This guideline applies to adult patients 19 and older with suspected obstructive sleep apnea (OSA). While sleep apnea may occur in 1-4% of children 1 , pediatric diagnosis and management is beyond the scope of this guideline. For a brief pediatric overview, see Appendix A: Sleep Apnea in Children. Other conditions that may contribute to daytime sleepiness are also out of the scope of this guideline. Please see Appendix B: Other Conditions Associated with Daytime Sleepiness.- If OSA is suspected, conduct a detailed history and a physical examination, focused on the upper airway. 2 - The STOP-Bang questionnaire can be used to help determine if a patient is at increased risk of moderate to severe OSA. 2 - While the most common symptom of OSA is excessive daytime sleepiness, the clinical presentation can vary. Completion of the Epworth Sleepiness Scale is recommended. 2 - Patients with untreated OSA may have increased perioperative morbidity. 3 Consider appropriate screening when referring patients for potential surgery (e.g., STOP-Bang Questionnaire). See also the BC Surgical Rehabilitation Toolkit for further information.# Testing and Referral
- Home Sleep Apnea Test (HSAT) should not be used to screen asymptomatic patients. HSAT is only recommended for the diagnosis of OSA in symptomatic patients who are determined to be at an increased risk of moderate-to-severe OSA, and who have no exclusion criteria (see Requisition). 2 - A negative or equivocal HSAT does not exclude OSA. If an HSAT is negative, inconclusive or technically inadequate, and OSA is suspected, polysomnography is recommended. 2 - BC now has a Standard Requisition for HSAT that referring practitioners are required to use.
- Symptomatic patients for which the HSAT is not the appropriate diagnostic test should be referred for a sleep disorder consultation for polysmnography. 2 
Management and Follow-up - When assessing whether a patient should be treated, it is important to consider the severity of the symptoms, presence and severity of any comorbid disease, presence of any safety-critical occupation and the results of all sleep studies. - OSA is a serious chronic disease that warrants regular follow-up, short-term to ensure initial compliance and response to treatment and long-term to confirm continued effectiveness. 3 - Patients with OSA may be prone to drowsiness while driving. Physicians caring for these patients should be familiar with BC's Driver Medical Fitness Information for Medical Professionals.  - Surgery for OSA, including minimally invasive techniques to reduce tissue volume, incurs typical surgical risks. Since there may be effective medical alternatives to surgery, prior referral to a sleep disorder physician is recommended.

# Types of Sleep Apnea
There are four types of sleep apnea:
- Obstructive sleep apnea (OSA) is the most common type of sleep apnea encountered in primary care. It is characterized by complete cessation or transient reduction in breathing with maintained or increasing respiratory effort. Home Sleep Apnea Testing (HSAT) should only be performed on patients who present with an increased risk of moderate-to-severe OSA. - Other less common types of sleep apnea include:
 Central sleep apnea is characterized by complete cessation or transient reduction in breathing with absent respiratory effort. This occurs in patients with neurological disease or in association with drug/substance abuse or high altitude.  Cheyne-Stokes breathing is characterized by a crescendo-decrescendo pattern of respiration between central apnea.
This frequently occurs in patients with heart failure or cerebrovascular disease.  Complex sleep apnea is characterized by the persistence or emergence of central apneas or hypopneas when treated with Continuous Positive Airway Pressure (CPAP or BiPAP) and obstructive apnea has been resolved. This may occur in up to 10% of patients with OSA treated with CPAP.
Sleep hypoventilation is a sleep disorder characterized by significant hypercapnia and hypoxemia during sleep. This usually occurs in patients with OSA and morbid obesity or obstructive or restrictive lung disease. These patients usually require urgent evaluation. 4

# Epidemiology
OSA is associated with poor quality of life 6,8,9 and has been linked to severe chronic health conditions such as obesity, diabetes, metabolic syndrome 3,10 and neuro-psychiatric problems. 10 Moderate-severe OSA is associated with an increased risk of cardiovascular disease, resulting in hypertension, coronary disease, stroke, heart failure, and atrial fibrillation. 5 OSA is widely underdiagnosed; 86% to 95% of individuals found in population surveys with clinically significant OSA report no prior OSA diagnosis. 6 The  13 - traumatic brain injury 14 - nasal and nasopharyngeal obstruction 15 - neuromuscular disease 16 - Marfan syndrome 17 - polycystic ovarian disease 18 Risks of Untreated or Undertreated OSA 2,19-21
Untreated or undertreated OSA pose serious risks and have been associated with: daytime sleepiness, impaired quality of life, motor vehicle crashes, occupational injury, systemic hypertension, type 2 diabetes, cardiac arrhythmia, aortic dilatation/ dissection, coronary artery disease, heart failure, stroke, depression, cognitive impairment, cancer, ocular disease, pneumonia, renal dysfunction, dementia, seizures, hypogonadism, maternal/fetal health, post-operative complications, and premature death.
Patients with untreated OSA may have increased perioperative morbidity (postoperative cardiac events, acute respiratory failure, desaturation and reintubation); 21 consider appropriate screening when referring patients for potential surgery (e.g., using the STOP-Bang Questionnaire, Appendix C: STOP-Bang Questionnaire). See also the BC Surgical Rehabilitation Toolkit for further information.

# History and Physical Examination
- History and physical examination are crucial first steps towards the recognition and diagnosis of OSA. 2 Patient history should focus on nocturnal breathing abnormalities, daytime sleepiness, and family and personal medical history. - Consider using the STOP-Bang questionnaire to help determine if a patient is at increased risk of moderate to severe OSA (Appendix C: STOP-Bang Questionnaire). 2 - Determine the patient's risk factors for OSA (see list on pages 2-3 above).
- While the clinical presentation of OSA can vary, the most common symptom is excessive daytime sleepiness. Inquire about the impact of daytime sleepiness (e.g., "Have you had any accidents or near misses related to sleepiness while driving?" or "Have you ever had to stop an activity due to sleepiness?"). Request completion of the Epworth Sleepiness Scale. A score of greater than 10 suggests significant daytime sleepiness, although a score of 10 or less does not exclude daytime sleepiness or OSA. - All patients should be questioned about driving or safety critical occupation (e.g., truck, taxi, bus drivers, railway engineers, commercial pilots 22 ) where sleepiness could be a hazard, whether they operate heavy equipment, the class of their driver's license and whether they have fallen asleep at the wheel or have come close to doing so in the past 5 years.
Physical examination:
- Head and neck examination are important.  Measure the neck circumference if feasible  Examine the upper airway and it may be useful to evaluate the Mallampati score -Mallampati Classification (Appendix D: Mallampati Classification). A higher Mallampati classification has been associated with OSA diagnosis and increased AHI.
For every 1-point increase in the Mallampati score, the odds of having OSA increased by more than 2-fold. 23 .

# Testing and Referral
- To determine if a patient requires a diagnostic test for OSA, it is important to first identify if they are at increased risk of moderate-to-severe OSA. This is indicated by the presence of excessive daytime sleepiness or fatigue and at least two of the following three criteria:  witnessed apneas or gasping or choking  habitual loud snoring  diagnosed hypertension
- If the patient is at an increased risk of moderate-to-severe OSA, then the Home Sleep Apnea Test (HSAT) is an appropriate diagnostic test, rather than a polysomnography. - However, HSAT is not the appropriate test if one or more of the following exclusion criteria apply (any one item precludes HSAT):  concern for non-respiratory sleep disorder (e.g., chronic insomnia, sleep walking/talking)  risk of hypoventilation (e.g., neuromuscular disease, BMI  40 kg/m 2 ) chronic/regular opiate medication use significant cardiopulmonary disease (e.g., history of stroke, heart failure, moderate-to-severe lung disease)  previous negative or equivocal HSAT  age < 16 years  inability to complete necessary steps for self-administered HSAT (e.g., cognitive, physical, or other barriers)
- Recognizing that some patients may not have a bed partner, the referring physician may, while conducting a physical examination, assess whether there is a reasonable suspicion of nocturnal breathing events such as apneas, gasping, choking or habitual loud snoring. - HSAT is not recommended for pediatric patients, however, physician evaluation, rather than age, may be the best way to determine whether an adolescent presents as an adult. - Patients at increased risk of moderate-to-severe OSA but with one of more of the exclusion criteria above should be referred to a sleep disorder physician for potential polysomnography (PSG). - Referral for HSAT is limited to:  Registrants of the College of Physicians and Surgeons of British Columbia  Nurse practitioners or other designated health professional as authorized by the College of Physicians and Surgeons of British Columbia. - If an HSAT is negative, equivocal, or the patient has been mis-referred:
- The diagnostic facility is to notify the referring physician that the patient did not/does not meet the requirements for an HSAT and recommend a sleep disorder consultation and/or Level 1 polysomnogram study (preferred), or 2. The diagnostic facility's Medical Director or interpreting physician may refer the patient for a sleep disorder consultation and/or Level 1 study and notify the originating/referring physician, ensuring the originating/referring physician receives a copy of the HSAT result. In this case the Medical Director or interpreting physician is responsible for patient follow up as the ordering physician and cannot assume the original referring physician will provide patient follow up on the test.
Facilities must have a policy and procedure for notifying the referring physician of critical results immediately.
- To order HSAT or to request a referral for a sleep disorder consultation, see Associated Documents.
- For patients with suspected OSA, Figure 1. outlines the patient pathway.  

# Interpretation of Results
- The diagnostic sleep report should provide an assessment as to whether the patient has OSA and whether it is mild, moderate, or severe. - Apnea Hypopnea Index (AHI): Is defined by the number of apnea and hypopnea per hour of measured sleep. - In addition to symptoms and presence of comorbid disease, AHI is one of the criteria used to determine the severity of sleep apnea.
 AHI values should be considered in conjunction with clinical presentation, including a patient's symptoms, co-morbidities and occupation, and all sleep monitoring abnormalities such as degree of hypoxemia (see Table 1: AHI Interpretation below). 

# OSA Management
When assessing whether a patient should be treated it is important to consider the severity of the symptoms, presence and severity of any comorbid disease, presence of any safety-critical occupation and all the sleep monitoring abnormalities.
Patients with OSA and daytime sleepiness and/or sleep related arterial oxygen desaturation appear more likely to develop vascular complication if left untreated. It is important to treat most patients with OSA if they have comorbid disease or work in a safety critical occupation such as a commercial driver. Treatment should be considered in patients with fatigue and/or sleepiness even if the AHI is in the milder range.
Patients with OSA may be prone to drowsiness while driving. Physicians caring for these patients should be familiar with BC's Driver Medical Fitness Information for Medical Professionals. Surgical options are primarily for patients with tonsillar hypertrophy or craniofacial abnormalities and require referral to a sleep disorder physician and to the appropriate surgeon for more comprehensive evaluations.

# Healthy Behaviours and Diet:
The importance of healthy behaviours and diet, including exercise and weight loss, should be recommended for patients with elevated BMI, although it is not adequate as a stand-alone therapy if the patient is sleepy or has moderate to severe OSA. Weight loss is more successful if the patient uses definitive therapy to control their OSA and then retest after their weight goal is achieved to see if definitive therapy is still required.

# Continuous Positive Airway Pressure (CPAP):
CPAP is generally the most effective treatment for OSA. If a patient is diagnosed with OSA and is unwilling or intolerant of CPAP, consider alternate therapies or refer to sleep disorder physician.
Positional Therapy: Avoiding sleeping in the supine position is an option if testing shows that OSA is primarily in the supine position. There are electronic devices that can monitor and record sleeping positions.
Other devices (oral, etc.): Oral appliances may be useful for mild to moderate OSA or those intolerant/unwilling to use CPAP and can be effective for some patients.
For additional OSA management information, see Appendix F: OSA Management Options. For additional information on oral and other devices, see Appendix G: Oral and Other Devices.

# Follow-Up
- OSA is a serious chronic disease that warrants regular follow-up; short-term to ensure initial compliance and response to treatment and long-term to confirm continued effectiveness. 3 - There is no need to re-test if the patient is doing well on long-term CPAP therapy and there is no change in clinical status.
 Annual follow-up is recommended with CPAP download  Indications for retesting: Persistent daytime symptoms, abnormal overnight oximetry or residual sleep disordered breathing based on CPAP download - Whatever treatment is used, the patient should be followed until the AHI is normal (less than 5 events per hour), the Epworth Sleepiness Scale score is 10 or less, the patient feels rested, and a bed partner reports no residual snoring. Ideally, the patient is using the treatment every night, all night. - CPAP machines also provide a patient accessible read out of 'events per hour' . This is an index of residual sleep apnea and not a true AHI as it is not derived from sleep monitoring but is a useful daily indication of therapy effectiveness.

# Problem Solving CPAP therapy
After treatment, non-adherence to CPAP therapy, CPAP intolerance and persistent sleepiness after therapy may occur. Considerations include:
- CPAP non-adherence: Lack of interest/understanding of OSA -importance of treatment can be reinforced; depends on indications for treatment and severity of disease. 24 CPAP intolerance -is common and should be addressed by the CPAP provider. 24 See table below for common causes of intolerance. See Table 2: CPAP Intolerance and Treatment Recommendations below. 

# Methodology
These guideline recommendations are tailored to support practice in British Columbia and are based on the ADAPTE Collaboration guideline adaption methodology. 25 Clinical recommendations were developed based on the sourced guidelines, 2,3,19, a Primary Care Pathway: Uncomplicated Obstructive Sleep Apnea, 24 as well as expert clinical consensus where evidence was insufficient or unavailable.
The source guidelines were chosen following an environmental scan of internationally available guidelines. Guidelines were chosen for adaptation following an evaluation using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) tool. 30 In situations where there is a lack of rigorous evidence, best clinical opinion has been provided to support decision making and high-quality patient care.
The guideline development process includes significant engagement and consultation with primary care providers, sleep disorder physicians, and key stakeholders. For more information about Guidelines and Protocols Advisory Committee (GPAC) guideline development processes, refer to the GPAC handbook available at BCGuidelines.ca.
The level and quality of evidence for the key recommendations are based on those used by the AASM: Clinical Practice Guideline for Diagnostic Testing for Adult Obstructive Sleep Apnea (2017). 2 Please refer to those guidelines for a summary of the levels of evidence (table 5). Where evidence was insufficient or unavailable expert clinical consensus was used and is indicated in the key recommendations as "expert opinion".

# Resources

# Abbreviations
The principles of the Guidelines and Protocols Advisory Committee are to:
- encourage appropriate responses to common medical situations - recommend actions that are sufficient and efficient, neither excessive nor deficient - permit exceptions when justified by clinical circumstances