What is the recommended definition of hypopnea according to the AASM?

The recommended definition of hypopnea according to the American Academy of Sleep Medicine (AASM) is a decrease of the nasal pressure signal by at least 30% for at least 10 seconds, accompanied by a minimum of 4% desaturation. This definition is significant because it incorporates both a measurable reduction in airflow and a quantifiable impact on oxygen levels in the blood, which reflects the physiological consequences of impaired breathing during sleep.

By specifying the parameters of 30% reduction in airflow and a 4% desaturation, the definition ensures that hypopnea is linked to clinically relevant events that can trigger adverse health outcomes, such as excessive daytime sleepiness or cardiovascular issues. This dual criterion emphasizes that a mere reduction in airflow is not sufficient; the subsequent drop in oxygen saturation indicates a more severe impact on the body's oxygen delivery system, which is crucial for maintaining metabolic functions.

The combination of these factors makes this definition applicable for diagnosing and understanding the impact of obstructive sleep apnea and other related sleep disorders, allowing clinicians to prioritize patient management effectively.