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“What’s Your Number?”Diagnosing OSA in 2019

Douglas Kirsch, MD, FAAN, FAASM

President, American Academy of Sleep Medicine

Professor, Neurology and Internal Medicine, Atrium Healthhttp://www.dumpaday.com/funny-pictures/funny-pictures-of-the-day-55-pics-6/attachment/867-5309-funny-phone-numbers/

Outline

• OSA, briefly

• Understanding Alphabet Soup

• Types of Sleep Testing

– Laboratory

– Home

– Apps

• Summary

OSA, In a Nutshell

https://www.convertwithcontent.com/web-marketing-in-a-nutshell/

http://wallpapersafari.com/w/2CJxwZ/

OSA?

Video

Pathophysiology of Apnea

http://64.143.176.9/library/healthguide/en-us/support/topic.asp?hwid=tp12620

https://en.wikipedia.org/wiki/File:Stop_sign_light_red.svg

Clinical Consequences of OSA

Sleep Apnea

Excessive daytime

sleepiness

Sleep fragmentation,

Hypoxia/Hypercapnia

Cardiovascular

Complications

Morbidity

Mortality

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OSA is associated with adverse clinical outcomes

OSA

CoronaryArtery

Disease

HTN Stroke / TIA

Neuro-CogSymptoms

GERDArrhythmias

WorsenDiabetes

MoodSymptoms

Early Sleep Studies

• 1957 – William Dement and Kleitman discovered recurring pattern of REM/NREM sleep

– All night EEG recordings

– 126 nights from 33 subjects

– Predictable sequence of events

– Cyclical variations every 90-100 minutes

http://www.npi.ucla.edu/sleepresearch/Kleitman/Kleitman.htm

Sleep Monitoring…• Sleep and its REM and non-REM stages can be

monitored by electrical recordings. – Muscle activity - assessed by electromyography (EMG)

– Eye movements - recorded by electrooculography (EOG)

– The collective activity of cortical neurons (the brain) is monitored by electroencephalography (EEG).

http://www.musclesbodybuilding.com/wp-content/uploads/2009/07/build-muscle-fast.jpg

http://www.psychologytoday.com/files/u243/s-for-Under-Eye-Dark-Circles-or-Puffy-Eyes-2.jpg

http://malefis.u-strasbg.fr/site/images/homer-brain.jpg

Sleep Hypnogram

http://www.howsleepworks.com/images/hypnogram.jpg

Why Respiratory Channels Were Added to Sleep Studies…

http://chestjournal.chestpubs.org/content/135/2/563/F2.large.jpg

Analog Sleep System 1988

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A “Modern” Sleep Laboratory… Polysomnography

http://insomnia.ygoy.com/2011/05/16/polysomnography-%E2%80%93-sleep-study/

Respiratory Channels

• Nasal Pressure Transducer

• Nasal-oral Thermistor

• Effort Bands (Thorax and Abdomen)

• Pulse Oximetry

Ideal Metric to Measure OSA Severity?

The metric would:

– 1) Be associated with symptoms

– 2) Be associated with adverse sequelae

– 3) Improve with treatment

– 4) Improve clinical outcomes

Respiratory Events

Apnea Hypopnea

OSA Severity Markers

• Primary Markers

– Frequency of Respiratory Events

– Depth of Oxygen Desaturation

• Secondary Markers

– Length of Respiratory Events

– Length of Oxygen Desaturations

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Alphabet Soup

http://iomechallenge.org/wp-content/uploads/2015/03/Alphabet-Soup.jpg

Definitions

• AHI = Apnea-Hypopnea Index

– Apnea + Hypopnea / hr of sleep

• RDI = Respiratory Disturbance Index

– Apnea +Hypopnea + RERAs (respiratory effort-related arousals) / hr of sleep

• REI = Respiratory Event Index

– Apnea + Hypopnea / hr of recording time

– Used primarily with home-based apnea testing

In-lab Polysomnography

37 y/o man (weight = 270 lbs) in stage REM sleep (2 minutes).

In-lab Polysomnography

In-lab PolysomnographySleep Study Report

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AHI and Hypertension

Odds

Ratio

0

0.5

1

1.5

2

2.5

3

0 0.1 - 4.9 5 - 14.9 > 15

Apnea / Hypopnea Index (AHI)

Prospective Study of Association Between OSA and Hypertension

Adjusted

for age, sex,

BMI, neck circ.,

cigs., ETOH,

baseline Htn

Adapted from Peppard PE et al. N Engl J Med 2000;342.

AHI and Strokes

• As AHI goes up, risk goes up.Marin, NEJM 2005

AHI and Death:Survival Curve from Wisconsin Sleep Cohort

Young, 2008 -- Excluding patients treated with PAP

Assumptions & Problems with the AHI

• Apnea = hypopnea with respect to biological effects

• Hypopnea 4% = Hypopnea 8%

• Short events = Long events

• Temporal Distribution - Clustered events have same effects as events spread out over the night

• No quantification of work of breathing

Punjabi NM, et al. Chest

2016; 149:16 – 19.

Short events = Long events

Punjabi NM, et al. Chest

2016; 149:16 – 19.

The Spectrum of Airway Obstruction

Courtesy of Indu Ayappa, PhD

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Unfortunate Disagreement

• Sleep doctors currently can’t even agree on a single definition of what a hypopnea is…

https://31.media.tumblr.com/687b7352a99961cb35cd92da9f39015a/tumblr_inline_nboumj5ZO61qersu1.png

Scoring Hypopneas (1A) - 2015

• 1A. Score a respiratory event as a hypopnea if ALL of the following criteria are met:N1,N2,N3 (see Figure 2)

• a. The peak signal excursions drop by ≥30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative hypopnea sensor (diagnostic study).

• b. The duration of the ≥30% drop in signal excursion is ≥10 seconds.

• c. There is a ≥3% oxygen desaturation from pre-event baseline or the event is associated with an arousal.

Scoring Hypopneas (1B) - 2015

• 1B. Score a respiratory event as a hypopnea if ALL of the following criteria are met:N1,N2,N3

• a. The peak signal excursions drop by ≥30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative hypopnea sensor (diagnostic study).

• b. The duration of the ≥30% drop in signal excursion is ≥10 seconds.

• c. There is a ≥4% oxygen desaturation from pre-event baseline.

Range of AHI based on Criteria

Redline, SHHS, 2000

Citation: Malhotra RK, Kirsch DB, Kristo DA, Olson EJ, Aurora RN, Carden KA, Chervin RD, Martin JL, Ramar K, Rosen CL, Rowley JA, Rosen IM;

American Academy of Sleep Medicine Board of Directors. Polysomnography for obstructive sleep apnea should include arousal-based scoring: an American

Academy of Sleep Medicine position statement. J Clin Sleep Med. 2018;14(7):1245–1247.

• Therefore, it is the position of the AASM that the RECOMMENDED AASM Scoring

Manual scoring criteria for hypopneas, which includes diminished airflow

accompanied by either an arousal or ≥ 3% oxygen desaturation, should be used to

calculate the AHI.

• If the ACCEPTABLE AASM Scoring Manual criteria for scoring hypopneas, which

includes only diminished airflow plus ≥ 4% oxygen desaturation (and does not allow

for arousal-based scoring alone), must be utilized due to payer policy requirements,

then hypopneas as defined by the RECOMMENDED AASM Scoring Manual criteria

should also be scored.

• Alternatively, the AASM Scoring Manual includes an option to report an RDI which

also provides an assessment of the sleep-disordered breathing that results in

arousal from sleep.

Different Scoring Definitions Impact on SDB Severity

Ho V, et al. Sleep 2015; 38: 1887-92.

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Event Venn Diagram

Ayappa, 2005

39 patients in the study

80 respiratory events evaluated

per pt.

“The requirement for a

confirmatory consequence, such

as oxygen desaturation, currently

written into many definition of

hypopnea, has been shown to

increase scoring reliability;

however, confirmatory use to

increase reliability is distinct from

any published proof that this

identifies all physiologically

meaningful respiratory events.”

Summary, Part I

• 1) AHI is a universally accepted metric for discussion of OSA severity

– Many research studies using this metric

– Correlates with other disease states

• 2) However, AHI may or may not be theOPTIMAL metric that would evaluate sleep-disordered breathing

– Currently, problems with non-standard definitions.

Home Sleep Apnea Testing

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http://pad1.whstatic.com/images/thumb/0/09/Deal-with-Sleep-Apnea-Step-2-Version-2.jpg/aid21562-728px-Deal-with-Sleep-Apnea-Step-2-

Version-2.jpg

History of Home Sleep Apnea Testing• Portable monitoring has been available for many years

• 1st major review in 1994 by the ASDA (pre-AASM)– Insufficient information for widespread use

• 2003 Comprehensive Review from AASM, ATS, and ACCP– Type III portable monitors were acceptable when attended, but

that broad use was discouraged

• AASM re-reviewed in 2007; clinical guidelines put into place

Home Sleep Apnea Testing

• Medicare approved CPAP on basis of diagnosis by HST in 2008

– Sleep study must be interpreted by Board Certified Sleep Specialist or at an accredited sleep center

– May not be performed by DME supplier

• Approval by other 3rd party payors mixed

AASM Guidelines For Use of HSATs

• HSAT for the diagnosis of OSA should be performed only in conjunction with a comprehensive sleep evaluation.

• To be used in patients who have a high pre-test probability for moderate to severe OSA.

• In the absence of a comprehensive sleep evaluation, there is no indication for the use of HSAT.

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Patient presents to BCSS for eval. of suspected OSA

Does the patient have a high pretest

probability of moderate to severe

OSA?

Does the patient have symptoms or signs of co-morbid medical disorders?

Does patient have symptoms or signs for co-morbid sleep

disorders?

Evaluate for other sleep disorders;

consider in lab PSG

Sleep Study(PM or in-lab PSG)

PM

In-lab PSG OSA Diagnosed?

Treatment

No

No

No

No

Yes

Yes

Yes

Yes

No

2007 PM Flow Chart The Intended Use of HSATs

• Who are you going to give it to?

– High pre-test probability of moderate to severe OSA

• What does this mean?

• Snoring, EDS, High BMI?

– Who aren’t you going to give it to?

• Patients with sleep co-morbidities

• Patients with major medical co-morbities

• Is this realistic?

Mulgrew et al., Ann Int Med, 2007

• 68 subjects with high suspicion for OSA tested via Portable Monitors– Age 52-55, ~75% men, med. RDI 27-31

• Randomized to in-lab titration or auto-PAP with conversion to fixed PAP in 2 wks.

• Outcomes similar at 3 months• Higher PAP compliance in autoPAP

• AutoPAP: 6 hrs, mean 12 cm

• Standard PAP: 5.4 hrs, mean 11.2 cm

HSAT Growth – What Happened?

• 1) Bottom Line– Cost savings to health management companies

(insurance, ACOs, systems)– High Deductible Plans – cheaper alternative for

patients

• 2) Used by providers on a local level for many years– Kaiser Permanente and other Sleep Centers

• 3) Recent Research Studies

HSAT Accuracy & Outcomes

• Large trials evaluating both accuracy & outcomes

– HomePAP trial (Rosen CL, et al.)

– Veterans Sleep Apnea Treatment Trial (Kuna ST, et al.)

• Initial data shows generally equivalent responses between in-lab PSG/titration & Home study/AutoPAP

– Symptomatic response

– PAP compliance

Home PAP:Percent Adherent: Medicare Criteria

Lab Home

1 month

% a

dher

ent (

at le

ast 7

0% o

f nig

hts)

020

4060

8010

0

Lab Home

3 months

020

4060

8010

0

Courtesy of Carol Rosen, MD

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Kuna et al., AJRCCM 2011

• VA Study

• 300 patients

• Randomized to In-lab or HST

• Results:– Similar PAP use

– Similar improvement in daytime sx

American Journal of Respiratory and Critical Care Medicine Vol 183. pp. 1238-1244, (2011)

Initial Response from Many Sleep MDs to HSAT

http://glee.wikia.com/wiki/File:Ostrich_head_in_sand.jpg

Response from Insurance Companies

http://tripwow.tripadvisor.com/tripwow/ta-00c7-7e48-bb4a

Or Perhaps More Accurately…

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Example of Impact of HSAT rules

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Feb2011

Mar2011

April2011

May2011

June2011

July2011

Aug2011

Sept2011

Oct2011

Nov2011

Dec2011

Jan2012

Feb2012

Mar2012

April2012

May2012

June2012

July2012

% HST

% In-lab

Uh-oh…

http://youheardme-achilles3.blogspot.com/2011/04/and-this-is-why-scott-adams-is-shit.html

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Examples of HSATs

http://sleepapneadisorder.info/tag/home-sleep-testing/http://www.alltransmedical.com/home_sleep_test.html

http://www.millbraedental.com/

• Airflow (Nasal Pressure / Thermistor)– Is the patient moving air through the nose/mouth?

• Thoraco-abdominal Effort– Is the patient trying to move air from the chest?

• Oximeter– What are the patient’s oxygen saturations?

• Other Signals– Measurement of Sleep Time (Actigraphy, EEG)– Arterial Tonometry (PAT)– Venous Pulsation

Typical and Atypical HSAT Sensors

What Do You Get From a HSAT?

• REI = Respiratory Event Index

– Remember Recording Time, not Sleep Time

– No EEG arousals

– Different than the 3% desaturation and/or Arousal AHI!

– May underestimate OSA severity or miss it inpatients with mild OSA

Stardust II: OSA – 5 min

Apnea Link +: OSA – 5 min ARES: OSA - 5 mins

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Clevemed SleepView: OSA (6 min) WatchPAT 200: Snoring w/OSA - 10 mins

A Patient Pitfall:Where We Can Miss the Mark

http://tenfey.wordpress.com/2011/04/

Pitfall Patient

• 64 year old woman presents with fragmented sleep and mild daytime sleepiness

• Mild snoring

• No PMHx

• Exam:

– MP III

– BMI 29 kg/m2

– Neck Circ – 16 in

• HSAT approved, but not in-lab test

These are unscorable on a HSAT (no arousal), but suggestive of sleep-disordered breathing

Subtle Sleep Apnea?

2 min page

These events cannot be truly scored without the oxygen saturation lead

Another Example of Possible OSA

2 min page

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Prolonged Obstructive Apnea?(Stardust - 5 minute epoch)

• An experienced sleep technician/ technologist, or health care practitioner either needs to educate the patient or apply the sensors to the patient– Data loss ranges 3-18% for Type 3 device

• Common center data 7-10%

• May require repeat HSTs or in-laboratory PSG

• Can affect efficiency and revenue

HSAT Failure Rate (Collop, 2007)

HomePAP “Failure” Rates

Study Type Failure Rate

Split-Night Study 0.0658

Full-Night Diagnostic Study 0.0106

Home Diagnostic Study (n=180)* 0.117 after 2 tries

Home Titration Study (n=103)** 0.097 after 2 tries

* 82% ≥ 15 on 1st try; 60% ≥ 15 on second try; n=8 cross back; 25% did not complete** 71% first try; 77% second try; n=6 cross back, 50% did not complete

Courtesy of Carol Rosen, MD

Summary, Part II

• Home Sleep Apnea Testing (HSAT) is a growth industry within Sleep Medicine

• There are benefits to using a HSAT, but there are some downsides as well.

– Risk of non-diagnosis in patients with mild disease

– May have non-OSA sleep disorders that would be missed

Patients and Their Smartphones

https://crazyaboutdroids.files.wordpress.com/2013/01/phonemaster-630x250.jpg

Sleep Assessment and Snoring By Mobile Devices

• Minimal scientific data about these apps

• “Quantification without Justification”

• However, perhaps there is some value, depending on use and future directions

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Sleep Evolving

SLEEPPROBLEMS

Not a Medical Problem

Ultra-specialized

Medical Problem

Specialized, but Testable in the

Home

Your Mobile Phone is a Sleep

Tester

Sleep in Evolution (Actual Timeline)

SLEEPPROBLEMS

• Given the lack of validation and United States Food and Drug Administration (FDA) clearance, CSTs cannot be utilized for the diagnosis and/or treatment of sleep disorders at this time. However, CSTs may be utilized to enhance the patient-clinician interaction when presented in the context of an appropriate clinical evaluation. The ubiquitous nature of CSTs may further sleep research and practice. However, future validation, access to raw data and algorithms, and FDA oversight are needed.

Citation: Khosla S, Deak MC, Gault D, Goldstein CA, Hwang D, Kwon Y, O’Hearn D, Schutte-Rodin S, Yurcheshen M, Rosen IM, Kirsch DB, Chervin RD,

Carden KA, Ramar K, Aurora RN, Kristo DA, Malhotra RK, Martin JL, Olson EJ, Rosen CL, Rowley JA; American Academy of Sleep Medicine Board of

Directors. Consumer sleep technology: an American Academy of Sleep Medicine position statement. J Clin Sleep Med. 2018;14(5):877–880.

Phone Apps for Snoring: An Analysis

• (1) Select smartphone snoring applications can be useful for recording and playing back snorting sounds

• (2) The most critical application feature is the ability to graphically display nocturnal events, with a zooming function for second-by-second analysis

• (3) The applications demonstrate excellent positive predictive value for application snoring detection (93.3%–96%)

• (4) More user studies are required to enhance the relevance of these applications.

Sleep Med Clin 11 (2016) 461–468

http://dx.doi.org/10.1016/j.jsmc.2016.08.008

Sample of Snoring Apps

The Journal of Laryngology & Otology (2015), 129, 974–979.

Noise Disturbance Tracking

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Real Patient Data – Smart Alarm Quit Snoring

The Journal of Laryngology & Otology (2015), 129, 974–979.

Snoring: App vs. PSG

The Journal of Laryngology & Otology (2015), 129, 974–979.

Another Snore App

http://www.snorelab.com/#demo

SnoreLab: Used by a MIT Engineer Sleep Apnea Assessment Via App?

• Nakano, Sleep 2014

• 50 patients

– 10 pts = development; 40 pts = validation

• Smartphone (SH-12C, Sharp Corp) attached to the anterior chest wall over the sternum.

• Acquired ambient sound from the built-in microphone and analyzed it using a fast Fourier transform on a real-time basis.

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Nakano, Sleep 2014

• Snoring time measured by the smartphone highly correlated with snoring time measured by PSG (r = 0.93).

• Moreover, the respiratory disturbance index estimated by the smartphone (smart-RDI) highly correlated with the apnea-hypopnea index (AHI) obtained by PSG (r = 0.94).

• The diagnostic sensitivity and specificity of the smart-RDI for diagnosing OSA (AHI ≥ 15) were 0.70 and 0.94, respectively.

ApneaApp (UW)

Nandakumar, APSS 2015Diagnosing OSA

• AHI is the gold standard currently, but room for improvement

• The REI is a bit more abstract, the numbers perhaps a bit less solid

• Apps are a bold new future, but will the severity markers be better? Likely not in the short term.

Final Summary• 1) The location of OSA diagnosis is continuing to

evolve from lab -> home, from medical devices -> phone/wearable

• 2) As testing evolves, it remains unclear whether our best metric of severity (AHI) will evolve as well

• 3) Don’t forget the patient!!!

– Clinical history remains paramount and is essential to help steer patients down the appropriate diagnostic pathway (and onward to treatment)

Questions Welcome.

http://www.memegen.it/meme/yyccht