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Sleep Apnea:. C Tyler. Sleep Apnea. Kaiser SF Sleep Lab a.k.a. ‘ apnea clinic ’ Part 3 C Tyler, Sep 2016 Medical Director Kaiser, San Francisco. History of Sleep Apnea. 1956, Burwell et al Obesity-hypoventilation syndrome (Pickwickian) 1966, Gastaut et al
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Sleep Apnea: • C Tyler
Sleep Apnea Kaiser SF Sleep Lab a.k.a. ‘apnea clinic’ Part 3 C Tyler, Sep 2016 Medical Director Kaiser, San Francisco
History of Sleep Apnea • 1956, Burwell et al • Obesity-hypoventilation syndrome (Pickwickian) • 1966, Gastaut et al • episodic upper-airway obstruction • terminated by brief arousals • 1978, Remmers et al • airway pressure vs EMG activity of the genioglossus muscle • tracheostomy recognized as an effective treatment • 1981 Sullivan et al • CPAP prevents upper-airway collapse, normalizes nocturnal sleep, alleviates EDS • 1993 by Young et al. • Prevalence: 2% and 4% of middle-aged women and men
Raising Awareness of OSA • 20,000,000 Americans • 85% undiagnosed • Health care costs: = 2x those without OSA
Definitions • Apnea = • 10 seconds + 3% desat • Hypopnea = • 50% reduction in flow + 3% desat • RERA = • respiratory effort related arousal • Arousal = • Transient ‘lightening’ of EEG • Central • Crescendo/decrescendo • Cheyne-Stokes Resp • Obstructive • Effort persists through strangulation
Cardinal Sx of OSA: • Snoring (+/- observed apneas) • Clinical features of Sleep Fragmentation • Daytime hypersomnolence (EDS) • Non-refreshing sleep • Insomnia • Initiation Insomnia • Maintenance Insomnia • Obvious Sx: Choking/gasping • Subtle Sx: Nocturia
Prevalence: • OSA syndrome (ESS > 10, AHI > 5) • 4% of middle-aged North American men • 2% of middle-aged North American women • if ESS < 10/24 included… • 24% of North American men • 9% of North American women • these data precede current obesity epidemic
The hot button items: Race Sex Age Weight Family
Race and OSA • more severe in African Americans • (Same prevalence) • More severe: Severe OSA 17% vs 8% in whites • Odds ratio of 2.55 for severe SDB • more severe in Asian • For given age, sex, BMI
Women and OSA • Prevalence slightly less • More symptomatic at given severity • Menopause is a significant risk factor
Obesity and OSA • Strongest Risk Factor • 70% of OSA • occurs in obese patients • 10% weight gain • results in 6x increase risk • 10% weight loss • results in 26% decr in severity
Familial/Genetic Factors • OSA in first-degree relatives: • prevalence 22 to 84% • If OSA in family member • Odds ratio = 2 to 46 • Whites: recessive Mendelian inheritance • Accounts for 21 to 27% • African Americans: co-dominant gene • accounting for 35% • Twin concordance for snoring • significantly higher in monozygotic than in dizygotic twins
Pathogenesis: • Three factors • anatomical abnormalities • airway predisposed to collapse during sleep/anesthesia • regulation of pharyngeal dilator muscle activation • Genioglossus m. Hypoglossal nerve. • normal redux during sleep • unstable ventilatory control (high loop gain) • intrinsic stability of a negative-feedback control system • arousal – CO2 drop over-shoot (below apnea threshold)
Levels of obstruction: Midretropalatal (RP) Midretroglossal (RG)
Anatomic Suspects? • Obese (BMI > 35) • Neck circumfrence (> 17 inches) • Retrognathia / underbite • High arched palate • Mallampati Score
Morphologic Features • High arched palate • Nasal septal deviation • Retrognathia • Mallampati Score
Who to Refer: • Cardinal Symptoms • Snoring • Observed Apneas • Daytime Hypersomnolence • Commercial Drivers / Pilots • Pre-op: • STOP-BANG
Work-up of Snoring • Adjusted Neck Circ (ANC) • Add 4cm if HTN • Add 3cm if snores • Add 3cm if choking and gasping is reported
Sleepiness:Vigilance Impairment Judgment Impairment Micro-sleeps
SleepinessDaytime Hyper-somnolenceExcess Daytime Sleepiness (EDS) • Not fatigue! • Not amotivational state! • Not depression! • Not weakness! • Measure of propensity to fall asleep. • Sleep Latency Test (objective) • Epworth Sleepiness Scale (subjective)
Epworth Sleepiness Score • How likely are you to doze off or fall asleep in the following situations? • 0=No chance of dozing • 1=Slight chance of dozing • 2=Moderate chance of dozing • 3=High chance of dozing • Sitting and reading • Watching TV • Sitting inactive in public • Passenger in a car • Lying down to rest • Sitting and talking • Sitting quietly after lunch • In a car, stopped in traffic
Epworth Sleepiness Score • 0=No chance of dozing • 1=Slight chance of dozing • 2=Moderate chance of dozing • 3=High chance of dozing • Sitting and reading my kids won’t read a book • Watching TV my kids watch TV constantly (until sleep) • Sitting inactive in public I’ve never seen my kids do this • Passenger in a car they’re usually driving • Lying down to rest not sure – that usually occurs around 3am • Sitting and talking they don’t talk, they text or snap-chat • Sitting quietly after lunch lunch is in front of video games • In a car, stopped in traffic I’m pretty sure they don’t stop
Dept of Motor VehiclesCommercial License • BMI > 40; Neck Circ. > 17” • Triggers testing or license is suspended • Mandatory efficacy and compliance requirements • AHI • Rx must result in AHI < 5 (10 if UPPP or dental device) • Compliance • > 4 hours use, > 70% of nights
OSA and Commercial Drivers • 6x more likely to have a crash • 7x more likely to have multiple accidents • Year 2000: • 800,000 drivers involved in OSA-related car crashes • $15.9 billion in damage • 1,400 lives
Peri-op Medicine • STOP-BANG questionnaire • Expedited Evaluation • Expedited Treatment • Peri-op safety strategies: • Oximetry / CO2 monitor • InptvsOutpt surgery • Narcotic and PCA management
1. Snoring? Yes / No 2. Tired? Yes / No 3. Observed Apneas? Yes / No 4. Blood Pressure? Yes / No 5. BMI - > 35kg/m2? Yes / No 6. Age - > 50? Yes / No 7. Neck ? > 40cm? Yes / No 8. Gender -male? Yes / No HIGH RISK: 2 or more (STOP) 3 or more (STOP/BANG) STOP-BANG questionnaire
Diagnostic Treatment Initiation Titration Prescription Follow-Up Special Situations DMV BMI>37, Neck >17” Compliance Monitoring POM (Peri-op Medicine) STOP-BANG questionnaire Types of Studies: PSG (Polysomnogram) WatchPAT (Pulse Tonometery) Embletta Oximetry CPAP titrations CPAP device interrogation Other supporting data: Questionnaires: Initial F/U Sleep Lab Processes
Polysomnogram • Obstruction of airflow + progressive effort • Explosive release (intermittent snore) • Desaturation
Embletta • Oximetry • Actigraph • Nasal Thermistor • Microphone • Inductance Coils • Abdominal Excursion • Thoracic Excursion
WatchPAT • Arterial Tonometry • Surrogate for Sympathetic Tone • Pulse Oxymetry • Heart Rate • Actigraphy • RDI and AHI correlate with PSG
Auto-CPAP titration(incl advanced devices) • Data Download: • Pressure Histogram • AHI • Hours used • Daily • Average • Days > 4hr use
Obstructive hypopnea - snoring • Vibration on inspiratory flow • Progressive resp effort (Pesoph) with constant flow • Mild hypoxemia
Definitions: • Apnea-Hypopnea Index: AHI • Apnea (10 seconds of no airflow) • Hypopnea (10 sec > 50% redux) • Or < 50% + 4% O2 desat • REM-AHI • (REM atonia + reduced hypoxic drive) • Resp Disturb Index: RDI = AHI + RERA • RERA (Resp Effort Related Arousal) • Oxygen Desat Index: ODI
Diagnostic Criteria: • Apnea-Hypopnea Index: • <5 events per hour: normal • 5-15 events per hour: mild • 15-30 events per hour: moderate • > 30 events per hour: SEVERE • Resp Disturb Index: • Same
Severity criteria:what do they mean? • Arbitrary Cuttoffs • AHI>20: • inflection point for increased health risks • Alternately classify SRBD as • ‘CPAP responsive’ vs CPAP unresponsive’
Who to Treat? • Mild OSA(S) (AHI/RDI 5-15) • (‘S’ is for Syndrome which includes EDS, sleep fragmentation) • Presence of Cardiovascular Co-morbidities • Moderate and Severe OSA (AHI/RDI >15)