Hi,

I am trying to really understand my sleep study.  I got the basics understood - I have severe sleep apnea and no restless legs.  But if you all would be so kind as to help me understand more, here is a synopsis of the 6 pages they gave me:

total recording time:  455.3 min
total sleep period:  448.1 min
total sleep time:  389.0
sleep efficiency:  85.4%

Sleep onset - 7.2 minutes
number of stage 1 shifts - 46
number of stage shifts - 153
number of awakenings - 49

number of REM - 1
REM latency - 147.0 min
REM latency minus Awake - 133.5 min

Then they have a section on stage distribution with says basically that I spent
59.1 minutes awake after sleep onset
59 minutes in stage 1 (TST - 15.2%, latency 0 min)
216.5 minutes in stage 2(TST - 55.7%, latency 21 min)
68 minutes in stage 3 (TST - 17.5%, latency 091.5 min)
zero minutes in stage 4
REM for 45.5 minutes ((TST - 11.7%, latency 147 min)

Then next page says I have no central sleep apneas, no mixed, and then:
obstuctive apneas:
number 116
index 17.9
mean duration (sec) 15.7
longest duration (sec) 48.1
occur in REM 38
non rem 78
rem index - 50.1
non rem index 13.6

hyphpnea events
number 2
index .3
mean duration 20.2
longest duration 23.6
rem 0
non rem 2
rem index 0
non rem index .3

Then under respitory events it has this mysterious word "index" again for:
apneas and hypopneas:  18.2  total 118
RERA's 43.2 total 280
All respitory events 61.4 total 398
supine 75.9 total 200
non supine 51.5 total 198.

It goes on to talk about oxygen saturation and apparently the high was 94.5 and low was 82.8.

what do they mean by index?  
what exactly is the oxygen saturation telling me?  When is it "bad" or "worrisome".

I go back for a titration study but would like to know what you all can teach me before I do (its a few weeks from now).

Thank you.

The standard criteria for diagnosing, or aiding in the diagnosis, sleep apnea is a measure of respiratory events per hour. More than likely you didnt sleep an even amount of hours, so the computer computes your data and packages it into an INDEX. This quantifies your data, so that it can be read and compared with others. All in all, when you see the word index, you can take the number associated with that and think... wow, I had X amount of apneas in one hour of sleep.

Total AHI is important, but do not let anyone fool you, REM AHI is important too.

Total AHI was 18.2 (This is what classifies your OSA as mild, moderate or severe)
REM AHI was 50.1
NREM 13.6

Oxygen saturations

Some physicians set protocols to keep patients above 90% some 92%. It really depends on what the lab you are attending prefers. CPAP treatment can usually fix the hypoxia, however oxygen can be administered also. In terms of what is worriesome.

<88% in my opinion. I am not a physician, so take it for what its worth.

Also, its important to know how long during the study you were at the lower levels. If you were having sustained oxygen level drops, then it is more serious than an occasional drop, if that makes sense. In any event, its time to be concerned if you get to 88 and below for periods of time.

Hey, RAM, I've gotta question. How many sleep cycles (thru all stages) does the average individual w/o disturbed sleep go thru in an 8 hour night?


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CrohnieToo wrote:

Hey, RAM, I've gotta question. How many sleep cycles (thru all stages) does the average individual w/o disturbed sleep go thru in an 8 hour night?

4 to 5

Mathematically, it should be 5, but in todays age where people tend to sleep less than 8 hours, 4 may be the number that many people see.

Okay, then I am confused about this part:

apneas and hypopneas:  18.2  total 118
RERA's 43.2 total 280
All respitory events 61.4 total 398

They told me that my sleep apnea was severe because of the "all respitory events" number of 61.4.  But your saying that they should have looked at the Apneas and Hypopneas number?  That number seems to indicate moderate from what I am finding on the internet.

So what is the difference between apneas, hypopneas, and "all respitory events"?

crossfit wrote:

Okay, then I am confused about this part:

apneas and hypopneas:  18.2  total 118
RERA's 43.2 total 280
All respitory events 61.4 total 398

They told me that my sleep apnea was severe because of the "all respitory events" number of 61.4.  But your saying that they should have looked at the Apneas and Hypopneas number?  That number seems to indicate moderate from what I am finding on the internet.

So what is the difference between apneas, hypopneas, and "all respitory events"?

Apnea - Cessation of beathing or 10% or less of your baseline breath.

Hypopnea - 30% reduction in baseline breath, however more than 10% of the total baseline.

AHI - Apneas + Hypopneas per hour

A RERA (Respiratory effort-related arousal) is defined as an arousal from sleep that follows a 10 second or longer sequence of breaths that are characterized by increasing respiratory effort, but which does not meet criteria for an apnea or hypopnea. Snoring, though usually associated with this condition need not be present. Respiratory effort is measured via esophageal pressure monitoring. Where esophageal pressure is being monitored the pattern is one of progressively more negative pressure terminated by a sudden change to a less negative level and an arousal. An alternative to esophageal pressure monitoring is the use of nasal pressure signal with progressive inspiratory flattening followed by an arousal.  RERAs have the same implications for sleep fragmentation and consequent daytime sleepiness as do apneas and hypopneas. Some patients who have symptoms suggestive of OSA have few apneas or hypopneas on polysomnography, but frequent respiratory effort related arousals to which their clinical presentation can be related.  This condition has been termed Upper Airway Resistance Syndrome

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They are combining everything into your total index of 61.4, however the RERAs, as mentioned above, would diagnose you with UARs. It is likely that you have both OSA and UARS, with the treatment for both being CPAP.

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I hope this helps.

yes, that helps a lot.  thanks.  I really should have insisted on seeing my doctor yesterday and not being rushed through my the nurse.  I appreciate you filling in the gaps.