Revisiting Hypopnea Scoring: The Significance of Respiratory Arousals

Document Type

Conference Proceeding

Publication Date

5-2025

Publication Title

Sleep

Abstract

Introduction: The debate surrounding the criteria for hypopnea scoring—3% versus 4% oxygen desaturation—remains unresolved. In 2012, the AASM Scoring Manual recommended defining hypopnea based on a ≥3% oxygen desaturation and/or arousal, while also recognizing ≥4% desaturation as an acceptable alternative, subsequently adopted by CMS (Centers for Medicare & Medicaid Services). However, the 4% AHI (Apnea-Hypopnea Index) criterion excludes arousals, which are indicative of fragmented sleep and sympathetic activation. Respiratory events that trigger arousals are associated with severe sleep symptoms, including poor sleep quality, excessive daytime sleepiness, and increased risk for adverse health outcomes, such as hypertension, amyloidogenesis, and other conditions. Treatment with positive airway pressure (PAP) therapy has shown significant symptom improvement in such patients. Report of case: Case 1: A 59-year-old female presented with snoring, daytime fatigue, insomnia, irritability, and mood disorder. Polysomnography (PSG) revealed a 3% AHI of 14.7, REM AHI of 41.2, and a 4% AHI of 1.3, with a respiratory arousal index (RAI) of 13.9. Case 2: A 53-year-old male with a recent stroke, loud snoring, witnessed apnea and unrefreshed sleep underwent PSG, which showed a 3% AHI of 21, REM AHI of 32.4, and a 4% AHI of 2.6, with an RAI of 14.8. Case 3: A 75-year-old female with snoring, chronic obstructive pulmonary disease, and pulmonary hypertension had a PSG revealing a 3% AHI of 21.4, 4% AHI of 1, and an RAI of 18.8. Case 4: A 48-year-old female with known obstructive sleep apnea (OSA) and end-stage renal disease on hemodialysis presented with morning headaches after discontinuing PAP therapy. PSG showed a 3% AHI of 12.6, REM AHI of 31.1, and a 4% AHI of 2.22, with an RAI of 11.7. Conclusion: These cases highlight the significant disparity between the 3% and 4% AHI criteria, emphasizing the need to incorporate respiratory arousals into the 4% scoring metrics. The exclusive reliance of CMS on the 4% criterion results in inappropriate management, persistent symptoms, and a poor quality of life for patients. Adopting a standardized scoring system that captures the full spectrum of sleep-disordered breathing is crucial for ensuring optimal care and improved patient outcomes.

Volume

48

Issue

Suppl 1

First Page

A647

Last Page

A647

Comments

39th Annual Meeting of the Associated Professional Sleep Societies, June 8-11, 2025, Seattle, WA

DOI

10.1093/sleep/zsaf090.1513

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