Sleep Academic Award

1

sleep apnea

syndrome

Based on Introduction to

Polysomnography by S. Harding
and L. Shigley

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Polysomnography

• EOG - Electrooculogram
• EEG - Electroencephalogram
• EMG - Electromyogram
• EKG - Electrocardiogram
• Tracheal noise
• Nasal and oral airflow
• Thoracic and abdominal respiratory

effort

• Pulse oximetry

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Left EOG

Right EOG

Central
EEG

Occipital
EEG
Chin EMG

LEAD II
ECG
Left and
Right
Leg EMG

Tracheal
Noise
SAO2

Nasal and
oral Airflow

Thoracic
Respiratory
Effort

Left and Right

Electrooculogram

Left and Right

Electrooculogram

LOC

LOC

ROC

ROC

Eye
Blinks

Eye
Blinks

Electrooculography picks up

the inherent voltage of the

eye. The cornea has a

positive voltage output,

while the retina has a

negative polarity.

Electrooculography picks up

the inherent voltage of the

eye. The cornea has a

positive voltage output,

while the retina has a

negative polarity.

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Sleep Academic Award

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C3

O1

Electroencephalogra
phy in the

Overnight Sleep

Study

G1

G2

Paper or computer screen

A2

Differential

Amplifier

C3-A2

O1-A2

G1

G1

G2

G2

Relaxed Jaw

Relaxed Jaw

Differential

Amplifier

G1

G1

G2

G2

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Open mouth or

Clenched Teeth

Open mouth or

Clenched Teeth

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Differential Amplifier

G1

G1

G2

G2

• Combination of

two dissimilar
metals

• Voltage changes

are seen with
exhalation and
inhalation

Thermocouple

Differential

Amplifier

Differential

Amplifier

Differential

Amplifier

Tracheal
Sound

Piezo Respiratory Effort

Anterior Tibialis
EMG

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Sleep Academic Award

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Scoring Respiratory

Events

Basic Course

Obstructive Apnea

Central Apnea

Mixed Apnea

Hypopneas

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Common Rules

• All respiratory events need to be at

least 10 seconds long

• All events need to have at least a

3% SaO

2

desaturation

• EEG arousals will occur with most

respiratory events

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Obstructive Apnea

• No airflow for > 10 seconds

• Increasing respiratory effort.

Usually seen as paradoxical.

• SaO

2

desaturation <3% (may be

adjusted)

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Obstructive Apnea A complete blockage of the airway

despite efforts to breath. Notice the effort gradually

increasing ending in airway opening.

Blood oxygen levels
reduce to < 3% of
basline value

Inhal
e

Exhal
e

Airway obstructs

Airway
opens

Paradoxi

ng

Paradoxing

Ends

EKG

Airflow

Thoraci
c effort

Abd.
effort

SAO2

Effort gradually
increases

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• Hypopneas may be scored as

apnea when the SaO

2

<10% of

baseline level

• Same physiological consequence

as apnea

When Hypopneas are
Apnea

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Hypopnea This is an 18 second hypopneic event. The
airflow signal is reduced by approximately 50% during
this event.

Airflow reduction

SAO2 desaturation

> effort with paradox

Paradox ends

Inhale

Exhale

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Mixed Apnea

• A complete absence of nasal and

oral airflow

• A total absence of respiratory

effort at the beginning of the
event, followed by a gradual
increase in effort which
eventually breaks the apnea

• An oxygen desaturation of >3%

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Mixed Apnea

• May have a short central

component or a large one

• As with all events, mixed apneas

may be longer in REM

• May be created by

hyperventilation following an
obstructive apnea

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Mixed Apnea

EKG

Airflow

Thoracic Effort

Abdominal Effort

SAO2

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Central Apnea

• Absence of airflow at the nose and

mouth for > 10 seconds

• A complete absence of respiratory

effort as measured by:

– Thoracic Expansion

– Abdominal Expansion

– Intercostal / Diaphragmatic EMG

• SaO

2

drop of > 3%

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Central Apnea These are central apneas (2) with

minimal oxygen desaturation. Notice the low SAO2 at

the beginning of this tracing. This is associated with a

previous apnea.
Both of these events range between 13-16 seconds in
duration.

Airflo
w

Airflo
w

Thor.
Effor
t

Thor.
Effor
t

Abd.
Effor
t

Abd.
Effor
t

SAO

2

SAO

2

ECG

ECG

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Sleep Academic Award

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OSA Treatment

• Obesity:

– Diet & behavior modification
– Bariatric surgery

• Positional Therapy:

– Raise the HOB
– Alarm
– Tee shirt (ball)

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OSA Treatment

• Increase muscle tone:

– Medications
– Electrical stimulation of the

genioglossus

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OSA Treatment

• Mechanically stent the upper airway:

– Nasal CPAP, BiPAP, Auto CPAP
– Oral devices

• Alter the upper airway:

– Soft tissue surgery
– Skeletal surgery

• Bypass the upper airway:

– Tracheostomy

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Positional Therapy: Raise HOB

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OSA Treatment

• Nasal CPAP is the treatment of choice
• Results in successful treatment in 95%
• Not as costly as surgery
• Long term compliance rates of 60-70%
• Improved long term survival (vs. UPPP)
• Can re-titrate the pressure if the

patient’s clinical condition changes

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Consequences of OSA

• Hypertension
• Heart infarction
• Stroke
• Heart arrhythmias
• Increased risk of traffic accidents

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Factors enhancing OSA

• Alcohol
• Drugs (morphine)
• Sedatives