Obstructive sleep apnea/hypopnea syndrome

Area of Science:

• Sleep Medicine
• Respiratory Physiology
• Clinical Diagnostics

Background:

• Obstructive sleep apnea/hypopnea syndrome (OSAHS) is defined by recurrent upper airway collapse during sleep, leading to reduced airflow, oxygen desaturation, and potential CO2 increase.
• These events often trigger arousals, causing sleep disruption and leading to clinical consequences like excessive daytime sleepiness.

Purpose of the Study:

• To outline the minimal diagnostic criteria for OSAHS, encompassing both daytime symptoms and objective sleep-disordered breathing.
• To discuss the definitions and recommended diagnostic standards for OSAHS events by the American Academy of Sleep Medicine (AASM).

Main Methods:

• Diagnostic criteria include excessive daytime sleepiness or specific symptoms (e.g., choking, gasping, unrefreshing sleep) combined with over five obstructed breathing events per hour.
• Obstructive apnea/hypopnea events are defined by duration (≥10s) and severity (e.g., >50% airflow reduction with 3% oxygen desaturation or arousal).

Main Results:

• The Apnea/Hypopnoea Index (AHI) shows a weak correlation with quantified sleepiness measures (e.g., Epworth Sleepiness Scale), suggesting interindividual variability in coping with sleep fragmentation.
• Epidemiological studies on OSAHS prevalence are limited by non-uniform definitions, with reported AHI prevalence varying significantly based on symptom inclusion.

Conclusions:

• Despite defined criteria, the correlation between breathing disturbances and daytime sleepiness in OSAHS is weak.
• Accurate prevalence estimation of OSAHS is challenging due to definition inconsistencies and the need to consider both breathing patterns and subjective symptoms.