REVIEW CPD

Diagnosis and treatment of obstructive in adults

Cheryl R. Laratta MD, Najib T. Ayas MD MPH, Marcus Povitz MD MSc, Sachin R. Pendharkar MD MSc n Cite as: CMAJ 2017 December 4;189:E1481-8. doi: 10.1503/cmaj.170296

CMAJ Podcasts: author interview at https://soundcloud.com/cmajpodcasts/170296-view

bstructive (OSA) is characterized by recur- ring episodes of cessation (apnea) or reduction (hypop- KEY POINTS nea) in airflow during sleep caused by obstruction of • (OSA) is likely underdiagnosed in Othe upper airway. In recent population-based studies, the esti- Canada; however, lack of appropriate treatment puts many at mated prevalence of moderate to severe sleep-disordered risk of poor quality of life, comorbidity, motor vehicle crashes ranges from 3% to nearly 50% depending on age group and increased health care utilization. and sex.1,2 A survey conducted by the Public Health Agency of • Obstructive sleep apnea should be considered in symptomatic Canada in 2009 found that 26% of Canadian adults reported patients with suggestive craniofacial features or comorbidities, even in the absence of classic risk factors such as older age, symptoms and risk factors that are associated with a high risk of male sex or . OSA;3 however, prevalence data in Canada are limited by the • is the gold standard for diagnosis; absence of studies using objective sleep testing. Obstructive however, home sleep apnea testing may be used to confirm sleep apnea may be underdiagnosed; only 3% of Canadians aged the diagnosis in symptomatic patients with a high pretest 18 years or older reported a formal diagnosis despite high rates probability of OSA and without clinically important of symptom reporting;3 yet, high-quality prospective studies cardiopulmonary comorbidity. have shown clear benefit of treatment for patients with sleepi- • Good evidence supports treatment of OSA with targeted ness, cognitive or psychological dysfunction, or poor quality of therapies including continuous or oral appliances, as well as promotion of weight loss and moderate life owing to obstructive sleep apnea.4–6 Large population-based exercise for those who are overweight (alternative treatments studies have shown that untreated moderate or severe OSA is may be tried for those who do not tolerate usual therapies). associated with serious complications.7–9 We review signs, symptoms and morbidity associated with OSA, along with diagnostic options, treatments and consider- What signs, symptoms and risk factors should ations for long-term follow-up, based on evidence and recom- prompt consideration of obstructive sleep mendations from clinical guidelines, systematic reviews and pri- apnea? mary studies (Box 1). About 25% of patients with OSA report daytime sleepiness; a greater proportion report unrefreshing sleep or fatigue.10 Other Box 1: Evidence used in this review symptoms include frequent nocturnal waking due to or We conducted a structured literature search of MEDLINE and the gasping, nocturia, morning headaches, poor concentration, irri- Cochrane Database of Systematic Reviews for “obstructive sleep tability and erectile dysfunction.11–13 Bed partners may report apnea” or “sleep apnea,” in addition to targeted searches on PubMed. We excluded other forms of sleep disordered breathing. or witnessed . Atypical symptoms, which are We limited our search to human studies that involved adults and more frequently reported by women, include insomnia, impaired that were published in the previous five years and written in memory, mood disturbance, reflux and nocturnal enuresis.14 English; however, we included several key papers that were However, the correlation of symptoms with disease severity is published more than five years ago that substantially contributed poor,15 which is why it is important for physicians to be alert to to the field. We found 2921 articles, which were screened for relevance based on a review of titles and abstracts. Studies were milder symptoms. There are many underlying risk factors, pre- selected for inclusion based upon the quality of evidence and disposing conditions and associated comorbidities for OSA; they relevance to the clinical questions discussed in this review. are summarized in Appendix 1, available at www.cmaj.ca/ lookup/suppl/doi:10.1503/cmaj.170296/-/DC1.

© 2017 Joule Inc. or its licensors CMAJ | DECEMBER 4, 2017 | VOLUME 189 | ISSUE 48 E1481 REVIEW hour or women with an AHI of more than 25 events perhour. hour orwomenwithanAHIofmorethan25 events per with anapnea–hypopneaindex(AHI)ofmorethan19 events increased inpatientswithuntreatedOSA,particularlymen dictor ofcardiovascularriskthanAHI, Although recurrent, intermittent may be a better pre- fibrillation, resistanthypertensionandinsulinresistance. Other importantcardiometabolicassociationsincludeatrial patients withahighpretestprobabilityforOSA; cussed aboveincreasethepretestprobabilityforOSA. to excludethediagnosisofOSA.However,featuresdis- neither historynorphysicalexaminationissufficientlyaccurate weight). sia, gestationalhypertension, pretermdelivery,lowbirth plications areincreasedinthe presence ofOSA(e.g.,preeclamp- compared with patients without OSA. times theriskofpostoperativecardiopulmonarycomplications naire, nisms predisposingtoOSAarecomplexandoverlapping; E1482 founders suchasbodymassindex. heart failureorcardiovasculardeathaftercontrollingforcon- myocardial infarction,coronaryrevascularization,congestive increasedriskofincident SevereOSAconfers a2.6 times Box 2). in severallargepopulationstudies(definitions availablein erate or severe OSA and several complications have been shown quences ofmildOSA,butassociationsbetweenuntreatedmod- There islimitedevidencetosupportadversehealthconse- apnea important? Why ismakingadiagnosisofobstructivesleep sleepiness andtreatmentresponse. sign questionnaire times increasedriskofamotor vehiclecrash, underlying mechanismismorecomplexthanhypoxemiaalone. hypertension withnocturnaloxygentherapysuggeststhatthe the EpworthSleepinessScale ation whenimplementingtheminroutinepractice.Although high-prevalence populations,whichisanimportantconsider- patients withOSA, changes indentalocclusion. tonsillar enlargement, soft palate elongation, macroglossia or and increasedmortality. risk ofasevereexacerbation,leadingtoadmissionhospital and chronic obstructive pulmonary disease have an increased that areassociatedwithOSA.PatientsconcomitantOSA retrognathia. pharynx asestimatedbytheMallampatiorFriedmanscore, tion orturbinatehypertrophy,crowdingoftheposteriororo- cumference, increased neck circumference), nasal septal devia- OSA includesignsofcentralobesity(e.g.,increasedwaistcir- with ahighfinancial andhealthcost. gists checklist. include theSleepApneaClinicalScore, Various clinicalpredictionrulescanassistinidentifying Some retrospective cohort studies have shown other diseases Features onphysicalexaminationthatareassociatedwith 22 cricomentaldistance, 41,42 Obstructivesleepapneaisalso associatedwithatwo 16–18 27 Thesetoolshavetypicallybeenvalidatedin Oropharyngeal crowding may be caused by 20 26 itisausefultoolforevaluatingsubjective andAmericanSocietyofAnesthesiolo- 37,38 PatientswithOSAhavetwo-tothree 18 23 Thepathophysiologicmecha- 28 OSA50, maynotaccuratelyidentify 30 39,40 34,35 Riskofischemicstrokeis 4 Furthermore,untreated CMAJ Maternal and fetal com- lackofimprovementin 24 STOP-Bang, 21 BerlinQuestion- | DECEMBER 4,2017 43 acomplication 25 20 elbow 19 these thus, 32,33 36 31

| VOLUME 189 increased riskofoccupationalinjury. OSA isassociatedwithreducedworkproductivityandan (Box 2). obstructive respiratoryeventsperhourinasymptomaticpatients respiratory eventsperhourorby15morepredominantly ties associatedwithfiveormorepredominantlyobstructive defines OSA as the presence of symptoms or certain comorbidi- By consensus,theInternationalClassificationofSleepDisorders diagnosed? How shouldobstructivesleepapneabe mitigate manyoftheserisksandiscost-effective. OSA usingsleepdiagnostictesting. population screeningofasymptomaticindividualsatlowrisk ance onscreeningforOSA,thereisnoclearevidencetosupport event indexasoutlinedinBox 2. fied bytheAHI,respiratorydisturbanceindexor According torecentUSPreventiveServicesTaskForceguid- Box 2:Diagnosingobstructivesleepapnea • • • Severity ofOSA: • C. Polysomnographyorhomesleepapneatestingshows: • B. Polysomnographyorhomesleepapneatestingshows: • • • • A. Thepresenceofoneormorethefollowing: sleep apnea(OSA). A andB,orCsatisfythecriteriaforadiagnosisofobstructive Definitions oftermsquantifyingOSA Severe OSA:AHI≥ Moderate OSA:AHI≥ Mild OSA:AHI≥ sleep apnea hour oftotalrecordingtimeonhome monitoringdevicesfor Respiratory eventindex(REI):no.of apneasandhypopneasper polysomnography respiratory effort–relatedarousals per hourofsleepduring Respiratory disturbanceindex(RDI): AHIwiththeadditionof per houroftotalsleeptime Apnoea–hypopnea index(AHI):no.ofapneasandhypopneas monitoring duringhomesleepapneatesting. per hourofsleepduringpolysomnographyor Fifteen ormorepredominantlyobstructiverespiratoryevents monitoring duringhomesleepapneatesting. hour ofsleepduringpolysomnographyorper Five ormorepredominantlyobstructiverespiratoryeventsper patient. failure, atrialfibrillationortype2diabetesmellitusinthe dysfunction, coronaryarterydisease,stroke,congestiveheart A diagnosisofhypertension,amooddisorder,cognitive breathing interruptionsorbothduringthepatient’ssleep. The bedpartnerorotherobserverreportshabitualsnoring, The patientwakeswithbreathholding,gaspingorchoking. insomnia symptoms. The patientreportssleepiness,nonrestorativesleep,fatigueor 29 Thenumberofobstructiverespiratoryeventsisquanti- | ISSUE 48 fiveeventsperhour 20 30eventsperhour

29 15eventsperhour 48 8 44,45 TreatmentofOSAmay 4,46,47

REVIEW E1483 Although Although Therefore, 4 56 Continuous Continuous and does not and does 4,9 20 52 Sn: 0.66–0.88 Sn: 0.66–0.88 Sn: 0.55–0.91 Sn: 0.92–0.96 Sn: 0.94–0.95 Sp: 0.62–1.00 Sp: 0.62–1.00 Sp: 0.70–0.82 Sp: 0.77–1.00 Sp: 0.76–0.77 Gold standard AHI ≥ 15 events/h 37 20 modality* 57 - patients with a moder In symptomatic 20 Sn: 0.96† Sn: 0.96† Sp: 0.82† Sp: 0.43† Sn: 0.80–0.96 Sn: 0.90–1.00 Sn: 0.88–0.97 Sp: 0.65–0.83 Sp: 0.30–0.67 Sp: 0.50–0.56 Gold standard As many as 17% of home sleep apnea tests are 17% of home sleep As many as Operating characteristics for sleep testing sleep testing for characteristics Operating AHI ≥ 5 events/h 53,54 and up to 18% have technical failures. and up to 18% have technical ISSUE 48 ISSUE 55 | The respiratory event index underestimates AHI because it mea- because it AHI underestimates index event The respiratory Level IV studies record one to two channels of data. One two channels of data. One one to Level IV studies record sures time when the patient is not actually asleep when the patient is sures time channel is oximetry, whereas the second channel may record whereas the second channel may record channel is oximetry, rate. A recent randomized controlled snoring, airflow or heart that clinicians diagnosed OSA with lower trial (RCT) showed was used compared with level IIIconfidence when oximetry testing or polysomnography. detect arousals from sleep. detect arousals Table 2 summarizes the effectiveness of three different treat- positive airway pres- ments for patients with OSA: continuous advancement. sure, oral appliance and maxillomandibular Continuous positive airway pressure a trial of treat- Symptomatic patients with OSA should undergo ment with continuous positive airway pressure. What are the benefits of different treatment What are the benefits of different options? positive airway pressure reduces AHI and sleepiness. positive airway pressure reduces AHI and false negatives ate-to-high pretest probability of OSA and no substantial cardiopul- OSA and no substantial pretest probability of ate-to-high level IIIcomorbidity, monary diagnosisthe for adequate are studies of OSA (Table 1). if results for home sleep apnea testing are negative in a patient for apnea testing are negative in a patient if results for home sleep index of suspicion, physicians should seekwhom there is a high Level III studies may also be usefultesting using polysomnography. - or illness preclude attendance for polysom when immobility, safety of treatment efficacy. nography and for confirmation VOLUME 189 VOLUME | Indications for use for Indications DECEMBER 4, 2017 | 50 CMAJ Moderate-to-high probability of OSA without probability Moderate-to-high comorbidity of immobility or because PSG perform Unable to infirmity efficacy Confirm treatment Low-to-moderate probability of OSA probability Low-to-moderate OSA and suspected HSAT/oximetry Nondiagnostic than OSA other Suspected or CSA Suspected purposes research used for Predominantly Home-based polysomnography polysomnography Home-based 49 20 Level III therefore, sleep; do not record studies 51 Polysomnography is also indicated for the evaluation of sus- Polysomnography is Two- or three-channel study or three-channel Two- Single-channel study study tone arterial Peripheral Home sleep apnea testing Home sleep apnea III study Level Polysomnography (level I study) Attended (level II study) Unattended Note: AHI = apnea–hypopnea index, CSA = , HSAT = home sleep apnea testing, OSA = obstructive sleep apnea, PSG = polysomnography, Sn = sensitivity, Sp = specificity. Sn = sensitivity, = polysomnography, PSG sleep apnea, OSA = obstructive testing, = home sleep apnea HSAT sleep apnea, = central index, CSA AHI = apnea–hypopnea Note: 87%). prevalence (estimated populations high-prevalence for and reported with PSG modalities when compared of these testing characteristics *Operating study. †Based on one validation Sleep test Table 1: Different types of diagnostic sleep testing sleep of diagnostic types 1: Different Table pected sleep disorders other than OSA or after nondiagnostic other than OSA or after nondiagnostic pected sleep disorders among patients with a high pretest home sleep apnea testing probability of OSA.

Home sleep apnea testing are in clinical use. Several types of home sleep apnea testing Level III sleep studies record a minimum of three channels of data while the patient sleeps at home. Level III studies usually body position, monitor airflow, snoring, respiratory excursion, validated devices heart rate and oxygen saturation, but some as such variables, use surrogate measurements for these is constantly tonometry or actigraphy, and the technology evolving. The gold standard for diagnosis of OSA is attended polysomno ­ of OSA is attended for diagnosis The gold standard graphy (level I or more collection of seven study), which involves data channels,- and electroocu including electroencephalogram electrocardiogram sleep staging, electromyogram, logram for channels. and respiratory Polysomnography (level II Sleep is not used commonly except for research. study) and polysomnography is particularly specialist assessment or are at risk of central sleep apnea important when patients conditions are suggested by the presence hypoventilation; these neuromuscular disease, congestive heart of neurologic disease, opioid use or obesity with a serum failure, severe lung disease, more than 27 mmol/L. bicarbonate level of severity of OSA is estimated using the respiratory event index, event index, severity of OSA is estimated using the respiratory per hour of total which is the number of desaturation events recording time. REVIEW severe OSA. risk ofmotorvehiclecrashesinpatientswithmoderateto therapy usingcontinuouspositiveairwaypressurereducedthe patients whowereadherenttocontinuouspositiveairwaypres- OSA. maternal complications(e.g.,preeclampsia)associatedwith currently uncleariftreatmentcanpreventsomeofthefetaland less than 4 hours pernight). less than4 hours below acceptedguidelines for adequateuse(meanadherenceof ence to the use of continuous positive airway pressure was reductions inbloodpressure(–4.39to–1.41 mm Hg). associated morbidity.Randomizedcontrolledtrialshaveshown ongoing researchtoestablishthebenefitsofOSAtreatmenton E1484 ous positive airway pressure improves quality of life. some recentwell-designedRCTssupportthattheuseofcontinu- previous meta-analyseshavenotbeendefinitive,thefindingsof ness. who hadpreexistingcardiovasculardisease and minimal sleepi- using continuouspositiveairwaypressureinpatientswithOSA reported thattherewasnocardiovascularbenefitoftreatment CPAP inCoronaryArteryDiseaseandSleepApnea[RICCADSA]) vascular Endpoints[SAVE]andRandomizedInterventionwith adherent totreatment, risk ofcardiovasculareventsinpatientswithsevereOSAwhoare pressure onglycemiccontrolinpatientswithdiabetes. flicting evidenceontheeffectsofcontinuouspositiveairway airway pressureforOSAarelessclear.Forexample,thereiscon- advancement, OA =oral appliance, OSA=obstructive sleep apnea, QoL=qualityoflife. Note: AHI=apnea–hypopnea index,BP=bloodpressure, CPAP = continuous pressure, positive airway CV =cardiovascular, ESS =Epworth SleepinessScale, MMA=maxillomandibular Moderate to severe Severity of OSA Table 2:Benefits of treatment for obstructive sleepapnea, by disease severity Mild Although observationalstudieshavesuggestedadecreased Other healthbenefitsoftreatmentusingcontinuouspositive 59–61 6,64 7 An important limitation of both studies was that adher- Asystematicreviewandmeta-analysisshowedthat 62 4 May improve outcomes after stroke May decrease riskofstroke Cerebrovascular: Unclear impact onCV events treatment Improves responsiveness ofatrial fibrillation to Decreases BP Cardiovascular: Improves QoL Reduces ESS Symptoms: AHI: Decreases AHI Unclear impact Cerebrovascular: Unclear reduction in CV events Unclear effect on BP Cardiovascular: Unclear impact onQoL Unclear impact onESS Symptoms: AHI: Decreases AHI 63 tworecentRCTs(SleepApneaCardio- 65 Analysisoftheoutcomesin 5,6 CMAJ CPAP | DECEMBER 4,2017 4

4–6 There is 4,58 Itis Unclear impact Cerebrovascular: Unclear impact onCV events Decreases BP Cardiovascular: Unclear impact onQoL Reduces ESS Symptoms: AHI: Decreases AHI Unclear impact Cerebrovascular: Unclear impact onCV events Unclear impact onBP Cardiovascular: Unclear impact onQoL Unclear impact onESS Symptoms: AHI: Decreases AHI | Impact of treatment VOLUME 189 RCTs. fits showninadherentpatientsconsistentwiththefindings in lightofhealth,qualitylifeandworkplaceproductivitybene- severe OSA(regardlessofsymptoms)shouldbeofferedtherapy disease prevention. In our view, patients with moderate to troversy regardingthebenefitoftreatmentforcardiovascular vascular benefits of therapy. These studies have generated con- whichmaynothavebeenlongenoughtoseecardio- 3.7 years, Furthermore, patientswerefollowed onlyforan averageof may have more potential for reducing cardiovascular events. ing time)inwhomcontinuouspositiveairwaypressuretherapy (oxygen saturationoflessthan80%formore10%record- study excludedpatientswithsubstantialnocturnalhypoxemia risk ofcerebraleventsorstrokeintheSAVEstudy.The or cardiovascular mortality in the RICCADSA study and a lower coronary arteryrevascularization,myocardialinfarction,stroke sure identifiedalowerriskofthecompositeoutcomerepeat Oral appliancesarerecommended Oral appliances determine if use of oral appliances improves quality of life. ous positiveairwaypressure. that oralappliancesdecreaseAHItoalesserextentthancontinu- improve sleepiness,althoughasystematicreviewalsoidentified advancement ortongue-retainingdevices.Oralappliances pressure orprefernottouseit.Theseareeithermandibular moderate OSAwhoareintolerantofcontinuouspositiveairway cular eventsinasymptomaticpatients. airway pressureprimarilyforsecondarypreventionofcardiovas- 6,66 However,wedonotsuggestusingcontinuouspositive OA | ISSUE 48 4 Furtherresearchisneededto Unclear impact Cerebrovascular: Unclear impact onCV events Decreases BP Cardiovascular: Unclear impact onQoL Reduces ESS Symptoms: AHI: Decreases AHI Unclear impact Cerebrovascular: Unclear impact onCV events Cardiovascular: Unclear impact Symptoms: AHI: Unclear impact 9,67 forpatientswithmildto MMA 4

REVIEW

- 67,71 E1485 The Canadian 85 these standards these standards 86 When appropriate, appropriate, When 82 this type of device is this type of device is 89,90 83 87 ISSUE 48 ISSUE | 88 Important adverse effects of oral appliances include Important adverse effects of oral appliances include 90 The criteria for when to notify provincial and territorial The criteria for when 84 Adherence to treatment with oral appliances can be assessed Adherence to treatment with oral appliances A consensus position paper on driving safety recommends driving safety recommends position paper on A consensus sleepiness blockers). About 5% of patients have persistent sleepiness - aggravation of temporomandibular joint dysfunction, teeth shift, teeth dysfunction, joint temporomandibular of aggravation pain, gingival problems, excessive salivation or dry mouth. patients who are obese may be referred for bariatric surgery; surgery; bariatric for referred be may obese are who patients indicated to testing may be weight loss, repeat after sustained if OSA persists. determine ministries of transportation about a patient with OSA varies and about a patient with OSA varies and ministries of transportation the physician’s assessment of risk. The is typically based on non for guideline practice clinical Society Thoracic American if classifies patients as being at high risk commercial drivers unintentional or inappropriate sleep during there is a history of either a recent motor vehicle crash or near daily activities, with fatigue or inattention. miss owing to sleepiness, by patient report. Although some devices have built-in technol- by patient report. Although some devices ogy to objectively measure adherence, that all patients with OSA should be counselled about driving driving be counselled about with OSA should that all patients safety. Council of Motor Transport Administrators publishes medical Administrators publishes medical Council of Motor Transport drivers with OSA; standards for commercial Residual daytime sleepiness despite effective treatment of OSA OSA of treatment effective despite sleepiness daytime Residual may occur. Causes include chronic sleep restriction, central sleep apnea that comes to light with therapy using continuous positive airway pressure, another sleep disorder (e.g., narcolepsy), chronic medical or psychiatric conditions (e.g., depression) or adverse antihistamines, sedatives, (e.g., medications to owing effects β Supporting adherence to treatment continuous positive Initiation and maintenance of therapy using Important concerns airway pressure requires technical support. are discussed in Appendix 2, available at www.cmaj.ca/lookup/ this therapy Adherence to suppl/doi:10.1503/cmaj.170296/-/DC1. of long-term within the first few days is a strong predictor adherence. Addressing persistent symptoms after successful treatment for obstructive sleep apnea specify that individuals without excessive sleepiness and an AHI excessive sleepiness without specify that individuals of less than 20 events per hour are eligible to hold a commercial who those whereas OSA, for treatment receiving without licence with falling asleep or have had a motor vehicle crash associated driving must be have reported excessive sleepiness while regarding treatment treated. The physician’s recommendations 20 eventsthan more of AHI an with those of consid- are hour per The Canadian Medi- ered when determining licensure eligibility. criteria for mandatory cal Association’s driver’s guide provides such as com- reporting of patients in safety-critical occupations, roles in aviation, the mercial drivers, or those with key navigation railway or at sea. not encountered frequently outside of clinical trials. Compliance in the use of oral appliances is increased if there is a reduction in snoring. Regular dental follow-up is important for all patients who are prescribed oral appliances. sleep time or functional outcomes of sleep. of outcomes time or functional sleep VOLUME 189 VOLUME |

​ - 77 71 and a and a 80 A meta- 9

75 70 Tracheostomy is DECEMBER 4, 2017 73 | Decision aids for Decision aids for 75,78 After the oral appliance After the oral appliance reported, respectively, respectively, reported, 67 CMAJ 81 Like continuous positive air- Like continuous Tonsillectomy and adenoidec- 72 4,6,67–69 79 yet rarely necessary unless there is substantial yet rarely necessary unless there is substantial 74 However, a retrospective case–control study found found However, a retrospective case–control study However, other cardiovascular benefits of therapy benefits of therapy However, other cardiovascular - Laser-assisted uvuloplasty or uvulopalatopharyngo 4 76 75 The 2015 update of the American Academy of American Academy of Sleep Medicine The 2015 update of the Patients frequently ask about surgery for treatment of OSA. OSA. of treatment for surgery about ask frequently Patients comorbidity and other treatments are ineffective. way pressure, oral appliances can improve blood pressure pressure can improve blood oral appliances way pressure, modestly. and American Academy of Dental Sleep Medicine clinical practice clinical Medicine Sleep Dental of Academy American and that, for best effect, appliances should guideline recommended - dentist with extensive experience or addi be custom fitted by a sleep medicine. tional training in dental Maxillomandibular advancement, with or without genial tubercle Maxillomandibular advancement, with or that may be an advancement, is an invasive surgical procedure other of intolerant are who patients selected highly for option therapies.

The Canadian Thoracic Society guideline for the diagnosis and The Canadian Thoracic Society guideline for the diagnosis and recom adults in breathing disordered of sleep treatment What are the principles of ongoing management and follow-up? mended that patients with sleep disordered breathing should be mended that patients with sleep disordered breathing should be counselled to avoid excessive alcohol and sedative use. Alternative treatment options include nasal expiratory positive expiratory positive Alternative treatment options include nasal oropharyngeal airway pressure valves, exercises to strengthen nerve stimula- muscles (myofunctional therapy) and hypoglossal tion (not approved in Canada). Alternative treatments Lower efficacy may be balanced by greater adherence to this to this adherence greater by may be balanced efficacy Lower airway with continuous positive compared form of treatment dis- thus, in mild to moderate v. 50%–70%); pressure (80%–90% to continu- may be similar treatment effectiveness ease, overall airway pressure. ous positive tomy may help when tonsillar enlargement encroaches on the encroaches on the tomy may help when tonsillar enlargement upper airway, particularly in younger patients. using oral appliances have not been established. using oral appliances patients are under development and may help match treatments and may help match patients are under development to patient preferences. has been custom fitted and jaw protrusion has been optimized, a and jaw protrusion has been optimized, has been custom fitted to evaluate treatment efficacy. sleep test should be ordered longitudinal prospective cohort study cohort prospective longitudinal that exercise of moderate intensity and weight loss of 10% of that exercise of moderate intensity and weight loss of 10% of obese overweight or weight in patients who are baseline resulted in modest reductions in AHI. For patients with supine- found a systematic review and meta-analysis OSA, predominant 10 events to up by AHI reduce may therapy positional that per there addition, in adherence; poor by limited be may but hour total sleepiness, in improvements of evidence clear no was plasty are unreliable for reducing the AHI or improving patient or improving patient plasty are unreliable for reducing the AHI outcomes, and are not recommended. Regular follow-up to assess for recurrence of OSA is recom- Regular follow-up to assess for recurrence mended. that 13.9% of patients had a major complication that required that required that 13.9% of patients had a major complication maxillomandibular after surgery unplanned or admission repeat can occur. advancement, and numerous minor complications highly effective, analysis of the effects of exercise training on sleep apnea REVIEW Canadians withsleepdisorderedbreathing. patient preference,willbeimportanttoimprovethecareof to improve timely access to care, funding for OSA treatment and into themodelsofservicedeliveryforOSA,includingstrategies in thediagnosisandtreatmentofOSAwithinCanada. OSA, itisimportantthatattentionbepaidtothewidevariations E1486 11. 10. References adverse outcomesassociatedwithOSA. to identifybiomarkersandgeneticfactorsthatmightpredict nocturnal rostralfluidshift.Furthermore,researchisunderway cles orhypoglossalnervefunction;decreasedlungtethering;and reduced arousalthreshold;ineffectiveupperairwaydilatormus- lapse; increasedventilatorycontrolinstability(loopgain); gation includeananatomicpredispositiontoupperairwaycol- physiology. Pathophysiologic mechanisms of OSA under investi- underlying OSAandaimtotailortreatmentsthepatient’s approaches acknowledgethecomplexbiologicalmechanisms diagnosis andmanagementofOSA.Individualizedtreatment There isemerginginterestinpersonalizedapproachestothe questions Future perspectivesandunanswered promote wakefulness. despite exclusionofthesecausesandmaybenefitfromdrugsto 1. 9. 8. 7. 6. 5. 4. 3. 2.

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