Apnea-Hypopnea Index (AHI) measures sleep apnea severity. The AHI is the sum of the number of apneas (pauses in breathing) plus the number of hypopneas (periods of shallow breathing) that occur, on average, each hour.
To count in the index apneas and hypopneas, collectively called events, must have a duration of at least 10 seconds.
The AHI, as with the separate Apnea Index and Hypopnea Index, is calculated by dividing the number of events by the number of hours of sleep.
From the AHI rating chart here, we see that an index less that 5 is considered normal. For an Apnea-Hypopnea Index (or AHI) from 5 to 15 denotes mild sleep apnea. Fifteen to 30 is moderate, while a greater than 30 AHI is considered severe.
- AHI = sum of the number of apneas (pauses in breathing) plus the number of hypopneas (periods of shallow breathing) occurring, on average, each hour.
- Apneas and hypopneas, collectively called events, must last at least 10 seconds to count as events.
- The AHI is calculated by dividing the number of events by the number of hours of sleep.
What does a Central Apnea Chart look like since that number is not included in the AHI number?
Central apneas are indeed calculated in the AHI. Central apneas are still apneas
Central apneas are indicated by the non-obstructive apneas.
i started on a bi-pap machine 30 days ago. i had a terrible time for nearly the whole month in tryat ing to make the full mask work. I started calling to complain. I even went back in to the provider to see if the mask fit. finally, the manager, a respiratory therapist heard my pleas and called. she was at my house within the hour and gave me a different mask which has worked 100%. In the last 10 days, i have had 100% mask fit. The AHI is up and down and i dont know what makes the difference in higher or lower, but i think i am sleeping better and will hopefully improve as time goes by. i no longer dread putting on the machine and i no longer have red marks and pain from the ill-fitting mask. do not settle for an inferior fitting when you can get relief if the techs will only take the time that this manager did with me
Paula, it will take time for your apneas to start to decline. Your brain is still getting used to having air at night. I started my bipap last April, and after about a month, I was still getting 13 apneas an hour, but more alert and awake during the day. After a couple more months it dropped to 10, and after 8 months, I now average around 6.5 per hour. Still having good nights and bad, but that is part of the process. Hang in there.
What is the difference between AHI and RDI (respiratory disturbance index). I did some basic research and it seems like RDI is considered “more accurate” but the clear differences are not elucidated very clearly. Any small clarifications would be greatly appreciated.
The RDI includes all the elements of the AHI plus “respiratory-effort related arousals (RERAs).” These are events where respiration is more difficult, but doen’t meet the criteria for the three factors included in AHI: viz., obstructive apneas, non-obstructive apneas, and hyponeas (reduced airflow below 80%, but not apnea).
Is .5 and 5 the same measure? What does it mean when your number increases from .5 to 1.0? The decimal point is confusing. Where do these numbers fall on the chart from normal to severe?
It’s simple if you sleep 2 hours but only have one event during that two hours it will show up as point five or if you see point five and you slept 8 hours that means you had four events if you slept 8 hours and only had two events it would show up as .25
I have sleep apnea my machine is set on 8 but my air pressure was drying out my nose so i call where i pickrd up machine and she told me to turn it up and i put it on 4 the air pressure is this right
You should never adjust your air pressure you should only be adjusting your humidity if your air pressure is set to 8 you should not change it you should discuss it with your doctor however if you called and they told you to turn it up they were more than likely speaking about the humidity level and that you can adjust on your own my machine comes set to 4 standard or by default I actually turned it up to 5 to get a little more humidity to stop B from drying out this is a good setting for me
No wonder you’re not getting enough air with [lack of] punctuation like that…
I suggest you to buy Philips Dreammaker with Humidifier attached to it. I bought this machine, fully Auto Pressure, I feel how beautiful the human invention is! I have Bluetooth attached to my mobile phone, Morning you just need to synchronise to get the data overnight, take a screenshot and store day by day in your phone in a separate folder.
I got the same few weeks back and within a day i was sleeping a sound sleep. I can monitor my sleep on the app.Its a very good machine and would surely recommend
I was diagnosed with sarcoidosis about 7 years ago. I immediately fought against EXTREME fatigue. My pulmonary doctor recently told me that the sarcoidosis has been in remission for a couple of years now. I went and had a sleep study done. It revealed that I had 131 episodes an hour. Oxygen dropped as low as 60 and I stopped breathing up to 32.5 seconds. The doc said I am basically not sleeping at all. I got my CPAP machine and the next morning I felt so refreshed. It’s scary to think about how long my cells may not have had an opportunity to rejuvenate. I pray that any damage can be reversed with dedicated use of the CPAP machine.
congrats on the progress!!
I received a nasal mask, and was asked if I wanted a chin strap. I was told if I snored and breathed through my mouth, it wouldn’t do any good. I took the chin strap, but went without the first night (last night). My AHI over 10 hours was 3.9, so I’m thinking I don’t need to use it. What do you think?
If you are breathing through your mouth and your mouth is extremely dry when you wake up I would recommend the chin strap. You will know you are breathing through your mouth if it is dry. Hope this helps.
I breath through my mouth often at night due to nasal passages that easily get stuffy. My doctor prescribed me a mask that goes over my mouth as well.
If one’s AHI is 2.5 events per hour, what does the decimal point *(.5) represent? Is this reading considered low/medium/high?
A number below 5 is “normal”, but lower (like 2.5; i.e. 2 and a half) is better.
If you had 5 events in two hours, your AHI would be 5/2=2.5 which is considered normal.
Is the reading of 2.5 for events per hour considered low/medium/or high?
What does the decimal ( . 5 ) represent?
I’ve had my CPAP machine since 2003 & use it nightly. My insurance company now requires a sleep study showing AHI of 15 or more before they’ll pay for a new machine. After using the machine for so long I am sure hoping my sleep study will show 15 or more AHI. My first study records are no longer available.
Your reading is excellent. Less than 5 is considered normal. Good for you!!
The .5 is the result of the math – total apnea events during your night sleep divided by total hours slept.
I recently changed from a nasal mask to a full face mask. The reason was I was getting a dry mouth . However my API was running from .1 to 4.0 now with the full face mask it has be 11.0 to 12.0 – can you tell me what is causing this
Suggest you ask your MD.
Do you have a humidifier attached? If yes, increase the setting for dry mouth. The nasal mask is better. Also, use a heated tube. Your earlier readings were great.is your CPAP machine auto. If yes, it should automatically adjust the air pressure.
It seems like with the full mask the pressure is not adequate.
Due to various nasal problems, it is getting increasingly harder to wear a mask. I have tried 6 different ones, but none are right. As I have not only apnea but also hypopnea (low oxygen) does anyone know if the oral devices help the hypopnea?
Suggest you ask your MD.
Just starting My therapy it’s been 4 days. I wake up my sinuses are horrible and puffy eyes
You should contact the supplier of the equipment to advise you on this… you need the humidity level adjusted to a lower level.
Your CPAP provider should have advice.
I’ve had my CPAP machine for 18 months. I wear a nose mask and tape my mouth at night. Still get a dry mouth! Still struggling to get a reading below 9. I’ve also had sinus and cough on and off, especially in Winter. I won’t give up but it’s frustrating. Any idea of what else might help?
I was put on CPAP for Atrial Fibrillation. My AHi was between 15 and 25. My doctor moved me to BIPAP machine set inhale 19 and 14 exhale. My AHI is now aroune 1 to 4 a night. I usually have either 0 or 1 obstructive apneas (versus 25-30) but I have @ 10 central Apneas a night ( as low as 6 and as high as 13). Is that good or am I supposed to eliminate the central apeas?