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© Copyright Annals of Internal Medicine, 2014 Ann Int Med. 161 (5):
ITC5-1.
in the clinic
Obstructive sleep apnea
INTRODUCTION: Obstructive sleep apnea (OSA) is a disorder defined
by repeated episodes of upper airway closure during sleep, which
result in recurrent oxyhemoglobin desaturation and sleep
fragmentation. OSA is common. In the general adult population, “OSA
syndrome”— defined as 5 or more obstructive respiratory events per
hour of sleep combined with excessive daytime sleepiness—occurs in
4% of men and 2% of women (1). Clinically significant,
moderate-to-severe OSA (15 or more obstructive respiratory events
per hour of sleep, irrespective of symptoms) occurs in 9% of men
and 4% of women (1). In conjunction with increasing rates of
obesity—one of the strongest risk factors for OSA (2)—the
prevalence of OSA is increasing, with 5-year incidence rates of
7%–11% in middle-aged adults (3, 4). Furthermore, OSA has long-term
health consequences. The associated sleep fragmentation can result
in daytime sleepiness leading to increased risk for motor vehicle
and occupational accidents (5) and reduced quality of life. The
associated oxyhemoglobin desaturations and physiologic stresses
with repetitive upper airway obstruction can lead to increased
blood pressure and cardiovascular disease (6). However, despite the
prevalence and impact on health, most patients with OSA remain
undiagnosed and untreated: Only about 1 in 50 patients with
symptoms suggestive of the OSA syndrome are evaluated and treated
for the disease (7). Here, we aim to increase clinician familiarity
with OSA and describe the importance of diagnosis and
treatment.
Sleep Study Terminology and Obstructive Sleep Apnea
Definitions
Terminology
• Apnea: Breathing cessation for ≥ 10 seconds
• Hypopnea: Breathing flow reduction for ≥ 10 seconds accompanied
by either a ≥3% or ≥4% oxyhemoglobin desaturation or by arousal
from sleep
• AHI: Episodes of apnea and hypopnea/h of sleep
• Oxygen desaturation index: Episodes of ≥ 3% or ≥ 4% oxyhemoglobin
desaturations/h of sleep
• Time below SpO2 90%: Sleep or study time spent with oxyhemoglobin
saturation less than 90%
Definitions
• Severe OSA: AHI ≥ 30 events/h
• The OSA syndrome: AHI ≥ 5 events/h with daytime sleepiness
AHI = apnea-hypopnea index; OSA = obstructive sleep apnea.
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All adults who answer yes to either question:
Are they dissatisfied with their sleep?
Do they have daytime sleepiness?
Patients with risk factors
Family history of obstructive sleep apnea
Retrognathia
Patients with high-risk driving occupations or daytime sleepiness +
motor vehicle crash
Who should be screened for OSA?
Who should be screened for OSA?
As part of a routine health maintenance evaluation, the American
Academy of Sleep Medicine (AASM) recommends asking all adults
whether they are dissatisfied with their sleep or have daytime
sleepiness. Those with positive responses should be screened for
OSA using further clinical history or screening instruments (8)
(see the Box). All obese patients should be screened for OSA.
Obesity, and in particular central obesity, is the major risk
factor for OSA, and the risk for OSA increases as obesity
increases. In fact, excess weight is responsible for 41% of all OSA
and 58% of moderate-to-severe OSA cases (9),
and weight gain over time is associated with OSA incidence: A 10%
increase in weight predicts a 6-fold increase in the likelihood of
developing clinically significant OSA (10). Not all OSA patients
are obese, however. AASM guidelines also recommend screening
patients with a family history of OSA, those who have retrognathia
(Figure 1), and those with diseases known to have a high
co-prevalence of OSA, such as type 2 diabetes, treatment-resistant
hypertension, heart failure, atrial fibrillation, and stroke. Other
diseases with a high co-prevalence of OSA include polycystic
ovarian disease; the Down syndrome; acromegaly; and head and neck
cancer patients, particularly after surgery or radiation therapy.
Patients with pulmonary hypertension should also be screened for
OSA because therapy may reduce pulmonary artery pressure (11).
Finally, all patients who are in high-risk driving occupations,
such as commercial truck drivers and public transit operators,
should be screened for OSA due to the potential public health
impact. Any patient with significant daytime sleepiness and a
history of either a recent motor vehicle crash or near miss
attributable to sleepiness should be screened (12).
BOX: Risk Factors for Obstructive Sleep Apnea
Obesity, especially with body mass index > 35 kg/m2
Family history of obstructive sleep apnea
Retrognathia
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What are the screening tools?
Berlin questionnaire (primary care setting)
10 items
STOP-BANG screening test (preoperative setting)
8 items
BANG: elevated BMI, Age > 50, increased Neck circumference,
Gender male
Neither tool precludes formal sleep testing
What are the screening tools?
Multiple screening tools have been developed to identify high-risk
patients (13); however, of note, no screening tool based on signs
and symptoms is accurate enough to preclude formal sleep testing.
The Berlin questionnaire and the STOP-BANG screening test are 2
widely used, well-validated instruments. The Berlin questionnaire
(www.sleepapnea.org/assets/files/pdf/Berlin%20Questionnaire.pdf )
was developed for a primary care population and consists of 10
questions focused on the severity of snoring, witnessed apnea, the
significance of daytime sleepiness, and the presence of obesity and
hypertension. When the questionnaire was evaluated in an urban U.S.
primary care setting, more than 1 of 3 respondents were found to be
at high risk for OSA, and the survey had an 86% sensitivity for
predicting the presence of OSA (14). The STOP-BANG screening test
(see the Box) was developed to assess patients in the preoperative
setting. It is an 8-item screening tool with 1 point each for
snoring, daytime sleepiness, observed apnea, high blood pressure
history, elevated body mass index, advanced age, increased neck
circumference, and male gender. A STOP-BANG score of ≥3 out of 8
among perioperative patients had an 84% sensitivity for predicting
any OSA, and a score of ≥ 5 was more predictive of clinically
relevant moderate-to-severe OSA (15).
BOX: STOP-BANG*
S Do you snore loudly?
T Do you often feel tired, fatigued, or sleepy during the
day?
O Has anyone observed you stop breathing during sleep?
P Do you have or are you being treated for high blood
pressure?
BANG
A Age > 50 years?
G Gender male?
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Can OSA be prevented?
May also achieve remission
Can OSA be prevented?
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CLINICAL BOTTOM LINE: Screening and Prevention...
Ask all adults about sleep problems or daytime sleepiness
If response is positive: perform OSA screening
Take further clinical history
Significant obesity
History of drowsiness while driving
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What symptoms should prompt consideration of OSA?
Witnessed episodes of apnea
Loud, frequent, bothersome snoring
What symptoms should prompt consideration of OSA?
Snoring is the symptom with the highest sensitivity for OSA but is
very nonspecific (19). To distinguish simple snoring from that
suggestive of OSA, patients should be asked for details. Patients
with OSA are more likely than simple snorers to report loud,
nightly snoring that is bothersome to others (14). Symptoms of OSA
are given in the Box. Daytime sleepiness, defined as sleepiness
that occurs in a context where alertness would be expected, is also
a nonspecific finding. The Epworth Sleepiness Scale (ESS) is an
8-item scale quantifying sleepiness in everyday activities, and
although it inconsistently correlates with objective measurements
of sleepiness, it can help standardize the evaluation of a
patient’s subjective perception (20) (Figure 2). A history of
drowsiness or falling asleep while driving should be explicitly
explored during evaluation.
Patients should be also questioned on use of caffeine or other
stimulants because it may indicate attempts to self-treat
sleepiness.
Although relatively insensitive, choking or gasping during sleep is
highly specific for moderate-to-severe OSA, as is the presence of
morning headaches (19). Other suggestive symptoms include observed
episodes of apnea as well as nocturia and nocturnal
awakenings.
Obtaining a history from a bed partner or cohabitant can be
particularly helpful because many of these symptoms may not be
apparent to the patient. Manifestations of untreated OSA may also
include decreased libido, decreased concentration, or memory loss.
Of note, OSA frequently presents in an atypical fashion, with
insomnia and fatigue as the predominant symptoms, particularly in
women. Despite population-based studies that find a 2:1 male–female
prevalence, utilization data indicate that the ratio for referrals
is 9:1 male, suggesting that clinicians do not adequately consider
OSA in women (21).
Box: Symptoms of Obstructive Sleep Apnea
Witnessed episodes of apnea
Loud, frequent, bothersome snoring
Unrefreshing sleep
Sleep fragmentation
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In the absence of symptoms, what other diseases should prompt
evaluation?
Morbid obesity
Hypertension
If refractory to medical therapy
In the absence of symptoms, what other diseases should prompt
evaluation?
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What other conditions should be considered?
Chronic sleep deprivation disorder (shift-work disorder)
Circadian rhythm disorder
Depression and anxiety
Opiate-induced central sleep apnea
What other conditions should be considered?
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What physical exam findings are important?
Respiratory, CV, and neurologic systems
Presence and degree of obesity
Signs of upper airway narrowing
Neck >16” women, >17” men
Mallampati score of 3 or 4
Macroglossia, tonsillar hypertrophy
Nasal obstruction
What physical examination findings are important?
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What type of sleep study should be ordered?
Polysomnography in the sleep laboratory
Standard method for diagnosis and determining severity
Assesses other sleep disorders
Recommended: “full-night” sleep study
Then positive airway pressure titration the same night
What type of sleep study should be ordered?
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What is the role of in-home sleep studies?
Used for uncomplicated cases
Convenient and lower cost
Definitively exclude diagnosis
What is the role of in-home sleep studies?
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What variables are reported on a sleep study report, and what do
they mean?
Apnea-hypopnea index (AHI)
Mild OSA: AHI ≥5 and <15/h
Moderate OSA: AHI ≥15 and <30
Severe OSA: AHI ≥30
Apnea: airflow cessation ≥10 sec
Hypopnea: airflow reduction ≥10 sec plus 3% or 4% OxyHb
desaturation or arousal from sleep
Other measures of sleep-disordered breathing, total sleep time,
measures of sleep quality
Epileptiform EEG, limb movement, nocturnal arrhythmia
What variables are reported on a sleep study report, and what do
they mean?
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Do patients need to be seen by a sleep specialist before a sleep
study is ordered?
Sleep specialist evaluation recommended
Other sleep disorder suspected
Prior evaluation not needed in other cases
But clinician should discuss options with patient first
Explain OSA therapy and why it may be initiated
Do patients need to be seen by a sleep specialist before a sleep
study is ordered?
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CLINICAL BOTTOM LINE: Diagnosis...
Loud snoring, nocturnal choking or gasping
Significant daytime sleepiness, history drowsy driving
Witnessed episodes of apnea
Undergoing bariatric surgery
Have treatment-resistant hypertension
In-lab sleep testing: gold standard
In-home sleep testing: if high clinical suspicion for OSA and no
significant cardiopulmonary comorbid conditions
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Which patients with OSA require treatment?
Counsel overweight patients about weight loss
Treat any nasal congestion
Offer trial of therapy (CPAP) if patient has
Daytime sleepiness or frequent nocturnal awakenings
Recent accident or near-miss attributable to sleepiness
Controversial: whether to treat asymptomatic patients with mild or
moderate OSA
Which patients with OSA require treatment?
Patients with OSA who are overweight or obese should be counseled
about losing weight through diet and exercise. All OSA patients may
also benefit from conservative measures, including treatment of any
nasal congestion and avoidance of alcohol close to bedtime. Beyond
these considerations, the decision to start treatment for OSA
should include a discussion with the patient about the potential
for alleviation of symptoms and cardiovascular risk reduction.
Determining whether attributable symptoms, such as daytime
sleepiness or frequent nocturnal awakenings, are present is
critical when deciding on OSA therapy. High-level evidence
indicates that patients with daytime sleepiness, regardless of
severity, should be offered a trial of therapy (30, 31). In
particular, those who have recently had a motor vehicle accident or
near-miss attributable to sleepiness should be aggressively
treated, specifically with continuous positive airway pressure
(CPAP) therapy for any degree of OSA, because CPAP is the only
treatment shown to reduce crash rates (12).
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What is the role of weight loss and exercise?
Helps reduce severity and symptoms
Recommend dietary modification
Recommend regular exercise
What is the role of weight loss and exercise?
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Can OSA be effectively managed by alterations in sleep
position?
If AHI lower when nonsupine: avoid supine position
Up to 1/3 mild or moderate cases are position-dependent
Methods for adherence
Wearable positional avoidance devices
Can OSA be effectively managed by alterations in sleep
position?
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How should CPAP be initiated?
CPAP prescription should include:
Traditionally: in-lab overnight titration study
Alternative for uncomplicated OSA: autotitrating CPAP
Educate patients on equipment, maintenance, care
Also: on benefits of therapy and potential problems
How should CPAP be initiated?
CPAP provides pneumatic splinting of the upper airway and is
indicated as primary therapy for moderate-to-severe OSA,
symptomatic OSA, and for any OSA in high-risk drivers. CPAP
settings are traditionally determined with an in-lab overnight
titration sleep study. A new prescription for CPAP should include
specification for the pressure setting, mask type and size, heated
humidifier, and associated device supplies (tube, filters, mask
straps). For patients with uncomplicated OSA, empirical
prescription of autotitrating CPAP (APAP) is an alternative
to the in-lab overnight titration and CPAP. The autotitrating
devices detect upper airway narrowing in real time and
automatically adjust pressure to remain therapeutic. Overall, APAP
performs as well as CPAP in terms of patient adherence and reducing
sleepiness. However, APAP is contraindicated in patients at risk
for Cheyne-Stokes breathing (e.g., those with congestive heart
failure or stroke), given its increased potential to induce central
apnea. APAP has also not been well-studied in patients with
significant pulmonary disease. APAP used in lieu of an overnight
titration study is typically prescribed with a wide initial
pressure range, such as 5–20 cm H2O. This allows the clinician to
interrogate the device 1–2 weeks after therapy initiation and
reduce the range or adjust to the minimum effective pressure.
Continuing with a range rather than setting a fixed pressure may
have the advantage of allowing pressures to self-adjust if changes
in therapy requirements are expected, such as during pregnancy,
after bariatric surgery, or with fluctuating sedative use in the
postoperative period. However, preliminary data suggest that
long-term APAP therapy may not reduce blood pressure to the same
extent as CPAP (35).
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What amount of CPAP use constitutes sufficient adherence?
Patients should use CPAP whenever they sleep
CMS: adequate CPAP use ≥4 h/night on 70% of nights
Linear relationship between hours of CPAP use and improvements
in:
Sleepiness
What amount of CPAP use constitutes sufficient adherence?
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What factors can optimize patient adherence to CPAP therapy?
Early follow-up (within 1–2 weeks of therapy initiation)
Support groups and bed partner support
Cognitive behavioral therapy focused on CPAP
Aid in therapy goal-setting
Support in troubleshooting difficulties
Other PAP modes if patient has intolerance to pressure
Short-term sedative hypnotic (for select patients only)
What factors can optimize patient adherence to CPAP therapy?
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How should CPAP masks be chosen?
No one mask type is superior to another
Select mask to maximize patient comfort
Oronasal (“full face”) masks
Nasal masks
Better tolerated with claustrophobia
Nasal pillows (sit under the nose and fit in the nares)
Also better tolerated with claustrophobia
Patients with unusual nasal bridge anatomy, facial hair, or absent
dentition
How should CPAP masks be chosen?
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What is the role of mandibular advancement devices?
Decrease airway collapsibility and enlarge upper airway
Requires adequate dentition, may exacerbate TMJ
Refer to experienced dentist (sleep dentistry accreditation)
Less effective than CPAP for normalizing the AHI
Mild or moderate OSA: May be reasonable initial therapy
Severe OSA: Not recommended as initial therapy
Patients tend to accept better than CPAP
Follow-up sleep study needed to document adequacy
What is the role of mandibular advancement devices?
Custom-made mandibular advancement devices (MAD) are oral
appliances that hold the mandible in a forward position and treat
OSA by decreasing airway collapsibility and enlarging the upper
airway. These devices are less effective than CPAP at normalizing
the AHI and are therefore not recommended as initial therapy for
severe OSA (34). For patients with mild or moderate OSA, however,
MADs may be a reasonable initial therapy (41). Despite reduced
efficacy, they tend to be more acceptable to patients and, as a
result, are associated with greater adherence. Among patients with
mild-to-moderate OSA, MADs have similar “real-world” effectiveness
to CPAP regarding improvements in sleepiness and quality of life.
For patients with severe OSA who do not tolerate CPAP despite
attempts to address therapy barriers, MADs can be considered a
secondary therapy option.
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What is the role of surgical intervention?
Uvulopalatopharyngoplasty (UPPP)
Tonsillectomy, nasal septoplasty
Maxillomandibular advancement
Cure rate >90%, particularly in nonobese with retrognathia
Tracheostomy
What is the role of surgical intervention?
Most surgeries to decrease upper airway collapsibility do not
significantly reduce OSA severity or symptoms (42). The
uvulopalatopharyngoplasty (UPPP) is perhaps best known, but
reduction in symptoms with this procedure is generally small, and
fewer than one half of patients have significant reduction in OSA
severity over the long term.
Maxillomandibular advancement is an invasive procedure with
prolonged postoperative recovery but has an OSA cure rate of
>90%, particularly in nonobese patients with retrognathia.
Tracheostomy also cures OSA and can be used in life-threatening
situations. For very select patients, these 2 surgeries, which
offer the potential for a cure, may be preferable to a lifetime of
CPAP therapy, but for most patients, the intensity of the procedure
and associated morbidity preclude routine application.
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How should treatment be monitored?
Ensure CPAP use during all sleep sessions
Assess symptom resolution
Assess comorbid conditions associated with OSA
Monitor remission due to weight loss or surgery
Monitor remission in those with history drowsy driving
If relapse occurs, investigate stepwise:
Inadequate therapy adherence
How should treatment be monitored?
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How should OSA be treated when a patient is admitted to the
hospital?
Patients should use their CPAP or MAD in the hospital
Just as they would at home
Use sedative and opiate medications cautiously
If moderate sedation used intraoperatively
Monitor ventilation by continuous oximetry and continuous
capnography
Consider CPAP administration during sedation
Beware untreated OSA in periop setting
Higher rate cardiopulmonary complications, ICU transfers
How should OSA be treated when a patient is admitted to the
hospital?
There is little evidence to support a particular management
strategy of patients with OSA admitted to a medical service.
Nevertheless, patients should be encouraged to use their CPAP or
MAD while hospitalized, just as they would at home. Nursing,
respiratory therapy, and engineering processes should be
established to facilitate this. For example, patients should be
allowed to use their own mask rather than hospital-provided masks,
which typically do not fit as well. Sedative and opiate medications
can worsen OSA and should be used cautiously among OSA
inpatients.
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When should a sleep specialist be consulted for management?
Complicated management situations
When should a sleep specialist be consulted for management?
For uncomplicated OSA, studies suggest that when primary care
clinicians are educated about disease management and have trained
support staff, treatment outcomes are similar to sleep specialist
referral and management (46). However, if these prerequisites
cannot met, referral to a sleep specialist may be
appropriate.
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What should patients know about the effects of medications and
supplemental oxygen?
Use sedatives and opiates cautiously (can worsen OSA)
Exogenous testosterone may exacerbate or induce OSA
Don’t use supplemental oxygen as primary therapy
Treats oxyhemoglobin desaturation associated with OSA
Little evidence that it reduces symptoms, BP, CV risk
Some patients require both CPAP and supplemental oxygen
What should patients know about the effects of medications and
supplemental oxygen?
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Can treatment prevent or modify outcomes in other diseases?
CPAP and MAD therapy reduce blood pressure
Degree of adherence correlates with BP response
CPAP therapy may reduce hypertension
Effect of therapy on cardiovascular outcomes unclear
Other diseases may be modified by OSA therapy
May modestly increase ejection fraction in CHF
May reduce likelihood of Afib recurrence
Can treatment prevent or modify outcomes in other diseases?
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CLINICAL BOTTOM LINE: Treatment...
Symptomatic or severe OSA
Symptom resolution
Reduced cardiovascular risk
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