To count in the index apneas and hypopneas collectively called events must have a duration of at least 10 seconds. On some sleep study reports you will see the terms rdi or rei in place of ahi. 6 Secure Clever Tips 1x Micpap Anti Snoring Device Electric Apnea hypopnea index ahi the ahi is the number of apneas or hypopneas recorded during the study per hour of sleep. Ahi in sleep apnea test . The apneas pauses in breathing must last for at least 10 seconds and be associated with a decrease in blood oxygenation. Goal ahi to optimize cpap therapy. Ahi provides the severity of sleep apnea. Ahi is common part of results that sleep tests such as polysomnogram or home sleep testing. Apnea hypopnea index ahi measures sleep apnea severity. Cpap is not usually recommended as the first option for treating mild sleep apnea. Of all the numbers on your sleep apnea test report the ahi is the most important. If your doctor suspects you have sleep apnea you may need to undergo a s...