A brief overview of obstructive sleep apnea: causes, risk factors, diagnosis and medical management

1. Sleep apnea

2. During this time air traffic controllers were frantically radioing the flight
from Honolulu to Hilo for 18 minutes but receiving no response from the
pilots. Since this incident the airline captain has been diagnosed with
severe obstructive sleep apnea.
Shelley Perlman; BCMJ, Vol. 56, No. 2, March 2014, page(s) 94-96 WorkSafeBC

3. Contents
o Introduction
o Causes
o Risk factors
o Diagnosis
o Medical management
3

4. What is sleep apnea?
▪ Sleep apnea, is a sleep disorder characterized by
pauses in breathing or periods of shallow
breathing during sleep.
▪ Each pause can last for a few seconds to a few
minutes and they happen many times a night.
▪ In the most common form, this follows loud
snoring.
▪ There may be a choking or snorting sound as
breathing resumes.
41. "Sleep Apnea: What Is Sleep Apnea?". NHLBI: Health Information for the Public. U.S. Department of Health and Human Services. July 10, 2012.
2. "What Are the Signs and Symptoms of Sleep Apnea?". NHLBI. July 10, 2012.

5. Obstructive sleep apnea (OSA)
▪ OSA is a disorder that is characterized by
obstructive apneas and hypopneas due to
repetitive collapse of the upper airway during
sleep.
Untreated OSA has many potential consequences
and adverse clinical associations:
 excessive daytime sleepiness
 impaired daytime function
 metabolic dysfunction
 and an increased risk of cardiovascular disease and mortality
5

6. Obstructive sleep apnea (OSA)
Cardinal features in adults:
▪ Obstructive apneas, hypopneas, or respiratory effort
related arousals
▪ Daytime symptoms attributable to disrupted sleep, such
as sleepiness, fatigue, or poor concentration
▪ Signs of disturbed sleep, such as snoring, restlessness,
or resuscitative snorts
6

7. Prevalence in India
▪ In 2006, a population-based survey from north
India had estimated the prevalence of OSAS at
3.6% (males and females being 4.9 and 2.1%
respectively)
▪ In a hospital-based study of urban men between
35 and 65 yr from western India, the prevalence
of OSA was 19.5% and of OSAS was 7.5%
7
1. Sharma SK, Kumpawat S, Banga A, Goel A. Prevalence and risk factors of obstructive sleep apnoea syndrome in a population of Delhi, India. Chest 2006;
130 :149-56.
2. Udwadia ZF, Doshi AV, Lonkar SG, Singh CI. Prevalence of sleep disordered breathing and sleep apnoea in middle-aged urban Indian men. Am J Respir
Crit Care Med 2004; 169 : 168-73.

8. Risk factors
 Advancing age: prevalence of OSA increases from
young adulthood through the 6th to 7th decade
 Male gender: OSA is approximately 2 to 3 times more
common in males than females
 Obesity: prevalence of OSA progressively increases as
the BMI and associated markers (eg, neck
circumference, waist-to-hip ratio) increase
 Craniofacial or upper airway soft tissue abnormalities:
abnormal maxillary or short mandibular size, a wide
craniofacial base, tonsillar hypertrophy, and adenoid
hypertrophy, adeno-tonsillar hypertrophy in children 8

9. Additional risk factors
▪ Additional risk factors identified in some studies
include smoking, nasal congestion, menopause,
and family history.
▪ Rates of OSA are also increased in association
with certain medical conditions, such as
pregnancy, end-stage renal disease, congestive
heart failure, chronic lung disease, stroke.
9

10. Pathophysiology
of OSA
▪ OSA is characterized by recurrent,
functional collapse during sleep of
the velopharyngeal and/or
oropharyngeal airway, causing
substantially reduced or complete
cessation of airflow despite ongoing
breathing efforts.
▪ This leads to intermittent
disturbances in gas exchange (eg,
hypercapnia and hypoxemia) and
fragmented sleep.
10

11. Symptoms of
sleep apnea
11

12. Clinical presentation of OSA

13. Clinical Practice
Guideline for
Diagnostic Testing
for Adult OSA:
Clinical Practice Guideline 2017
13

14. Good Practice Statements
▪ Diagnostic testing for OSA should be performed
in conjunction with a comprehensive sleep
evaluation and adequate follow-up.
▪ Polysomnography is the standard diagnostic test
for the diagnosis of OSA in adult patients in
whom there is a concern for OSA based on a
comprehensive sleep evaluation.
Kapur, V.K., Auckley, D.H., Chowdhuri, S., Kuhlmann, D.C., Mehra, R., Ramar, K. and Harrod, C.G., 2017. Clinical practice guideline for diagnostic testing for
adult obstructive sleep apnea: an American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med, 13(3), pp.479-504.

15. Recommendations
1. We recommend that clinical tools, questionnaires and prediction
algorithms not be used to diagnose OSA in adults, in the absence of
polysomnography or home sleep apnea testing. (STRONG)
2. We recommend that polysomnography, or home sleep apnea testing
with a technically adequate device, be used for the diagnosis of OSA in
uncomplicated adult patients presenting with signs and symptoms that
indicate an increased risk of moderate to severe OSA. (STRONG)
3. We recommend that if a single home sleep apnea test is negative,
inconclusive, or technically inadequate, polysomnography be performed
for the diagnosis of OSA. (STRONG) 15

16. Recommendations (contd…)
4. We recommend that polysomnography, rather than home sleep apnea testing, be
used for the diagnosis of OSA in patients with significant cardiorespiratory
disease, potential respiratory muscle weakness due to neuromuscular condition,
awake hypoventilation or suspicion of sleep related hypoventilation, chronic
opioid medication use, history of stroke or severe insomnia. (STRONG)
5. We suggest that, if clinically appropriate, a split-night diagnostic protocol, rather
than a full-night diagnostic protocol for polysomnography be used for the
diagnosis of OSA. (WEAK)
6. We suggest that when the initial polysomnogram is negative and clinical
suspicion for OSA remains, a second polysomnogram be considered for the
diagnosis of OSA. (WEAK)
16

17. Clinical algorithm for implementation of
clinical practice guidelines
17

18. Clinical algorithm for implementation of
clinical practice guidelines (contd…)
18Kapur, V.K., Auckley, D.H., Chowdhuri, S., Kuhlmann, D.C., Mehra, R., Ramar, K. and Harrod, C.G., 2017. Clinical practice guideline for diagnostic testing for
adult obstructive sleep apnea: an American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med, 13(3), pp.479-504.

19. Polysomnography
▪ Polysomnography, a type of sleep
study, is a multi-parametric test
used in the study of sleep and as
a diagnostic tool in sleep
medicine.
▪ Nocturnal, laboratory-based
polysomnography (PSG) is the
most commonly used test in the
diagnosis of obstructive sleep
apnea syndrome (OSAS)
19

20. Home sleep apnea
testing (HSAT)
20

21. Management of OSA
▪ OSA is a chronic disease that requires long-term,
multidisciplinary management.
▪ The goals of therapy are to: reduce or eliminate
apneas, hypopneas, and oxyhemoglobin
desaturation during sleep and thereby improve
sleep quality and daytime function.
21

22. Management of OSA
Several international organizations have published
clinical practice guidelines for the management of
OSA in adults, including:
o American Academy of Sleep Medicine (AASM),
o American Thoracic Society (ATS)
o American College of Physicians (ACP)
o International Geriatric Sleep Medicine Force
The recommendations discussed below are generally
consistent with these guidelines.
22

23. Treatment of
obstructive sleep
apnea algorithm
23
AHI: apnea-hypopnea index; RERAs: respiratory effort
related arousals.

24. Management of OSA
Patient education:
▪ Management begins with patient education.
▪ Importantly, patients should be warned about the
increased risk of motor vehicle accidents
associated with untreated OSA and the potential
consequences of driving while sleepy.
24

25. Management of OSA
Patient education:
▪ Importantly, all patients should be warned about the
increased risk of motor vehicle accidents associated
with untreated OSA and the potential consequences of
driving or operating other dangerous equipment while
sleepy.
▪ Patients should also be counseled to avoid activities
that require vigilance and alertness if sleepy.
25Strohl KP, Brown DB, Collop N, et al. An official American Thoracic Society Clinical Practice Guideline: sleep apnea, sleepiness, and driving risk in
noncommercial drivers. An update of a 1994 Statement. Am J Respir Crit Care Med 2013; 187:1259.

26. Management of OSA
Behavior modification:
▪ Behavior modification is indicated for most
patients who have OSA.
This includes:
 losing weight & exercising
 changing the sleep position (if OSA is positional),
 abstaining from alcohol
 avoiding certain medications (benzodiazepines, barbiturates,
antiepileptic drugs, sedating antidepressants, antihistamines, and
opiates) 26

27. Management of OSA
Behavior modification:
▪ Weight loss & exercise recommended to all patients
with OSA who are overweight or obese
▪ Weight loss (including bariatric surgery), has been
shown to improve overall health and metabolic
parameters, decrease the AHI, reduce blood pressure,
improve quality of life, and probably decrease daytime
sleepiness
27AHI: apnea-hypopnea index (the number of apneas and hypopneas per hour of sleep)
Randerath WJ, Verbraecken J, Andreas S, et al. Non-CPAP therapies in obstructive sleep apnoea. Eur Respir J 2011; 37:1000.

28. ▪ 72 overweight patients (mean BMI 32 kg/m2) with mild
OSA (mean AHI 10 events per hour of sleep)
The patients were randomly assigned to receive:
A. a single session of general nutrition and exercise advice
B. or a more intensive program that included a low calorie
diet for three months plus nutrition and exercise
counseling for one year
Patients in group (B) had:
 significantly greater weight loss (11 vs 2 kg)
 reduction in the AHI (mean change from baseline, -4 vs 0.3
events per hour)
 improvement in quality of life compared with the control group 28

29. CONCLUSIONS:
▪ VLCD combined with active lifestyle counseling
resulting in marked weight reduction is a feasible and
effective treatment for the majority of patients with mild
OSA, and the achieved beneficial outcomes are
maintained at 1-year follow-up.
29
VLCD: very low calorie diet

30. In a 2014 meta-analysis that included five small
randomized trials, a supervised exercise program
was associated with significantly improved:
 AHI (mean change, -6 events/hour)
 sleep efficiency
 subjective sleepiness
 cardiorespiratory fitness with minimal change in body
weight
30

31. Management of OSA
Behavior modification: sleep position
▪ During the diagnostic sleep study, some patients will be
observed to have OSA that develops or worsens during
sleep in the supine position.
 Sleeping in a non-supine position (eg, lateral recumbent)
may correct or improve OSA in such patients and should
be encouraged but not generally relied upon as the sole
therapy
31
1. Jokic R, Klimaszewski A, Crossley M, et al. Positional treatment vs continuous positive airway pressure in patients with positional obstructive sleep apnea
syndrome. Chest 1999; 115:771.
2. Benoist L, de Ruiter M, de Lange J, de Vries N. A randomized, controlled trial of positional therapy versus oral appliance therapy for position-dependent
sleep apnea. Sleep Med 2017; 34:109.

32. Management of OSA
Behavior modification: alcohol avoidance
▪ All patients with untreated OSA should avoid alcohol,
as it can depress the CNS, exacerbate OSA, worsen
sleepiness, and promote weight gain.
▪ In patients who snore but do not have OSA at baseline,
alcohol consumption can prompt frank OSA.
32
Issa FG, Sullivan CE. Alcohol, snoring and sleep apnea. J Neurol Neurosurg Psychiatry 1982; 45:353

33. Continuous positive
airway pressure
(CPAP)
▪ CPAP therapy is the
mainstay of therapy for
adults with OSA.
▪ The mechanism of CPAP
involves maintenance of a
positive pharyngeal
transmural pressure so that
the intraluminal pressure
exceeds the surrounding
pressure
33

34. Continuous positive
airway pressure
(CPAP)
▪ CPAP also stabilizes the
upper airway through
increased end-expiratory
lung volume.
▪ As a result, respiratory
events due to upper airway
collapse (eg, apneas,
hypopneas) are prevented.
34

35. Management of OSA
Positive airway pressure therapy:
▪ For patients with severe OSA (AHI ≥30 events per
hour) → positive airway pressure as initial
therapy
▪ For patients with mild to moderate OSA →
positive airway pressure as initial therapy rather
than an oral appliance (Grade 2B).
35

36. Management of OSA
Positive airway pressure therapy:
▪ For patients who anticipate problems with positive
airway pressure therapy adherence, an oral appliance
(eg, mandibular advancement devices, tongue retaining devices) is a
reasonable alternative as first-line therapy.
36

37. In a meta-analysis of 35
randomized trials,
CPAP compared with sham resulted in significant
reduction in:
 AHI (mean difference -33.8 events/hour)
 improved daytime sleepiness as assessed by the Epworth
Sleepiness Scale (mean difference -2 points),
 systolic and diastolic blood pressure
 sleep-related quality of life.
▪ No appreciable effect on mortality was reported.
37Jonas DE, Amick HR, Feltner C, et al. Screening for Obstructive Sleep Apnea in Adults: Evidence Report and Systematic Review for the US Preventive
Services Task Force. JAMA 2017; 317:415.

38. In a meta-analysis of 22
randomized trials (1160 patients)
▪ Compared nocturnal CPAP with a control (sham
CPAP, placebo tablets, or conservative
management)
 Nocturnal CPAP significantly improved both
subjective and objective sleepiness, quality of life,
cognitive function, and depression
38Giles TL, Lasserson TJ, Smith BJ, et al. Continuous positive airways pressure for obstructive sleep apnoea in adults. Cochrane Database Syst Rev 2006;
:CD001106.

39. Network meta-analysis of 80
randomized controlled trials
Objective:
▪ To synthesize evidence from available studies on the
relative efficacies of CPAP, mandibular advancement
device (MAD), supervised aerobic exercise training and
dietary weight loss in patients with OSA.
Results:
▪ CPAP decreased AHI the most [by 25.27 events/hour
(22.03 to 28.52)] followed by exercise training, MADs
and dietary weight loss.
39Iftikhar IH, Bittencourt L, Youngstedt SD, et al. Comparative efficacy of CPAP, MADs, exercise-training, and dietary weight loss for sleep apnea: a network
meta-analysis. Sleep Med 2017; 30:7.

40. Network meta-analysis of 80
randomized controlled trials
Conclusion and highlights of the study:
1. CPAP is the most efficacious in complete resolution of
sleep apnea.
2. Exercise training can significantly improve daytime
sleepiness.
3. Exercise training can be a useful adjunct to CPAP and
MADs.
40Iftikhar IH, Bittencourt L, Youngstedt SD, et al. Comparative efficacy of CPAP, MADs, exercise-training, and dietary weight loss for sleep apnea: a network
meta-analysis. Sleep Med 2017; 30:7.

41. Apnea-hypopnea index (AHI)
▪ AHI is calculated by dividing the number of apnea
events by the number of hours of sleep.
The AHI values for adults are categorized as:
41
Category AHI
Normal <5
Mild sleep apnea 5 to 14
Moderate sleep apnea 15 to 29
Severe sleep apnea >30

42. Patient selection for therapy
1. Patients with an AHI >5 events per hour of sleep
plus one or more clinical or physiologic sequelae
attributable to OSA.
2. Patients with an AHI ≥15 events per hour of
sleep, even in the absence of symptoms.
3. Patients with an increased number of RERAs (eg,
≥10 per hour) and excessive daytime sleepiness,
even if the AHI is ≤5 events per hour.
42
RERA: Respiratory-effort related arousal

43. Patient selection for therapy
4. Patients who perform mission critical work (eg,
airline pilots, air traffic controllers, locomotive engineers, bus
and truck drivers) and have an AHI 5 to 15, even if
there are no clinical or physiological symptoms
attributable to OSA.
 The decision to initiate therapy therefore requires some
clinician judgement as well as recognition that the
driver may be poorly motivated to report symptoms.
43

44. Modes of positive airway pressure
therapy: CPAP
▪ CPAP delivers positive airway pressure at a level that
remains constant throughout the respiratory cycle.
▪ It is used most often because it is the simplest, the most
extensively studied, and associated with the most
clinical experience.
▪ A pressure relief setting (ie, lowers the positive airway
pressure at the onset of exhalation) is sometimes used
to improve comfort and tolerance of the device.
44

45. Modes of positive airway pressure
therapy: BPAP
Bilevel positive airway pressure
▪ (BPAP) delivers a preset inspiratory positive airway
pressure (IPAP) and expiratory positive airway pressure
(EPAP).
▪ The degree of pressure support and consequently tidal
volume is related to the difference between the IPAP
and EPAP.
 There is no proven advantage to using BPAP instead of
CPAP for the routine management of OSA
45

46. Modes of positive airway pressure
therapy: APAP
Automatic positive airway pressure
▪ (APAP) increases or decreases the level of positive
airway pressure in response to a change in airflow, a
change in circuit pressure, or a vibratory snore (signs
that generally indicate that upper airway resistance has
changed).
▪ The degree of improvement of major outcomes
conferred by APAP and CPAP is similar
46

47. Selecting PAP
▪ For most patients with OSA, CPAP as the initial mode of
PAP is ideal (Grade 2C).
▪ Auto-titrating CPAP is a reasonable alternative in
patients with uncomplicated OSA who are diagnosed by
home sleep apnea testing, particularly if access to a
sleep laboratory is limited
▪ For patients who do not tolerate fixed CPAP, a trial of
an alternative mode of PAP before abandoning positive
pressure therapy (Grade 2C). BPAP and auto-titrating
CPAP are acceptable options. 47

48. Selecting PAP
BPAP may be preferred initial therapy in certain subgroups
of patients with OSA, like:
 patients with coexisting OSA and chronic hypercapnic
respiratory failure
 patients with coexisting OSA and significant central
sleep apnea.
48

49. Selecting PAP
▪ The appropriate amount of PAP is determined by
titration.
▪ This is performed during a sleep study, in order to
confirm that the amount of PAP to be prescribed
effectively eliminates respiratory events and snoring.
49

50. Pt compliance with PAP
Contributing factors include:
 Patient education
 Close follow-up
 Treatment of complications
 Comfort of the patient-device interface
 Subjective success of the patient's first night using PAP
at home
 Support of the patient's bed partner
50

51. Management of OSA
Pharmacological approach:
▪ A variety of pharmacologic agents have been
investigated in randomized trials as primary therapeutic
agents for the management of sleep-disordered
breathing on OSA.
▪ This includes drugs that might act to stimulate
respiratory drive directly (eg, theophylline) or indirectly
(eg, acetazolamide) or drugs that reduce upper airway
collapsibility (eg, desipramine)
51Taranto-Montemurro L, Sands SA, Edwards BA, et al. Desipramine improves upper airway collapsibility and reduces OSA severity in patients with minimal
muscle compensation. Eur Respir J 2016; 48:1340.

52. Management of OSA
Surgical management:
▪ Surgical therapy is generally reserved for selected
patients in whom positive airway pressure or an oral
appliance was either declined, not an option, or
ineffective.
▪ Examples of surgically correctable lesions that may
obstruct the upper airway include tonsillar hypertrophy,
adenoid hypertrophy, or craniofacial abnormalities
52
1. Epstein LJ, Kristo D, Strollo PJ Jr, et al. Clinical guideline for the evaluation, management and long-term care of obstructive sleep apnea in adults. J Clin
Sleep Med 2009; 5:263.
2. Randerath WJ, Verbraecken J, Andreas S, et al. Non-CPAP therapies in obstructive sleep apnoea. Eur Respir J 2011; 37:1000.
3. Senchak AJ, McKinlay AJ, Acevedo J, et al. The effect of tonsillectomy alone in adult obstructive sleep apnea. Otolaryngol Head Neck Surg 2015;
152:969.

53. Management of OSA
Surgical management:
▪ Hypoglossal nerve stimulation via an implantable
neurostimulator device is a novel treatment strategy
that may have a role in selected patients with moderate
to severe OSA who decline or fail to adhere to positive
airway pressure therapy
53
1. Eastwood PR, Barnes M, Walsh JH, et al. Treating obstructive sleep apnea with hypoglossal nerve stimulation. Sleep 2011; 34:1479.
2. Goding GS Jr, Tesfayesus W, Kezirian EJ. Hypoglossal nerve stimulation and airway changes under fluoroscopy. Otolaryngol Head Neck Surg 2012;
146:1017.
3. Schwartz AR, Barnes M, Hillman D, et al. Acute upper airway responses to hypoglossal nerve stimulation during sleep in obstructive sleep apnea. Am J
Respir Crit Care Med 2012; 185:420.

54. Conclusion:
Potential benefits of successful treatment of OSA
include:
 improved quality of life
 improved systemic blood pressure control
 reduced healthcare utilization and costs
 possibly decreased cardiovascular morbidity and
mortality
54