Interpret Sleep Studies - Any Thoughts?

My sleep studies show I had mostly Central Apneas, and yet I was prescribed a regular CPAP at 6 cm H2O.

I thought someone with mostly central apneas like me needs to be prescribed an Adaptive Servo-Ventilator machine. I've been trying to ask my sleep doctor this question, but he only responds to questions at a scheduled appointment, which takes weeks to get.

I got my DME to upgrade me to an APAP and my auto pressure has settled to around 9.0 to 11.0 on most nights, and my AHI is mostly around 7.2 (varies from 5.6 to 12.6). I've been using the machine for 3 weeks now and have used it faithfully, except for 3 nights.

Does anyone have insight into why my sleep doctor prescribed me a CPAP even though 2 sleep studies showed I have mostly central apneas. Here are the results from my first and second sleep study:

Complete PSG Study #1, no titration

Recording time: 418 min
Total sleep time: 297 min
Sleep latency: 36.5 min
Number of sleep stage shifts: 63
Number of awakenings: 12
Sleep efficiency: 72.6%
Total time in non-supine position: 0.0 min

Sleep Architecture
Stage 1: 4.2%
Stage 2: 65.3%
Stage 3: 7.6%
Stage 4: 12.8%
REM: 10.1% (REM latency was 340.5 min)

Respiratory Events Summary
1 Obstructive Apnea (1 during NREM, 0 during REM, avg. length 20.0 sec)
16 Central Apneas (6 during NREM, 10 during REM, avg. length 17.4 sec)
33 Hypopneas (28 during NREM, 5 during REM, avg. length 28.8 sec)

AHI – 30.0 for REM, 7.9 for NREM, 10.1 overall
RDI - 30.0 for REM, 15.3 for NREM, 16.8 overall

SaO2
Overall mean: 95%
Lowest: 92%
Time below 90%: 0.0 min

Cortical Arousal Index: 3.2
Periodic Leg Movements: 0.0 / hr
Limb Movement Arousal: 0.0 / hr
Total Arousal Index: 12.5

EKG showed no heart rate abnormalities

Diagnosis
1. Mild sleep (positional) apnea with no snoring
2. Moderately reduced sleep efficiency; Increased sleep Latency; Increased REM latency; Decreased REM
3. No PLMS (Periodic Leg Movements Syndrome)
4. EKG showed no heart rate abnormalities.



Complete PSG Study #2, CPAP titration

Recording time: 455 min
Total sleep time: 351 min
Sleep latency: 54.0 min
Number of sleep stage shifts: 106
Number of awakenings: 21
Sleep efficiency: 77.4%
Total time in non-supine position: 0.0 min

Sleep Architecture
Stage 1: 8.0%
Stage 2: 49.8%
Stage 3: 24.6%
Stage 4: 0.0%
REM: 17.6% (REM latency was 96.5 min)

Respiratory Events Summary
0 Obstructive Apnea
2 Central Apneas (1 during NREM, 1 during REM, avg. length 29.3 sec)
99 Hypopneas (72 during NREM, 27 during REM, avg. length 33.7 sec)

AHI – 27.1 for REM, 15.1 for NREM, 17.2 overall
RDI - 27.1 for REM, 15.1 for NREM, 17.2 overall

SaO2
Overall mean: 95%
Lowest: 92%
Time below 90%: 0.0 min

Cortical Arousal Index: 3.2
Periodic Leg Movements: 14.0 / hr
Limb Movement Arousal: 0.0 / hr
Total Arousal Index: 11.4

EKG showed no heart rate abnormalities

Diagnosis
1. Partial control of sleep apnea with total elimination of snoring. RDI was 10/hr at optimum CPAP pressure of 6 cm H2O. SaO2 remained above 90%
2. Mildly reduced sleep efficiency.
3. Mildly severe PLMs (Periodic Leg Movements Syndrome)
4. EKG showed no heart abnormalities

Recommendation
Regular use of CPAP on a pressure of 6 cm H2O
Monitoring of clinical progress in 6 to 8 weeks



Any insights would be appreciated. Thank you.

What is your software showing re number of the various sleep events, including any centrals, for the three weeks that you have been using your machine at home? It was only after I started to monitor and analyze my nightly numbers using software that I started to make progress in getting a more restful nights sleep. I spent hours each day during my first month reading the posts on this forum. I tried out the more supported/credible recommendations re stopping mouth and mask leaks, improving sleep hygiene, using the different CPAP modalities/pressures (I started on Auto but changed to a set pressure after a month), and implemented various other recommendations (hose management, humidifier, table fan, etc.). Knowing what was happening during my "sleeping" hours each morning from running the software and correlating that to changes that I had or could make re my Sleep Therapy usage of CPAP allowed me to progress rapidly. I didn't feel better at all after my first week on CPAP (still felt like a Zombie when I got up in the morning) - I had an AHI of over 8 with over 2% time-in-Apnea - not Good! Now 12 weeks later, I have energy and enthusiasm every day - can't wait to get up and get started on my projects and hobbies. Last week's numbers were AHI = 0.3 with 0.02% time-in-Apnea. I am very pleased that it was possible to reach my goal of a restful nights sleep. With software and the amazing help the people on this forum provide to new (and old) users, you have the same opportunity. Best wishes in your reaching your Sleep Therapy goals.

I described my process in using the software (Respironics Encore Pro, multiple smartcards, etc.) in my initial posts (I've only posted about 15 times so far). Most people would consider my process to be "overkill" but it worked for me. Since I will be on CPAP the rest of my, hopefully, longer life, I wanted to get "out of the blocks" as quick as I could and take control of my therapy. Being retired allowed me the time to spend on my new health "hobby".

FYI, my sleep study numbers on CPAP were all over the floor: 139 sleep stage changes and 6.1 awakenings/hour (after sleep onset), over 1% time-in-apnea, and so on - I felt just as bad in the morning after my CPAP study as I had without CPAP. I, however, did not experience any Centrals. I am now convinced that I have far fewer awakenings and sleep stage changes today. I look at my flat, low, and long duration leak lines and interpret them as meaning that I am not moving much when I am asleep, i.e., sleeping like a baby.

I have no insight into your doctor's mind, however, you have far more hypopneas than apneas, and they may have been obstructive.

Your sleep study results can be interpreted as follows:
Obstructive hyopneas disrupt your sleep
Your response to hypopneas is rapid breathing
After a bout of rapid breathing - or a sigh - or a deep breath - you stop breathing because there's enough oxygen and not much CO2 in your body. This is recorded as a central apnea.

You titration study can be interpreted as your body needing time to get used to pressure. You can see that you got less stage 2 sleep, and more stage 3 and REM sleep -- despite having more hypopneas. Under those condition, a Periodic Limb Movement disorder is revealed, but they do not wake you up.

Since recent research has shown that some people need time to get used to sleeping with pressure, the doc is giving your body a chance to adapt to that. The most important line is this one:
Monitoring of clinical progress in 6 to 8 weeks


Did you run the machine at the prescribed pressure for a while? What is the present setting on the APAP?

O.

ozij wrote: Did you run the machine at the prescribed pressure for a while? What is the present setting on the APAP?
O.

We ran a CPAP at the prescribed pressure of 6.0 for the first 3 nights. The numbers were as follows:

AHI - 10.5 / 13.7 / 11.8
AI - 3.9 / 3 / 10.7
HI - 6.6 / 3.2 / 8.6

Then my DME switched me to an APAP with a min pressure 5.0 and max pressure 15.0. With this new setting, my AI numbers went down by 50% and my HI numbers went down by about 25%.

The 95% percentile pressure in APAP mode was averaging around 10.5

Check the numbers you reported for the first three night, you may have transposed some of them. By definition AHI=AI+HI, but in your case the numbers for the second and third night don't compute.

To make sense they should look like this:



It looks like the Autoset is good for you - do your best to get it for a a keeper.
Resmed machines tend to record more hypopneas - but in your case, even the hypopneas are getting better with the added pressure the Autoset supplies.

The 95% means that you need pressure up to 10.5 for at least 95% of the night. Note the up to. On a fixed pressure machine, they would trying to have you on 10.5 all night long. The auto lets the pressure vary from 5 to wherever you need it - which may be more comfortable. Before you return the machine, if it's a loaner, and especially if the want to give you a fixed pressure one - insist on running the Autoset at that fixed pressure for a week. Some people actually sleep even better when their pressure is fixed, however, others sleep best when the pressure varies.

Looks to me like your doc and DME know what they're doing.

How do you feel?

O.

I'll leave the machine discussion to those more in tune, but I was just wondering about the "mildly severe PLMs". If you indeed have this syndrome, please just be aware that improved cpap treatment can provide a less disrupted sleep environment that allows the limb movements to fully express themselves. Wouldn't want you to not feel better and blame it on the cpap when it could be your legs at issue. If anyone observes your sleep, they would be aware if this were an issue. Thusfar in your testing they didn't wake you, but you can't be sure they won't if more fully expressed. But one thing at a time, and getting your breathing straightened out is priority. Best wishes.
Kathy