evaluation of osa

Evaluation of OSA

Dr Manohar, Resident ENTINHS ASVINI

• Introduction

• Aetiopathogenesis

• Clinical Presentation

• Classification

• Definitions:

• Apnea

• Hypoapnea

• Physiology of sleep:

• Non-REM Sleep: four stages

• Stage I (2-5%)

• Stage II (45-55%)

• Stage III (3-8%)

• Stage IV (10-15%)

• REM Sleep

• 20-25%

• Dreaming activity

• Muscular activity

Respiratory physiology during normal sleep

• Regulated by:

• 1. Chemical factors: O2, CO2, acidosis

• 2. Mechanical signals from lung, airway, and chest

receptors

• REM sleep: decreased sensory and motor function

->impairment of ventilatory responses->

hypoventilation

Respiratory physiology cont...

Hypoxic and hypercapnic ventilatory response during sleep

• During sleep voluntary control of respiration

is lost

• Ventilatory responses to both low O2 and high Co2

levels blunted -> marked hypoxemia seen during

REM sleep

Respiratory physiology cont...

Effects of sleep on respiration

Arousal responses to respiratory alterations during sleep

• Isocapnic hypoxia

• Hypercapnia

• Increased airway resistance: Inspiratory resistance

and occlusion strong precipitants of sleep arousals

Classification of Obstructive Sleep-RelatedBreathing Disorders

• 1. Snoring

• 2. Upper Airway Resistance Syndrome

• 3. Obstructive Sleep Apnea Syndrome

• Snoring:

• sound generated by the vibration of the pharyngeal

soft tissues.

• 40% of men and 20% of women

Classification cont...

Upper Airway Resistance Syndrome

• UARS is characterized by respiratory effort–related

arousals (RERAs).

• A RERA is defined as a sequence of breaths over at

least 10 seconds with increasing respiratory effort

that terminates with an arousal.


• Obstructive Sleep Apnea Syndrome

• Five or more respiratory events (apneas,

hypopneas,or RERAs) in association with excessive

daytime somnolence, waking with gasping, choking,

or breath-holding, or witnessed reports of apneas,

loud snoring, or both.


• EPIDEMIOLOGY and RISK FACTORS

• Obesity and Metabolic syndrome

• Neck size

• Adults and children with Down Syndrome

• Children with large tonsils and adenoids

• Endocrine disorders such as Acromegaly and

Hypothyroidism

• Smokers

Aetiopathogenesis

• Nose

• Nasal blockage might:

• Reduce nasal afferent reflexes that help to maintain

muscular tone of the upper airway

• Augment the tendency for mouth opening

• Reduce humidification, increase mucus viscosity, and

increase surface tension forces

• Increase upstream airway resistance, predisposing to

downstream airway collapse.

Aetiopathogenesis contd...

• Upper airway dilating muscles

• Activated by negative airway pressure

stimulating nasal and laryngeal receptors

• Recurrent hypoxia impaired dilating muscle activity


• Oval upper airway (fat deposition)-> impair upper

airway dilator muscle function

• Upper airway oedema-> chronic vascular over

perfusion, mechanical trauma (snoring)


• Pharyngeal soft tissues:

• Supine position

• MRI volumetric studies->tongue

size as a major predictor

• Sagittally oriented airways that were speculated to

result in unfavorable muscular mechanics for reopening

the airway


• Oral to palatal airspace is smaller, and the posterior

airspace behind both the tongue and palate is

narrower.

• Cross-sectional shape of the airway- elliptical

• Biomechanically weaker structure that is more easily

collapsed at less negative pressures.


• Body/jaw position/gravity

• Structural considerations

• Balance of forces


Consequences of OSAH syndrome


• Fujita classified ( Anatomical basis)

• Type I- collapse in the retropalatal region

• Type II- collapse in both retropalatal and retrolingual

regions

• Type III- collapse in the retrolingual region only

Starling resistor

Clinical Presentation:

• Snoring

• Fatigue

• Witnessed

breath-holds

• Gasping and choking

• ESS

• Fragmented sleep

• Reduced alertness

• Mood changes

• Nocturia

Clinical Presentation contd...

• BMI

• Neck circumference

• Complete head and neck examination

• Muller’s manoeuvre

Clinical Presentation contd...

Diagnosis

• Detailed history:

• Obtained in three settings

• First- routine health maintenance evaluation

• Second- evaluation of symptoms of OSA

• Third- comprehensive evaluation of patients of high

risk for OSA

• Overnight oximetry:

• Oxygen desaturation index

subject with ODI of 55, 4 percent oxygen dips per hour. This trace shows the whole night's data. Minimum oxygen saturation is approximately 45 percent

• Home multichannel testing:

• Advantages

• Disadvantages

Polysomnography

• Equipment

• Four types of sleep studies

• Level I:

• Standard PSG with a minimum of seven parameters

measured, including EEG, EOG, EMG, and EKG, as

well as monitors for airflow, respiratory effort, and

oxygen saturation.

• Level II:

• Comprehensive portable PSG studies are essentially

the same, except that a heart rate monitor can

replace the ECG

• Level III

• Modified portable sleep apnea testing is a

cardiorespiratory study in which a minimum of 4

parameters must be measured, including

ventilation , heart rate or EKG, and oxygen saturation

• Level IV:

• Continuous (single or dual) bioparameter recordings

where devices that measure a minimum of one

parameter, usually oxygen saturation are utilized

• EEG

• ECG

• EOM

• EMG

• Pulse oximetry

• Nasal and Oral airflow

Polysomnography contd...

• Sleep position

• Blood pressure

• Oesophageal pressure


• Polysomnography can also diagnose other sleep

disorders:

• Narcolepsy

• Periodic limb movements disorder (moving your legs

often during sleep)

• REM behavior disorder

Indices of Sleep-Disordered Breathing

• Apnea index- Number of apneas per hour of

total sleep time

• Hypopnea index- Number of hypopneas per hour of

total sleep time

• Apnea-hypopnea index Number of apneas and

hypopneas per hour of total sleep time

• Respiratory effort–related arousals (RERAs) index-

Number of RERAs per hour of total sleep time

• Respiratory disturbance index (RDI)-Number of

apneas, hypopneas, and RERAs per hour of total

sleep time

Indices of Sleep cont....

• Central apnea index- Number of central apneas per

hour of total sleep time

Indices of Sleep cont....

• Types

• Mild OSA: AHI of 5-15

• Involuntary sleepiness during activities that require little

attention, such as watching TV or reading

• Moderate OSA: AHI of 15-30

• Involuntary sleepiness during activities that require some

attention, such as meetings or presentations


• Severe OSA: AHI of more than 30

• Involuntary sleepiness during activities that require

more active attention, such as talking or driving


• Pulse transit time: interval between the R wave on an

electrocardiogram (ECG) and the arrival of the pulse

at the finger.

• Increased in increased respiratory effort and

decreased in the presence of tachycardia associated

with arousal.

Sleep nasendoscopy

• Rigid laryngobronchoscopy:

• Pathology distal to the glottis that may be

exacerbating the upper airway symptoms

Consequences of Untreated ObstructiveSleep Apnea

• He and colleagues- apnea index >20 increased

mortality

• Motor vehicle accidents by 2.5-fold

• Threefold increase in fatal and nonfatal

cardiovascular events

• Metabolic syndrome

• GERD

• Attention

• Working memory

Consequences cont....

References

• Scott-Brown’s 7th edition

• Cummings 5th edition

• OCNA

THANK YOU

evaluation of osa

Health & Medicine