Sleep Study Completed

Hello Everyone,

I received the results of my sleep study and am considering next steps. I was told by my sleep doctor that I was a difficult case to treat because my numbers were borderline mild to moderate. The large majority of abnormal respiratory events were hypopneas and during those events I was only mildly desaturated. He would not recommend therapy, except for the fact that I am a former Atrial Fibrillation patient, who recently (3 months ago) received an ablation, which so far has been successful. He pointed to the fact that there weren't a lot of data/studies to help understand how mild/moderate sleep apnea affects atrial fibrillation. As a patient, I'm torn. I want to do everything I can to lower my risk of AFib recurrence, however I would like to avoid unneeded therapy. I thought that I would share my case here and ask for any advice.

Thank you in advance

BTW: happy to share more specific sleep study data as needed

Hi Que. Congratulations on completing your sleep study. That's the first step to making an informed decision about your condition. Have you considered seeking a second opinion? That might help ease your mind about your doctor's recommendation. For patients in a situation like yours, I think different providers might feel differently about whether to treat. It might also be important to talk about how you feel physically and how you feel about your sleep. Some people with mild sleep apnea choose treatment for several reasons. Examples are that it helps stop snoring, they feel like they get deeper sleep, or they feel more rested in the morning. Have you considered asking your sleep doctor, if you are interested, if you can try treatment to see if it makes a difference in how you feel? Let us know how you're doing, and maybe other forum users who have had similar experiences might share them. Good luck!

Thanks DanM. I have another appointment with the Sleep Doc and will ask him what his opinion is. Seems like a tough call.

Bought a didgeridoo today and started playing. I'm also wondering if there is a way to measure at home if some personal steps that I'm taking are making an improvement. For example, I think that I saw an oximeter for sale. My thinking is that if I'm noticing that the didgeridoo and positional therapy is keeping my O2 levels normal overnight that might be enough since I'm mild/moderat AP.

Hi Que. Glad you're going to talk to sleep physician about your results, and congratulations on the didgeridoo. I have never tried one. As for measuring at home, probably the most important thing to note is how you are feeling when you wake up each morning (still tired, refreshed, etc.) and how you're feeling throughout the day. Most of the home O2 units are meant for spot-checks of O2 and do not record a full night of oximetry. If you can find one that records a full night and lets you review, that would be the better option. You could also consider asking your physician about ordering oximetry monitoring at home. Good luck!

Hi Dan,

I have a little more info from my last doctor's visit at Stanford. Even though my AHI score was 16 and my lowest oxygen saturation was 91%, my REM Respiratory Index was 39.4 while Supine. That seems to be of particular worry. Can someone please explain what that means exactly? I was told that while I'm in REM I was aroused nearly 40 times per hour. I suppose that is bad since REM is the most restful portion of sleep. Correct?

Thank you, Que

Hi @Que. It is not uncommon for patients to have sleep apnea symptoms that are worse in both REM and in the supine position. In REM, the muscles relax. This is often referred to as REM sleep atonia. When the muscles associated with breathing and the airway relax during REM sleep, the respiratory event index tends to rise as breathing worsens. When in the supine position, the tongue has a tendency to fall toward the back of the mouth. Other tissue in the throat and upper airway can also contribute to airway obstruction. The respiratory event index, referred to as the AHI or sometimes the RDI, is the number of respiratory events per hour of sleep. This is usually provided for the entire night, for REM sleep and for non-REM sleep. Arousals are also reported as an index per hour of sleep and can be reported for the entire night, for REM sleep and for non-REM sleep. The respiratory event index and the arousal index are reported separately because not all respiratory events are associated with an arousal. Arousals can occur for many reasons--ambient noise, general discomfort and the need to change body position, coughing, etc. As for restful sleep, stages 3 and 4 (more commonly now called stage 3 or slow wave sleep) is usually the deepest and most restorative sleep. However, REM is very important because it also helps provide energy and supports some of the body's daytime functions. The National Sleep Foundation has a page that gives an overview of sleep stages that you might find interesting: http://sleepfoundation.org/how-sleep-works/what-happens-when-you-sleep. Treatment for sleep apnea can help restore normal sleep architecture by helping to prevent respiratory events and associated arousals. I hope this information helps answer your questions. How is the didgeridoo playing coming along?

Hi Dan,

Thanks for the explanation of REM sleep. It's really helpful. I'm still trying to understand the significance of my study results. It seems that I have a high number of hypopnea events but I am not desaturating significantly but I aroused. The question I have is how troublesome is that?

--

HYPOPNEA EVENTS: NREM

Number of Hypopnea Events Supine & Non-Supine: Total 55, w/AR: 46, w/Desat:2, w/AR+Desat: 7

NREM Index: 8.7

--

HYPOPNEA EVENTS: REM

Number of Hypopnea Events Supine & Non-Supine: Total: 44, w/AR: 39, w/Desat:4, w/AR+Desat: 1

REM Index: 6.9

--

Thanks, Que

Hi @Que,

I will provide some general information, but your sleep physician should provide more guidance based on your entire clinical picture--medical history, sleep study results, medication history, etc. You should also discuss how you generally feel on a day-to-day basis. Are you frequently fatigued? Do you have a tendency to want to fall asleep or nap? Do you feel rested in the mornings after a full night in bed? All of these things are important to consider when discussing treatment options. In general, your hypopnea event indices are considered mild. However, some patients with mild sleep apnea report feeling very fatigued or drowsy during the day. This can sometimes be caused by frequent arousals that cause fragmented sleep. The American Academy of Sleep Medicine defines sleep apnea severity using the following AHI criteria: 5-15 is mild, 15-30 is moderate, more than 30 is severe. I hope this is helpful, and good luck as you continue to seek answers!

Thanks Dan,

I appreciate your advice. I have a few more questions:

• Can you please tell me what is the definition of an Hypopnea Event is? In my case I had 33 Supine and 16 Non-Supine.

• When it's stated that patients with OSA have an increased risk for mortality, stroke, Atrial Fibrillation, and cancer, how is that measured? Does a patient need to have a certain AHI score or similar measurement to have that risk?

Thank you, Que

BTW: Didgeridoo is coming along :)

Hello @Que,

You're most welcome. To answer your questions:

There are a couple of "official" definitions used when assessing a sleep study, but a hypopnea is generally a reduction in airflow (breathing usually measured through a nasal cannula or by an alternate sensor) that results in a blood oxygen desaturation of at least 4% or that causes an arousal from sleep that lasts at least 3 seconds.

Regarding increased risk of mortality and the other issues you list, this data has been obtained through years of research showing the associations between sleep apnea and other conditions. The specific disorders, conditions or illnesses can be related to different things associated with sleep apnea. There is no single score or measurement associated with all of the conditions. Some risks may be related to decreased blood oxygen levels associated with respiratory events while others may be related to hypertension that is often worsened by sleep apnea. The important thing to understand is that research has shown us that sleep apnea can contribute to development of, or exacerbation of, many health conditions. There is also research that has shown that treating sleep apnea may lower the risk of developing some conditions and may even help improve other conditions. I wish it was as easy as assigning a score, but I hope this helps!

Hi Dan,

Thank you again for your help. I really appreciate it. A couple more questions if you don't mind.

1) Can you please explain why I would have a high number of hypopnea events but a lower index number.

• NREM Supine Events: 39 and Index 6.1

• NREM Non-Supine Events: 16 and Index 2.5

• REM Supine Events: 44 and Index 6.9

• REM Non-Supine Events: 0 and Index 0

2) Are the hypopnea events that are not contributing to my index number troublesome/detrimental to my well-being?

All the best, Que

Hi @Que,

The index is lower because it is an average. Calculating an index in a sleep study involves counting all of the events, hypopneas are one example, and then dividing the number of events by a length of time. For example, an apnea-hypopnea index (AHI) is calculated by counting the total number of apneas plus the total number of hypopneas, and then dividing that total number by the total amount of time you slept during the study. To further calculate your NREM Supine Index, only events that occur while you are on your back and in NREM sleep are counted. That total number of events is then divided by the amount of time you spent in NREM sleep during your study. Until the advent of computerized systems, a technologist did all of this manually--literally counting the number of different types of events, the number of minutes in each stage of sleep, the number of minutes spent in various body positions, etc.--and calculated all of these indices. Modern systems used to collect, score and generate sleep study data do these calculations automatically.

For your second question, all of the hypopnea events would normally contribute to your overall index. The difference is that some are associated with decreases in blood oxygenation levels and some are associated with arousals. The best case would be that a patient have as few arousals or decreases in blood oxygen levels related to respiratory events as possible. It is normal, as I've said in an earlier post, to have some arousals (ambient noise, general discomfort). But excessive arousals cause fragmented sleep which can contribute to fatigue. I encourage you to talk to your sleep physician about your concerns. Hopefully, the exchanges on the forum have helped you to understand more about your sleep study results. And all the best to you as well!

Thanks, Dan

Hi Dan,

Ok, that is making sense. Your explanations are really helpful especially since it is hard to get much time with my sleep medicine doctor. Of course, I understand it is best for you to provide general advice instead of specific to my condition advice. I have a few more general questions if you don't mind.

Can you please provide the ranges for normal to abnormal TcCO2 and PLM index.

Thanks! Que

Hi Que. Happy to hear my explanations are helpful, and I don't mind the questions at all. Normal CO2 values are generally in the 35 to 45 mm Hg range, and the equipment usually used to measure this in sleep studies can be very sensitive and requires proper calibration. As for the PLM index, normal is usually considered less than 15 events per hour. However, there are other things to consider with limb movements. For example, are they causing discomfort or causing you to arouse from sleep? For some patients, the index may exceed 15 events per hour and not necessarily be causing any problems. Limb movements require a greater level of assessment and communication between patient and physician. All the best for a great week ahead!

Dan

Thanks Dan! I'm actually going in for another sleep study this week for a clinical trial at Stanford. So, it should be an interesting week. I also have an appointment with a sleep dentist. Hopefully making some progress on all of this.

Regarding the TcCO2, my report says:

There was a TcCO2 reading at 57 torrs with increase in sleep. Can you please tell me what that means. It seems like it may be using a different scale than you mention.

All the best, Que

Hi Que. The conversion for torr to mm Hg is almost 1:1. What this actually means is a better question for your physician. Your physician will be able to put this in better context, as he or she will consider your entire sleep study and your medical history. Like your PLM question, there are other factors that may need to be considered outside of a single reading or event. I know this is probably not the most helpful answer, and my apologies for that! But this is also sort of like oxygen desaturations--there is a difference in a single desaturation event to 88% versus a patient spending half of the night at 88%. Thanks, and have a great evening!

No problem Dan, I am planning to see him this week and will ask him that question.

Thanks for the help and frame of reference.

Que