Obstructive Sleep Apnoea

Question 1

what is the definition of OSA

Answer 1

cessation of airflow for >10sec despite evidence of continued respiratory effort, due to repetitive collapse of upper airway.

OR

cyclical interruption of ventilation, each cycle lasting 15-90s and resulting in hyperaemia, hypercapnia, and resp acidosis terminating in an arousal from sleep followed by the resumption of normal ventilation, a return to sleep and so on.

Question 2

Who are more likely to have OSA

Answer 2

Men are twice as likely as womrn

Question 3

How common is OSA

Answer 3

~20 %

Question 4

what is the pathophysiology of OSA

Answer 4

reduced upper airway size due ti excess surrounding soft tissue or a highly compliant airway.

Question 5

what risk factors are there for OSA

Answer 5

obesity
cranio-facial and upper airway soft tissue abnormalities
genetic
smoker (2x more likely)
nasal congestion

Question 6

What co-morbidities is OSA associated with?

Answer 6

Heart failure
stroke
COPD
interstitial pulmonary fibrosis

Question 7

What are the classic features of OSA

Answer 7

1. obstructive apneas, hypopnoeas, or respiratory effort related arousals
2. Daytime symptoms - sleepiness, fatigue, poor concentration
3. signs of disturbed sleep - snoring, restlessness or resuscitative snorts.

Question 8

What objective scales can be used to measure OSA and its symptoms?

Answer 8

fatigue severity scale

epworth sleepiness scale

Question 9

When would you perform a polysomnography/alt sleep study

Answer 9

complaints of snoring with daytime tiredness, or >2 clinical features, or mission-critical worker repeat a normal test if high clinical suspicion

Question 10

what other symptoms may present with OSA

Answer 10

insomnia, sore/dry mouth, moodiness/irratbility, morning headaches, depression, dcr libido, poor concentration

Question 11

what is polysomnography

Answer 11

full/split night, attended in lab

Question 12

who would be a suitable candidate for home sleep studies?

Answer 12

Pt with high positive predictive probability and no com-morbities

Question 13

What grades are there for OSA

Answer 13

mild/mod/severe

Question 14

what is the definition of mild OSA

Answer 14

apnoea hypopnoea index: 5-15 events /hr,
asymptomatic
some day time somnolence, not affecting ADLS
30% respond to treatment
mx behaviourally
generally no assoc co-morbidities

Question 15

what is the definition of moderate OSA

Answer 15

apnoea hypopnoea index 15-30 events /hr
pt aware of daytime sleepiness - tries to avoid falling asleep
HTN possible
nil other assoc co-mrbidities
responds to CPAP generally

Question 16

what is the definition of severe OSA

Answer 16

apnoea hypopnoea index >30 events /hr and/or dcr sats to <90% for more than 20% of total sleep time
daytime sleepiness that interferes with daytime activities
multiple co-morbidities
Prompt Rx- CPAP, Surgery
tracheostomy in very severe cases with life threatening apnoeas

Question 17

what is your differential for daytime sleepiness causes

Answer 17

periodic movements of sleep
rotating shift workers
narcolepsy
upper airway resistance syndrome
central sleep apnoeas
respiratory disease
primary snoring
GORD

Question 18

what are the driving regulations for someone who has OSA

Answer 18

For those with dx from a sleep study and excessive daytime sleepiness and thought to be at risk due to the level of sleepiness — NO licence
if they are compliant with treatment and have had a satisfactory response they can have a CONDITIONAL
License, subject to periodic review and if Dr thinks suitable.

Question 19

what behavioural therapies for OSA are there?

Answer 19

weight loss >10%
smoking cessation
positional
avoidance of alcohol and sleep deprivation
medication review
nasal obstruction

Question 20

What pressure devices are there and what is the benefit

Answer 20

CPAP
BPAP
APAP
they reduce the number of apnoeas and improve QOL

Question 21

what are the treatment options for OSA

Answer 21

behavioural
pressure
oral appliances
surgery

Question 22

How do oral appliances in OSA work?

Answer 22

They push the mandible forward, or hold the tongue in a more anterior position

Question 23

How affective are oral appliances

Answer 23

They decrease the frequency of respiratory evens

improve daytime sleepiness/QOL and neurocognitive function

Question 24

Are there any drugs that can help OSA

Answer 24

no, none have been proven to be effective

Question 25

when should you refer an OSA pt

Answer 25

socially disruptive snoring despite optimal behavioural management
snoring assoc with CV co-morbidities 0 HTN, IHD, stroke, TIA, Diabetes
Snoring assoc with MVA, excessive sleepiness, inattention at work impaired cognition.

Question 26

what age does OSA plateau

Answer 26

55-65yrs