CSA and is
commonly associated with heart failure or
stroke.

14. Hypoventilation syndromes
Patients with one of the hypoventilation
syndromes generally have mild
hypercarbia when awake, which worsens
during sleep.
Two hypoventilation syndromes, Congenital
Central Hypoventilation Syndrome (CCHS)
and Obesity Hypoventilation Syndrome
(OHS).

15. Clinical presentation and diagnosis
Daytime sleepiness
Nonrestorative sleep Obesity
Large neck circumference
Systemic hypertension
Hypercapnia
Cardiovascular disease
Cerebrovascular disease
Cardiac dysrhythmias
Narrow or "crowded" airway
Pulmonary hypertension
Cor pulmonale
Polycythemia
Menstrual irregularities
Witnessed apneas by bed partner
Awakening with choking
Nocturnal restlessness
Insomnia with frequent awakenings

16. Polysomnography
Polysomnography (PSG) is considered the gold-standard
diagnostic test for OSAH.
It is typically performed in a laboratory as the patient
sleeps while connected to monitoring devices.
Physiologic variables measured during PSG include: Sleep
stages ,Respiratory effort ,Airflow, Arterial oxygen
saturation, Cardiac rate, and rhythm Body position
Limb movements.

17. Total sleep time, Sleep efficiency Sleep
stage percentage, latency, and distribution
Abnormal events (eg, arousals, apneas,
and hypopneas, flow limitation) Diagnostic
indices (eg, apnea-hypopnea index, leg
movement index) Snoring Oxygen
desaturation Body position Limb
movements Cardiac rhythm disturbances