aitc 1411 obstructive sleep apnea

Slide 1© Copyright Annals of Internal Medicine, 2014 Ann Int Med. 161 (5): ITC5-1.
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© Copyright Annals of Internal Medicine, 2014 Ann Int Med. 161 (5): ITC5-1.
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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
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
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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aitc 1411 obstructive sleep apnea

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