sleep related disorder

resulting in recurrent, partial (hypopnoea) or complete(apnoea) obstruction of upper airways

caused by relaxation of airway muscles during sleep

allows soft tissue to collapse and block upper airway

apnoea -> spo2 drop -> CO2 increase -> brief arousal to resume breathing

apnoea = 10-30sec

can occur hundreds of times / night

leads to broken sleep

  • upper airway resistence syndrome and centra sleep apnoea less common with OSA

Central sleep apnoea

  • caused by instability or imbalance in control mechanisms that drive respiration

  • apnoea and hyperpnoea

Apnoea-hypopnoea index

  • # of pauses each hour that ≥ 10 sec

\| OSA sleep apnoea severity \| apnoea-hypopnoea index (AHI) \|

| ———— | ———|

| normal | \<5|

| mild | 5-15 |

| moderate | 16-30 |

| severe | >30 |

Prevalence

  • 4% adult males

  • 2% adult F

  • increase Maori and Pacific peoples

  • OSA 2x maori compared to pakeaha

Obesity

  • 40-90% OSA are obese

    • excess fat tissue around neck exerts pressure on upper airways

    • increase likelihood of upper airway collapse during sleep

  • Abdomin al obesity reduce lung volumes

  • 1kg/m2 in BMI = 30% increase in risk of upper airway collapse

  • sleep loss further increase obesity

  • smoking increase prevlance

  • EtoH

    • decrease muscle tone

  • increase in hypothyroidism

  • increase in PCOS

  • seveirty of untreated OSA may be worsened in males using testosterone supplementation

Mortality

  • mod. to severe OSA increase risk of all cause mortality

    • increase in age of 17.5yrs

    • 29mmhg in mean arterial blood pressure

  • increase cardiovascular risk

    • htn

    • hypertensive cardiomyopathy

    • coexisting cad, dm, obestiy

  • accidents increased

symptoms

Awake

  • excessive day time sleepiness

  • lack of concentration

  • cognitive deficits

  • changes in mood

  • morning headahces

  • dry mouth

  • decrease libido / impotence

during sleep

  • snoring

  • witnessed apnoea

  • non-refreshing sleep

  • choking

  • restlessness

  • vivid dreams

  • GORD

  • insomina/frequent wakening

  • nocturia

  • hypersalivation

  • diaphoresis

  • all people with OSA snore

    • but not all who snore have OSA

Epworth Sleepiness Score

  1. Sitting and reading

  2. Watching television

  3. Sitting in a public place

  4. As a passenger in a car for an hour

  5. Lying down to rest in afternoon

  6. Sitting while conversing

  7. Sitting after lunch (without EtOH)

  8. As a passenger in a car stopped in traffic for a few minutes

Score - 0 = never, 1= slight change, 2 = moderate change, 3 = high chance

score >10 = abnormal

score > 16 pathological daytime sleepiness

epworth sleepiness

  • Mallampati score can be used to assess degree of airway obstruction

sleep apnoea prediction tools

  • adjusted enck circumference calculation

    • doesn’t categorise potential seveirty

    • neck circ + add:

      • 3cm for snoring

      • 3cm for witnessed apnoea

      • 4cm for htn

    • \<43cm = low risk

      • 17% probability

    • 43-47.9cm intermediate

    • ≥ 48cm = high

      • 81% probability

  • OSA50 + overnight pulse oximetry

    • Obesity (Waist >102M, >88F): +3

      • snoring: +3

      • Apnoea: +2

      • 50: +2

      • if ≥5 -> overnight pulse oximetry

    • rule out moderate - severe OSA

    • PPV 55-65%

    • NPV = 97-99%

      • have mild sleep apnoea or no sleep apneoa

differntial diagnosis

  • insufficient sleep

  • primary insomnia

  • secondary causes insomonia

    • depression

    • ansiety

  • circadian rhythm disorders

    • jet lag

    • shift work

    • delayed sleep phase syndrome

    • sedating medciaine

  • chronic conditions

    • cardiac

    • resp.

    • neuromuscular disease

  • CO2 retunetion

    • severe obesity

    • central hypoventialtion syndrome

    • COPD

investigations

  • refer for overnight sleep study

  • treatment aimed at improving daytime symptoms

  • usually with CPAP

    • poorly tolerated by people without daytime sleepiness

Referral information

  • patient history - snoring, apnoea

  • previous otolaryngological assessment/procedures

  • comorbidities: cvs, metabolic, psychiatric

  • social circumstances

  • occupational

  • current medicines

  • BMI and any recent weight change

Contraindications to unattended home diagnositc studies:

  • CHF

  • stroke

  • cor pulmonale

  • copd

  • hypoventilation

  • other serious medical disorders

Treatment

Lifestyle

  • simplest

  • weight loss

  • smoking cessation

Avoidance of medicines/drugs that may contribute

  • etoh

  • bdz

  • opioids

CPAP

  • 100% effective at eliminating osa if tolerated

  • improve cognitive function

  • reduce arterial blood pressure

  • reduce rate of motor vehicle accidents by up to 83%

  • imroved glycaemic control

  • not assocaited with weight loss

  • prevents upper airway collapse

mandibular advancement devices

  • widen upper airway

  • push pharyngeal pads laterally

  • adverse effects;

    • teeth and jaw pain

Tongue retaining devices

  • as effective

  • poorly tolerated

Driving risk

  • can drive if condition well-managed

  • not:

    • high level of concern regarding sleepiness when driving

    • history of sleep-related motor vehicle accidents and report daytime sleepiness

    • severe OSA untreated or unwilling to accept treatment