Understanding the AHI/Events Per Hour

Hello. I am new to the forum. I was diagnosed in 2008 and have been on CPAP ever since. Recently I got a new machine, a ResMed Airsense10. My previous machine did not have a readout that I could see in the morning, but my doctor had told me I was at about 3-5 events per hour. On the AS10 - my report shows anywhere from 0 to .5 per hour most nights and up to 3.5 some nights. What I don't understand is this - when I see .5 events per hour, does that truly mean that I am averaging one half of an event per hour (or 1 event per two hours on average)? Thanks for your input.

Hello, and good question. The AHI is an index, so it is an average of total events per hour. An AHI of 0.5 would indeed indicate that you are having about 1 event every 2 hours. Someone who sleeps for 8 hours and has an AHI of 0.5 would have 4 events over the course of the 8 hours.