Sleep Apnoea

Question 1

Definition of apnoea

Answer 1

Cessation of airflow for 10+ seconds

Question 2

Central apnoea

Answer 2

Respiratory control centre - no resp effort

Question 3

Obstructive sleep apnoea

Answer 3

Collapse of pharyngeal airway during sleep

OSA: 5 or more obstructive apnoeas/hour

Question 4

Hypopnoea

Answer 4

Decrease in airflow by 50% accompanied by desaturation of 4% arousal from sleep

Question 5

Risk factors

Answer 5

Male, obese, 43 cm neck circumference, family history, smoking, alcohol, sedative use, craniofacial/pharyngeal abnormalities, sleeping supine

Question 6

What is it associated with

Answer 6

Increased soft tissue
Enlarged tonsils
Pharynx - resistance/tone/caliber
Abnormal chin
Nasal pathology
Normal tongue relaxation

Question 7

Pathology

Answer 7

Sleep -> relaxation of muscles around pharyngeal airway -> collapse/obstruction of airway -> apnoea -> arousal -> muscle tone returns -> resumption of breathing

Question 8

Clinical features

Answer 8

Snoring, nocturnal choking, restless sleep, dry mouth, headaches, sleepiness, nocturnia

Question 9

Complications

Answer 9

Cor pulmonale
Secondary respiratory disease
Secondary polycythaemia

Question 10

Investigation

Answer 10

Epworth sleepiness scale and sleep studies

Nocturnal oximetry

Question 11

Diagnosis

Answer 11

Apnoeas + hypopnoeas/total sleep (hr)
Mild: 5-14 per hour
Moderate 15-30
Severe 30+

Question 12

Management

Answer 12

Resolve signs and symptoms
Normalise AHI and oxyhaemoglobin sats levels
Behaviour change
Mandibular advancement devices
Surgery
Continuous positive airway pressure