The determination of respiratory disturbance severity during sleep involves quantifying the number of apneas and hypopneas per hour of sleep. An apnea is defined as a cessation of breathing for at least ten seconds. A hypopnea is a reduction in airflow, typically associated with a decrease in oxygen saturation or arousal from sleep. The index derived from these events provides a measure of sleep-disordered breathing severity.
This metric is crucial for diagnosing and managing sleep apnea, a condition linked to cardiovascular disease, stroke, and other health complications. Its development and subsequent use in clinical practice have revolutionized the identification and treatment of sleep-related breathing disorders, improving patient outcomes and overall quality of life. Accurate measurement allows clinicians to tailor treatment plans, such as continuous positive airway pressure (CPAP) therapy, to the specific needs of each patient.