Sleep Flashcards
What is REM sleep?
Interesting and vivid dreams at their peak , usually associated muscle atonia and resultant paralysis to stop us acting our dreams
What is associated with REM Sleep Behaviour Disorder ?
- SSRI initiation / cessation
- Can arise in PD/ Narcolepsy
What is catharaemia
Groaning / moaning during expiration
What is Somniloquy?
Talking in sleep
What is Kleine Levin Syndrome
XS Sleep, XS eating , XS sex drive
What assessments do we use for OSA?
Epworth Sleepiness Scale and STOP-BANG
Do not use ESS alone , as not all patients with OSAHS are sleepy
Who are the patients prioritized for assessment w sleep study?
Vocational driving job
Vigilance critical to safety in job
Pregnant
Pre-Operatively
Unstable CDV risk
NAAION
How do we classify AHI results ?
<5 Normal
5-14 Mild
15-29Moderate
>30 Severe
What are the options if AHI 5-15?
MILD OSAHS
- Tx not usually needed and lifestyle modifications usually effective
- If significantly affecting QOL offer fixed level CPAP and lifestyle advice
Who can be offered auto CPAP?
High pressure needed for certain times of the night
OR
Unable to tolerate fixed level CPAP
OR
Telemetry can’t be used
OR
Auto CPAP is available at same /lower cost
Who can be offered mandibles advancement splint ?
If aged 18 years or over and have optimal dental and peridontal health
Useful for snoring and for mild OSA
What is the treatment for Moderate and Severe OSAHS
Mod (AHI 15-30 ) and Severe( AHI >30)
- fixed level CPAP and lifestyle measures
Who can you consider tonsillectomy in with OSAHS?
Large obstructive tonsils and BMI <35
What is obesity hypoventilation syndrome?
Obesity (BMI > 30) and Raised Arterial pCO2 and Apnoeas /Hypopneas when asleep or hypoventilating
What are the features of nocturnal hypoventilation?
Waking headaches
Peripheral oedema
Hypoxaemia
Unexplained polycythaemia
Who gets prioritised for OHS assessment ?
Severe hypercapnia >7 when awake
Hypoxaemia
Acute ventilatory failure
Vocational driving job
Hypervigilant job
Significant CDV or co-morbidity
Pregnancy
NAAION
Pre operative assessment
How can we diagnose OHS?
If pre-test probability is low can do a pre-test venous HCO3 and if <27 OHS is unlikely
Otherwise Resp Polygraphy to determine presence of OSAHS in those with OHS and consider adding transcutaneous CO2
What is the usual life style advice in OSAHS?
Stop smoking
Lose weight
DVLA guidance
What is the initial treatment for patients with OHS and severe OSAHS?
CPAP
What is the treatment for OHS and OSAHS who sx not improving and hypercapnia persisting and AHI/ODI not reduced enough in CPAP?
NIV
What is the treatment for OHS and nocturnal hypoxaemia ?
NIV
What is the treatment for those with OHS and acute ventilatory failure ?
Offer NIV to ppl with OHS and ventilatory failure ; once resolved can go to CPAP and if relapses then back to NIV
What is the first line treatment for COPD - OSAHS overlap?
CPAP first line if pCO2 < 7
NIV first line if pCO2 > 7
What is the DVLA guidance if no somnolence?
No need to stop driving or inform
What is the ESS threshold for a high risk driver (ie one with moderate to severe day time sleepiness)
17
What is the advice for mild OSA?
GROUP 1:
Must not drive ; driving may resume only after satisfactory symptom control. If symptom control cannot be achieved in 3 months DVLA must be informed
GROUP 2 (Bus/Lorry)
Must not drive ; driving may resume only after satisfactory symptom control , if symptom control not achieved by 3 months DVLA must be informed
What is the DVLA advice for Moderate to severe OSA?
Group 1
Must not drive and Must inform the DVLA
Subsequent licensing will require control of condition , improved sleepiness and tx adherence
DVLA will need confirmation of the above and must be reviewed every 3 years
Group 2
Must not drive and must notify DVLA
Subsequent licensing will require control of condition , improved sleepiness and tx adherence
DVLA will need confirmation of the above and must be reviewed every 3 years
If patient excessively sleepy due to suspected OSA what is DVLA advice?
Must not drive ; only once satisfactory control
What is central sleep apnoea?
Actual apnoea referred to as Cheney Stoke’s breathing when there is regular and symmetrical waxing and waning usually in the context of left ventricular failure
Outline absent or reduced ventilatory drive accounting for Central Sleep Apnoea
Brain stem involvement from strokes /tumours etc ; presents with unexplained ventilatory failure much worse during sleep
Lung function usually normal with no evidence of resp muscle weakness
Often maintain adequate or near adequate ventilation when awake as non metabolic drive and then during Non REM sleep this awake drive is most and ventilation is dependent on PaO2 and PaCO2 , during REM slightly better as awake like drive
Outline neuromuscular inspiratory weakness
Diurnal ventilatory failure
Particularly when supine VC falls below 20% predicted (often late sign tho)
Accessory muscles become very important , when during REM sleep these are lost with physiological paralysis then profound hypoventilation
Metabolic ventilatory drive is maintained and therefore this will result in arousal and interrupted sleep; but this gets progressively blunted
Outline chest wall restrictive diseases
Scoliosis or post thoracoplasty , muscles not weak
Worry when VC <1L
In REM sleep what is the resp muscle working?
Diaphragm is the only resp muscle working as all other muscles are profoundly hypotonic ; if diaphragm paralysed then REM sleep is very vulnerable
Outline Cheyne Stoke’s breathing associated with heart failure
Raised left atrial pressure of the left heart which increases ventilatory drive through stimulating the J receptors this in addition to ventilatory stimulation from hypoxaemia from pulmonary oedema
This ventilatory stimulation reduces the awake pCO2 causing resp alkalosis (and use of diuretics may cause it s metabolic alkalosis)
J receptor ventilatory stimulations reduces at sleep onset and this together with loss of the awake ventilatory drive allows central hypoventilation
This hypoventilation / apnoea will continue until PaCO2 increases driving ventilation again or reduces pO2 provoking arousal(may cause patient to awaken)
Cycle maintained
Outline Cheyne Stoke’s breathing associated with r altitude
Acute hypoxia following ascent to altitude provokes increased ventilation (degree variable) ; sleep onset lessening of hypoxic drive and removal of the awake drive and uncomplicated alkalosis will allow hypoventilation and apnoea , get arousals due to reduced sats or increased paCO2 ; sleep is fragmented
The larger the resp alkalosis the greater the tendency to sleep hypoventilate
Two tx approaches : Pre-acclimatise with acetazolamide which produces mild metabolic acidosis or hypnotics
O2 would abolish the problem
What does pCO2 normal and raised HCO3 indicate?
Nocturnal hypoventilation and incipient resp failure
HCO3 is the HbA1c of PaCO2 !!
For CSA what do we see on sleep study?
Fall in sats with associated hypoventilation but no evidence of OSA and no snoring
Oscillation in sats more sinusoidal than in OSA
If moderate sleep apnoea is left untreated , what is the risk of cardiovascular mortality ?
2-3 fold increase
What is an apnoea?
> 90% reduction of airflow (measured by nasal monitor) lasting 10 seconds with or without desaturation
What is a hypopnoea?
10 seconds reduction in airflow of >30% with 4% oxygen desaturation
How common is OSA syndrome ?
4% of men and 2% of women aged 30-60 years
How common is OSA? (On sleep study but without day time symptoms)
20%
Does ODI derived from overnight oximetry correlate with AHI derived from polysomnography?
Yes
What is included in limited PSG?
Nasal airflow
Thoracic-abdominal bands
Snore vibration sensor
Pulse oximeter
What is OHS?
BMI > 30 , sleep disordered breathing and daytime pCO2 >6kpa
PSG will show sleep hypoventilation with nocturnal hypercapnia with or without obstructive sleep apnoea /hyponea eventd
OHS strongly associated with pulmonary HTN
How do you diagnose narcolepsy?
A multiple sleep latency test <8minutes and two or more sleep onset rapid eye movements (SOREMs)
What are the indications for NIV in motor neuron disease ?
- Breathlessness, particularly orthopnea
- Daytime sleepiness
- Daytime hypercapnia >6 req urgent referral
- Nocturnal desaturation or daytime saturation <94%
- Reduced FVC <50% predicted (or <80% and signs/symptoms)
- SNIP < 40 or a SNIP < 65 in men and <55 in women plus any resp sx
- Postural VC drop
