obstructive sleep apnoea

1. obstructive sleep apnoea Emma Heap ST3 2012

2. Fred 40 Last seen by you 6/12 ago to do his HGV medical No PMH of note Comes in saying his wife has sent him because of his snoring What alarm bell is ringing immediately? What would you ask?

3. History • Excessive sleepiness (Epworth sleepiness score) • Loud snoring, witnessed apnoeas and choking noises • Feeling unrefreshed on waking • Poor concentration • Mood swings,personality changes or depression • Nocturia • Employment • Evening alcohol • Night sedation • Weight • Nasal congestion

4. Epworth sleepiness score • For each situation below, give yourself a score of 0 to 3 where: • 0 = would never doze • 1 = slight chance of dozing • 2 = moderate chance of dozing • 3 = high chance of dozing Sitting and readingWatching TelevisionSitting, inactive in a public place (e.g. a theatre, meeting)As a passenger in a car for an hour without a breakLying down to rest in the afternoon Sitting and talking to someoneSitting quietly after lunch (when you have not had alcohol) In a car, while stopped for a few minutes in traffic Score 0-10 normal range 10-12 borderline 12-24 abnormal

5. Obstructive sleep apnoea • 3rd most common respiratory condition after asthma and COPD • Affects 2% of middle aged men and 1% of women • Severe OSA is a MAJOR risk factor for RTA due to falling asleep at the wheel • Treatable and treatment can make a major difference to people’s lives • Risk factor for hypertension and probably vascular disease

6. Aetiology • Occurs due to repetitive narrowing and closure of the pharynx during sleep • Results in sleep fragmentation and repeated oxygen desaturations • Causes daytime symptoms such as excessive somnolence, impaired alertness and poor cognition • The pharyngeal obstruction leads to asphyxia – a drop in arterial O2 saturationsand a rise in Pa CO2 levels. This induces a rise in the ventilatory drive and the brain detects and registers the increasing, frustrated intrathoracic pressure swings as inappropropriate. This provokes arrousal sufficient to increase the pharyngeal tone and re-opens the airway, leading to a sudden inflow of air (heard as gasping or choking) and a rise in saturations. This cycle repears almost immediately leading to fragmented and unrefreashing sleep. • The other major effect is a rise in noctural BP with every arousal from sleep which in severe cases seems to lead to daytime hypertension • Also nocturia from raised atrial natriuretic peptide level from increased central blood volume resulting from low intrathoracic pressures during obstructed breathing

7. Risk factors • Being a middle aged man • Being overweight • Being a snorer • Having a collar size >17” • Having a craniofacial abnormality e.g. rethrognathia • Large tonsils • Hypothyroidism • Neuromuscular disease e.g. stroke, myotonic or Duchenne dystrophy and MND • Rare causes – Mucopolysaccharidoses, Acromegaly, Cushing’s, Marfan’s, Downs

8. What would you examine?

9. Examination • BMI • Neck circumference >17” carries higher risk • Oropharynx – large tonsils and boggy mucosa • Teeth – crowding suggests a small mandible • Nasal patency • Respiratory function – signs of cor pulmonale, FEV1, SpO2 • Blood pressure • Evidence of endocrine abnormalities • Evidence of neuromuscular disorders • Evidence of heart failure

10. Investigations • Routine haematology and biochemistry • Thyroid function tests • Fasting lipids, glucose and folate (higher vascular risk in these patients) • Arterial or capillary blood gas estimation if the patient’s resting SaO2 is <93% or you suspect respiratory failure

11. Initial management • Supported weight loss • Reduce alcohol consumption • Reduce sedative medications • Lateral body position during sleep • Good sleep hygiene • Mandibular advancement splint (from dentist)

12. referral • Failed trail of mandibular advancement device • Alcohol intake <2units /night • Severe antisocial snoring • Epworth score >10/24 • BMI<30 • Refer patient urgently if you feel they may have possible respiratory failure (awake hypoxia SaO2 <94%) or they are a professional driver whose job is at risk

13. Nocturnal continuous positive airways pressure therapy The only consistently effective treatment in those with conform OSA is nocturnal continuous positive airways pressure therapy This consists of a blower attached to a length of tubing that fits onto an airtight mask on the nose. They may need a full face mask if they have nasal congestion or blockage If a patient has a positive sleep study and excessive daytime somnolence they probably need treatment Only works if compliance is good – needs a careful induction programme in the correct setting Pitfalls – pain and ulceration on the bridge of the nose, claustrophobia, nasal congestion

14. CSA case • Harry • 52 • Not been in in last year

15. Examination • BMI 43 • BP 176/87 • Ankle oedema to mid calf • SpO2 88% on air • Chest clear

16. Harry, 52 year old bus driver presents with snoring, witnessed apnoeas and morning headache. His colleagues at work have been complaining that he falls asleep at his desk in between jobs and he is concerned because he had a near miss 2 weeks ago on the motorway (describes hitting the rumble strips). He also describes increasing breathlessness for the last few months and has noticed his ankles swell considerably. He is a smoker and is very obese. His resting SpO2 is 88%

17. What would you do? • What would you tell him about work? • What about driving in general?

18. Needs urgent ref to clinic – I would phone consultant as he is showing signs of respiratory failure • Sign him off work • Shouldn’t be driving whilst under investigation – but can drive once treated

19. What about driving? • in studies patients with moderate to severe sleep apnoea were 7 times more likely to have a fatal RTA than controls!!!! • The law says that drivers are responsible for their vigilence while driving and should not drive if sleepy for what ever reason • A person with obstructive sleep apnoea must notify the DVLA, who will only revoke their licence if they have continued sleepiness • Full licencing is possible once they have effective treatment. • Patients with a HGV or PSV licence must have an annual check at a specialist centre to confirm treatment is continuing and effective. • DVLA booklet – tiredness can kill – advice for drivers http://www.dft.gov.uk/dvla/medical.aspx

20. Useful websites • www.sleep-apnoea-trust.org • www.britishsnoring.co.uk