Sleep apnea machines have one main goal and that is to improve breathing. To diagnose the severity of the sleep apnea with a patient, the apnea-hypopnea index (AHI) is used. This measures the severity of the condition at baseline and helps track the effectiveness of any treatment.
The AHI measurement is usually presented in a sleep study report. It is the number of times per hour of sleep that the upper airway (soft palate of throat or tongue) completely or partially collapses. This leads to a brief awakening or a drop in blood oxygen levels.
The AHI can classify the severity of the sleep apnea and assess how well treatment is going with machines such as the CPAP. To count in the AHI, the breathing pauses must last for at least 10 seconds or be associated with the decrease of oxygen levels in the blood.