Obesity Hypoventilation
Syndrome
Pickwickian Syndrome
Obstructive sleep apnea
was called the
Pickwickian syndrome in
the past because Joe the
Fat Boy who was
described by Charles
Dickens in the Pickwick
papers had typical
features with snoring,
obesity, sleepiness and
“dropsy”.
OHS: Definition
- Obesity (BMI 30 kg/m2)
- Hypercapnia (PaCO2  45 mmHg)
- Sleep-disordered breathing
Thomas Nast, The Pickwick Papers
OHS: Clinical Presentation
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Middle-aged
2:1 male-to-female
Extremely obese
Significant sleep-disordered breathing
(fatigue, hypersomnolence, snoring, AM
headache)
OHS: Epidemiology
• Prevalence among OSA: 10-20%
• No clear ethnic or racial predominance
In USA, prevalence of OSAS
among middle-aged men and
women were 4% and 2%
(Young et al)
OHS: Hypercapnia
• Increased CO2 production
• Decreased respiratory drive (will not
breathe)
• Respiratory pump malfunction or
increased airway compliance (cannot
breathe)
• Inefficient gas exchange
Obesity
Leptin resistance
Increased mechanical load
and weak respiratory
muscles
OSA
Upper airway resistance
Acute hypercapnia
during sleep
Blunted
ventilatory
response
Chronic
hypercapnia
Increased serum
bicarbonate
Mokhlesi, B et al., Recent Advances in Obesity
Hypoventilation Syndrome, Chest
OHS: Lung Volumes
TLC
TLC
TV
TV
RV
RV
OHS: Lung Volumes
Volume
Lungs
TLC
TLC
Chest Wall
FRC
FRC
RV
RV
Pressure
Mechanism of OSAS
• The upper airway dilating muscles,like all
striated muscles-normally relax during sleep.
• In OSAS, the dilating muscles can no longer
successfully oppose negative pressure in the
airway during inspiration.
• Apneas and hypopneas are caused by the
airway being sucked and closed on
inspiration during sleep.
Anatomy of OSA
NORMAL
SNORING
SLEEP APNEA
Symptoms of OSA,OHS
Night time
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Snoring
Witnessed apnoea
Frequent nocturnal awakenings
Waking up choking or gasping for air
Unrefreshed sleep
Restless sleep
nocturia
Dry mouth
decreased libido
Symptoms of OSA,OHS
Daytime
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Early morning headaches
Fatigue
Daytime sleepiness
Poor memory, concentration or motivation
Unproductive at work
Falling asleep during driving
Depression
Symptoms of
Sleep Apnea
Syndrome
Features of Excessive Sleepiness
Motor vehicle crashes
Work related accidents
Impaired school or work performance
Marital problems
Memory and concentration difficulties
Depression
Impaired quality of life
OHS,OSA & Cardiovascular
Diseases
• Uncontrolled HTN- 83% have OSAH;
activation of sympathetic drive.
• Acute coronary syndrome- 40-50% has
OSA
• Cardiac arrhythmias mostly Af
• Heart Failure
• Sudden cardiac death
• Stroke
OSA,OHS and DM
• Patients from the sleep clinic
with AHI>10 are much more
likely to have impaired glucose
tolerance and diabetes
(Meslier et al Eur Respir J 2003)
Diagnosis
• A good sleep history
• Assessment of obesity, oral cavity
• Assessment of possible predisposing
causes: HTN, hypothyroidism,
acromegaly and
• Polysomnography: gold standard tool
Polysomnography
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EOG - Electrooculogram
EEG - Electroencephalogram
EMG - Electromyogram
EKG - Electrocardiogram
Tracheal noise
Nasal and oral airflow
Thoracic and abdominal respiratory effort
Pulse oximetry
Overnight PSG
Apnea-Hypopnea Index
• Apnoea-hypopnoea index (AHI)= number of
apnea/hypopnea per hour of sleep
• AHI<5 Normal
• AHI 5-15 Mild OSA
• AHI 15-30 Moderate OSA
• AHI >30 Severe OSA
OHS: Treatment
• PAP (CPAP or BiPAP)
– No standard protocol for titration
• Oxygen therapy
• Surgery
– Tracheostomy
– Weight reduction
• Pharmacotherapy
– Medroxyprogesterone
– Acetazolamide
Behavioral Treatments
1. Attain an ideal body weight
2. Sleep on the side
3. Avoid sedative medication before sleep
4. Avoid being sleep deprived
5. Avoid alcohol before sleep
6. Elevate the head of the bed
7. Promptly treat colds and allergies
8. Avoid large meals before bedtime
9. Stop smoking
Body Position
• Raise HOB
• Avoid supine
position
Strategies• Tennis ball in
pajamas
• Backpacks
CPAP Therapy
• Works as a pneumatic
Splint
• 1st choice of treatment
in moderate to severe
OSAHS
• Success rate 95-100%
• Long term compliance
60-70%
• Retitrate pressure if
needed
Oral Appliances
□ Not yet available in Iran
□ Appropriate first-line
treatment for Mild OSA,
primary snoring, upper
airway resistance syndrome
( UARS )
□ Not as effective as
CPAP,
52% OSA have AHI<10%
□ Young, non-obese
□ Second line therapy for
moderate-severe OSA
□ Patient’s choice - Not
tolerating / refuse to use
CPAP, or are not surgical
candidates
MAD
TRD
Medical Treatments
1. Weight loss
2. Pharmacological
3. Oxygen therapy
4. Nasopharynegeal intubation
5. Nasal CPAP
6. BiLevel CPAP
7. Automatic CPAP
8. Oral Appliances
9. Atrial Pacing
Oxygen Therapy
• Improves oxygen saturation during sleep
• May prolong apneic episodes
• Reduces cardiac arrythmias
• Useful additive treatment with CPAP
• Rarely reduces apneic episodes
• Can improve daytime sleepiness
• May cause CO2 retention
Pharmacological Therapy
Protriptyline
Medroxyprogesterone
Fluoxetine
Antihistamines
Nasal Steroids
Theophylline
Acetazolamide
Modafinil
Magalang UJ et al, 2003
Conclusion
• With the increasing problem of obesity,
the impact of undetected OHS & OSAS
as a public health burden cannot be
undermined among our population,
• It merits appropriate preventive and
treatment strategies.
references
Mokhlesi, B., Tulaimat, A. (2007), “Recent Advances in Obesity
Hypoventilation Syndrome”, Chest 132 (4),1322-1332.
Weinberger, S.E., Drazen, J.M., “Disturbances in Respiratory
Function”, in Kasper et al (eds), Harrison’s Principles of Internal
Medicine (16th Edition), New York: McGraw-Hill, pp. 14981505.
Guyton, A.C., Hall, J.E. (2000), Textbook of Medical Physiology
(10th edition), Philadelphia: W.B. Saunders.