This document defines and describes sleep apnea, its types (obstructive, central, mixed), risk factors, symptoms, complications, diagnosis via polysomnography (PSG), and treatment options including weight loss, CPAP, oral devices, surgery, and management of obesity hypoventilation syndrome. Sleep apnea is characterized by pauses in breathing during sleep caused by airway collapse and is associated with daytime sleepiness and cardiovascular issues. PSG is the gold standard test to evaluate sleep architecture and breathing disturbances. Treatment focuses on maintaining an open airway through lifestyle changes and devices.

1. SLEEP APNEA
Dr.Sushrut Ganpule
Dr. K.K. Dang

2. Definitions
• Apnea
It is defined by American Academy of Sleep
Medicine (AASM) as the airflow (measured by
the oronasal thermal sensor) reduction by
90% for >10s or for 90% of the duration of
the event.

3. • HYPOPNEA
Hypopnea is defined by a consensus
conference(Chicago Criteria) as including one
of three features:
A. Substantial reduction in airflow (>50%),
B. Moderate reduction in airflow (<50%) with
desaturation (>3%)
C.Moderate reduction in airflow (<50%) with
EEG evidence of arousal.

4. • AASM provide two definitions of hypopnoea
(A and B)
A. At least 30% reduction in airflow
accompanied by a fall in oxygen saturation of
4% or more. (Recommended)
B. At least 50%reduction in airflow accompanied
by an arousal or a fall in oxygen saturation of
3% or less.(Alternative)

5. • RERA ( Respiratory Effort Related Arousal)
It is defined as increasing respiratory effort for 10
seconds or longer leading to an arousal from sleep but
one that does not fulfill the criteria for a hypopnea or
apnea.
• AROUSAL RESPONSE
Arousal response has an important role in termination
of sleep, inducer of cough reflex, life saving
gestures, termination of apnea episode etc. BUT
associated with
1. Fragmentation of sleep
2. Sympathetic surge that is associated with various
cardiovascular events

6. • AHI (Apnea Hypopnea Index)
Apnea and Hypopnea episodes are measured by
an index known as Apnea Hypopnea Index (AHI)-
No. of Apnea or Hypopnea episodes per Hr of
sleep.
• Up to 5 AHI’s can occur during sleep in normal
individuals and is considered irrelevant.
• > 5 AHI are clinically relevant and they are sub
classified as mild (5-15) moderate
(15-30)and severe (>30).

7. SLEEP
Sleep predominantly occurs in two stages
1. REM
2. NREM
• Both have different effects on blood pressure
heart rate and respiration
• Adults usually spend 70-80% sleep in NREM
while children and aged usually spend 70% of
sleep in REM.Physiological effects of these
stages are as follows

8. STAGES OF SLEEP
• It is characterized by two stages which alternates during whole of
sleep
1. NREM ( Non Rapid Eye Movement ):-
• 90-120 mnts. (each cycle)
• 75% of total duration.
• It is further classified into 4 stages as I, II, III,IV. Stage IV is deepest
sleep ( slow wave sleep)
• In general NREM is characterized by reduction in sympathetic
outflow and increase in parasympathetic outflow. (↑ Vagal tone)
• Leads to ↓ B.P. , ↓H.R. , ↓C.O. ↓ Tidal ventilation and minute
ventilation. Control of ventilation is majorly by chemical means
(compared with values when person is awake)

9. Stages of sleep cont…
2. REM ( rapid eye movement sleep)
• 10-20 mnts duration. alternates with NREM
sleep .
• Makes 15-20% of total sleep duration
• It is characterized by loss of all sensory inputs
and motor outputs of brain but brain is
metabolically active, rapid rolling type eye
movements, dreaming, awakening, paralysis, c
onsolidation of memory, satisfaction of sleep.

10. Continued..
• Return of sympathetic tone causes ↑ in
H.R., B.P. and C.O. to the values similar to
wakefulness
• Phasic activity that occurs in bursts
• Causes both ↑ and ↓ in H.R. and predisposes
to MI and Asystole resp.
• Ventilation is reduced than NREM. v High
propensity of apnea,

11. SLEEP APNEA
• It is further classified as
1. OBSTRUCTIVE
2. CENTRAL
3. MIXED

12. Types contd..
• OBSTRUCTIVE
It is most common type, occurs because of collapse of
upper airways at intervals during sleep
• CENTRAL
It occurs because of problem in brain or its neural
pathways stimulating and controlling breathing without
any change in the physical status of the airways.
• MIXED
Absence of thoracoabdominal movements during
initial part of airflow cessation but appear gradualy as
the episode terminates.

14. Collapse of airways
Apnea (↑PCO2,↓PO2 )
Sympathetic surge
Awakening
Openning of airways
Termination of episode

15. Structural factors
Structural factors related to craniofacial bony
anatomy that predispose patients with OSA
to pharyngeal collapse during sleep include
the following:
• Innate anatomic variations
• Retrognathia and micrognathia
• Mandibular hypoplasia
• Inferior displacement of the hyoid

16. • Adenotonsillar hypertrophy, particularly in
children and young adults
• Pierre Robin syndrome
• Down syndrome
• Marfan syndrome
• Prader-Willi syndrome
• High, arched palate (particularly in women)
• Brachycephalic head form - Associated with an
increased AHI in whites but not in African
Americans.

17. Tonsillar hypertrophy

18. High arched palate

19. Micrognathia Retrognathia

20. Innate anatomical variations in OSA
• Presence of excessive soft tissue for given
craniofacial anatomy
• Large tongue
• Longer soft palate
• Less lateral dimensions
• Increased parapharyngeal pad of fats
• Sedative use
• Smoking

21. Nonstructural risk factors
Nonstructural risk factors for OSA include the
following:
• Obesity
• Central fat distribution
• Male sex
• Age
• Postmenopausal state
• Alcohol use

22. Nonstructural factors contd…
• Sedative use
• Smoking
• Habitual snoring with daytime somnolence
• Supine sleep position

23. Etiology contd..
Other conditions associated with the
development of OSA are as follows:
• Hypothyroidism
• Neurologic syndromes
• Stroke
• Acromegaly
• Environmental exposures

24. Clinical manifestation
Symptoms
Neuropsychological Cardio respiratory
(repeated arousals) (recurrent apnea)

25. Neuropsychological
usually day time symptoms
• Excessive daytime sleepiness- initially to passive
events , directly related to severity
• Fatigue
• Decreased energy
• Inability to concentrate
• Irritability
• Mental clouding
• Early morning headache

26. Cardio respiratory
Related to apneic events, occurs nocturnal
• Snoring- most common symptom, present for many
years, patient may be unaware, interrupted
periodically by silence.
• Awakening with choking, gasping or air hunger
• Nocturia
• Insomnia
• Unrefreshing sleep, mental clouding, early morning
headache
• PND
• Symptoms of HTN, Stroke, Acute anginal events

27. complications
Acute coronory events
Hypertension Congestive heart failure
MI
Malignant and non Pulmonary HTN
Angina
respnsive RVF
Metabolic syndrome Chronic hyprecapnia

28. Investigation and diagnosis
• Middle aged or elderly man or woman
(postmenopausal)
• Overweight, hypertensive
• Comes with C/O unrefreshing
sleep, snoring, choking and daytime
sleepiness
• It can be suspected in any of the primary
cardiovascular events previously mentioned

29. Physical examination
• Age
• Neck circumference
• BMI
• Visualization of pharynx to assess crowding
• Soft tissue dimensions and craniofacial
abnormalities
• Blood pressure

30. Evaluation of daytime sleepiness

31. PSG
• AASM guidelines for the indications and performance of
PSG include the following:
• Sleep stages are recorded via an EEG, electrooculogram,
and chin electromyogram (EMG).
• Heart rhythm is monitored with a single-lead ECG.
• Leg movements are recorded via an anterior tibialis EMG.
• Breathing is monitored, including airflow at the nose and
mouth (using both a thermal sensors and a nasal pressure
transducer), effort (using inductance plethysmography),
and oxygen saturation.
• The breathing pattern is analyzed for the presence of
apneas and hypopneas, determined according to
definitions standardized by the AASM.

32. • PSG can be done in home by portable PSG devices -
unattended, cheap. Sleep stage, sleep position, RERA
cant be measured and negative study cant exclude
OSA.
• In lab or attended PSG – gold slandered
1. Standard PSG- evaluation and severity of OSA on
night 1 pt again comes on next day for CPAP
monitoring.
2. Split night study-both can be done in single
night, cost effective ,user friendly , OSA evaluation
in 1st half and CPAP monitoring in 2nd half.

33. Treatment
• General measures
• Specific medical therapies
• Intraoral devices
• Surgical intervention

34. • General measures
1. Weight reduction
2. Maintenance of position during sleep
3. Avoidance of alcohol and sedatives
• No any pharmacological agent is
recommended

35. • Specific medical therapies include
1.Behavioral therapy
2.CPAP
• CPAP – acts as a airway pneumatic splint
• Maintains positive press throughout in all
stages of sleep
• Can be given by nasal mask, nasal inserts and
full face mask

36. Intraoral devices
• Used in patients intolerant to OSA
1. Tongue retaining devices
2. Palatal lifting devices
3. Mandibular advancements technique

38. UPPP

39. Obesity hypoventilation syndrome
• it is defined by morbid obesity(BMI>40Kg/M2 )
• chronic hypoventilation with hypercapnia even during wakefulness
(PACO2 >45mmHg )
• Sleep disordered breathing
It is different from OSA and defect lies at three levels
1. Excessive load on respiratory system-high upper airway
resistance, low FRC, altered resp. muscle movements ,and altered
resiratory mechanics
2. Reduced central resp. drive
3. Sleep disordered breathing
• As defect lies at different levels only CPAP does not suffice
• Weight reduction and nocturnal non invasive ventilation is the
treatment of choice