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Simon Bowler Director Medicine
Mater Adult Hospital
Mater Private Hospital
Queensland Sleep
Sleep apnea: the essentials
Sleep Apnea Most OSA is straightforward
Most does not need specialist attention
Areas of uncertainty
CPAP vs no CPAP therapy in borderline cases
Disconnect between symptoms and measurements
More complex forms (eg central)
Commercial drivers need specialist review
Who should have a sleep study?
How do you assess severity of OSA?
Who needs CPAP – who doesn’t?
What is the risk of untreated OSA?
What to do if patient doesn’t tolerate CPAP?
Can changing posture cure sleep apnea
Does weight loss fix sleep apnea
Sleep apnea, driving and the law?
Wisconsin Sleep Cohort
Study
NEJM 1996;328:1230
How common is sleep apnoea? 30-60 yr old public servants
602 polysomnograms
AHI>15 (ie sig. OSAS) in
• 17% male heavy snorers 7.5% all males
• 7% female heavy snorers 2% of all females..
Scenario Peter aged 48
Bulldozer driver coal fields
Well. BMI 35
Hypertension on Coversyl
Snores - some apneas
No daytime somnolence ESS 6
No MV accidents
5
Nasal obstruction:
Alcohol / sedatives
reduce muscle tone
& reduce compensatory
increases in dilator activity
Supine sleep
Genetics: eg receding jaw
resp response
Increased sub mucosal tissue:
Obesity (NB neck circumference),
Acromegaly
Tonsillar enlargement
Reduced sleep time..
Etiological /exacerbating factors Male gender
Post menopausal status:
Which snorers should have a
sleep study?
No daytime somnolence ESS ≤ 10 ESS>10
No study Study
Normotensive Hypertensive
No observed apneas Observed apneas
Neck circum < 40cm Neck circum ≥ 40cm
No cardiovascular pathology Cardiovascular pathology
No high risk occupation High risk occupation
Lancet 1981;317:862
Pete’s PSG
9
Peter’s
PSG
10
5.7% time SaO2<90%..
Tot RDI 32.5/h
Non supine 24.7/h Supine 52.9 /h RDI
354 min Tot sleep
90% Sleep effic. 30.8/hr Arousal index
Assessing sleep apnea severity Respiratory Disturbance Index events/hr
normal mild moderate severe
RDI ≤5 5-19 20-35 >35
Plus modifying factors
Extent/duration hypoxic episodes
Duration apnoeas / hypopnea
Fragmentation of sleep - loss of cycling
11
Pete’s RDI 32.5
Treatment based on AHI
1. General meas: Wt reduction 2. attention to nasal patency 3.± avoid supine
sleep
AHI
0 10 15 20 30
Mild Moderate Severe
(If sleepy++; marked supine or REM effects or hypoxia) ….
(If less sleepy; intolerant CPAP)
MAS
CPAP
± MAS
± CPAP
Pete’s RDI
Scenario
Pete: “I’m feeling fine - no way
I’m wearing a Darth Vader mask
to bed”
Wife Susan says: “You’ll have a
heart attack and die if you don’t -
or end up paraplegic in a car
accident”
13
The consequences of OSA Susan: from the web:
NIH: “When your sleep is interrupted throughout the
night, you can be drowsy during the day. People with
sleep apnea are at higher risk for car crashes, work-
related accidents and other medical problems. If you
have it, it is important to get treatment.”
ASA: “..increased chance of heart attack or stroke
..x4 as likely to have a motor vehicle accident
14
CARDIOVASCULAR
DISEASE
15
Sleep apnea and CV disease
16
Metabolic syndrome
Sleep apnea Cardiovascular
events
?
17 Marin Lancet 2005; 365: 1046
Fatal events
Months
Non Fatal events
Months
OSA CPAP and
CV outcomes
Outcomes: MI / CVA vs normals
Marin Lancet 2005; 365: 1046
Caveats
•not a randomised study
• differences between CPAP / no CPAP groups not excluded
• no account of subsequent Rx or compliance
18
• Severe untreated OSA had x3 the chance of a heart attack or
stroke compared with normal or treated severe OSA
Meta analysis of CPAP and Syst BP
Fava C Chest 2013 Online 10.1378/chest.13-1414
CPAP produces small but
significant drop in BP
Consequences of OSA
20
Insulin resistance
Sympathetic dysfunction
T2 Diabetes
Lipid metabolism
Inflammation
Oxidative stress
Endothelial dysfunction
Coagulation abnormalities
Metabolic dysregulation
Dysrhythmias
Hundreds of episodes a
night of semi asphyxiation,
hypoxia, sympathetic
overdrive, recurrent arousal
and fragmented sleep
experienced over years can
be very bad for some / most
but perhaps not all patients
Sleep and driving
21
CPAP and driving skills: reaction time
22 Mazza ERJ 2006 28: 1020
OSA pre
CPAP
OSA post
CPAP
NL x 2
CPAP + number of
MVA’s
23 George Thorax 2001;56:508
n= 210
age 52± 11y
BMI 35±10
RDI 54±29
OSA No OSA
For Pete ?
24
• An asymptomatic patient
• What to do
• Will CPAP make him feel better?
Treatment based on AHI
1. General meas: Wt reduction 2. attention to nasal patency 3.± avoid supine
sleep
AHI
0 10 15 20 30
Mild Moderate Severe
(If sleepy++; marked supine or REM effects or hypoxia) ….
(If less sleepy; intolerant CPAP)
MAS
CPAP
± MAS
± CPAP
Pete’s RDI
CPAP will in disease modeling:
Increase the probability of survival by 25%.
Decrease the relative risk of having a cardiovascular event
by 46%
Decrease the relative risk of having a stroke by 49%
Decrease the relative risk of having an RTA by 31%.
Increase the probability of event-free survival by 92%.
for a cost-reduction of £973 (95% CI: -£1,983; £1,508) over
14 years
Guest J Thorax online April O8 10.1136/thx.2007.086454
Effect of CPAP in non sleepy OSA
27
• Parallel gp study
• CPAP vs Sham
Baseline mean
• n=29 vs 25
• ESS 8 vs 6
• BMI 29 vs 29
• AHI 57 vs 57
• 6 weeks Rx
Barbe Ann Intern Med. 2001;134:1015
No benefit
found..
Positional therapy and OSA
16 pats with positional OSA
Time supine fell 42.8 ±26 to 5.8 ±7.2 %
AHI fell 26.7 ± 17 to 6.0 ±3.0
ESS 9.4 ±5 to 6.6 ±5
Used device for 74% nights 8.0± 2.0h/n
Good compliance at 3 months – results persisted
Heinzer Sleep 2012:13;425
Weight reduction and OSA
25 pat (17m) 44y; 154kg; BMI 52.7
Lap band
Mean weight loss 44.7kg (50% excess weight loss)
AHI fell from 61.6 ±34 to 13.4 ± 13
ESS from 13 ±7 to 3.8 ±3
Improved depression, T2DM, metabolic syndrome
Int J Obesity 2005;29:1048
For Pete ?
30
• Long term implications for untreated sleep
apnea in an asymptomatic patient are
unknown
• Is he really asymptomatic ?
•? Trial of CPAP
•? MWT (NB occupation)
• Treat cardio vascular risk factors
• Lose weight
• If he’s really asymptomatic observe only
• Control of snoring
http://www.austroads.com.au/
In summary: driving and sleep If the patient has sleep apnea (RDI>10) and (or) is
sleepy (ESS ≥ 16) and or has had sleepiness driving or
crashes due to sleepiness –
Must use CPAP (and have improved sleepiness)
You must be happy the patient is adhering (ESS; download)
You should fill in an F7312 and the patient should submit
You have legal protection in reporting the patient if you believe non
compliance or a risk driving
Refer if worries
If the patient holds a commercial license and meets
above condition
Should be referred to a sleep physician