hypopneic

Hypopneic refers to a state of breathing that is shallower and slower than normal. This reduction in breathing rate and depth is a significant characteristic of certain sleep-related breathing disorders, most notably obstructive sleep apnea (OSA). During a hypopneic event, airflow to the lungs decreases, but not to the point of complete cessation as seen in an apnea. However, this reduction in breathing is still sufficient to disrupt sleep and can lead to a drop in blood oxygen levels. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and other medical literature often define a hypopneic event based on a reduction in airflow by at least 30% for a specified duration, accompanied by a decrease in blood oxygen saturation or a brief arousal from sleep. Physicians use the frequency of these events, often measured as the apnea-hypopnea index (AHI), to diagnose and assess the severity of sleep apnea. Symptoms associated with frequent hypopneic events can include daytime sleepiness, snoring, and morning headaches.