Interpreting Sleep Study Reports: A Primer for Pulmonary Fellows By

Interpreting Sleep Study Reports: A Primer for Pulmonary Fellows By Martha E. Billings, MD MSc for the Sleep Education for Pulmonary Fellows and Practitioners, SRN ATS Committee August 18, 2014

Obstructive Sleep Apnea Obstructive sleep Apnea: total cessation apnea: repeated of air flow for 10 sec closure or narrowing Hypopnea: 10 sec of of upper airway reduced air flow reducing airflow Obstructive respiratory events are associated with snoring, thoracoabdomnial paradox & increasing effort AASM Scoring Manual Version 2.1, 2014

Polysomnogram (PSG) Warvedaker NV et al. Best Practice of Medicine. Sept. 1999

Scoring Criteria: Respiratory Events Hypopnea definition flow 30% from baseline for at least 10 seconds 1A. (AASM) with 3% O2 desaturation OR arousal Requires EEG monitoring 1B. (CMS) with 4% O2 desaturation Amenable to portable studies Respiratory Effort Related Arousal (RERA) Flattening of inspiratory portion of nasal pressure (or PAP flow) with increasing respiratory effort leading to arousal No associated desaturation Requires EEG monitoring AASM Scoring Manual Version 2.1, 2014

Apnea Hypopnea Index AHI (# apneas # hypopneas) / sleep hours AHI 5 normal AHI 5 – 15 mild AHI 15 – 30 moderate AHI 30 severe RDI (# apneas # hypopneas # RERAs) / sleep hours – Can be large difference in AHI vs. RDI if young, thin patient who is less likely to desaturate by 4% with events – Treatment not covered by Medicare if AHI 5 but some insurances accept RDI 5 (with AHI 5) with symptoms

PSG Epoch: Obstructive Apneas

In-lab PSG Data Respiratory Data: # Central, obstructive apneas, hypopneas & RERAs – AHI & RDI by position and sleep stage – Central apnea index & if Cheyne-Stokes pattern Oximetry: – Oxygen Desaturation Index – Mean O2 saturation & nadir Hypoxemic burden ̶ Cumulative % of sleep time spent under 90%

In-lab PSG Data EEG Data: Sleep efficiency & latency – Normal 80% efficient – Latency 30 min, REM latency 60-120 min Sleep stages & architecture – Normal about 5% stage N1, 50% N2, 20% N3 (slow wave sleep) and 2025% REM Arousal Index (AI): sleep disruption – Normal AI 10-25 (large variation by age) Norms are all age dependent – in general less REM & SWS, more arousals, WASO and lower sleep efficiency as age EEG abnormalities – Epileptiform activity, alpha intrusion

Sleep Architecture Over Lifespan Ohayon MM, Carskadon MA, Guilleminault C, Vitiello MV. Meta-analysis of quantitative sleep parameters from childhood to old age in healthy individuals: developing normative sleep values across the human lifespan. Sleep 2004;27(7):1255-73

In-lab PSG Data EMG Data & Video Limb Movements – periodic limb movements index in wake & sleep Normal PLMI 15 adults – Movements during REM (loss of atonia) Parasomnias – Sleep walking, talking – Bruxism – REM sleep behavior disorder

Classic OSA (300 sec)

Sample PSG Results Sleep Architecture: Sleep latency 13 min Sleep efficiency 64% WASO 28% REM latency 143 min Arousal index 53 Predominantly respiratory Limb Movements PLM index 7 % Sleep Stage N1 N2 N3 REM

Sleep Study Sample Report EEG Data: sleep architecture & arousals Sleep Summary – Whole Night: Time at Lights Off Time at Lights On Total Recording Time (TRT) Sleep Period Time (SPT) Total Sleep Time (TST) Sleep Efficiency (SE) 21:50:57 05:50:42 479.8 min. 452.0 min. 413.5 min. 86.2% Sleep Stage Summary – Whole Night: Stage Duration (min) WASO 38.5 Stage N1 30.0 Stage N2 242.0 Stage N3 64.5 Stage REM 77.0 % TST 7.3 58.5 15.6 18.6 Sleep Continuity – Whole Night: Source of Arousals NREM Count Spontaneous 0 Apneas / Hypopneas 72 RERAs 45 Snoring 0 PLM / Limb Mvmnts 0 Total Arousals 117 NREM Index 0.0 12.8 8.0 0.0 0.0 20.9 Sleep Onset Latency (SL) Number of Stage N1 Shifts Number of Stage Shifts Number of Awakenings 27.8 min. 36 206 17 REM Latency 141.0 min. % SPT 8.5 6.6 53.5 14.3 17.0 REM Count 0 31 7 0 0 38 Latency (min) 0.0 2.0 22.5 141.0 REM Index 0.0 24.2 5.5 0.0 0.0 29.6 Total Count 0 103 52 0 0 155 Total Index 0.0 14.9 7.5 0.0 0.0 22.5

Sample PSG Results: OSA Respiratory Data: Apnea Hypopnea Index: AHI 17 12 obstructive apneas, 45 hypopneas RERA index 34 Oxygenation Desaturation Index: ODI 13 Nadir O2Saturation: 86% Hypoxemic Burden: 13% of study O2 sat 90% Most severe supine, REM sleep (AHI 53) Total RDI: 55

Sample PSG Report Events by sleep stage & position Respiratory Summary – Pre-Treatment: Types of Respiratory Events Respiratory Events Number Obstructive Apneas 65 Mixed Apneas 0 Central Apneas 0 Total Apneas 65 Total Hypopneas* 48 Apneas Hypops* 113 Index 22.3 /hr 0.0 /hr 0.0 /hr 22.3 /hr 16.5 /hr 38.9 /hr Respiratory Effort Related Arousal (RERA) Events Parameter Total Index Total: 24 8.3 Non-REM: 23 8.3 REM: 1 6.7 Supine: 24 8.3 Lateral: N/A N/A Prone: N/A N/A Oxygen Saturation Summary – Pre-Treatment: Mean SaO2: % TST SaO2 90%: % TST SaO2 89%: Minutes SaO2 90%: Minutes SaO2 88%: 95.2% 2.3% 1.7% 4.0 5.5 Lowest SaO2: # Desaturation 4% or : Desaturation Index: NREM Desaturations Index: REM Desaturations Index: 79.0% 91 31.3 28.6 80.0

Respiratory Events by Position Supine 206.9 min. 53.0% TST in Position: % of TST Number Obstructive Apneas Mixed Apneas Central Apneas Total Apneas Total Hypopneas Apneas Hypops 2 0 1 3 80 83 Prone 0.0 min. 0.0% Index 0.6 0.0 0.3 0.9 23.2 24.1 Number Supine 189.4 48.5% Obstructive Apneas Mixed Apneas Central Apneas Total Apneas Total Hypopneas Apneas Hypops AHI 2 0 1 3 60 63 20.0 REM TST in Position: % of TST: Supine 17.5 4.5% Obstructive Apneas Mixed Apneas Central Apneas Total Apneas Total Hypopneas Apneas Hypops 0 0 0 0 20 20 68.6 AHI Index N/A N/A N/A N/A N/A N/A NREM TST in Position: % of TST: Left 154.1 min. 39.5% Number N/A N/A N/A N/A N/A N/A Prone 0.0 0.0% N/A N/A N/A N/A N/A N/A N/A Prone 0.0 0.0% N/A N/A N/A N/A N/A N/A N/A Index Right 29.5 min. 7.6% Number 7 0 1 8 56 64 2.7 0.0 0.4 3.1 21.8 24.9 0 0 0 0 10 10 Left 125.6 32.2% Right 7.5 1.9% Upright 0.0 0.0% 6 0 1 7 44 51 24.4 0 0 0 0 0 0 0.0 Left 28.5 7.3% 1 0 0 1 12 13 27.4 Right 22.0 5.6% 0 0 0 0 10 10 27.3 Upright 0.0 min. 0.0% Index Number 0.0 0.0 0.0 0.0 20.3 20.3 N/A N/A N/A N/A N/A N/A N/A Upright 0.0 0.0% N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Total 322.5 82.6% 8 0 2 10 104 114 21.2 Total 68.0 17.4% 1 0 0 1 42 43 37.9 Index N/A N/A N/A N/A N/A N/A

Sample Hypnogram RESPIRATORY 50 0 9:50 PM 10:50 PM 11:50 PM 12:50 AM 1:50 AM 2:50 AM 3:50 AM 4:50 AM LEGS LMs PLMs LMs/Ar PLMs/Ar 9:50 PM 10:59 PM 12:08 AM 1:16 AM 2:25 AM 3:33 AM 4:42 AM 5:50 AM 10:59 PM 12:08 AM 1:16 AM 2:25 AM 3:33 AM 4:42 AM 5:50 AM OXIMETRY 100 90 80 70 60 50 9:50 PM

Dramatic OSA in REM

PSG: 120sec Epoch Obstructive hypopneas/ RERAs with clear arousals but not consistent desaturation

Home Sleep Study (OCST) Respiratory data only (estimated AHI, ODI) calculated from recording time – Underestimates AHI as recording time time asleep – Problematic if insomnia No EEG to determine sleep or arousal – No arousal associated hypopneas scored – No respiratory effort related arousals (RERAs) – No information by sleep stage (REM/NREM or if asleep) Higher rates of technical failure Appropriate for high likelihood OSA & no other sleep disorders or respiratory/cardiac disease

Home Study Tracing

Sample OCST Results Total recording time: 423 minutes Supine sleep: 34% AHI 8.4 – 3 obstructive apneas, 2 central apneas Oximetry – ODI 7 – Nadir saturation 87%, mean 94% Same patient as in sample PSG but lower AHI estimated b/c of poor sleep efficiency & less REM

Summary In lab PSG provides details regarding EEG, EMG to give more complete evaluation of sleep disorder When interpreting sleep study results, remember to consider: – % supine, REM sleep captured – AHI often underestimated in OCST – RDI vs. AHI & hypopnea criteria used